Sex-specific programming of offspring emotionality after stress early in pregnancy

Epigenome-wide association study identifies a specific panel of DNA methylation signatures for antenatal and postpartum depressive symptoms

Depression during pregnancy and postpartum poses significant risks to both maternal and child well-being. The underlying biological mechanisms are unclear, but epigenetic variation could be exploited as a plausible candidate for early detection. We investigated whether DNA methylation signatures are associated with antenatal depressive symptoms (ADS) and whether early alterations in methylation patterns could be used to predict postpartum depressive symptoms (PDS). 201 pregnant women in early pregnancy, without a prior history of depressive disorders, from the STratification of Risk of Diabetes in Early Pregnancy study (STRiDE) were recruited. Using the Patient Health Questionnaire-9 (PHQ-9), 92 women were identified with ADS, while 109 served as controls. Edinburgh Postnatal Depression Scale (EPDS) was used to assess PDS during 6-12 weeks after delivery. The dataset was split into 80 % for training and testing and 20 % for validation, to discern potential CpGs for ADS using a support vector machine classifier. Analysis revealed 591 CpGs significantly associated with ADS, from which a panel of 7 CpGs was identified to discriminate between ADS and controls with high sensitivity and specificity (AUC: 0.85 in test, 0.73 in validation). Pathway analysis highlighted involvement in inositol phosphate metabolism, notch, and calcium signaling. The same 7 CpGs predicted PDS with an AUC of 0.76 (95 % CI: 0.66-0.87). Integration of CpG data with patient-reported information significantly enhanced PDS prediction. Our study identified DNA methylation signatures that could potentially differentiate ADS from controls and predict PDS. This suggests potential for developing a CpG panel for diagnostic and preventive strategies for perinatal depression.

Windows of susceptibility to air pollution during and surrounding pregnancy in relation to longitudinal maternal measures of adiposity and lipid profiles

Pregnancy is a critical window for long-term metabolic programming of fetal effects stemming from airborne particulate matter ≤2.5 μm (PM2.5) exposure. Yet, little is known about long-term metabolic effects of PM2.5 exposure during and surrounding pregnancy in mothers. We assessed potential critical windows of PM2.5 exposure during and surrounding pregnancy with maternal adiposity and lipid measures later in life. We included 517 pregnant women from the PROGRESS cohort with adiposity [body mass index (BMI), waist circumference (WC), % body fat] and lipids [total cholesterol, high-density-lipoprotein (HDL), low-density-lipoprotein (LDL)] measured repeatedly at 4, 6 and 8 years post-delivery. Monthly average PM2.5 exposure was estimated at each participant's address using a validated spatiotemporal model. We employed distributed lag interaction models (DLIMs) adjusting for socio-demographics and clinical covariates. We found that a 1 μg/m3 increase in PM2.5 exposure throughout mid-/late-pregnancy was associated with higher WC at 6-years post-delivery, peaking at 6 months of gestation: 0.04 cm (95%CI: 0.01, 0.06). We also identified critical windows of PM2.5 exposure during and surrounding pregnancy associated with higher LDL and lower HDL both measured at 4 years post-delivery with peaks at pre-conception for LDL [0.17 mg/dL (95%CI: 0.00, 0.34)] and at the 11th month after conception for HDL [-0.07 mg/dL (95%CI: -0.11, -0.02)]. Stratified analyses by fetal sex indicated stronger associations with adiposity measures in mothers carrying a male, while with lipids in mothers carrying a female fetus. Stratified analyses also indicated potential stronger deleterious lagged effects in women with folic acid intake lower than 600mcg/day during pregnancy.

Reliable Multimodal Brain Signatures Predict Mental Health Outcomes in Children

BACKGROUND

Interindividual brain differences likely precede the emergence of mood and anxiety disorders; however, the specific brain alterations remain unclear. While many studies focus on a single imaging modality in isolation, recent advances in multimodal image analysis allow for a more comprehensive understanding of the complex neurobiology that underlies mental health.

METHODS

In a large population-based cohort of children from the ABCD (Adolescent Brain Cognitive Development) Study (N > 10,000), we applied data-driven linked independent component analysis to identify linked variations in cortical structure and white matter microstructure that together predict longitudinal behavioral and mental health symptoms. Brain differences were examined in a subsample of twins depending on the presence of at-risk behaviors.

RESULTS

Two multimodal brain signatures at ages 9 to 10 years predicted longitudinal mental health symptoms from 9 to 12 years, with small effect sizes. Cortical variations in association, limbic, and default mode regions linked with peripheral white matter microstructure together predicted higher depression and anxiety symptoms across 2 independent split-halves. The brain signature differed between depression and anxiety symptom trajectories and related to emotion regulation network functional connectivity. Linked variations of subcortical structures and projection tract microstructure variably predicted behavioral inhibition, sensation seeking, and psychosis symptom severity over time in male participants. These brain patterns were significantly different between pairs of twins discordant for self-injurious behavior.

CONCLUSIONS

Our results demonstrate reliable, multimodal brain patterns in childhood, before mood and anxiety disorders tend to emerge, that lay the foundation for long-term mental health outcomes and offer targets for early identification of children at risk.

Social-defeat stress exposure during pregnancy induces abnormalities in spontaneous activity, sociality, and resilience to stress in offspring of mice

BACKGROUND

Environmental stress during prenatal periods can lead to neurodevelopmental disorders. Psychosocial stress can be studied using the social-defeat stress (SDS) animal model. However, the effects of prenatal exposure to SDS on the behavior of mature offspring mice have not been clarified. The present study assessed the spontaneous activity and social interaction of pups born to mothers exposed to SDS during gestation, as well as their post-maturity responses to environmental stimuli, focusing on changes in anxiety-like behavior following restraint stress exposure.

METHODS

Pregnant C57BL/6 J mice were subjected to SDS for 4 days, from E12.5-E15.5, using aggressive male ICR mice. We assessed the mature offspring (after 10 weeks of age) born to these mothers for spontaneous activity, anxiety-like behavior, and social interactions, and evaluated their activity levels post-maturity following restraint stress exposure.

RESULTS

The open field test (OF) indicated reduced travel distance and duration in the SDS group versus controls, whereas home-cage monitoring showed increased area traveled. In a novel environment, the SDS group showed a decrease in interest in stranger mice. In a multiple-animal rearing environment, the SDS group showed an increase in the frequency and number of contact with other individuals. Movement duration in the OF following restraint stress reduced significantly from 30 min to 4 h in the control versus SDS group.

CONCLUSIONS

Prenatal exposure to SDS can result in behavior resembling developmental disorders, impacting spontaneous activity and social interactions. Altered responses to stress suggest potential brain function abnormalities in offspring after maturation due to maternal SDS exposure.

Peripubertal antagonism of corticotropin-releasing factor receptor 1 results in sustained changes in behavioral plasticity and the transcriptomic profile of the amygdala

Peripuberty is a significant period of neurodevelopment with long-lasting effects on the brain and behavior. Blocking type 1 corticotropin-releasing factor receptors (CRFR1) in neonatal and peripubertal rats attenuates detrimental effects of early-life stress on neural plasticity, behavior, and stress hormone action, long after exposure to the drug has ended. CRFR1 antagonism can also impact neural and behavioral development in the absence of stressful stimuli, suggesting sustained alterations under baseline conditions. To investigate this further, we administered the CRFR1 antagonist (CRFR1a) R121919 to young adolescent male and female rats across 4 days. Following each treatment, rats were tested for locomotion, social behavior, mechanical allodynia, or prepulse inhibition (PPI). Acute CRFR1 blockade immediately reduced PPI in peripubertal males, but not females. In adulthood, each assay was repeated without CRFR1a exposure to test for persistent effects of the adolescent treatment. Males continued to experience deficits in PPI while females displayed altered locomotion, PPI, and social behavior. The amygdala was collected to measure long-term effects on gene expression. In the adult amygdala, peripubertal CRFR1a induced alterations in pathways related to neural plasticity and stress in males. In females, pathways related to central nervous system myelination, cell junction organization, and glutamatergic regulation of synaptic transmission were affected. Understanding how acute exposure to neuropharmacological agents can have sustained impacts on brain and behavior, in the absence of further exposures, has important clinical implications for developing adolescents.

Toward Understanding and Halting Legacies of Trauma

Echoes of natural and anthropogenic stressors not only reverberate within the physiology, biology, and neurobiology of the generation directly exposed to them but also within the biology of future generations. With the intent of understanding this phenomenon, significant efforts have been made to establish how exposure to psychosocial stress, chemicals, over- and undernutrition, and chemosensory experiences exert multigenerational influences. From these studies, we are gaining new appreciation for how negative environmental events experienced by one generation impact future generations. In this review, we first outline the need to operationally define dimensions of negative environmental events in the laboratory and the routes by which the impact of such events are felt through generations. Next, we discuss molecular processes that cause the effects of negative environmental events to be initiated in the exposed generation and then perpetuated across generations. Finally, we discuss how legacies of flourishing can be engineered to halt or reverse multigenerational influences of negative environmental events. In summary, this review synthesizes our current understanding of the concept, causes, and consequences of multigenerational echoes of stress and looks for opportunities to halt them.

Windows of Opportunity: How Age and Sex Shape the Influence of Prenatal Depression on the Child Brain

Maternal prenatal depression can affect child brain and behavioral development. Specifically, altered limbic network structure and function is a likely mechanism through which prenatal depression impacts the life-long mental health of exposed children. While developmental trajectories are influenced by many factors that exacerbate risk or promote resiliency, the role of child age and sex in the relationship between prenatal depression and the child brain remains unclear. Here, we review studies of associations between prenatal depression and brain structure and function, with a focus on the role of age and sex in these relationships. After exposure to maternal prenatal depression, altered amygdala, hippocampal, and frontal cortical structure, as well as changes in functional and structural connectivity within the limbic network, are evident during the fetal, infant, preschool, childhood, and adolescent stages of development. Sex appears to play a key role in this relationship, with evidence of differential findings particularly in infants, with males showing smaller and females larger hippocampal and amygdala volumes following prenatal depression. Longitudinal studies in this area have only begun to emerge within the last 5 years and will be key to understanding critical windows of opportunity. Future research focused on the role of age and sex in this relationship is essential to further inform screening, policy, and interventions for children exposed to prenatal depression, interrupt the intergenerational transmission of depression, and ultimately support healthy brain development.

Prenatal stress alters mouse offspring dorsal striatal development and placental function in sex-specific ways

Prenatal stress is a risk factor for neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD). However, how early stress modification of brain development contributes to this pathophysiology is poorly understood. Ventral forebrain regions such as dorsal striatum are of particular interest: dorsal striatum modulates movement and cognition, is altered in NDDs, and has a primarily GABAergic population. Here, we examine effects of prenatal stress on adult movement, cognition, and dorsal striatum neurobiology in mice using striatal-dependent behavioral assays, immunohistochemistry, embryonic ventral forebrain transcriptomics, and placental transcriptomics. We found prenatal stress affected adult procedural, habit, and reversal learning in sex-specific ways. Stress also increased adult dorsal striatal GABAergic neurons - an effect largely driven by males. We sought to examine the developmental origins of these adult brain changes. We found similar sex-specific dorsal striatal cellular changes in earlier points of development. The dorsal striatum primordium--embryonic ventral forebrain-showed that prenatal stress increased DNA replication and cell cycle pathways in male but not female transcriptomics and cellular biology. Unique signatures may have arisen from male-female placental differences. Stress-induced placental transcriptomics showed upregulated morphogenesis pathways in males while females downregulated morphogenic, hormonal, and cellular response pathways. Our findings suggest that prenatal stress could affect placenta function and also alter the GABAergic population of dorsal striatum differentially between the sexes.

Sex-specific association between maternal childhood adversities and offspring's weight gain in a Brazilian cohort

Maternal adverse childhood experiences (ACEs) are linked to negative health and developmental outcomes in offspring. However, whether maternal ACEs influence infant weight gain in the first months of life, and if this effect differs by infant sex, remains unclear. This study included 352 full-term newborns from low-risk pregnancies and their mothers in low-income settings in Brazil. Anthropometric data (weight, length, head circumference) and other information (feeding type, offspring sex, family income) were collected at delivery (W0), discharge (W1), and up to 8 weeks postpartum (W2). ACEs were assessed using the CDC-Kaiser Questionnaire, and weight gain was calculated as the difference between W2 and W1, divided by the number of days between measurements. The association between maternal ACEs and offspring weight gain was positive only in male offspring (unstandardized coefficient (male) = 1.82, SE = 0.438, p < 0.001); for each 1-point increase in the ACEs score (e.g., from 0 to 1), weight gain increased by 1.8 g/day. These findings indicate that maternal ACEs are associated with increased weight gain in male infants during the first two months of life, potentially increasing the risk of future obesity. Further research is required to investigate the underlying biological mechanisms and their neurodevelopmental implications.

Epigenetic Mechanisms Underlying Sex Differences in Neurodegenerative Diseases

Neurodegenerative diseases are characterized by profound differences between females and males in terms of incidence, clinical presentation, and disease progression. Furthermore, there is evidence suggesting that differences in sensitivity to medical treatments may exist between the two sexes. Although the role of sex hormones and sex chromosomes in driving differential susceptibility to these diseases is well-established, the molecular alterations underlying these differences remain poorly understood. Epigenetic mechanisms, including DNA methylation, histone tail modifications, and the activity of non-coding RNAs, are strongly implicated in the pathogenesis of neurodegenerative diseases. While it is known that epigenetic mechanisms play a crucial role in sexual differentiation and that distinct epigenetic patterns characterize females and males, sex-specific epigenetic patterns have been largely overlooked in studies aiming to identify epigenetic alterations associated with neurodegenerative diseases. This review aims to provide an overview of sex differences in epigenetic mechanisms, the role of sex-specific epigenetic processes in the central nervous system, and the main evidence of sex-specific epigenetic alterations in three neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Understanding the sex-related differences of these diseases is essential for developing personalized treatments and interventions that account for the unique epigenetic landscapes of each sex.

Transplacental signals involved in the programming effects of prenatal psychosocial stress on neurodevelopment

Exposure to psychosocial stress during pregnancy has been associated with the emergence of neurodevelopmental and neuropsychiatric disorders in offspring. The placenta is known to orchestrate various functions that are essential for normal fetal development, including the brain. It has therefore been postulated that alterations in such functions, and downstream signaling, have the potential to dramatically affect brain developmental trajectories and contribute to adverse neurodevelopmental outcomes. This review will focus on discussing various placental functions that have been proposed to be affected by exposure to prenatal psychosocial stress and the implications of such disruptions on long-term neurodevelopmental programming.

Immune Alterations in the Intrauterine Environment Shape Offspring Brain Development in a Sex-Specific Manner

Exposure to immune dysregulation in utero or in early life has been shown to increase risk for neuropsychiatric illness. The sources of inflammation can be varied, including acute exposures due to maternal infection or acute stress, or persistent exposures due to chronic stress, obesity, malnutrition, or autoimmune diseases. These exposures may cause subtle alteration in brain development, structure, and function that can become progressively magnified across the lifespan, potentially increasing the likelihood of developing a neuropsychiatric conditions. There is some evidence that males are more susceptible to early-life inflammatory challenges than females. In this review, we discuss the various sources of in utero or early-life immune alteration and the known effects on fetal development with a sex-specific lens. To do so, we leveraged neuroimaging, behavioral, cellular, and neurochemical findings. Gaining clarity about how the intrauterine environment affects offspring development is critically important for informing preventive and early intervention measures that may buffer against the effects of these early-life risk factors.

Prenatal Stress Modulates Placental and Fetal Serotonin Levels and Determines Behavior Patterns in Offspring of Mice

Available evidence from animal studies suggests that placental serotonin plays an important role in proper fetal development and programming by altering brain circuit formation, which later translates into altered abnormal adult behaviors. Several environmental stimuli, including stress and maternal inflammation, affect placental and, hence, fetal serotonin levels and thus may disturb fetal brain development. We investigated the effect of prenatal stress of varying intensities on the formation of adaptive behaviors in mouse offspring and the role of placental serotonin in these processes. Mild prenatal stress increased placental serotonin synthesis, whereas exposure to moderate stress decreased it. Prenatal stress of varying intensities also resulted in multidirectional changes in animal behavior in progeny, consistent with changes in serotonin levels in the placenta and fetal tissues. Mice exposed to mild prenatal stress showed higher sociality and exploratory activity, whereas, after moderate stress, in contrast, they avoided contact with other individuals of their species and had reduced exploratory activity, with no effect on locomotor activity. Thus, in mice, stressors of varying intensities during the critical period of intrauterine development can affect the synthesis of serotonin by the placenta and lead to multidirectional changes in animal behavior in postnatal life.

The Mediating Effects of Chronic Diseases in the Relationship Between Adverse Childhood Experiences and Trajectories of Depressive Symptoms in Later Life: A Nationwide Longitudinal Study

Background: Numerous studies have established a link between adverse childhood experiences (ACEs) and the development of depression in later life. However, the interactive relationships between ACEs, depression, and chronic diseases are still not well understood. In this study, the aim was to investigate the impact of ACEs on depressive trajectories among middle-aged and elderly individuals in China, as well as to examine the mediating roles of chronic diseases in this association. Methods: Data were drawn from 6921 participants aged 45 and older, using the China Health and Retirement Longitudinal Study (CHARLS) data from 2011, 2013, 2015, and 2018, combined with the 2014 life history survey. Depressive symptom scores were assessed using the widely recognized CES-D-10 scale. The trajectories of depressive symptoms were identified via group-based trajectory modeling (GBTM). The association between ACEs and depressive trajectories was analyzed using multinomial logistic regression, and the KHB method was employed to test the mediating effects of different chronic diseases. Results: The age of the 6921 participants was 57.2 ± 8.0 years, with females comprising 53.9% and males 46.1%. We found that approximately 70% of Chinese middle-aged and older adults had experienced at least one ACE, and 4.8% had experienced four or more ACEs. The following four distinct trajectories of depressive symptoms were identified: continuing-low (N = 1897, 27.4%), continuing-low-to-middle (N = 2937, 42.4%), continuing-middle-to-high (N = 1649, 23.8%), and continuing-high (N = 438, 6.3%). Compared to individuals without ACEs, those with four or more ACEs had a significantly higher likelihood of following the continuing-low-to-middle trajectory (OR = 2.407, 95%CI: 1.633-3.550), the continuing-middle-to-high trajectory (OR = 7.458, 95%CI: 4.999-11.127), and the continuing-high trajectory (OR = 20.219, 95%CI: 12.115-33.744), rather than the continuing-low trajectory. Exposure to a greater number of ACEs was associated with an increased risk of following an adverse trajectory of depressive symptoms. Multiple chronic diseases significantly mediated the relationship between ACEs and depressive trajectories, with arthritis or rheumatism exerting the largest mediating effect, followed by digestive and respiratory diseases. Conclusions: These findings indicated that ACEs were associated with a higher risk of worse depressive symptom trajectories, with different chronic diseases mediating this relationship. Therefore, developing public measures to prevent ACEs can reduce the risk of chronic diseases and depression in middle-aged and elderly people. Additionally, strengthening the prevention and management of chronic diseases in individuals exposed to ACEs may further reduce their subsequent risk of depression.

Prenatal Social Determinants of Health: Narrative review of maternal environments and neonatal brain development

The Social Determinants of Health, a set of social factors including socioeconomic status, community context, and neighborhood safety among others, are well-known predictors of mental and physical health across the lifespan. Recent research has begun to establish the importance of these social factors at the earliest points of brain development, including during the prenatal period. Prenatal socioeconomic status, perceived stress, and neighborhood safety have all been reported to impact neonatal brain structure and function, with exploratory work suggesting subsequent effects on infant and child behavior. Secondary effects of the Social Determinants of Health, such as maternal sleep and psychopathology during pregnancy, have also been established as important predictors of infant brain development. This research not only establishes prenatal Social Determinants of Health as important predictors of future outcomes but may be effectively applied even before birth. Future research replicating and extending the effects in this nascent literature has great potential to produce more specific and mechanistic understanding of the social factors that shape early neurobehavioral development. IMPACT: This review synthesizes the research to date examining the effects of the Social Determinants of Health during the prenatal period and neonatal brain outcomes. Structural, functional, and diffusion-based imaging methodologies are included along with the limited literature assessing subsequent infant behavior. The degree to which results converge between studies is discussed, in combination with the methodological and sampling considerations that may contribute to divergence in study results. Several future directions are identified, including new theoretical approaches to assessing the impact of the Social Determinants of Health during the perinatal period.

Brain health equity and the influence of social determinants across the life cycle

Social determinants of health are social, economic and environmental factors known to influence health and development of infants, children and adults. Advancing equity in brain health relies upon interdisciplinary collaboration and recognition of the impact of social determinants on brain health through the lifespan and across generations. Critical periods of fetal, infant and early childhood development encompass intrinsic genetic and extrinsic environmental influences with complex gene-environment interactions. This review discusses the influence of social determinants on the continuum of brain health from preconception and pregnancy health, through fetal, infant and childhood neurodevelopment into adulthood. Opportunities for intervention to address the social determinants of brain health across the life cycle are highlighted.

Neonatal Nucleus Accumbens Microstructure Modulates Individual Susceptibility to Preconception Maternal Stress in Relation to Externalizing Behaviors

OBJECTIVE

Maternal stress influences in utero brain development and is a modifiable risk factor for offspring psychopathologies. Reward circuitry dysfunction underlies various internalizing and externalizing psychopathologies. This study examined (1) the association between maternal stress and microstructural characteristics of the neonatal nucleus accumbens (NAcc), a major node of the reward circuitry, and (2) whether neonatal NAcc microstructure modulates individual susceptibility to maternal stress in relation to childhood behavioral problems.

METHOD

K-means longitudinal cluster analysis was performed to determine trajectories of maternal stress measures (Perceived Stress Scale [PSS], hair cortisol) from preconception to the third trimester. Neonatal NAcc microstructural measures (orientation density index [ODI] and intracellular volume fraction [ICVF]) were compared across trajectories. We then examined the interaction between maternal stress and neonatal NAcc microstructure on child internalizing and externalizing behaviors, assessed between ages 3 and 4 years.

RESULTS

Two trajectories of maternal stress magnitude ("low"/"high") were identified for both PSS (n = 287) and hair cortisol (n = 336). Right neonatal NAcc ODI (rNAcc-ODI) was significantly lower in "low" relative to "high" PSS trajectories (n = 77, p = .04). PSS at preconception had the strongest association with rNAcc-ODI (r = 0.293, p = .029). No differences in NAcc microstructure were found between hair cortisol trajectories. A significant interaction between preconception PSS and rNAcc-ODI on externalizing behavior was observed (n = 47, p = .047).

CONCLUSION

Our study showed that the preconception period contributes to in utero NAcc development, and that NAcc microstructure modulates individual susceptibility to preconception maternal stress in relation to externalizing problems.

PLAIN LANGUAGE SUMMARY

In the S-PRESTO population-based cohort study conducted in Singapore with 351 women and their children, higher levels of maternal perceived stress within the year before pregnancy were associated with increased dendritic complexity within offsprings' nucleus accumbens, indicative of a more advanced developmental profile. Variations in right nucleus accumbens microstructure significantly modulated the association between maternal perceived stress at preconception and externalizing behaviors in early childhood. Study findings suggest that maternal stress in the preconception period accelerates in-utero nucleus accumbens development, leading to differential risk to externalizing problems in later childhood.

Epigenetic Modifications and Neuroplasticity in the Pathogenesis of Depression: A Focus on Early Life Stress

Major depressive disorder (MDD) is a debilitating mental illness, and it is considered to be one of the leading causes of disability globally. The etiology of MDD is multifactorial, involving an interplay between biological, psychological, and social factors. Early life represents a critical period for development. Exposure to adverse childhood experiences is a major contributor to the global burden of disease and disability, doubling the risk of developing MDD later in life. Evidence suggests that stressful events experienced during that timeframe play a major role in the emergence of MDD, leading to epigenetic modifications, which might, in turn, influence brain structure, function, and behavior. Neuroplasticity seems to be a primary pathogenetic mechanism of MDD, and, similarly to epigenetic mechanisms, it is particularly sensitive to stress in the early postnatal period. In this review, we will collect and discuss recent studies supporting the role of epigenetics and neuroplasticity in the pathogenesis of MDD, with a focus on early life stress (ELS). We believe that understanding the epigenetic mechanisms by which ELS affects neuroplasticity offers potential pathways for identifying novel therapeutic targets for MDD, ultimately aiming to improve treatment outcomes for this debilitating disorder.

Maternal affective symptoms and sleep quality have sex-specific associations with placental topography

BACKGROUND

The impacts of prenatal maternal affective symptoms on the placental structure are not well-established. Employing Geographic Information System (GIS) spatial autocorrelation, Moran's I, can help characterize placental thickness uniformity/variability and evaluate the impacts of maternal distress on placental topography.

METHODS

This study (N = 126) utilized cohort data on prenatal maternal affective symptoms and placental 2D and 3D morphology. Prenatal maternal depression, stress, anxiety and sleep quality were scored for each trimester using the Edinburgh Postnatal Depression Scale (EPDS), Stressful Life Event Scale (SLE), Penn State Worry Questionnaire (PSWQ), and Pittsburgh Sleep Quality Index (PSQI), respectively. Placental shape was divided into Voronoi cells and thickness variability among these cells was computed using Moran's I for 4-nearest neighbors and neighbors within a 10 cm radius. Sex-stratified Spearman correlations and linear regression were used to study associations between mean placental thickness, placental GIS variables, placental weight and the average score of each maternal variable.

RESULTS

For mothers carrying boys, poor sleep was associated with higher mean thickness (r = 0.308,p = 0.035) and lower placental thickness uniformity (r = -0.36,p = 0.012). Lower placental weight (r = 0.395,p = 0.003), higher maternal depression (r = -0.318,p = 0.019) and worry/anxiety (r = -0.362,p = 0.007) were associated with lower placental thickness uniformity for mothers carrying girls.

LIMITATIONS

The study is exploratory and not all GIS models were developed. Excluding high-risk pregnancies prevented investigating pregnancy complications related hypotheses. A larger sample size is needed for greater confidence for clinical application.

CONCLUSIONS

Placental topography can be studied using GIS theory and has shown that prenatal maternal affective symptoms and sleep have sex-specific associations with placental thickness.

Unraveling the Molecular Mechanisms of the Neurodevelopmental Consequences of Fetal Protein Deficiency: Insights From Rodent Models and Public Health Implications

Fetal brain development requires increased maternal protein intake to ensure that offspring reach their optimal cognitive potential in infancy and adulthood. While protein deficiency remains a prevalent issue in developing countries, it is also reemerging in Western societies due to the growing adoption of plant-based diets, some of which are monotonous and may fail to provide sufficient amino acids crucial for the brain's critical developmental phase. Confounding variables in human nutritional research have impeded our understanding of the precise impact of protein deficiency on fetal neurodevelopment, as well as its implications for childhood neurocognitive performance. Moreover, it remains unclear whether such deficiency could predispose to mental health problems in adulthood, mirroring observations in individuals exposed to prenatal famine. In this review, we sought to evaluate mechanistic data derived from rodent models, placing special emphasis on the involvement of neuroendocrine axes, the influence of sex and timing, epigenetic modifications, and cellular metabolism. Despite notable progress, critical knowledge gaps remain, including understanding the long-term reversibility of effects due to fetal protein restriction and the interplay between genetic predisposition and environmental factors. Enhancing our understanding of the precise mechanisms that connect prenatal nutrition to brain development in future research endeavors can be significantly advanced by integrating multiomics approaches and utilizing additional alternative models such as nonhuman primates. Furthermore, it is crucial to investigate potential interventions aimed at alleviating adverse outcomes. Ultimately, this research has profound implications for guiding public health strategies aimed at raising awareness about the crucial role of optimal maternal nutrition in supporting fetal neurodevelopment.

Atopic Dermatitis and Autism Spectrum Disorders: Common Role of Environmental and Clinical Co-Factors in the Onset and Severity of Their Clinical Course

Increasing evidence suggests an association between atopic dermatitis, the most chronic inflammatory disease of the skin, and autism spectrum disorders, which are a group of neurodevelopmental diseases. Inflammation and immune dysregulation associated with genetic and environmental factors seem to characterize the pathophysiological mechanisms of both conditions. We conducted a literature review of the PubMed database aimed at identifying the clinical features and alleged risk factors that could be used in clinical practice to predict the onset of ASD and/or AD or worsen their prognosis in the context of comorbidities.

Global inequities in adverse pregnancy outcomes: what can we do?

The Health Equity Leadership & Exchange Network states that "health equity exists when all people, regardless of race, sex, sexual orientation, disability, socioeconomic status, geographic location, or other societal constructs, have fair and just access, opportunity, and resources to achieve their highest potential for health." It is clear from the wide discrepancies in maternal and infant mortalities, by race, ethnicity, location, and social and economic status, that health equity has not been achieved in pregnancy care. Although the most obvious evidence of inequities is in low-resource settings, inequities also exist in high-resource settings. In this presentation, based on the Global Pregnancy Collaboration Workshop, which addressed this issue, the bases for the differences in outcomes were explored. Several different settings in which inequities exist in high- and low-resource settings were reviewed. Apparent causes include social drivers of health, such as low income, inadequate housing, suboptimal access to clean water, structural racism, and growing maternal healthcare deserts globally. In addition, a question is asked whether maternal health inequities will extend to and be partially due to current research practices. Our overview of inequities provides approaches to resolve these inequities, which are relevant to low- and high-resource settings. Based on the evidence, recommendations have been provided to increase health equity in pregnancy care. Unfortunately, some of these inequities are more amenable to resolution than others. Therefore, continued attention to these inequities and innovative thinking and research to seek solutions to these inequities are encouraged.

Sex-dimorphic pathways in the associations between maternal trait anxiety, infant BDNF methylation, and negative emotionality

Maternal antenatal anxiety is an emerging risk factor for child emotional development. Both sex and epigenetic mechanisms, such as DNA methylation, may contribute to the embedding of maternal distress into emotional outcomes. Here, we investigated sex-dependent patterns in the association between antenatal maternal trait anxiety, methylation of the brain-derived neurotrophic factor gene (BDNF DNAm), and infant negative emotionality (NE). Mother-infant dyads (N = 276) were recruited at delivery. Maternal trait anxiety, as a marker of antenatal chronic stress exposure, was assessed soon after delivery using the Stait-Trait Anxiety Inventory (STAI-Y). Infants' BDNF DNAm at birth was assessed in 11 CpG sites in buccal cells whereas infants' NE was assessed at 3 (N = 225) and 6 months (N = 189) using the Infant Behavior Questionnaire-Revised (IBQ-R). Hierarchical linear analyses showed that higher maternal antenatal anxiety was associated with greater 6-month-olds' NE. Furthermore, maternal antenatal anxiety predicted greater infants' BDNF DNAm in five CpG sites in males but not in females. Higher methylation at these sites was associated with greater 3-to-6-month NE increase, independently of infants' sex. Maternal antenatal anxiety emerged as a risk factor for infant's NE. BDNF DNAm might mediate this effect in males. These results may inform the development of strategies to promote mothers and infants' emotional well-being.

Sex Dimorphism in Pain Threshold and Neuroinflammatory Response: The Protective Effect of Female Sexual Hormones on Behavior and Seizures in an Allergic Rhinitis Model

Our previous research demonstrated that allergic rhinitis could impact behavior and seizure threshold in male mice. However, due to the complex hormonal cycles and hormonal influences on behavior in female mice, male mice are more commonly used for behavioral tests. In this study, we aimed to determine whether these findings were replicable in female mice and to explore the potential involvement of sexual hormones in regulating neuroinflammation in an allergic model. Our results indicate that pain threshold was decreased in female mice with allergic rhinitis and the levels of IL-23/IL-17A/IL-17R were increased in their Dorsal root ganglia. However, unlike males, female mice with AR did not display neuropsychological symptoms such as learning and memory deficits, depression, and anxiety-like behavior. This was along with decreased levels of DNA methyl transferase 1 (DNMT1) and inflammatory cytokines in their hippocampus. Ovariectomized mice were used to mitigate hormonal effects, and the results showed that they had behavioral changes and neuroinflammation in their hippocampus similar to male mice, as well as increased levels of DNMT1. These findings demonstrate sex differences in how allergic rhinitis affects behavior, pain sensitivity, and seizure thresholds. Furthermore, our data suggest that DNMT1 may be influenced by sexual hormones, which could play a role in modulating inflammation in allergic conditions.

Upregulation of MAOA in the hippocampus results in delayed depressive-like behaviors in burn mice

OBJECTIVE

To observe depressive-like behavior and hippocampus monoamine oxidase A (MAOA) changes in burned mice.

METHODS

We tested depression and anxiety like behaviors of burn C57 mice with the sucrose preference test, forced swimming test (FST), open field test and elevated plus maze test and then detected the MAOA content and MAOA gene transcriptional levels in the hippocampus with western blot analysis and real-time quantitative PCR analysis. We then sought to reverse depressive-like behavior of burned mice with an MAOA inhibitor.

RESULTS

(1) Mice showed depressive and anxiety like behaviors one week after they were burned; (2) The content of MAOA in the hippocampus of burned mice was significantly higher than that in control mice (P<0.05); (3) MAOA gene transcription in the hippocampus of burned mice was significantly increased (MAOA mRNA was increased, P<0.05); (4) treatment with a MAOA inhibitor (phenelzine) significantly increased the sucrose preference rate and decreased FST immobility time in burned mice, and also decreased elevated expression of MAOA in the hippocampus of burned mice.

CONCLUSION

Burned mice showed "delayed" depressive-like behavior combined with a degree of anxiety; this phenomenon is likely associated with the increase in MAOA expression in the hippocampus.

Sex Differences in Stress Susceptibility as a Key Mechanism Underlying Depression Risk

PURPOSE OF REVIEW

Although females are at relatively greater risk for a variety of disorders, including depression, the biological mechanisms underlying this striking health disparity remain unclear. To address this issue, we highlight sex differences in stress susceptibility as a key mechanism potentially driving this effect and describe the interacting inflammatory, hormonal, epigenomic, and social-environmental mechanisms involved.

RECENT FINDINGS

Using the Social Signal Transduction Theory of Depression as a theoretical framework, women's elevated risk for depression may stem from a tight link between life stress, inflammation, and depression in women. Further, research finds hormonal contraceptive use alters cortisol and inflammatory reactivity to acute stress in ways that may increase depression risk in females. Finally, beyond established epigenetic mechanisms, mothers may transfer risk for depression to their female offspring through stressful family environments, which influence stress generation and stress-related gene expression. Together, these findings provide initial, biologically plausible clues that may help explain the relatively greater risk for depression in females vs. males. Looking forward, much more research is needed to address the longstanding underrepresentation of females in biomedical research on the biology of stress and depression.

How is prenatal stress transmitted from the mother to the fetus?

Prenatal stress programmes long-lasting neuroendocrine and behavioural changes in the offspring. Often this programming is maladaptive and sex specific. For example, using a rat model of maternal social stress in late pregnancy, we have demonstrated that adult prenatally stressed male, but not prenatally stressed female offspring display heightened anxiety-like behaviour, whereas both sexes show hyperactive hypothalamo-pituitary-adrenal (HPA) axis responses to stress. Here, we review the current knowledge of the mechanisms underpinning dysregulated HPA axis responses, including evidence supporting a role for reduced neurosteroid-mediated GABAergic inhibitory signalling in the brains of prenatally stressed offspring. How maternal psychosocial stress is signalled from the mother to the fetuses is unclear. Direct transfer of maternal glucocorticoids to the fetuses is often considered to mediate the programming effects of maternal stress on the offspring. However, protective mechanisms including attenuated maternal stress responses and placental 11β-hydroxysteroid dehydrogenase-2 (which inactivates glucocorticoids) should limit materno-fetal glucocorticoid transfer during pregnancy. Moreover, a lack of correlation between maternal stress, circulating maternal glucocorticoid levels and circulating fetal glucocorticoid levels is reported in several studies and across different species. Therefore, here we interrogate the evidence for a role for maternal glucocorticoids in mediating the effects of maternal stress on the offspring and consider the evidence for alternative mechanisms, including an indirect role for glucocorticoids and the contribution of changes in the placenta in signalling the stress status of the mother to the fetus.

Geniposide improves depression-like behavior in prenatal stress male offspring through restoring HPA axis- and glucocorticoid receptor-associated dysfunction

AIMS

Prenatal stress (PS) has an important impact on the brain development of offspring, which can lead to attention deficits, anxiety and depression in offspring. Geniposide (GE) is a kind of iridoid glycoside extracted from Gardenia jasminoides Ellis. It has various pharmacological effects and has been proved that have antidepressant effects. The aim of this study was to investigate the effect of GE on depression-like behavior in PS-induced male offspring mice and explore the possible molecular mechanisms.

METHODS

We used a prenatal restraint stress model, focusing on male PS-induced offspring mice to study the effects of GE.

KEY FINDINGS

The results showed that GE administration for 4 weeks significantly improved the depression-like behavior in PS offspring mice, which was manifested by markedly increasing the sucrose preference of PS offspring and the activity in the open field test, and reducing the immobility time in the forced swimming test. In addition, GE significantly reduced the levels of hypothalamic-pituitary-adrenal (HPA) axis-related hormones and exceedingly increased the protein expression of MAP2 and GAP43 in PS offspring. Furthermore, GE increased Glucocorticoid receptors (GR) nuclear translocation in the hippocampus of PS offspring, and enhanced the expression of synaptic plasticity-related proteins.

CONCLUSION

The results of this study showed that GE exerts antidepressant effects in male PS offspring mice by regulating the HPA axis, GR function and proteins related to synaptic plasticity.

Sex-Biased Expression and Response of microRNAs in Neurological Diseases and Neurotrauma

Neurological diseases and neurotrauma manifest significant sex differences in prevalence, progression, outcome, and therapeutic responses. Genetic predisposition, sex hormones, inflammation, and environmental exposures are among many physiological and pathological factors that impact the sex disparity in neurological diseases. MicroRNAs (miRNAs) are a powerful class of gene expression regulator that are extensively involved in mediating biological pathways. Emerging evidence demonstrates that miRNAs play a crucial role in the sex dimorphism observed in various human diseases, including neurological diseases. Understanding the sex differences in miRNA expression and response is believed to have important implications for assessing the risk of neurological disease, defining therapeutic intervention strategies, and advancing both basic research and clinical investigations. However, there is limited research exploring the extent to which miRNAs contribute to the sex disparities observed in various neurological diseases. Here, we review the current state of knowledge related to the sexual dimorphism in miRNAs in neurological diseases and neurotrauma research. We also discuss how sex chromosomes may contribute to the miRNA sexual dimorphism phenomenon. We attempt to emphasize the significance of sexual dimorphism in miRNA biology in human diseases and to advocate a gender/sex-balanced science.

The Maternal Microbiome as a Map to Understanding the Impact of Prenatal Stress on Offspring Psychiatric Health

Stress and psychiatric disorders have been independently associated with disruption of the maternal and offspring microbiome and with increased risk of the offspring developing psychiatric disorders, both in clinical studies and in preclinical studies. However, the role of the microbiome in mediating the effect of prenatal stress on offspring behavior is unclear. While preclinical studies have identified several key mechanisms, clinical studies focusing on mechanisms are limited. In this review, we discuss 3 specific mechanisms by which the microbiome could mediate the effects of prenatal stress: 1) altered production of short-chain fatty acids; 2) disruptions in TH17 (T helper 17) cell differentiation, leading to maternal and fetal immune activation; and 3) perturbation of intestinal and microbial tryptophan metabolism and serotonergic signaling. Finally, we review the existing clinical literature focusing on these mechanisms and highlight the need for additional mechanistic clinical research to better understand the role of the microbiome in the context of prenatal stress.

Maternal preconception stress produces sex-specific effects at the maternal:fetal interface to impact offspring development and phenotypic outcomes†

Entering pregnancy with a history of adversity, including adverse childhood experiences and racial discrimination stress, is a predictor of negative maternal and fetal health outcomes. Little is known about the biological mechanisms by which preconception adverse experiences are stored and impact future offspring health outcomes. In our maternal preconception stress (MPS) model, female mice underwent chronic stress from postnatal days 28-70 and were mated 2 weeks post-stress. Maternal preconception stress dams blunted the pregnancy-induced shift in the circulating extracellular vesicle proteome and reduced glucose tolerance at mid-gestation, suggesting a shift in pregnancy adaptation. To investigate MPS effects at the maternal:fetal interface, we probed the mid-gestation placental, uterine, and fetal brain tissue transcriptome. Male and female placentas differentially regulated expression of genes involved in growth and metabolic signaling in response to gestation in an MPS dam. We also report novel offspring sex- and MPS-specific responses in the uterine tissue apposing these placentas. In the fetal compartment, MPS female offspring reduced expression of neurodevelopmental genes. Using a ribosome-tagging transgenic approach we detected a dramatic increase in genes involved in chromatin regulation in a PVN-enriched neuronal population in females at PN21. While MPS had an additive effect on high-fat-diet (HFD)-induced weight gain in male offspring, both MPS and HFD were necessary to induce significant weight gain in female offspring. These data highlight the preconception period as a determinant of maternal health in pregnancy and provides novel insights into mechanisms by which maternal stress history impacts offspring developmental programming.

Epigenetic mechanisms underlying sex differences in the brain and behavior

Sex differences are found across brain regions, behaviors, and brain diseases. Sexual differentiation of the brain is initiated prenatally but it continues throughout life, as a result of the interaction of three major factors: gonadal hormones, sex chromosomes, and the environment. These factors are thought to act, in part, via epigenetic mechanisms which control chromatin and transcriptional states in brain cells. In this review, we discuss evidence that epigenetic mechanisms underlie sex-specific neurobehavioral changes during critical organizational periods, across the estrous cycle, and in response to diverse environments throughout life. We further identify future directions for the field that will provide novel mechanistic insights into brain sex differences, inform brain disease treatments and women's brain health in particular, and apply to people across genders.

Improving behavioral deficits induced by perinatal ethanol and stress exposure in adolescent male rat progeny via maternal melatonin treatment

BACKGROUND AND AIM

Early-life stressful situations and binge drinking have been thus far acknowledged as two burdensome conditions that potentially give rise to negative outcomes and then synergistically affect brain development. In this context, the hippocampus, with the greatest number of glucocorticoid receptors (GCRs) in the brain, is responsible for regulating negative responses to stress. Prolonged glucocorticoid (GC) exposure can accordingly cause oxidative stress (OS), leading to cognitive and emotional dysfunction. Against this background, melatonin, as a powerful antioxidant and hypothalamus-pituitary-adrenal (HPA) axis regulator, was administered in this study to ameliorate cognitive impairments induced by perinatal ethanol and stress exposure in adolescent male rat progeny.

METHODS

Wistar rat dams were exposed to ethanol (4 g/kg) and melatonin (10 mg/kg) from gestational day (GD) 6 to postnatal day (PND) 14 and then limited nesting material (LNS) from PND0 to PND14 individually or in combination. Maternal behavior was then investigated in mothers. Afterward, the plasma corticosterone (CORT) concentration, the OS marker, the corticotropin-releasing hormone receptor type 1 (CRHR1) expression, and the GCR and brain-derived neurotrophic factor (BDNF) levels were measured in the male pups. Moreover, behavioral tasks, including the elevated plus maze (EPM), the Morris water maze (MWM), the novel object recognition (NORT), and the object-location memory (OLM) tests were completed and assessed.

RESULTS

The quantity and quality of maternal care significantly decreased in the mothers with dual exposure to ethanol and stress. The plasma CORT concentration in the progeny also dropped in the Ethanol + LNS group, but the risk-taking behavior elevated significantly. The ethanol and stress exposure further revealed a significant fall in the GCR and CRHR1 expression levels, compared with stress alone. The results of learning and memory tasks also indicated a significant reduction in spatial learning and memory among animals exposed to ethanol and stress. The BDNF mRNA levels correspondingly increased in the Ethanol + LNS group, compared with LNS alone. In the presence of ethanol and stress, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities correspondingly declined. On the other hand, the malondialdehyde (MDA) levels augmented in the hippocampus of the animals with ethanol and LNS dual exposure, as compared with the control group. Melatonin treatment (MT) thus improved nursing behaviors in dams, prevented OS, enhanced the CRHR1 and GCR expression, and reduced the BDNF levels to the similar ones in the control group. The animals in the Ethanol + LNS + MT group ultimately showed an ameliorated performance at behavioral tasks, including the memory and risk-taking behavior.

CONCLUSION

It was concluded that MT could prevent stress response and memory impairments arising from dual exposure to ethanol and stress by inhibiting OS.

Legacies of salient environmental experiences-insights from chemosensation

Evidence for parental environments profoundly influencing the physiology, biology, and neurobiology of future generations has been accumulating in the literature. Recent efforts to understand this phenomenon and its underlying mechanisms have sought to use species like rodents and insects to model multi-generational legacies of parental experiences like stress and nutritional exposures. From these studies, we have come to appreciate that parental exposure to salient environmental experiences impacts the cadence of brain development, hormonal responses to stress, and the expression of genes that govern cellular responses to stress in offspring. Recent studies using chemosensory exposure have emerged as a powerful tool to shed new light on how future generations come to be influenced by environments to which parents are exposed. With a specific focus on studies that have leveraged such use of salient chemosensory experiences, this review synthesizes our current understanding of the concept, causes, and consequences of the inheritance of chemosensory legacies by future generations and how this field of inquiry informs the larger picture of how parental experiences can influence offspring biology.

Ultrasound-Induced Prenatal Stress: New Possibilities for Modeling Mental Disorders

The development of animal models of mental disorders is an important task since such models are useful for studying the neurobiological mechanisms of psychopathologies and for trial of new therapeutic drugs. One way to model pathologies of the nervous system is to impair fetal neurodevelopment through stress of the pregnant future mother, or prenatal stress (PS). The use of variable frequency ultrasound (US) in rodents is a promising method of imitating psychological stress, to which women in modern society are most often subjected. The aim of our study was to investigate the effect of PS induced by exposure to variable frequency ultrasound (US PS) throughout the gestational period on the adult rat offspring, namely, to identify features of behavioral alterations and neurochemical brain parameters that can be associated with certain mental disorders in humans, to determine the possibility of creating a new model of psychopathology. Our study included a study of some behavioral characteristics of male and female rats in the elevated plus maze, open-field test, object recognition test, social interaction test, sucrose preference test, latent inhibition test, Morris water maze, forced swimming test, acoustic startle reflex, and prepulse inhibition tests. We also determined the activity of the serotonergic, dopaminergic, and noradrenergic neurotransmitter systems in the hippocampus and frontal cortex by HPLC-ED. Concentration of norepinephrine, dopamine, DOPAC, serotonin, and HIAA, as well as DOPAC/dopamine and HIAA/serotonin ratios were determined. A correlation analysis of behavioral and neurochemical parameters in male and female rats was performed based on the data obtained. The results of the study showed that US PS altered the behavioral phenotype of the rat offspring. US PS increased the level of anxious behavior, impaired orientation-research behavior, increased grooming activity, decreased the desire for social contacts, shifted behavioral reactions from social interaction to interaction with inanimate objects, impaired latent inhibition, and decreased the startle reflex. US PS activated the serotonergic, dopaminergic, and noradrenergic neurotransmitter systems of the rat frontal cortex and hippocampus. A correlation between neurochemical and behavioral parameters was revealed. Our study showed that US PS leads to a certain dysfunction on behavioral and neurochemical levels in rats that is most closely associated with symptoms of schizophrenia or autism. We hypothesize that this could potentially be an indicator of face validity for a model of psychopathology based on neurodevelopmental impairment.

Exogenous corticosterone administration during pregnancy in mice alters placental and fetal thyroid hormone availability in females

INTRODUCTION

Maternal prenatal psychological stress is associated with adverse pregnancy outcomes and increased risk of adverse health outcomes in children. While the molecular mechanisms that govern these associations has not been fully teased apart, stress-induced changes in placental function can drive sex-specific phenotypes in offspring. We sought to identify and examine molecular pathways in the placenta that are altered in response to maternal prenatal stress.

METHODS

We previously employed a mouse model of maternal prenatal stress where pregnant dams were treated with stress hormone (CORT) beginning in mid-gestation. Using this model, we conducted RNAseq analysis of whole placenta at E18.5. We used qRT-PCR to validate gene expression changes in the placenta and in a trophoblast cell line. ELISAs were used to measure the abundance of thyroid hormones in maternal and fetal serum and in the placenta.

RESULTS

Dio2 was amongst the top differentially expressed genes in response to exogenous stress hormone. Dio2 expression was more downregulated in placenta of female fetuses from CORT-treated dams than both control placenta from females and placenta from male fetuses. Consistent with Dio2's role in production of bioactive thyroid hormone (T3), we found that there was a reduction of T3 in placenta and serum of female embryos from CORT-treated dams at E18.5. Both T3 and T4 were reduced in the fetal compartment of the placenta of female fetuses from CORT-treated dams at E16.5. Exogenous stress hormone induced reduction in thyroid hormone in females was independent of circulating levels of TH in the dams.

DISCUSSION

The placental thyroid hormone synthesis pathway may be a target of elevated maternal stress hormone and modulate fetal programming of health and disease of offspring in a sex-specific fashion.

Sex differences in innate and adaptive immunity impact fetal, placental, and maternal health†

The differences between males and females begin shortly after birth, continue throughout prenatal development, and eventually extend into childhood and adult life. Male embryos and fetuses prioritize proliferation and growth, often at the expense of the fetoplacental energy reserves. This singular focus on growth over adaptability leaves male fetuses and neonates vulnerable to adverse outcomes during pregnancy and birth and can have lasting impacts throughout life. Beyond this prioritization of growth, male placentas and fetuses also respond to infection and inflammation differently than female counterparts. Pregnancies carrying female fetuses have a more regulatory immune response, whereas pregnancies carrying male fetuses have a stronger inflammatory response. These differences can be seen as early as the innate immune response with differences in cytokine and chemokine signaling. The sexual dimorphism in immunity then continues into the adaptive immune response with differences in T-cell biology and antibody production and transfer. As it appears that these sex-specific differences are amplified in pathologic pregnancies, it stands to reason that differences in the placental, fetal, and maternal immune responses in pregnancy contribute to increased male perinatal morbidity and mortality. In this review, we will describe the genetic and hormonal contributions to the sexual dimorphism of fetal and placental immunity. We will also discuss current research efforts to describe the sex-specific differences of the maternal-fetal interface and how it impacts fetal and maternal health.

Exogenous corticosterone administration during pregnancy alters placental and fetal thyroid hormone availability in females

Introduction

Maternal prenatal stress is associated with adverse pregnancy outcomes and predisposition to long-term adverse health outcomes in children. While the molecular mechanisms that govern these associations has not been fully teased apart, stress-induced changes in placental function can drive sex-specific phenotypes in offspring. We sought to identify and examine molecular pathways in the placenta that are altered in response to maternal prenatal stress.

Methods

Using a mouse model of maternal prenatal stress, we conducted RNA-seq analysis of whole placenta at E18.5. We used qRT-PCR to validate gene expression changes in the placenta and in a trophoblast cell line. ELISAs were used to measure the abundance of thyroid hormones in maternal and fetal serum and in the placenta.

Results

Dio2 was amongst the top differentially expressed genes in response to elevated maternal stress hormone. Dio2 expression was more downregulated in female placenta from stressed dams than both female control and male placenta. Consistent with Dio2's role in production of bioactive thyroid hormone (T3), we found that there was a reduction of T3 in placenta and serum of female embryos from stressed dams at E18.5. Both T3 and T4 were reduced in the fetal compartment of the female placenta from stressed dams at E16.5. Stress hormone induced reduction in thyroid hormone in females was independent of circulating levels of TH in the dams.

Discussion

The placental thyroid hormone synthesis pathway may be a target of maternal stress and modulate fetal programming of health and disease of offspring in a sex-specific fashion.

Viral Infections and Schizophrenia: A Comprehensive Review

Schizophrenia is a complex mental disorder with multiple genetic and environmental factors contributing to its pathogenesis. Viral infections have been suggested to be one of the environmental factors associated with the development of this disorder. We comprehensively review all relevant published literature focusing on the relationship between schizophrenia and various viral infections, such as influenza virus, herpes virus 1 and 2 (HSV-1 and HSV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), retrovirus, coronavirus, and Borna virus. These viruses may interfere with the normal maturation of the brain directly or through immune-induced mediators, such as cytokines, leading to the onset of schizophrenia. Changes in the expression of critical genes and elevated levels of inflammatory cytokines have been linked to virally-induced infections and relevant immune activities in schizophrenia. Future research is necessary to understand this relationship better and provide insight into the molecular mechanisms underlying the pathophysiology of schizophrenia.

Gestational administration of vitamin D improves maternal care and prevents anxiety-like behavior in male and female Wistar rats prenatally exposed to dexamethasone

Prenatal overexposure to glucocorticoids (GC) can lead to behavioral changes in adulthood. We aimed to explore the effects of gestational administration of vitamin D on the behavioral responses of dams and their offspring prenatally exposed to dexamethasone (DEX). Vitamin D (500UI) was given daily during the whole pregnancy (VD group). Half of the groups that received vitamin D were treated with DEX (0.1 mg/kg, VD + DEX group) daily between the 14th and 19th days of pregnancy. The corresponding control groups of progenitors were assigned (CTL and DEX groups, respectively). Maternal care and the dam's behaviors were evaluated during lactation. The offspring had developmental and behavioral parameters evaluated during lactation and at 3, 6, and 12 months of age. Gestational administration of vitamin D increased maternal care and had an anxiolytic-like effect on the dams, but the latter was blocked in DEX-treated dams. Prenatal DEX partially impaired neural development and caused an anxiety-like phenotype in the male and female offspring at 6 months, which was prevented by gestational administration of vitamin D. As well, gestational vitamin D improved memory just in the male offspring, but this response was suppressed by prenatal DEX. We concluded that gestational vitamin D could prevent anxiety-like behavior in adult male and female rats prenatally exposed to DEX, which might be, in part, a result of the maternal care improvement.

Prenatal programming of environmental sensitivity

According to several theories, people differ in their sensitivity to environmental influences with some more susceptible than others to both supportive and adverse contextual conditions. Such differences in environmental sensitivity have a genetic basis but are also shaped by environmental factors. Herein we narratively build on our previous work proposing that prenatal experiences contribute to the development of environmental sensitivity. This hypothesis of prenatal programming of postnatal plasticity has considerable empirical support. After presenting illustrative animal and human evidence consistent with this claim, we discuss a range of biological mechanisms likely involved in the pathway from prenatal stress exposure to postnatal environmental sensitivity. We also consider work suggesting that genetic differences, gender, as well as the timing, duration and intensity of prenatal exposures may moderate the effects of prenatal programming on postnatal environmental susceptibility or sensitivity. Before concluding, we highlight "unknowns in the prenatal programming of environmental sensitivity" and their practical implications. Ultimately, we conclude that prenatal stress does not necessarily predispose individuals to problematical development, but rather increases sensitivity to both adverse and supportive postnatal contexts. Thus, prenatal stress may actually foster positive development if paired with supportive and caring postnatal environments.

Influence of maternal psychological distress during COVID-19 pandemic on placental morphometry and texture

The Coronavirus Disease 2019 (COVID-19) pandemic has been accompanied by increased prenatal maternal distress (PMD). PMD is associated with adverse pregnancy outcomes which may be mediated by the placenta. However, the potential impact of the pandemic on in vivo placental development remains unknown. To examine the impact of the pandemic and PMD on in vivo structural placental development using advanced magnetic resonance imaging (MRI), acquired anatomic images of the placenta from 63 pregnant women without known COVID-19 exposure during the pandemic and 165 pre-pandemic controls. Measures of placental morphometry and texture were extracted. PMD was determined from validated questionnaires. Generalized estimating equations were utilized to compare differences in PMD placental features between COVID-era and pre-pandemic cohorts. Maternal stress and depression scores were significantly higher in the pandemic cohort. Placental volume, thickness, gray level kurtosis, skewness and run length non-uniformity were increased in the pandemic cohort, while placental elongation, mean gray level and long run emphasis were decreased. PMD was a mediator of the association between pandemic status and placental features. Altered in vivo placental structure during the pandemic suggests an underappreciated link between disturbances in maternal environment and perturbed placental development. The long-term impact on offspring is currently under investigation.

The Epigenetics of Animal Personality

Animal personality, consistent individual differences in behaviour, is an important concept for understanding how individuals vary in how they cope with environmental challenges. In order to understand the evolutionary significance of animal personality, it is crucial to understand the underlying regulatory mechanisms. Epigenetic marks such as DNA methylation are hypothesised to play a major role in explaining variation in phenotypic changes in response to environmental alterations. Several characteristics of DNA methylation also align well with the concept of animal personality. In this review paper, we summarise the current literature on the role that molecular epigenetic mechanisms may have in explaining personality variation. We elaborate on the potential for epigenetic mechanisms to explain behavioural variation, behavioural development and temporal consistency in behaviour. We then suggest future routes for this emerging field and point to potential pitfalls that may be encountered. We conclude that a more inclusive approach is needed for studying the epigenetics of animal personality and that epigenetic mechanisms cannot be studied without considering the genetic background.

Prospective associations between various prenatal exposures to maternal psychological stress and neurodevelopment in children within 24 months after birth

BACKGROUND

There is increasing evidence that prenatal exposure to maternal psychological distress may be a factor influencing offspring neurodevelopment, but stress type-dependent effects of maternal psychological distress on offspring neurodevelopment in early childhood have yet to be fully elucidated. Additionally, although positive maternal mental health exerts potential effects in protecting against adverse health outcomes, few investigators have considered the effects of positive maternal mental health on offspring neurodevelopment in early childhood.

AIMS

To determine the associations between various prenatal exposures to maternal psychological distress and positive life-event experiences and offspring neurodevelopment within 24 months of age.

METHODS

A total of 4412 mother-child dyads were recruited from the Shanghai Maternal-Child Pairs Cohort (Shanghai MCPC). Maternal perceived stress, negative life-event stress, positive life-event experiences around the time of conception (i.e., three months prior to and after conception) were assessed at 12-16 gestational weeks, and maternal anxiety and depressive symptoms were assessed at 32-36 gestational weeks. We measured children's neurodevelopment using the Ages and Stages Questionnaire, Third Edition (ASQ-3) at two, six, 12, and 24 months postnatally. We then exploited generalized linear models to estimate the associations between prenatal maternal psychological distress and positive life-event experiences and children's neurodevelopment at the above periods, and generalized linear mixed models were applied to assess the associations between maternal psychological distress and positive life-event experiences and suspected developmental delay (SDD) in children within 24 months after birth based on a longitudinal design.

RESULTS

Maternal perceived stress and negative life-event stress around the time of conception, and anxiety and depressive symptoms during late pregnancy were negatively associated with scores of children's neurodevelopment at two, six, 12, and 24 months of age; while maternal life-event experiences were positively associated with scores of children's neurodevelopment. Longitudinal analysis revealed that higher levels of maternal negative life-event stress and depressive symptoms augmented the risk of SDD in personal-social (OR = 1.435, 1.681). Mothers who experienced higher levels of positive life-event experiences exhibited a reduced risk of SDD in gross motor and personal-social domains (OR = 0.373, 0.350).

CONCLUSIONS

Prenatal exposure to maternal psychological distress is negatively associated with children's neurodevelopment in early childhood depending upon the type of distress. Maternal positive life-event experiences around the time of conception appeared to present potential benefits for child neurodevelopment.

Prenatal Stress Induces Translational Disruption Associated with Myelination Deficits

Disruptions to neurodevelopment are known to be linked to behavioral disorders in childhood and into adulthood. The fetal brain is extremely vulnerable to stimuli that alter inhibitory GABAergic pathways and critical myelination processes, programing long-term neurobehavioral disruption. The maturation of the GABAergic system into the major inhibitory pathway in the brain and the development of oligodendrocytes into mature cells capable of producing myelin are integral components of optimal neurodevelopment. The current study aimed to elucidate prenatal stress-induced mechanisms that disrupt these processes and to delineate the role of placental pathways in these adverse outcomes. Pregnant guinea pig dams were exposed to prenatal stress with strobe light exposure for 2 h/day on gestational age (GA) 35, 40, 45, 50, 55, 60, and 65, and groups of fetuses and placentae were collected after the stress exposure on GA40, GA50, GA60, and GA69 (term). Fetal plasma, placental, and brain tissue were collected for allopregnanolone and cortisol quantification with ELISA. Relative mRNA expression of genes of specific pathways of interest was examined with real-time PCR in placental and hippocampal tissue, and myelin basic protein (MBP) was quantified immunohistochemically in the hippocampus and surrounding regions for assessment of mature myelin. Prenatal stress in mid-late gestation resulted in disruptions to the translational machinery responsible for the production of myelin and decreased myelin coverage in the hippocampus and surrounding regions. The male placenta showed an initial protective increase in allopregnanolone concentrations in response to maternal psychosocial stress. The male and female placentae had a sex-dependent increase in neurosteroidogenic enzymes at term following prenatal stress. Independent from exposure to prenatal stress, at gestational day 60 - a critical period for myelin development, the placentae of female fetuses had increased capability of preventing cortisol transfer to the fetus through expression of 11-beta-hydroxysteroid dehydrogenase types 1 and 2. The deficits early in the process of maturation of myelination indicate that the reduced myelination observed at childhood equivalence in previous studies begins in fetal life. This negative programing persists into childhood, potentially due to dysregulation of MBP translation processes. Expression patterns of neurosteroidogenic enzymes in the placenta at term following stress may identify at-risk fetuses that have been exposed to a stressful in utero environment.

Extracellular vesicles are dynamic regulators of maternal glucose homeostasis during pregnancy

Homeostatic regulation of the maternal milieu during pregnancy is critical for maternal and fetal health. The placenta facilitates critical communication between maternal and fetal compartments, in part, through the production of extracellular vesicles (EVs). EVs enable tissue synchrony via cell-cell and long-distance communication and are at their highest circulating concentration during pregnancy. While much work has been done investigating how physiological challenges in pregnancy affect the fetus, the role of placental communication in maternal health has not been well examined. We previously identified placental O-glycosyl transferase (OGT), a glucose-sensing enzyme, as a target of maternal stress where OGT levels and activity affected the O-glycosylation of proteins critical for EV cargo loading and secretion. Here, we hypothesized that placental OGT plays an essential role in maternal homeostatic regulation during pregnancy via its regulation of maternal circulating EV concentrations. Our studies found that changes to key metabolic factors over the circadian cycle, including glucocorticoids, insulin, and glucose, were significantly associated with changes in circulating EV concentration. Targeting placental OGT in mice, we found a novel significant positive relationship between placental OGT and maternal circulating EV concentration that was associated with improving maternal glucose tolerance during pregnancy. Finally, an intravenous elevation in EVs, matching the concentration of EVs during pregnancy, shifted non-pregnant female glucose sensitivity, blunted glucose variance, and improved synchrony of glucose uptake. These data suggest an important and novel role for circulating EVs as homeostatic regulators important in maternal health during pregnancy.

Sex differences in neuroimmunoendocrine communication. Involvement on longevity

Endocrine, nervous, and immune systems work coordinately to maintain the global homeostasis of the organism. They show sex differences in their functions that, in turn, contribute to sex differences beyond reproductive function. Females display a better control of the energetic metabolism and improved neuroprotection and have more antioxidant defenses and a better inflammatory status than males, which is associated with a more robust immune response than that of males. These differences are present from the early stages of life, being more relevant in adulthood and influencing the aging trajectory in each sex and may contribute to the different life lifespan between sexes.

Exposure in utero to adverse events and health late-in-life: Evidence from China

This paper estimates the effect of in utero exposure to adverse events on late life diabetes, cardiovascular disease risks and cognition deficiency. We merge data on the regional violence during the Cultural Revolution and the excessive death rates during the Chinese Great Famine with data from the China Health and Retirement Longitudinal Study survey. Results show that female babies who were exposed in utero to the famine have higher diabetes risks, while male babies who were exposed to the Cultural Revolution are shown to have lower cognitive abilities.