INTRODUCTION:Granular neurons arise from external granular precursors (EGPs) in the external granule layer and internal granular progenitors (IGPs) in the internal granule layer (IGL) during cerebellar cortical histogenesis in ferrets. Additionally, IGPs have a potency on differentiating into Bergmann glia and astrocytes. This study aimed to clarify the effects of lipopolysaccharide (LPS) on granular neurogenesis in the developing ferret cerebellum and its association with the proliferation, differentiation, and apoptosis of EGPs and IGPs. METHODS:LPS (500 µg/g body weight) was administered to ferrets at postnatal days (PDs) 6 and 7. Ferrets also received 5-ethynyl-2'-deoxyuridine (EdU) and 5-bromo-2'-deoxyuridine (BrdU) on PDs 5 and 7, respectively, to label post-proliferative and proliferating cells at the time of LPS exposure. RESULTS:Two h after BrdU injection (PD 7), the densities of proliferating BrdU- and post-proliferative EdU-labeled cells did not differ in the external granular layer, molecular/Purkinje cell layers (ML/PCL), or IGL between LPS-exposed and control ferrets. BrdU-labeled cells contained 55-83% cells immunostained for proliferating cell nuclear antigen (PCNA), selectively expressed in IGPs. The S100-immunostained ratio among BrdU-labeled cells was significantly higher in the ML/PCL, but lower in the IGL of LPS-exposed ferrets compared to controls. On PD 20, NeuN-positive granular neurons generated on PD 7 (BrdU-labeled) were significantly denser in the IGL of LPS-exposed ferrets. CONCLUSION:These findings suggest that LPS enhances granular neurogenesis in the developing cerebellum of ferret neonates. LPS may have a location-specific effect on the glial differentiation of proliferating IGPs: enhancing and reducing in the ML/PCL and IGL, respectively.
INTRODUCTION:Atypical sensory processing, particularly auditory hypersensitivity, is a common and debilitating phenotype of Fragile X Syndrome (FXS). Electrophysiology studies in the FMR1-knockout (KO) mice previously observed hyperexcitability at the auditory cortex (AC), with enhanced neuronal firing to auditory stimuli. Prepulse inhibition (PPI), a behavioral measure of sensorimotor gating, is robustly impaired in FXS individuals. Interestingly, a related paradigm called gap-induced inhibition of the acoustic startle (GPIAS) is mediated by the AC, and a previous study observed decreased GPIAS in mature FMR1-KO mice. Further, habituation is also an important sensory filtering mechanism, which has been reported to be impaired in mature FMR1-KO mice. However, not much is known about GPIAS and habituation in the FMR1-KO mice during early development. METHODS:We evaluated GPIAS in male and female FMR1-KO mice at post-natal days 15 (P15), 20 (P20) and 30 (P30). The paradigm consisted of a prepulse stimulus (gap in continuous background noise) followed by a startle stimulus, at inter-stimulus intervals of 50 and 100 ms. Habituation was assessed prior to the GPIAS trials, with a series of startle only stimulus. RESULTS:We observed a trend for genotype difference in acoustic startle response (ASR) magnitude, particularly in the female mice at P30. No significant genotype differences were noted in GPIAS or latency of ASR. Response duration was significantly increased in the male FMR1-KO mice compared to their WT counterparts during early development. Significant genotype differences were also observed in habituation and sensitization. In terms of development, we observed a significant increase in GPIAS with maturation. Furthermore, we also observed significant changes in the magnitude, response latency and duration of ASR with maturation. Finally, significant sex differences were observed in ASR magnitude and duration. CONCLUSION:Our findings suggest that behavioral responses to auditory stimuli are dynamic during development and differ between females and males. This is an important consideration for future study designs and highlights the need for mechanistic studies to further understand the development- and sex-related differences. Additionally, the FMR1-KO mice display habituation deficits during early development, which could be an ideal window for addressing auditory hypersensitivity in FXS.
Cognitive development in late childhood and adolescence occurs alongside increasingly complex environments. To examine how cognitive abilities relate to neural processing of naturalistic experiences, we analyzed fMRI data from 309 children and adolescents (ages 7-15; majority White) in the Healthy Brain Biobank. Participants watched a 10-minute clip of Despicable Me during scanning and completed the WISC. Intersubject correlation (ISC) was used to measure brain synchrony during viewing. Adolescents (11-15) with higher cognitive scores showed greater ISC in default mode and frontoparietal networks. In contrast, younger children (7-11) with high scores showed increased between-subject synchrony only in somatosensory regions. These findings suggest age- and cognition-related differences in how children and adolescents process complex, real-world stimuli.
Background: The gut microbiota plays a vital role in shaping brain development through complex bidirectional communication within the microbiota-gut-brain axis. Emerging evidence highlights neural, immune, endocrine, metabolic, and epigenetic pathways by which gut microbes influence neurodevelopmental processes. Summary: This review synthesizes current knowledge on the temporal dynamics of gut colonization and brain maturation. Drawing on mechanistic insights from animal models, we emphasize the central role of the maternal microbiota and particularly, microbially derived metabolites that cross the feto-placental barrier and shape fetal brain development. We also discuss molecular and cellular targets of microbial influence, implications for neurodevelopmental disorders, and potential therapeutic strategies. Key Messages: Understanding these interactions opens new avenues for early-life interventions aimed at optimizing neurodevelopments and preventing neuropsychiatric conditions.
Introduction: Autism spectrum disorder (ASD) is a lifelong neurological and developmental disorder that is often accompanied by gastrointestinal (GI) issues. The bidirectional communication system known as the gut microbiota-brain axis may help explain how GI dysfunction contributes to neurological symptoms. Loss-of-function mutations in the histone demethylases KDM5A, KDM5B, or KDM5C are found in patients with intellectual disability and ASD. Here, we use a genetically tractable Drosophila model of loss-of-function of the ASD-associated chromatin regulator Kdm5 to investigate how host genetic disruption influences gut microbial composition and social behavior. Previous studies using a Drosophila Kdm5 loss-of-function (Kdm5LOF) revealed gut microbial dysbiosis, reduced abundance of Lactiplantibacillus plantarum, and impaired social behavior. While L. plantarum supplementation rescued intestinal abnormalities, it did not restore social behavior. Methods: We evaluated multiple microbiota-based interventions, including probiotic supplementation with L. plantarum, Lactobacillus helveticus, their combination, and fecal microbiota transplantation (FMT), to determine their capacity to modulate gut microbial composition and behavior in adult Kdm5LOF flies. Gut bacterial abundance was quantified using colony-forming unit assays and full-length 16S rRNA gene sequencing. Social behavior was assessed using the social distance assay, while anxiety-like behavior and locomotion were evaluated using the open field test. Gut-specific Kdm5 knockdown was used to assess tissue-specific contributions to microbiota and behavioral phenotypes. Results: Kdm5 deficiency resulted in reduced abundance of culturable Lactobacillus, Acetobacter, and Enterobacter species, accompanied by impaired social behavior. L. plantarum supplementation restored gut microbial abundance in both whole-body Kdm5LOF and gut-specific Kdm5 knockdown models but did not significantly rescue social behavior. In contrast, L. helveticus significantly improved social interaction in Kdm5LOF flies despite minimal effects on gut bacterial abundance, revealing a dissociation between microbial restoration and behavioral outcomes. Gut-specific Kdm5 knockdown phenocopied both microbial and social defects observed in Kdm5LOF mutants. Notably, FMT from healthy donors partially restored Lactobacillus abundance, reshaped gut microbial community structure, and partially improved social behavior in Kdm5LOF recipient flies. Conclusion: Together, these findings identify Kdm5 as a key regulator of gut microbial viability and social behavior and demonstrate that microbiota-based interventions exert strain- and phenotype-specific effects. Our results reveal that restoration of microbial abundance alone is insufficient to rescue social behavior and highlight the importance of functional host-microbe interactions in gut-brain communication. This work establishes Drosophila as a tractable platform for dissecting epigenetic regulation of microbiota-behavior relationships in the context of disruption of an ASD-associated gene and for studying microbiota-based modulation of host physiology and behavior. All experiments were conducted in adult flies, and thus, these findings reflect post-developmental effects of Kdm5 disruption.
Introduction: Maternal infection (MI) can result in significant neurodevelopmental abnormalities and long-term neurological sequelae in offspring. This study was designed to investigate MI-induced alterations in synaptic protein expression, axonal morphology, dendritic, and spine morphology, and behaviour in a neonatal rat model of bacterial meningitis. Methods: On gestational day 10, pregnant rats were randomly assigned to the following groups: (1) control (Ctrl), (2) MI (pregnant rats were infected with Cronobacter sakazakii by rectovaginal colonization), (3) MI +matrix metalloproteinase inhibitor (MI+MMPI) (C. sakazakii infected pregnant rats received a MMP-9 inhibitor). Male offspring from experimental groups were examined in the novel odor recognition (NOR) test on postnatal day (PND) 15 and the tail suspension test (TST) on PND-60. Results: Offspring from the MI group were impaired in NOR and exhibited depressive behaviour during TST, whereas MI+MMPI group responses were comparable to the Ctrl group. In addition, MI upregulated the expression of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), MMP-9, and nuclear factor erythroid 2-related factor 2 (Nrf2) in their offspring. In turn, MI downregulating Na+/K+-ATPase activity, postsynaptic density protein (PSD)-95, and multiple ankyrin repeat domain protein (SHANK3) altered the conversion of mature brain-derived neurotrophic factor precursor to mature (mBDNF). Further, MI induced bending and shortening of pyramidal neuronal axon length, reduced dendritic branching complexity, and alerted dendritic and spine morphology. Treatment with MMPI minimized these MI-induced effects. Conclusion: MI can cause microstructural rearrangements in the developing brain and behavioural deficits. Our experimental model mimics the neurological sequelae of neonatal meningitis and could be useful for developing therapeutic strategies.
Introduction: The developing brain shows remarkable capacity for adaptation following early adversity, but the behaviors that influence neural compensation mechanisms remain unclear. Prenatal stress exposure provides a natural model for studying these mechanisms, as it alters neurodevelopment while allowing examination of potential protective factors. However, whether early adaptive behaviors - the skills needed to meet everyday demands such as self-care and communication - can buffer against the neural consequences of prenatal stress has not been established. Natural disasters provide a unique opportunity to examine these mechanisms, as they serve as measurable prenatal stressors with well-defined exposure timing. Methods: In this pilot study, using a quasi-experimental design, we examined children with (n = 11) and without (n = 23) prenatal exposure to Superstorm Sandy (SS) to investigate how early adaptive behavior (aged 2-6 years) moderates the association between prenatal stress (i.e., exposure to a natural disaster) and later brain activity during emotional processing (age 8 years). We first examined main effects of SS on both adaptive behaviors over time (aged 2-6 years) and functional brain activation at age 8 years in brain regions responsible for facial emotional processing. Moderation models subsequently explored whether early-life adaptive behaviors influenced the association between SS and later brain activation. The Behavior Assessment System for Children, Second Edition (BASC-2) measured child adaptive behaviors. Functional magnetic resonance imaging (fMRI) measured regional brain activation using an emotional face processing task. Results: Prenatal stress exposure was associated with nonsignificant trends toward reduced adaptive behaviors over time and reduced brain activation in the right ventral anterior insula. Critically, early adaptive behaviors moderated the association between prenatal stress and later brain activation in the left amygdala and both hemispheres of the hippocampus, ventral anterior insula, and rostral anterior cingulate cortex. Simple slope analyses revealed that prenatal stress was associated with significantly reduced brain activation at low adaptive skills. However, this association was attenuated among children that exhibited higher adaptive skills such that activation patterns were comparable to their unexposed peers. Conclusion: Our preliminary moderation (i.e., interaction) findings provide initial evidence that adaptive behaviors may serve as a neural buffer against prenatal stress. This protective pattern indicates that early adaptive skills may help maintain neural responsiveness following prenatal stress exposure. If validated in larger, adequately powered samples, interventions targeting adaptive behaviors in early childhood could potentially reduce the neural burden of prenatal stress and support more resilient brain development in at-risk populations. These findings highlight adaptive behaviors as potential targets for early intervention to promote neural resilience following prenatal adversity.
INTRODUCTION:Neonatal hypoxic-ischemic (HI) brain injury is a major cause of mortality and long-term neurological disability, yet effective neuroprotective strategies remain limited. Microglia are central mediators of injury and repair, with arginase 1 (ARG1) marking anti-inflammatory, reparative states. However, the functional roles of ARG1+ microglia in tissue remodeling after HI are poorly understood. METHODS:Neonatal mice (P10) underwent HI using the Vannucci procedure. ARG1 activity was inhibited pharmacologically using N-omega-hydroxy-nor-L-arginine (nor-NOHA). ARG1 expression, microglial morphology, efferocytosis, tissue scar, and injury volume were assessed via immunohistochemistry, Western blotting, and arginase activity assays at 1 and 5 days post-injury. RESULTS:ARG1+ microglia rapidly engaged apoptotic neurons, exhibiting phagocytic activity confirmed by CD68 expression. Nor-NOHA treatment reduced ARG1 enzymatic activity, impaired microglial process extension, attenuated efferocytosis, and increased injury volume. ARG1+ microglia persisted in the glial scar and colocalized with collagen I alpha-1 (Col1a1), suggesting a role in extracellular matrix (ECM) deposition. Inhibition of ARG1 decreased Col1a1 expression, highlighting its contribution to tissue remodeling. CONCLUSIONS:ARG1+ microglia are pivotal in neonatal HI, mediating early efferocytosis and later ECM remodeling, thereby limiting injury and shaping scar architecture. Pharmacological blockade of ARG1 exacerbates injury, underscoring its reparative function. These findings establish ARG1 as a critical regulator of microglial-mediated neuroprotection and tissue repair, providing a potential therapeutic target for neonatal HI brain injury.
INTRODUCTION:Precise regulation of neurite initiation, elongation, and branching is critical for neuronal network formation. Rac1, a key regulator of cytoskeletal remodeling, influences neurite morphogenesis through protein phosphorylation-mediated signaling, but the global phosphorylation landscape that governs Rac1-mediated morphogenesis remains unknown. METHOD:To address this knowledge gap, we performed phosphoproteomics profiling of primary rat cortical neurons treated with 3, 10, or 30 µm of a Rac1 inhibitor for 48 h to evaluate phosphoprotein dynamics. Phosphorylation levels of 167 signaling proteins were quantified using a targeted phospho-antibody array and correlated with neuron count, neurite count and length, and branch point count. RESULTS:Correlation analysis identified morphology-specific phosphoproteins, such as Tau (Thr181), GluR1 (Ser863), TrkB (Tyr515), and Merlin (Ser10), whose phosphorylation levels were significantly altered across three Rac1 inhibitor concentrations, and multiple phosphorylation sites showed dose-specific correlations with neurite morphology features. CONCLUSION:These results define a correlation-based framework linking phosphoprotein signaling to neurite morphology and offer novel insights into neurodevelopmental processes, neuronal disorders, and developmental neurotoxicity.
Introduction: The long-term neurological consequences of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, are an area of growing concern, particularly for prenatally exposed individuals. Prior research has shown that APOE4, the leading genetic risk factor for late-onset Alzheimer's disease, is associated with increased COVID-19 severity and enhanced SARS-CoV-2 neurotropism. However, whether the interaction between APOE4 and SARS-CoV-2 infection leads to adverse neurodevelopmental outcomes remains unclear. Using human induced pluripotent stem cell-derived cortical and ganglionic eminence organoids (COs and GEOs) to model neurodevelopment, we have previously reported that SARS-CoV-2 preferentially infects glial cells, and that APOE4 promotes gliogenesis in COs and accelerates GABAergic neuron differentiation in GEOs. Here, we build upon our previous work by using COs and GEOs to examine how APOE4 modifies cellular responses to SARS-CoV-2 during late gestational development. Methods: Using low viral titers to better mimic natural infection, COs and GEOs were infected at 220-270 days in vitro, aligning with the third trimester, and were analyzed 7 days post infection. Results: We observed region-specific, APOE4-dependent changes. In infected COs, APOE4 elevated immature astrocyte marker, suggesting a genotype-dependent glial response. Additionally, infected GEOs exhibited reduced marker expression for mature neurons within both genotypes. Notably, APOE4 and SARS-CoV-2 interacted to modulate immature neuron expression in a region-specific manner. Conclusion: Taken together, this study suggests that APOE4 modulates region-specific responses to low-grade SARS-CoV-2 infection, underscoring the importance of exploring how genetic risk factors alter neurodevelopmental vulnerability to prenatal viral infection.
INTRODUCTION:According to literature, early stress may lead to a higher susceptibility to the action of various stressors later in life, thus largely contributing to the development of a wide range of affective disorders. Disrupting maternal care is one way to destabilize the environment for pups, which may result in the formation of an altered reaction to acute or moderate stress. METHODS:In this study, we analyzed the effects of limited bedding and nesting material (LBN) in PND2-PND9 on baseline gene expression in the hippocampus and frontal cortex of 1-month old rats and the expression of the same genes under conditions of 60-minute restraint. Among the analyzed genes, some were associated with glucocorticoids (Nr3c1 and Nr3c2), others with the activation of the immune system (Nfkbia, Ccl2, Il1b, Il6, Tnfα, Cx3cl1, Cx3cr1, and Ncf1), and yet others with the activation of neuronal networks under stress (Cfos, Ier-2). Gene expression was assessed using real-time PCR (RT-PCR). RESULTS:Exposure to LBN during early postnatal life significantly increased baseline expression of the Fos gene in the amygdala of adolescent rats. LBN exposure more slightly affected the expression of other analyzed genes (Nr3c1, Cx3cl1, Ier2, Ncf1) or evoked alterations of their expression in this group only after exposure to acute restraint stress. The hyperglycemic response to acute restraint was attenuated in LBN-exposed animals, while corticosterone levels were comparable to controls. Among the studied genes, the expression of Nfkbia, Il6, and Tnf was primarily influenced by acute restraint stress, independently of LBN history. The amygdala and ventral hippocampus were the brain regions where the expression of the analyzed genes appeared most sensitive to the experimental manipulations. CONCLUSION:These data indicate that early-life stress induced by LBN leads to a sustained increase in baseline Fos expression in the amygdala and alters the metabolic response to acute stress in adolescence. The findings further suggest that the amygdala and ventral hippocampus are key regions where the expression of a limited set of stress-related genes is modulated by the interplay of early-life adversity and acute stress. This points to a potential role for amygdalar circuits in the altered stress reactivity observed following adverse early-life conditions.
INTRODUCTION:Neonatal rats, but not juvenile rats, show spontaneous hindlimb locomotor recovery after complete thoracic spinal cord transection (SCT). Significant increases in parvalbumin-positive proprioceptive nerve terminals are observed on motoneurons in both neonatal and juvenile rats with SCT compared with intact rats. METHODS:In the present study, we focused on Chx10-positive V2a interneurons, which partially comprise the central pattern generator, and examined parvalbumin-positive nerve terminals on Chx10 neurons and the perineuronal net formation around these neurons using Wisteria floribunda agglutinin (WFA) as a marker 2 weeks after SCT on postnatal day 5 (neonatal) or day 20 (juvenile). RESULTS:Rats with CST during the neonatal period had a significantly greater number of parvalbumin-positive terminals on Chx10 neurons compared to age-matched intact rats, whereas no significant difference was detected between rats with SCT during the juvenile period and age-matched intact rats. Chx10 neurons for which ≥50% of the circumference was surrounded by WFA were identified as WFA-positive. The proportion of WFA-positive neurons among Chx10-positive neurons did not differ significantly between neonatal SCT and age-matched intact rats, but was significantly higher in juvenile SCT and age-matched intact rats. CONCLUSION:These findings suggest that SCT promotes the formation of proprioceptive afferent terminals on Chx10-positive neurons. The significant increase in terminals following SCT in neonatal rats might facilitate spontaneous motor recovery, whereas enhanced perineuronal net formation around Chx10 neurons following juvenile SCT might restrict synaptic formation and impair motor recovery.
INTRODUCTION:We recently identified variants in 10 genes that are members of either the p53 pathway or Fanconi Anemia Complex (FAC), regulators of DNA repair (DNA damage response [DDR]) in 17 cases with pediatric acute-onset neuropsychiatric syndrome (PANS) or regression in autism spectrum disorder and other neurodevelopmental disorders (NDD). We aimed to identify additional cases with genetic vulnerabilities in DDR and related pathways. METHODS:Whole-exome sequencing (WES) and whole-genome sequencing (WGS) data from 32 individuals were filtered and analyzed to identify ultrarare pathogenic or likely pathogenic variants. RESULTS:Variants affecting DDR were found in 14 cases diagnosed with PANS or regression (CUX1, USP45, PARP14, UVSSA, EP300, TREX1, SAMHD1, STK19, MYTl1, TEP1, PIDD1, ADNP, FANCD2, and RAD54L). The CUX1 variant is de novo, as are two cases that had mutations in genes that affect mitochondrial functions that are connected directly or indirectly to mitophagy (PRKN and POLG), which can trigger the same innate immune pathways when disrupted as abnormal DDR. We also found pathogenic or likely pathogenic secondary mutations in several genes that are primarily expressed in the gut that have been implicated in gut microbiome homeostasis (e.g., LGALS4, DUOX2, CCR9). CONCLUSION:These findings align with previous genetic findings and strengthen the hypothesis that abnormal DDR and mitochondrial dysfunction underlie pathogenic processes in at least some cases of neuropsychiatric decompensation. The potential involvement of genetic variants in gut microbiome homeostasis is a novel aspect of our study. Functional characterization of the downstream impact of DDR deficits may point to novel treatment strategies.
INTRODUCTION:This study aimed to investigate trunk control, balance, and upper extremity skill quality in ambulatory children with diplegic cerebral palsy (CP) classified as Gross Motor Function Classification System (GMFCS)-I and -II, as well as to compare the GMFCS groups among themselves and with healthy children. METHODS:Twenty-five children with spastic diplegic CP (11.80 ± 2.66 years) and 30 healthy children (13.57 ± 3.48 years) were included. Functional levels were classified with the GMFCS, with 13 children classified as GMFCS-I and 12 as GMFCS-II, while trunk control was assessed with the Trunk Control Measurement Scale (TCMS), balance with the Single-Leg Stance and Four-Square Step Tests, and upper extremity functionality with the Quality of Upper Extremity Skills Test (QUEST). RESULTS:There was no significant difference in age, body mass index, or gender distribution between the CP and control groups (p > 0.05). The healthy group outperformed both CP groups in all clinical evaluations. No significant differences were found between GMFCS-I and GMFCS-II groups in the Single-Leg Stance Test, Four-Square Step Test, and QUEST parameters (p > 0.05). However, TCMS subdomains static sitting (p = 0.009), dynamic reaching (p = 0.018), selective movement control (p = 0.012), and total scores (p = 0.006) were significantly higher in the GMFCS-I group. A moderate positive correlation and a 54% regression rate were observed between the QUEST and TCMS scores. CONCLUSION:Trunk control is a key determinant of upper extremity skill quality in children with CP. Core stabilization should be prioritized to improve upper extremity functionality and manage disability levels effectively.
INTRODUCTION:Inhibitory control during visually guided reaching allows for the development of flexible problem-solving in healthy infants born at term. Inhibitory control is often impaired among older children born preterm, but the developmental trajectory of inhibitory control in infants born preterm is not well understood. The objective of this study was to evaluate the developmental trajectory of inhibitory control on the Object Retrieval Task in infants born preterm. METHODS:This was a cross-sectional study including a convenience sample of infants born preterm (less than 37 weeks), who were evaluated at corrected ages 5-6, 7-8, 9-10, 11-12, 13-15, and 16-18 months. Children born preterm with additional diagnoses of congenital anomalies, known genetic disorders, focal stroke, neoplasm, or maternal HIV exposure or children in the care of the state were excluded. Children in each of the age-groups were asked to retrieve a toy from a Plexiglas box with an opening on one side. The orientation of the opening was rotated over three trials, and the visually guided reach patterns were scored based on methods used by Diamond. Visually guided reach patterns ranged from perseverative hitting of the box to immediately reaching through the box opening. Analysis consisted of Fischer's exact tests to compare categorical measures, Jonckheere-Terpstra tests to compare ordinal measures, F test from general linear models to compare continuous measures and ordinal logistic regression to assess the association between brain injury and reach patterns. RESULTS:The majority of infants born preterm in corrected age-groups of 5-6, 7-8, and 9-10 months perseveratively hit the box regardless of the orientation of the opening. This pattern of predominant immature visually guided reaching persisted at 12 months corrected age in this cohort of infants born preterm, with 75% participants demonstrating an immature reach with the box opening at the front and to the left and 88% demonstrating this with the box opening to the right. CONCLUSIONS:In this cohort of preterm infants, developmental progression of inhibitory control and progression of visually guided reaching did not follow the same developmental trajectory observed in full term typically developing infants previously documented by Diamond (1994). While 100% of typically developing infants born at term in Diamond's cohort demonstrated inhibitory control and mature visually guided reach patterns by age 12 months, 75% of participants in our cohort of infants born preterm continued to demonstrate a predominance of immature visually guided reach patterns. This study demonstrates identification of early impairments in inhibitory control using a resource-conscious, low-cost, and brief neurobehavioral assessment tool. This provides a window for early interventions to limit problems in executive dysfunction at school age and beyond.
INTRODUCTION:Inflammatory oxidative microenvironments can alter heme oxygenase-1 (HO-1) homeostasis. Dysregulation of HO-1 favors proinflammatory signals, while transferrin receptor 1 (TfR1) regulates anti-inflammatory signal transduction. Previously, we have shown that chorioamnionitis (CHORIO) induces sustained elevations in HO-1/TfR1 at postnatal day (P)2 and mononuclear cell-driven inflammation at term age equivalent P7. Here, we hypothesized that an altered HO-1/TfR1 developmental time course would coincide with inflammatory/immune signal changes in the brain. METHODS:To induce CHORIO in rats, we performed a laparotomy followed by bilateral transient uterine artery occlusion and intra-amniotic injection of lipopolysaccharide (LPS) at E18. The control group received laparotomy only with equivalent duration of anesthesia. We used real-time polymerase chain reaction (RT-PCR), multiplex electrochemiluminescent immunoassay (MECI), and flow cytometry (FC) to study changes in pro- and anti-inflammatory gene expression, immune cell secretome, and immune cells at critical and clinically relevant timepoints following CHORIO. RESULTS:We found an acute reduction in anti-inflammatory signals in the cortex on embryonic day (E)19. This was followed by an increased proinflammatory signature on postnatal day (P)2. There were also significant alterations in the phenotypic distribution of splenic T cells on P7, a key organ in immune function. Furthermore, we showed that the microenvironment of the cortex at P21 was skewed toward a proinflammatory state by significant increases in IL-6. The prominence of T-helper cells (Th) in brain concomitant with a proinflammatory state at P21 suggests emerging inflammation and potential for neural injury. CONCLUSIONS:Defining how these and other inflammatory/immune signatures contribute to perinatal brain injury and investigating distinct immune signatures at more developmental time courses will be beneficial for targeting emerging therapies.
Introduction: Repeated use of methamphetamine (METH) is known to dysregulate the dopaminergic system and induce long-lasting changes in behavior, which may be influenced by sex and age of exposure. Catechol-o-methyltransferase (COMT) is an enzyme that is involved in the breakdown of catecholamines, and its role in dopamine clearance is thought to be especially important in the prefrontal cortex (PFC) where dopamine transporter expression is relatively scarce. Methods: The first study in this report utilized a rat model to characterize the ontogeny of COMT protein expression in the PFC and nucleus accumbens (NAc) across adolescence, which is a developmental stage that has been shown to involve significant reorganization of dopaminergic innervation. Drug-na & iuml;ve male and female Sprague-Dawley rats were sacrificed on postnatal day (P) 29, 39, 49, or 69, and expression levels of COMT protein within the PFC and NAc were analyzed via Western blot. A separate group of rats were injected daily from P40 to P48 (adolescence) or P70 to P78 (adulthood) with saline or 3.0 mg/kg METH and sacrificed on P49 or P79. Results: We found that COMT expression in the PFC increases across adolescence in a sex-dependent manner but does not significantly change in the NAc during this timeframe. While METH decreased COMT in adult rats of both sexes, METH increased COMT expression in the PFC of rats exposed in adolescence. Conclusion: The results of this work suggest that exposure to METH during adolescence uniquely effects dopamine clearance within the PFC, potentially contributing to differences in neurobiological outcomes from METH use.
Introduction. Innervation of the paraventricular nucleus of the hypothalamus (PVN) by the orexigenic agouti-related protein (AgRP) and anorexigenic α-melanocyte-stimulating hormone (α-MSH) neurons of the arcuate nucleus (ARC) is a key element in the appetite-regulating neuronal circuitry whose development is influenced by circulating metabolic signals. In the present work, we studied if PVN innervation by the AgRP and α-MSH fibers is influenced by gut microbiota. Methods. To this aim, we compared, using immunohistochemistry, the innervation of PVN by AgRP and α-MSH fibers between germ-free and specific pathogen-free 7-week-old female mice. Results. We found that germ-free mice display an increased innervation of the PVN by both AgRP and α-MSH fibers, but also that the increase in AgRP fiber density was about twice as pronounced as that of α-MSH. Conclusion. These data reveal that gut microbiota plays a modulatory role in the development of the ARC/PVN axonal projections. An imbalance between AgRP and α-MSH innervation in germ-free mice may contribute to their metabolic and behavioral alterations.
INTRODUCTION:Lysophosphatidic acid (LPA) is a bioactive phospholipid that mediates a variety of biological actions through binding to G protein-coupled receptors known as LPA receptors (LPARs). In mammals, six LPAR subtypes (LPAR1-6) have been identified. This study aimed to determine the expression of LPAR4 in the developing mouse brain. METHODS:Brains samples were prepared from mice in various stages of development and biochemical and immunohistochemical analyses were conducted using anti-LPAR4. RESULTS:Western blot analysis detected two LPAR4-immunoreactive species at ∼50 kDa and ∼42 kDa from embryonic day 16.5 (E16.5). The ∼50 kDa molecule increased during development, reaching a peak at postnatal day 3 (P3), and then gradually decreased through P22. In contrast, the ∼42 kDa molecule continued to increase up to P22. Immunohistochemical analyses demonstrated strong LPAR4 expression in neural cells in the intermediate zone and cortical plate of the E15.5 cerebral cortex, whereas neural progenitors in the ventricular and subventricular zones exhibited weaker expression. At P15, fiber-like staining resembling the apical dendrites of cortical neurons and hippocampal pyramidal cells was also observed. CONCLUSION:This study demonstrated dynamic, spatiotemporal changes of LPAR4 expression in the brain from embryonic to postnatal stages. These findings support a potential role for LPAR4 in neural development.
Introduction: The combination of prenatal alcohol exposure (PAE) and placental insufficiency (PI) places infants at an increased risk for preterm birth and may worsen brain injury and neurobehavioral outcomes. In this preclinical study, the effect of PAE + PI on lateral, medial, and ventral prefrontal cortex (PFC), striatum and corpus callosum microstructure were investigated using diffusion tensor imaging (DTI). These brain regions are important for executive and higher cognitive functions, like cognitive flexibility. Methods: Pregnant Long-Evans rat dams voluntarily drank 5% ethanol in saccharin water or plain saccharin water until embryonic day 18 (E18) to mimic moderate PAE. On E19, an open laparotomy was completed, and the uterine arteries were transiently occluded for 1 h. The dams in the sham group underwent the same procedure, but without uterine artery occlusion. Offspring are delivered normally on E22 and matured with their dams. On postnatal day 35 (P35), tissue was collected from male and female rat offspring from all four prenatal treatment groups (Sham, PAE, PI, and PAE+PI). Fixed brain tissue was then scanned ex vivo on a Bruker 11.7 T magnetic resonance imaging. Fractional anisotropy (FA) and directional diffusion were measured in regions of interest. Two-way analysis of variance with Tukey’s correction was used, with p < 0.05 significant. Results: DTI analyses of the medial PFC (n = 14–30/group) revealed a significant impact of the prenatal exposure/insult on the FA (p < 0.05), with sham having the lowest FA (0.24 ± 0.01) and PI having the highest FA (0.28 ± 0.02) as well as a lower mean diffusivity (MD; 3.32 × 10−4 ± 2.35 × 10−5 mm2/s; p < 0.01) compared to PAE (4.35 × 10−4 ± 1.47 × 10−5 mm2/s). The lateral PFC was significantly impacted by prenatal exposure/insult with sham having the highest radial diffusivity (RD; 4.97 × 10−4 ± 2.20 × 10−5 mm2/s; p < 0.05) and MD (4.41 × 10−4 ± 2.10 × 10−5 mm2/s; p < 0.05) compared to the other groups. The striatum was sensitive to the prenatal exposure/insult, with the axial diffusivity (AD), RD, and MD all significantly increased in the PAE group and decreased in the PI group (p < 0.05). In the corpus callosum, the prenatal exposure/insult significantly decreased the AD (p < 0.05; PAE+PI AD: 5.00 × 10−4 ± 4.60 × 10−5 mm2/s). Conclusion: While all areas analyzed were impacted by the prenatal insults, the striatum, which consists primarily of efferent pathways, appears more vulnerable to injury compared to the PFC. Additional studies are needed to characterize the impact this may have on function related to these critical brain regions.
