Early Life Adversity and Neuropsychiatric Disease: Differential Outcomes and Translational Relevance of Rodent Models

A novel discovery platform for targeted drug repurposing: application for psychiatric disorders

Existing pharmacotherapies and psychotherapies are often inadequate, and discovery for new pharmacological treatments in psychiatry is slow. Existing pharmacotherapies are, however, often inadequate. Few truly novel pharmacotherapies have emerged in the past four decades, largely due to the absence of a known pathophysiology for each disorder. In this Personal View, we describe the platform we have adopted that enables targeted drug repurposing. With this approach, patient-derived stem cells are used to detect transcriptomic targets to identify existing drugs that address these targets. These drugs are then validated in non-human animal models and pharmacoepidemiological studies before being tested in clinical trials. Our targeted drug repurposing platform bypasses the absence of known pathophysiology. Validation steps bring greater scientific rigour and mechanistic insights to drug repurposing to allow only drug candidates with the strongest mechanistic evidence to be tested in clinical trials.

Early-life stress sensitizes response to future stress: Evidence and mechanisms

Early-life stress sensitizes individuals to additional stressors and increases lifetime risk for mood and anxiety disorders. Research in both human populations and rodent models of early-life stress have sought to determine how different types of stressors contribute to vulnerability, and whether there are developmental sensitive periods for such effects. Although differences in the type and timing of rodent early-life stress paradigms have led to differences in specific behavioral outcomes, this complexity is present among humans as well. Robust rodent research now shows how early-life stress increases sensitivity to future stressors at behavioral, neural circuit, and molecular levels. These recent discoveries are laying the foundation for translation to more effective interventions relevant for those who experienced childhood stress and trauma.

Deprescription of benzodiazepines and its management according to an overlapping strategy with a low-dose multicomponent medication: a Delphi consensus

BACKGROUND

About 20% of adults and between 6% and 13% of children experience mild to moderate anxiety and stress-related symptoms. Benzodiazepines (BZDs) are considered the referring medications for early-stage anxiety and stress-related symptoms management. Nevertheless, BZDs must be managed carefully because their use, especially chronic, could be linked with some adverse effects, and can promote the onset of psychological and physical dependence. They also often show progressive tolerance, necessitating an increase in dosage, and therefore their use should be discouraged. In the clinical management of patients with pathological/dysfunctional anxiety, one of the main issues related to the discontinuation of BZDs treatment is the occurrence of rebound effects and withdrawal syndrome, especially in subjects with certain personality disorders and poly-drug users. The deprescription of BZDs is advisable with the availability of other therapies and interventions, especially in elderly subjects. Therefore, an effective and safe alternative pharmacological tool for mild to moderate anxiety and stress-related symptoms is needed. After the identification of potentially new medications to flank BZDs, it is mandatory to revise and improve good clinical practices even through a consensus process.

METHODS

Taking into consideration all the above-mentioned premises, the present Delphi Consensus Study has explored whether there is agreement about the use of the low-dose multicomponent natural medication Ignatia-Heel in overlapping with BZDs is appropriate for the reduction and potential discontinuation of BZDs intake in patients on chronic BZDs treatment.

RESULTS

The Consensus Study also explored the possibility to maintain symptom remission or low disease activity with the long-term use of Ignatia-Heel in patients with pathological/dysfunctional anxiety, after clinical remission achieved with BZDs. For each questionnaire statement, consensus was achieved (being based on the agreement of at least 66.6% of the Consensus Panel and the acceptance of the scientific committee).

CONCLUSIONS

Ignatia-Heel can be considered a valid opportunity for the treatment of pathological anxiety favoring the deprescription of BZDs in patients under chronic BZDs treatment and the maintenance of a good control of symptomatology, i.e., a good low disease activity.

Spatial control of doping in conducting polymers enables complementary, conformable, implantable internal ion-gated organic electrochemical transistors

Complementary transistors are critical for circuits with compatible input/output signal dynamic range and polarity. Organic electronics offer biocompatibility and conformability; however, generation of complementary organic transistors requires introduction of separate materials with inadequate stability and potential for tissue toxicity, limiting their use in biomedical applications. Here, we discovered that introduction of source/drain contact asymmetry enables spatial control of de/doping and creation of single-material complementary organic transistors from a variety of conducting polymers of both carrier types. When integrated with the vertical channel design and internal ion reservoirs of internal ion-gated organic electrochemical transistors, we produced matched complementary IGTs (cIGTs) that formed high-performance conformable amplifiers with 200 V/V uniform gain and 2 MHz bandwidth. These amplifiers showed long-term in vivo stability, and their miniaturized biocompatible design allowed implantation in developing rodents to monitor network maturation. cIGTs expand the use of organic electronics in standard circuit designs and enhance their biomedical potential.

Methods for Modeling Early Life Stress in Rodents

Animal models of early life stress/adversity (ELS) have provided a foundation from which our understanding of the psychoneuroimmunology of childhood trauma has expanded over recent decades. Rodent models are a cornerstone of the ELS literature with many studies utilizing paradigms based on early life separation/deprivation protocols and manipulating the cage environment. However, no animal model is perfect. In particular, the lack of standardization across ELS models has led to inconsistent results and raised questions regarding the translational value of common preclinical models. In this chapter, we present an overview of the history of ELS rodent models and discuss considerations relevant to the ongoing efforts to both improve existing models and generate novel paradigms to meet the evolving needs of molecular- and mechanism-based ELS research.

Effects of maternal separation on punishment-driven risky decision making in adolescence and adulthood

Early life adversity (ELA) is associated with a multitude of neural and behavioral aberrations. To develop treatments to mitigate the effects of ELA, it is critical to determine which aspects of cognition are affected and when these disturbances manifest across the lifespan. Here, we tested the effects of maternal separation, an established rodent model of ELA, on punishment-driven risky decision-making longitudinally in both adolescence (25-55 days old) and adulthood (80-100 days old). Risk-taking was assessed with the Risky Decision-making Task, wherein rats choose between a small, safe reward and a large reward accompanied by an escalating risk of punishment (foot shock). We observed that rats exposed to maternal separation were more prone to risk-taking than controls during adolescence, and demonstrated reduced latency to make both risky and safe decisions. Interestingly, this augmented risk-taking was no longer evident in adulthood. Males and females displayed comparable levels of risk-taking during adolescence then diverged in adulthood, with adult males displaying a sharp increase in risk-taking. Finally, we observed that risk-taking changed across the lifespan in rats exposed to maternal separation, but not in control rats. Collectively, these data reveal that ELA engenders risk-taking in adolescence but not adulthood, and that sex differences in risky decision-making are not evident until adulthood. This has important implications for the development of both behavioral and biological treatments to improve decision-making during the vulnerable adolescent period.

FAAH Inhibition Reverses Depressive-like Behavior and Sex-Specific Neuroinflammatory Alterations Induced by Early Life Stress

Early life stress (ELS) increases predisposition to major depressive disorder (MDD), with neuroinflammation playing a crucial role. This study investigated the long-term effects of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on ELS-induced depressive-like behavior and messenger RNA (mRNA) of pro-inflammatory cytokines in the medial prefrontal cortex (mPFC) and CA1 regions. We also assessed whether these gene expression alterations were present at the onset of URB597 treatment during late adolescence. ELS induced a depressive-like phenotype in adult male and female rats, which was reversed by URB597. In the mPFC, ELS downregulated nuclear factor kappa B1 (nfκb1) in both sexes, while URB597 normalized this expression exclusively in males. In females, ELS downregulated interleukin (il) 6 and tumor necrosis factor alpha (tnfα) but upregulated il1β and corticotropin-releasing factor (crf); URB597 normalized il6, il1β, and crf. In the CA1, ELS downregulated il1β and tnfα in males and upregulated il1β expression in females, which was reversed by URB597. Some of these effects began in late adolescence, including mPFC-nfκb1 expression in both sexes, mPFC-il6 and mPFC-il1β in females, CA1-il1β and CA1-tnfα in males, and CA1-il1β in females. These findings highlight URB597 as a therapeutic approach for reversing ELS-induced depressive-like behavior by associating with changes in the gene expression of neuroinflammatory cytokines, with notable sex differences.

Environmental and neurodevelopmental contributors to youth mental illness

While a myriad of factors likely contribute to the development of mental illness in young people, the social environment (including early adverse experiences) in concert with neurodevelopmental alterations is undeniably important. A number of influential theories make predictions about how and why neurodevelopmental alterations may mediate or moderate the effects of the social environment on the emergence of mental illness. Here, we discuss current evidence supporting each of these theories. Although this area of research is rapidly growing, the body of evidence is still relatively limited. However, there exist some consistent findings, including increased striatal reactivity during positive affective processing and larger hippocampal volumes being associated with increased vulnerability or susceptibility to the effects of social environments on internalizing symptoms. Limited longitudinal work has investigated neurodevelopmental mechanisms linking the social environment with mental health. Drawing from human research and insights from animal studies, we propose an integrated mediation-moderation model and outline future research directions to advance the field.

Early Life Stress and Major Depressive Disorder-An Update on Molecular Mechanisms and Synaptic Impairments

Early life stress (ELS), characterized as abuse, neglect, and abandonment, can cause several adverse consequences in the lives of affected individuals. ELS experiences can affect an individual's development in variable ways, persisting in the long term and promoting lasting impacts, considering that early exposure to stressors can be biologically incorporated, as prolonged stimulation of stress response systems affects the development of the brain structure and other body systems, increasing the risk of diseases associated with stress and cognitive impairment. This type of stress increases the risk of developing major depressive disorder (MDD) in a severe form that does not respond adequately to traditional antidepressant treatments. Several alterations are studied as mechanisms that relate ELS with MDD, such as epigenetic alterations, neurotransmitters, and neuronal signaling. This review discusses research that brings evidence about the ELS mechanisms involved in synaptic impairments and MDD. The processes involved in epigenetic changes and the HPA axis are highlighted, as well as changes in neurotransmitters and neuronal signaling mechanisms.

Childhood abuse influences clinical features of major depressive disorder by modulating the functional network of the right amygdala subregions

Childhood trauma and the amygdala play essential roles in major depressive disorder (MDD) mechanisms. However, the neurobiological mechanism among them remains unclear. Therefore, we explored the relationship among the amygdala subregion's abnormal functional connectivity (FC), clinical features, and childhood trauma in MDD. We obtained resting-state functional magnetic resonance imaging (fMRI) in 115 MDD patients and 91 well-matched healthy controls (HC). Amygdala subregions were defined according to the Human Brainnetome Atlas. The case vs. control difference in FCs was extracted. After controlling for age, sex, and education years, the mediations between the detected abnormal FCs and clinical features were analyzed, including the onset age of MDD and the Hamilton Depression Scale-24 (HAMD-24) reductive rate. Compared with HC subjects, we found, only the right amygdala subregions, namely the right medial amygdala (mAmyg.R) and the right lateral amygdala (lAmyg.R), showed a significant decrease in whole-brain FCs in MDD patients. Only childhood abuse experiences were significantly associated with amygdala subregion connectivity and clinical features in MDD patients. Additionally, The FCs between the mAmyg.R and extensive frontal, temporal, and subcortical regions mediated between the early life abuses and disease onset or treatment outcome. The findings indicate that the abnormal connectivity of the right amygdala subregions is involved in MDD's pathogenesis and clinical characteristics.

Si-Ni-San alleviates early life stress-induced depression-like behaviors in adolescence via modulating Rac1 activity and associated spine plasticity in the nucleus accumbens

Background: Early life stress (ELS) is a major risk factor for depression in adolescents. The nucleus accumbens (NAc) is a key center of the reward system, and spine remodeling in the NAc contributes to the development of depression. The Si-Ni-San formula (SNS) is a fundamental prescription for treating depression in traditional Chinese medicine. However, little is known about the effects of SNS on behavioral abnormalities and spine plasticity in the NAc induced by ELS. Purpose: This study aimed to investigate the therapeutic effect and the modulatory mechanism of SNS on abnormal behaviors and spine plasticity in the NAc caused by ELS. Methods: We utilized a model of ELS that involved maternal separation with early weaning to explore the protective effects of SNS on adolescent depression. Depressive-like behaviors were evaluated by the sucrose preference test, the tail suspension test, and the forced swimming test; anxiety-like behaviors were monitored by the open field test and the elevated plus maze. A laser scanning confocal microscope was used to analyze dendritic spine remodeling in the NAc. The activity of Rac1 was detected by pull-down and Western blot tests. Viral-mediated gene transfer of Rac1 was used to investigate its role in ELS-induced depression-like behaviors in adolescence. Results: ELS induced depression-like behaviors but not anxiety-like behaviors in adolescent mice, accompanied by an increase in stubby spine density, a decrease in mushroom spine density, and decreased Rac1 activity in the NAc. Overexpression of constitutively active Rac1 in the NAc reversed depression-related behaviors, leading to a decrease in stubby spine density and an increase in mushroom spine density. Moreover, SNS attenuated depression-like behavior in adolescent mice and counteracted the spine abnormalities in the NAc induced by ELS. Additionally, SNS increased NAc Rac1 activity, and the inhibition of Rac1 activity weakened the antidepressant effect of SNS. Conclusion: These results suggest that SNS may exert its antidepressant effects by modulating Rac1 activity and associated spine plasticity in the NAc.

Early life stress in male mice blunts responsiveness in a translationally-relevant reward task

Early-life stress (ELS) leaves signatures upon the brain that persist throughout the lifespan and increase the risk of psychiatric illnesses including mood and anxiety disorders. In humans, myriad forms of ELS-including childhood abuse, bullying, poverty, and trauma-are increasingly prevalent. Understanding the signs of ELS, including those associated with psychiatric illness, will enable improved treatment and prevention. Here, we developed a novel procedure to model human ELS in mice and identify translationally-relevant biomarkers of mood and anxiety disorders. We exposed male mice (C57BL/6 J) to an early-life (juvenile) chronic social defeat stress (jCSDS) and examined social interaction and responsivity to reward during adulthood. As expected, jCSDS-exposed mice showed a socially avoidant phenotype in open-field social interaction tests. However, sucrose preference tests failed to demonstrate ELS-induced reductions in choice for the sweetened solution, suggesting no effect on reward function. To explore whether other tasks might be more sensitive to changes in motivation, we tested the mice in the Probabilistic Reward Task (PRT), a procedure often used in humans to study reward learning deficits associated with depressive illness. In a touchscreen PRT variant that was reverse-translated to maximize alignment with the version used in human subjects, mice exposed to jCSDS displayed significant reductions in the tendency to develop response biases for the more richly-rewarded stimulus, a hallmark sign of anhedonia when observed in humans. Our findings suggest that translationally-relevant procedures that utilize the same endpoints across species may enable the development of improved model systems that more accurately predict outcomes in humans.

Automated maternal behavior during early life in rodents (AMBER) pipeline

Mother-infant interactions during the early postnatal period are critical for infant survival and the scaffolding of infant development. Rodent models are used extensively to understand how these early social experiences influence neurobiology across the lifespan. However, methods for measuring postnatal dam-pup interactions typically involve time-consuming manual scoring, vary widely between research groups, and produce low density data that limits downstream analytical applications. To address these methodological issues, we developed the Automated Maternal Behavior during Early life in Rodents (AMBER) pipeline for quantifying home-cage maternal and mother-pup interactions using open-source machine learning tools. DeepLabCut was used to track key points on rat dams (32 points) and individual pups (9 points per pup) in postnatal day 1-10 video recordings. Pose estimation models reached key point test errors of approximately 4.1-10 mm (14.39 pixels) and 3.44-7.87 mm (11.81 pixels) depending on depth of animal in the frame averaged across all key points for dam and pups respectively. Pose estimation data and human-annotated behavior labels from 38 videos were used with Simple Behavioral Analysis (SimBA) to generate behavior classifiers for dam active nursing, passive nursing, nest attendance, licking and grooming, self-directed grooming, eating, and drinking using random forest algorithms. All classifiers had excellent performance on test frames, with F1 scores above 0.886. Performance on hold-out videos remained high for nest attendance (F1 = 0.990), active nursing (F1 = 0.828), and licking and grooming (F1 = 0.766) but was lower for eating, drinking, and self-directed grooming (F1 = 0.534-0.554). A set of 242 videos was used with AMBER and produced behavior measures in the expected range from postnatal 1-10 home-cage videos. This pipeline is a major advancement in assessing home-cage dam-pup interactions in a way that reduces experimenter burden while increasing reproducibility, reliability, and detail of data for use in developmental studies without the need for special housing systems or proprietary software.

Oligodendrocytes matter: a review of animal studies on early adversity

Exposure to adversities in early life appears to affect the development of white matter, especially oligodendrocytes. Furthermore, altered myelination is present in regions subjected to maturation during the developmental time when early adversities are experienced. In this review, studies applying two well-established animal models of early life adversity, namely maternal separation and maternal immune activation, focusing on oligodendrocyte alterations and resulting implications for psychiatric disorders are discussed. Studies revealed that myelination is reduced as a result of altered oligodendrocyte expression. Furthermore, early adversity is associated with increased cell death, a simpler morphology, and inhibited oligodendrocyte maturation. However, these effects seem to be region- specific as some brain regions show increased expression while others show decreased expression of oligodendroglia-related genes, and they occur especially in regions of ongoing development. Some studies furthermore suggest that early adversity leads to premature differentiation of oligodendrocytes. Importantly, especially early exposure results in stronger oligodendrocyte-related impairments. However, resulting alterations are not restricted to exposure during the early pre- and postnatal days as social isolation after weaning leads to fewer internodes and branches and shorter processes of oligodendrocytes in adulthood. Eventually, the found alterations may lead to dysfunction and long-lasting alterations in structural brain development associated with psychiatric disorders. To date, only few preclinical studies have focused on the effects of early adversity on oligodendrocytes. More studies including several developmental stages are needed to further disentangle the role of oligodendrocytes in the development of psychiatric disorders.

Early life adversity as a risk factor for cognitive impairment and Alzheimer's disease

Neurological conditions, including cognitive impairment and Alzheimer's disease (AD), impose a huge burden on society, affecting millions of people globally. In addition to genetic factors, recent studies indicate that environmental and experiential factors may contribute to the pathogenesis of these diseases. Early life adversity (ELA) has a profound impact on brain function and health later in life. In rodent models, exposure to ELA results in specific cognitive deficits and aggravated AD pathology. Extensive concerns have been raised regarding the higher risk of developing cognitive impairments in people with a history of ELA. In this review, we scrutinize findings from human and animal studies focusing on the connection of ELA with cognitive impairment and AD. These discoveries suggest that ELA, especially at early postnatal stages, increases susceptibility to cognitive impairment and AD later in life. In terms of mechanisms, ELA could lead to dysregulation of the hypothalamus-pituitary-adrenal axis, altered gut microbiome, persistent inflammation, oligodendrocyte dysfunction, hypomyelination, and aberrant adult hippocampal neurogenesis. Crosstalks among these events may synergistically contribute to cognitive impairment later in life. Additionally, we discuss several interventions that may alleviate adverse consequences of ELA. Further investigation into this crucial area will help improve ELA management and reduce the burden of related neurological conditions.

Amygdala circuit transitions supporting developmentally-appropriate social behavior

Social behaviors dynamically change throughout the lifespan alongside the maturation of neural circuits. The basolateral region of the amygdala (BLA), in particular, undergoes substantial maturational changes from birth throughout adolescence that are characterized by changes in excitation, inhibition, and dopaminergic modulation. In this review, we detail the trajectory through which BLA circuits mature and are influenced by dopaminergic systems to guide transitions in social behavior in infancy and adolescence using data from rodents. In early life, social behavior is oriented towards approaching the attachment figure, with minimal BLA involvement. Around weaning age, dopaminergic innervation of the BLA introduces avoidance of novel peers into rat pups' behavioral repertoire. In adolescence, social behavior transitions towards peer-peer interactions with a high incidence of social play-related behaviors. This transition coincides with an increasing role of the BLA in the regulation of social behavior. Adolescent BLA maturation can be characterized by an increasing integration and function of local inhibitory GABAergic circuits and their engagement by the medial prefrontal cortex (mPFC). Manipulation of these transitions using viral circuit dissection techniques and early adversity paradigms reveals the sensitivity of this system and its role in producing age-appropriate social behavior.

The effects of childhood maltreatment on cortical thickness and gray matter volume: a coordinate-based meta-analysis

Childhood maltreatment has been suggested to have an adverse impact on neurodevelopment, including microstructural brain abnormalities. Existing neuroimaging findings remain inconsistent and heterogeneous. We aim to explore the most prominent and robust cortical thickness (CTh) and gray matter volume (GMV) alterations associated with childhood maltreatment. A systematic search on relevant studies was conducted through September 2022. The whole-brain coordinate-based meta-analysis (CBMA) on CTh and GMV studies were conducted using the seed-based d mapping (SDM) software. Meta-regression analysis was subsequently applied to investigate potential associations between clinical variables and structural changes. A total of 45 studies were eligible for inclusion, including 11 datasets on CTh and 39 datasets on GMV, consisting of 2550 participants exposed to childhood maltreatment and 3739 unexposed comparison subjects. Individuals with childhood maltreatment exhibited overlapped deficits in the median cingulate/paracingulate gyri simultaneously revealed by both CTh and GM studies. Regional cortical thinning in the right anterior cingulate/paracingulate gyri and the left middle frontal gyrus, as well as GMV reductions in the left supplementary motor area (SMA) was also identified. No greater regions were found for either CTh or GMV. In addition, several neural morphology changes were associated with the average age of the maltreated individuals. The median cingulate/paracingulate gyri morphology might serve as the most robust neuroimaging feature of childhood maltreatment. The effects of early-life trauma on the human brain predominantly involved in cognitive functions, socio-affective functioning and stress regulation. This current meta-analysis enhanced the understanding of neuropathological changes induced by childhood maltreatment.

Neurochemical mechanisms of deep brain stimulation for depression in animal models

Deep brain stimulation (DBS) has emerged as a neuromodulation therapy for treatment-resistant depression, but its actual efficacy and mechanisms of action are still unclear. Changes in neurochemical transmission are important mechanisms of antidepressant therapies. Here, we review the preclinical DBS literature reporting behavioural and neurochemical data associated with its antidepressant-like effects. The most commonly studied target in preclinical models was the ventromedial prefrontal cortex (vmPFC). In rodents, DBS delivered to this target induced serotonin (5-HT) release and increased 5-HT1_B receptor expression. The antidepressant-like effects of vmPFC DBS seemed to be independent of the serotonin transporter and potentially mediated by the direct modulation of prefrontal projections to the raphe. Adenosinergic and glutamatergic transmission might have also play a role. Medial forebrain bundle (MFB) DBS increased dopamine levels and reduced D2 receptor expression, whereas nucleus accumbens (NAcc), and lateral habenula (LHb) stimulation increased catecholamine levels in different brain regions. In rodents, subthalamic nucleus (STN) DBS induced robust depression-like responses associated with a reduction in serotonergic transmission, as revealed by a decrease in serotonin release. Some of these effects seemed to be mediated by 5HT1_A receptors. In conclusion, the antidepressant-like effects of DBS in preclinical models have been well documented in multiple targets. Though variable mechanisms have been proposed, DBS-induced acute and long-term changes in neurochemical substrates seem to play an important role in the antidepressant-like effects of this therapy.

Early life adversity across different cell- types in the brain

Early life adversity (ELA)- which includes physical, psychological, emotional, and sexual abuse is one of the most common predictors to diverse psychopathologies later in adulthood. As ELA has a lasting impact on the brain at a developmental stage, recent findings from the field highlighted the specific contributions of different cell types to ELA and their association with long lasting consequences. In this review we will gather recent findings describing morphological, transcriptional and epigenetic alterations within neurons, glia and perineuronal nets and their associated cellular subpopulation. The findings reviewed and summarized here highlight important mechanisms underlying ELA and point to therapeutic approaches for ELA and related psychopathologies later in life.

Brain network changes in adult victims of violence

Introduction

Stressful experiences such as violence can affect mental health severely. The effects are associated with changes in structural and functional brain networks. The current study aimed to investigate brain network changes in four large-scale brain networks, the default mode network, the salience network, the fronto-parietal network, and the dorsal attention network in self-identified victims of violence and controls who did not identify themselves as victims.

Materials and methods

The control group (n = 32) was matched to the victim group (n = 32) by age, gender, and primary psychiatric disorder. Sparse inverse covariance maps were derived from functional resting-state measurements and from T1 weighted structural data for both groups.

Results

Our data underlined that mostly the salience network was affected in the sample of self-identified victims. In self-identified victims with a current psychiatric diagnosis, the dorsal attention network was mostly affected underlining the potential role of psychopathological alterations on attention-related processes.

Conclusion

The results showed that individuals who identify themselves as victim demonstrated significant differences in all considered networks, both within- and between-network.

The estrous cycle modulates early-life adversity effects on mouse avoidance behavior through progesterone signaling

Early-life adversity (ELA) increases the likelihood of neuropsychiatric diagnoses, which are more prevalent in women than men. Since changes in reproductive hormone levels can also increase the probability of anxiety disorders in women, we examined the effects of ELA on adult female mice across the estrous cycle. We found that during diestrus, when progesterone levels are relatively high, ELA mice exhibit increased avoidance behavior and increased theta oscillation power in the ventral hippocampus (vHIP). We also found that diestrus ELA mice had higher levels of progesterone and lower levels of allopregnanolone, a neurosteroid metabolite of progesterone, in the vHIP compared with control-reared mice. Progesterone receptor antagonism normalized avoidance behavior in ELA mice, while treatment with a negative allosteric modulator of allopregnanolone promoted avoidance behavior in control mice. These results suggest that altered vHIP progesterone and allopregnanolone signaling during diestrus increases avoidance behavior in ELA mice.