Prenatal immune stress induces a prolonged blunting of microglia activation that impacts striatal connectivity

Recent studies suggested that microglia, the primary brain immune cells, can affect circuit connectivity and neuronal function. Microglia infiltrate the neuroepithelium early in embryonic development and are maintained in the brain throughout adulthood. Several maternal environmental factors, such as aberrant microbiome, immune activation, and poor nutrition, can influence prenatal brain development. Nevertheless, it is unknown how changes in the prenatal environment instruct the developmental trajectory of infiltrating microglia, which in turn affect brain development and function. Here we show that after maternal immune activation (MIA) microglia from the offspring have a long-lived decrease in immune reactivity (blunting) across the developmental trajectory. The blunted immune response was concomitant with changes in the chromatin accessibility and reduced transcription factor occupancy of the open chromatin. Single cell RNA sequencing revealed that MIA does not induce a distinct subpopulation but rather decreases the contribution to inflammatory microglia states. Prenatal replacement of MIA microglia with physiological infiltration of naive microglia ameliorated the immune blunting and restored a decrease in presynaptic vesicle release probability onto dopamine receptor type-two medium spiny neurons, indicating that aberrantly formed microglia due to an adverse prenatal environment impacts the long-term microglia reactivity and proper striatal circuit development.

The Interplay Between Prenatal Adversity, Offspring Dopaminergic Genes, and Early Parenting on Toddler Attentional Function

Background: Few studies have explored the complex gene-by-prenatal environment-by-early postnatal environment interactions that underlie the development of attentional competence. Here, we examined if variation in dopamine-related genes interacts with prenatal adversity to influence toddler attentional competence and whether this influence is buffered by early positive maternal behavior.Methods: From the Maternal Adversity, Vulnerability and Neurodevelopment cohort, 134 participants (197 when imputing missing data) had information on prenatal adversity (prenatal stressful life events, prenatal maternal depressive symptoms, and birth weight), five dopamine-related genes (DAT1, DRD4, DRD2, COMT, BDNF), observed maternal parenting behavior at 6 months and parent-rated toddler attentional competence at 18 and 24 months. The Latent Environmental and Genetic Interaction (LEGIT) approach was used to examine genes-by-prenatal environment-by-postnatal environment interactions while controlling for sociodemographic factors and postnatal depression.Results: Our hypothesis of a three-way interaction between prenatal adversity, dopamine-related genes, and early maternal parenting behavior was not confirmed. However, consistent two-way interactions emerged between prenatal adversity and dopamine-related genes; prenatal adversity and maternal parenting behavior, and dopamine-related genes and maternal parenting behavior in relation to toddler attentional competence. Significant interaction effects were driven by the DAT1, COMT, and BDNF genotypes; prenatal stressful life events; maternal sensitivity, tactile stimulation, vocalization, and infant-related activities.Conclusions: Multiple dopamine-related genes affected toddler attentional competence and they did so in interaction with prenatal adversity and the early rearing environment, separately. Effects were already visible in young children. Several aspects of early maternal parenting have been identified as potential targets for intervention.

Influence of Prenatal Environment on Androgen Steroid Metabolism In Monozygotic Twins With Birthweight Differences

Objective Although low birthweight (bw) and unfavorable intrauterine conditions have been associated with metabolic sequelae in later life, little is known about their impact on steroid metabolism. We studied genetically identical twins with intra-twin bw-differences from birth to adolescence to analyze the long-term impact of bw on steroid metabolism. Methods 68 monozygotic twin pairs with a bw-difference of <1 standard deviation score (SDS; concordant; n = 41) and ≥1 SDS (discordant; n = 27) were recruited. At 14.9 years (mean age), morning urine samples were collected and analyzed with gas chromatography–mass-spectrometry. Results No significant differences were detected in the concordant group. In contrast, in the smaller twins of the discordant group, we found significantly higher concentrations not only of the dehydroepiandrosterone sulfate (DHEAS) metabolite 16α-OH-DHEA (P = 0.001, 656.11 vs 465.82 µg/g creatinine) but also of cumulative dehydroepiandrosterone and downstream metabolites (P = 0.001, 1650.22 vs 1131.92 µg/g creatinine). Relative adrenal (P = 0.002, 0.25 vs 0.18) and overall androgen production (P = 0.001, 0.79 vs 0.65) were significantly higher in the formerly smaller discordant twins. All twin pairs exhibited significant intra-twin correlations for all individual steroid metabolites, sums of metabolites, indicators of androgen production, and enzyme activities. Multiple regression analyses of the smaller twins showed that individual steroid concentrations of the larger co-twin were the strongest influencing factor among nearly all parameters analyzed. Conclusion In monozygotic twin pairs with greater intra-twin bw-differences (≥1 SDS), we found that bw had a long-lasting impact on steroid metabolism, with significant differences regarding DHEAS metabolites and relative androgen production. However, most parameters showed significant intra-twin correlations, suggesting a consistent interrelationship between prenatal environment, genetic background, and steroid metabolism.