Early Central Nervous System Development Research Articles

Neural System Impairment and Involved Microglia-Neuron Regulation of Broflanilide in Zebrafish Larvae.

Broflanilide is widely used to control pests and has attracted attention due to its adverse effects on aquatic organisms. Our previous study showed that broflanilide has a negative impact on the central nervous system (CNS) at lethal dosages; however, its neural effects under practical situations and the underlying mechanisms remain unknown. To elucidate how broflanilide affects the CNS, we exposed zebrafish larvae to broflanilide at 16.9 and 88.0 μg/L (the environmentally relevant concentrations) for 120 h. Zebrafish locomotion was significantly disturbed at 88.0 μg/L, with a decreased moving distance and velocity accompanied by an inhibited neurotransmitter level. In vivo neuroimaging analysis indicated that the nerves of zebrafish larvae, including the axons, myelin sheaths, and neurons, were impaired. The number of neurons was significantly reduced after exposure, with an impaired morphological structure. These changes were accompanied by the abnormal transcription of genes involved in early CNS development. In addition, an increased total number of microglia and an elevated proportion of amoeboid microglia were observed after 88.0 μg/L broflanilide exposure, pointing out to an upstream role of microglia activation in mediating broflanilide neurotoxicity. Meanwhile, increased inflammatory cytokine levels and brain neutrophil numbers were observed, implicating significant inflammatory response and immune toxicity. Our findings indicate that broflanilide interferes with microglia-neuron regulation and induces neurodevelopmental disorders.

Improving the protective ability of lignin against vascular and neurological development in BPAF-induced zebrafish by high-pressure homogenization technology

The lack of a sufficient amount of functional groups in the lignin structure limits its bioapplication. In this work, high-pressure homogenization was performed on original kraft lignin (L-ORI) to prepare lignin nanoparticles (L-NANO), which aimed to improve its functional group contents for further vascular and neurological applications. The results showed that the prepared L-NANO possessed spherical structures with diameters of 40.3–160.4 nm and increased amount of hydroxyl groups. Compared to L-ORI, L-NANO possessed better in vivo and in vitro antioxidant capacity, which could endow it with enhanced protective effects for the vascular and neural development of bisphenol AF (BPAF)-induced zebrafish. In addition, L-NANO reduced the neurotoxicity and cardiovascular toxicity of BPAF in zebrafish by upregulating the expression levels of oxidative stress-related genes (Cu/Zn-Sod and cat), which could further significantly upregulate the expression levels of neurogenesis genes (elavl3, gap43, mbp, and syn2a) and protect the contraction of the cardinal vein (CCV) and early central nervous system development by upregulating the expression levels of vascular genes (flk1 and flt4). The excellent cardiovascular and neurodevelopmental protective ability of L-NANO indicated that high-pressure homogenization is a promising technology for improving the bioactivity of lignin.

Pleiotrophin Signals Through ALK Receptor to Enhance the Growth of Neurons in the Presence of Inhibitory Chondroitin Sulfate Proteoglycans.

Chondroitin sulfate proteoglycans (CSPGs), one of the major extracellular matrix components of the glial scar that surrounds central nervous system (CNS) injuries, are known to inhibit the regeneration of neurons. This study investigated whether pleiotrophin (PTN), a growth factor upregulated during early CNS development, can overcome the inhibition mediated by CSPGs and promote the neurite outgrowth of neurons in vitro. The data showed that a CSPG matrix inhibited the outgrowth of neurites in primary cortical neuron cultures compared to a control matrix. PTN elicited a dose-dependent increase in the neurite outgrowth even in the presence of the growth inhibitory CSPG matrix, with optimal growth at 15 ng mL-1 of PTN (114.8% of neuronal outgrowth relative to laminin control). The growth-promoting effect of PTN was blocked by inhibition of the receptor anaplastic lymphoma kinase (ALK) by alectinib in a dose-dependent manner. Neurite outgrowth in the presence of this CSPG matrix was induced by activation of the protein kinase B (AKT) pathway, a key downstream mediator of ALK activation. This study identified PTN as a dose-dependent regulator of neurite outgrowth in primary cortical neurons cultured in the presence of a CSPG matrix and identified ALK activation as a key driver of PTN-induced growth.

Pairwise genetic meta-analyses between schizophrenia and substance dependence phenotypes reveals novel association signals with pharmacological significance

Almost half of individuals diagnosed with schizophrenia also present with a substance use disorder, however, little is known about potential molecular mechanisms underlying this comorbidity. We used genetic analyses to enhance our understanding of the molecular overlap between these conditions. Our analyses revealed a positive genetic correlation between schizophrenia and the following dependence phenotypes: alcohol (rg = 0.368, SE = 0.076, P = 1.61 × 10−6), cannabis use disorder (rg = 0.309, SE = 0.033, P = 1.97 × 10−20) and nicotine (rg = 0.117, SE = 0.043, P = 7.0 × 10−3), as well as drinks per week (rg = 0.087, SE = 0.021, P = 6.36 × 10−5), cigarettes per day (rg = 0.11, SE = 0.024, P = 4.93 × 10−6) and life-time cannabis use (rg = 0.234, SE = 0.029, P = 3.74 × 10−15). We further constructed latent causal variable (LCV) models to test for partial genetic causality and found evidence for a potential causal relationship between alcohol dependence and schizophrenia (GCP = 0.6, SE = 0.22, P = 1.6 × 10−3). This putative causal effect with schizophrenia was not seen using a continuous phenotype of drinks consumed per week, suggesting that distinct molecular mechanisms underlying dependence are involved in the relationship between alcohol and schizophrenia. To localise the specific genetic overlap between schizophrenia and substance use disorders (SUDs), we conducted a gene-based and gene-set pairwise meta-analysis between schizophrenia and each of the four individual substance dependence phenotypes in up to 790,806 individuals. These bivariate meta-analyses identified 44 associations not observed in the individual GWAS, including five shared genes that play a key role in early central nervous system development. The results from this study further supports the existence of underlying shared biology that drives the overlap in substance dependence in schizophrenia, including specific biological systems related to metabolism and neuronal function.

Cerebral Organoids Maintain the Expression of Neural Stem Cell-Associated Glycoepitopes and Extracellular Matrix

During development, the nervous system with its highly specialized cell types forms from a pool of relatively uniform stem cells. This orchestrated process requires tight regulation. The extracellular matrix (ECM) is a complex network rich in signaling molecules, and therefore, of interest in this context. Distinct carbohydrate structures, bound to ECM molecules like Tenascin C (TNC), are associated with neural stem/progenitor cells. We have analyzed the expression patterns of the LewisX (LeX) trisaccharide motif and of the sulfation-dependent DSD-1 chondroitin sulfate glycosaminoglycan epitope in human cerebral organoids, a 3D model for early central nervous system (CNS) development, immunohistochemically. In early organoids we observed distinct expression patterns of the glycoepitopes, associated with rosette-like structures that resemble the neural tube in vitro: Terminal LeX motifs, recognized by the monoclonal antibody (mAb) 487LeX, were enriched in the lumen and at the outer border of neural rosettes. In contrast, internal LeX motif repeats detected with mAb 5750LeX were concentrated near the lumen. The DSD-1 epitope, labeled with mAb 473HD, was detectable at rosette borders and in adjacent cells. The epitope expression was maintained in older organoids but appeared more diffuse. The differential glycoepitope expression suggests a specific function in the developing human CNS.

Modulation of retinoid-X-receptors differentially regulates expression of apolipoprotein genes apoc1 and apoeb by zebrafish microglia.

ABSTRACTTranscriptome analyses performed in both human and zebrafish indicate strong expression of Apoe and Apoc1 by microglia. Apoe expression by microglia is well appreciated, but Apoc1 expression has not been well-examined. PPAR/RXR and LXR/RXR receptors appear to regulate expression of the apolipoprotein gene cluster in macrophages, but a similar role in microglia in vivo has not been studied. Here, we characterized microglial expression of apoc1 in the zebrafish central nervous system (CNS) in situ and demonstrate that in the CNS, apoc1 expression is unique to microglia. We then examined the effects of PPAR/RXR and LXR/RXR modulation on microglial expression of apoc1 and apoeb during early CNS development using a pharmacological approach. Changes in apoc1 and apoeb transcripts in response to pharmacological modulation were quantified by RT-qPCR in whole heads, and in individual microglia using hybridization chain reaction (HCR) in situ hybridization. We found that expression of apoc1 and apoeb by microglia were differentially regulated by LXR/RXR and PPAR/RXR modulating compounds, respectively, during development. Our results also suggest RXR receptors could be involved in endogenous induction of apoc1 expression by microglia. Collectively, our work supports the use of zebrafish to better understand regulation and function of these apolipoproteins in the CNS.

ChHDAC11 mRNA Expression During Prenatal and Postnatal Chicken (Gallus gallus) Brain Development

Background: Histone deacetylation plays an essential role in transcriptional regulation of cell cycle progression and other evolutionary processes. Several results confirm the importance of the latest found HDAC11 gene to deacetylate histone core in neurons and their supportive cells in developing the vertebrate Central Nervous System (CNS). Objectives: This study investigates the HDAC11 potential role in early chicken CNS development by studying its mRNA expression profile which may have unique means in studying human subjects. Materials & Methods: Chicken HDAC11 RNAs were reverse transcribed to cDNAs, and the amount of chHDAC11 transcripts was measured by ΔCT mean calculation using the real-time quantitative PCR method. One-way ANOVA and Duncan’s analysis (SigmaStat software version 4.0) were used to test the statistical significance of the results. The levels of significance were set at P≤0.05. Quantitative data are presented as Mean±SD. Results: The amount of HDAC11 mRNAs gradually increases, at least 2-3 times, from as early as day 14 (E14/HH40) of prenatal cortex formation to day P0 (E20=HH45) and continue to increase to day 40 in both cortical and hippocampal regions of the postnatal chicken brain during development (*P≤0.05). HDAC11 mRNA is not only expressed in the postnatal cortex and hippocampi regions but also—for the first time—in the developing brain during the prenatal period. Conclusion: Our results show a possibly important role for the latest found HDAC11 conserved gene in the development of vertebrates’ embryonic brain, which in turn may have a significant impact on understanding human brain development.

Id2 and Id4 are not the major negative regulators of oligodendrocyte differentiation during early central nervous system development.

Myelin sheathes ensure the rapid conduction of neural impulse and provide nutritional support for neurons. Myelin sheathes are formed by differentiated oligodendrocytes (OLs) in the central nervous system. During OL development, the differentiation of oligodendrocyte progenitor cells (OPCs) into mature OLs is controlled by both positive differentiation factors (drivers) and negative regulatory factors (brakes). Previous studies have suggested Id2 and Id4 as the key negative factors for OL differentiation. However, these conclusions were mainly based on in vitro studies and the reported OL phenotype in Id4 mutants appear to be mild. In this study, we systematically investigated the in vivo function of Id2 and Id4 genes in OL differentiation in their genetic mutants and in embryonic chicken spinal cord. Our results showed that disruption of Id4 has no effect on OL differentiation and maturation, whereas Id2 mutants and Id2/Id4 compound mutants display a mild and transient precocity of OL differentiation. In agreement with these loss-of-function studies, Id2, but not Id4, is weakly expressed in OPCs. Despite their minor roles in OL differentiation, forced expression of Id2 and Id4 in embryonic chicken spinal cords strongly inhibit the differentiation of OPCs. Taken together, our detailed functional and expressional studies strongly suggest that Id2 and Id4 are not the major in vivo repressors of OPC differentiation during animal development, shedding new light on the molecular regulation of early OL development.

Sonic Hedgehog Signaling Agonist (SAG) Triggers BDNF Secretion and Promotes the Maturation of GABAergic Networks in the Postnatal Rat Hippocampus.

Sonic hedgehog (Shh) signaling plays critical roles during early central nervous system development, such as neural cell proliferation, patterning of the neural tube and neuronal differentiation. While Shh signaling is still present in the postnatal brain, the roles it may play are, however, largely unknown. In particular, Shh signaling components are found at the synaptic junction in the maturing hippocampus during the first two postnatal weeks. This period is characterized by the presence of ongoing spontaneous synaptic activity at the cellular and network levels thought to play important roles in the onset of neuronal circuit formation and synaptic plasticity. Here, we demonstrate that non-canonical Shh signaling increases the frequency of the synchronized electrical activity called Giant Depolarizing Potentials (GDP) and enhances spontaneous GABA post-synaptic currents in the rodent hippocampus during the early postnatal period. This effect is mediated specifically through the Shh co-receptor Smoothened via intracellular Ca2+ signal and the activation of the BDNF-TrkB signaling pathway. Given the importance of these spontaneous events on neuronal network maturation and refinement, this study opens new perspectives for Shh signaling on the control of early stages of postnatal brain maturation and physiology.

Inferring Regulatory Programs Governing Region Specificity of Neuroepithelial Stem Cells during Early Hindbrain and Spinal Cord Development.

Neuroepithelial stem cells (NSC) from different anatomical regions of the embryonic neural tube's rostrocaudal axis can differentiate into diverse central nervous system tissues, but the transcriptional regulatory networks governing these processes are incompletely understood. Here, we measure region-specific NSC gene expression along the rostrocaudal axis in a human pluripotent stem cell model of early central nervous system development over a 72-h time course, spanning the hindbrain to cervical spinal cord. We introduce Escarole, a probabilistic clustering algorithm for non-stationary time series, and combine it with prior-based regulatory network inference to identify genes that are regulated dynamically and predict their upstream regulators. We identify known regulators of patterning and neural development, including the HOX genes, and predict a direct regulatory connection between the transcription factor POU3F2 and target gene STMN2. We demonstrate that POU3F2 is required for expression of STMN2, suggesting that this regulatory connection is important for region specificity of NSCs.

Contactins in the central nervous system: role in health and disease.

Contactins are a group of cell adhesion molecules that are mainly expressed in the brain and play pivotal roles in the organization of axonal domains, axonal guidance, neuritogenesis, neuronal development, synapse formation and plasticity, axo-glia interactions and neural regeneration. Contactins comprise a family of six members. Their absence leads to malformed axons and impaired nerve conduction. Contactin mediated protein complex formation is critical for the organization of the axon in early central nervous system development. Mutations and differential expression of contactins have been identified in neuro-developmental or neurological disorders. Taken together, contactins are extensively studied in the context of nervous system development. This review summarizes the physiological roles of all six members of the Contactin family in neurodevelopment as well as their involvement in neurological/neurodevelopmental disorders.

Maternal Cannabinoid Use Alters Cannabinoid (CB1) and Endothelin (ETB) Receptor Expression in the Brains of Dams but Not Their Offspring

According to the 2015 National Survey on Drug Use and Health, cannabis (marijuana) is the most commonly used recreational drug in the US. Among pregnant women aged 14-55 years, 3.4% were cannabis users. Presently, little is known about the neurodevelopmental effect of cannabis use during pregnancy and/or nursing on neonates. Endothelin (ET) is essential for normal development of the central nervous system (CNS). Decreases in ET_B receptor expression correlate with a decline in nerve growth factor (NGF) and an increase in vascular endothelial growth factor (VEGF) in postnatal brain. Activation of ET_B and cannabinoid 1 (CB₁) receptors each promote neurogenesis and enhance angiogenesis, indicating that both ET and CB systems play a critical role during early CNS development. Hence the purpose of this study was to determine whether maternal CB abuse during pregnancy and lactation alters the expression of ET_B receptors, CB₁ receptors, VEGF, and NGF in the postnatal rat brain. Sixteen pregnant Sprague-Dawley rats were administered either saline or anandamide (AEA) at a dose of 3 mg/kg/day i.p. from gestational day 7 and continued through weaning on postnatal day (PND) 21. Rat pups were subdivided into 4 subgroups and sacrificed on PND 2, 7, 14, and 28. Brain tissue of the pups and dams (sacrificed on PND 21) was analyzed via Western blot for the expression of ET_B receptors, CB₁ receptors, VEGF, and NGF. AEA-exposed dams had significantly fewer live births (p = 0.027), and their pups presented with significantly lower body weights on PND 7 (p = 0.013) and PND 28 (p = 0.018). There was no significant difference noted in ET_B receptor, CB₁ receptor, NGF, or VEGF expression in the pup brains. In all pups, brain ET_B receptor expression decreased and CB₁ receptor expression increased with age. In the AEA-exposed dam brain, however, there was a decrease in ET_B receptor (p = 0.043) and an increase in CB₁ receptor expression (p = 0.033). AEA exposure during pregnancy appears to affect fetal viability and postnatal weight gain in offspring while not altering the expression patterns of ET_B receptors, CB₁ receptors, NGF, or VEGF in the pup brain. The observed trend to an increase in CB₁ receptor expression concurrent with a decrease in ET_B receptor expression in both dams and pups may point to a homeostatic regulation between these 2 systems in CNS development and neuroprotection.

α2-glycine receptors modulate adult hippocampal neurogenesis and spatial memory.

The α2-glycine receptors (GlyRs) play important roles during early central nervous system development. However, these receptors' possible involvement in neurodevelopmental events occurring in the adult brain remains to be explored. Adult hippocampal neurogenesis (AHN) is the process by which new granule cell neurons are added to the dentate gyrus (DG) throughout adulthood. In this study, we observed that hippocampal adult neural stem cells (ANSCs) express α2-containing GlyRs. Pharmacological inhibition of GlyRs by strychnine or picrotoxin decreased the proliferation of ANSCs, both in vivo and in vitro. Mice knockout for glra2, the gene coding for the GlyR α2 subunit, were determined to display impaired AHN, and this phenomenon was accompanied by deficits in spatial memory. These results, which reveal neurodevelopmental roles for α2-GlyRs in the adult brain, may be clinically relevant, given that a mutation in GLAR2, as well as AHN impairments, have been reported in autism spectrum disorder. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1430-1441, 2017.

Nicotinamide alone accelerates the conversion of mouse embryonic stem cells into mature neuronal populations.

IntroductionVitamin B3 has been shown to play an important role during embryogenesis. Specifically, there is growing evidence that nicotinamide, the biologically active form of vitamin B3, plays a critical role as a morphogen in the differentiation of stem cells to mature cell phenotypes, including those of the central nervous system (CNS). Detailed knowledge of the action of small molecules during neuronal differentiation is not only critical for uncovering mechanisms underlying lineage-specification, but also to establish more effective differentiation protocols to obtain clinically relevant cells for regenerative therapies for neurodegenerative conditions such as Huntington’s disease (HD). Thus, this study aimed to investigate the potential of nicotinamide to promote the conversion of stem cells to mature CNS neurons.MethodsNicotinamide was applied to differentiating mouse embryonic stem cells (mESC; Sox1GFP knock-in 46C cell line) during their conversion towards a neural fate. Cells were assessed for changes in their proliferation, differentiation and maturation; using immunocytochemistry and morphometric analysis methods.ResultsResults presented indicate that 10 mM nicotinamide, when added at the initial stages of differentiation, promoted accelerated progression of ESCs to a neural lineage in adherent monolayer cultures. By 14 days in vitro (DIV), early exposure to nicotinamide was shown to increase the numbers of differentiated βIII-tubulin-positive neurons. Nicotinamide decreased the proportion of pluripotent stem cells, concomitantly increasing numbers of neural progenitors at 4 DIV. These progenitors then underwent rapid conversion to neurons, observed by a reduction in Sox 1 expression and decreased numbers of neural progenitors in the cultures at 14 DIV. Furthermore, GABAergic neurons generated in the presence of nicotinamide showed increased maturity and complexity of neurites at 14 DIV. Therefore, addition of nicotinamide alone caused an accelerated passage of pluripotent cells through lineage specification and further to non-dividing mature neurons.ConclusionsOur results show that, within an optimal dose range, nicotinamide is able to singly and selectively direct the conversion of embryonic stem cells to mature neurons, and therefore may be a critical factor for normal brain development, thus supporting previous evidence of the fundamental role of vitamins and their metabolites during early CNS development. In addition, nicotinamide may offer a simple effective supplement to enhance the conversion of stem cells to clinically relevant neurons.

Spontaneous Activity Characteristics of 3D “Optonets”

Sporadic spontaneous network activity emerges during early central nervous system (CNS) development and, as the number of neuronal connections rises, the maturing network displays diverse and complex activity, including various types of synchronized patterns. These activity patterns have major implications on both basic research and the study of neurological disorders, and their interplay with network morphology tightly correlates with developmental events such as neuronal differentiation, migration and establishment of neurotransmitter phenotypes. Although 2D neural cultures models have provided important insights into network activity patterns, these cultures fail to mimic the complex 3D architecture of natural CNS neural networks and its consequences on connectivity and activity. A 3D in-vitro model mimicking early network development while enabling cellular-resolution observations, could thus significantly advance our understanding of the activity characteristics in the developing CNS. Here, we longitudinally studied the spontaneous activity patterns of developing 3D in-vitro neural network “optonets,” an optically-accessible bioengineered CNS model with multiple cortex-like characteristics. Optonet activity was observed using the genetically encodable calcium indicator GCaMP6m and a 3D imaging solution based on a standard epi-fluorescence microscope equipped with a piezo-electric z-stage and image processing-based deconvolution. Our results show that activity patterns become more complex as the network matures, gradually exhibiting longer-duration events. This report characterizes the patterns over time, and discusses how environmental changes affect the activity patterns. The relatively high degree of similarity between the network's spontaneously generated activity patterns and the reported characteristics of in-vivo activity, suggests that this is a compelling model system for brain-in-a chip research.

Reconstruction of the gene regulatory network involved in the sonic hedgehog pathway with a potential role in early development of the mouse brain.

The Sonic hedgehog (Shh) signaling pathway is crucial for pattern formation in early central nervous system development. By systematically analyzing high-throughput in situ hybridization data of E11.5 mouse brain, we found that Shh and its receptor Ptch1 define two adjacent mutually exclusive gene expression domains: Shh+Ptch1− and Shh−Ptch1+. These two domains are associated respectively with Foxa2 and Gata3, two transcription factors that play key roles in specifying them. Gata3 ChIP-seq experiments and RNA-seq assays on Gata3-knockdown cells revealed that Gata3 up-regulates the genes that are enriched in the Shh−Ptch1+ domain. Important Gata3 targets include Slit2 and Slit3, which are involved in the process of axon guidance, as well as Slc18a1, Th and Qdpr, which are associated with neurotransmitter synthesis and release. By contrast, Foxa2 both up-regulates the genes expressed in the Shh+Ptch1− domain and down-regulates the genes characteristic of the Shh−Ptch1+ domain. From these and other data, we were able to reconstruct a gene regulatory network governing both domains. Our work provides the first genome-wide characterization of the gene regulatory network involved in the Shh pathway that underlies pattern formation in the early mouse brain.

Moderate alcohol exposure during early brain development increases stimulus‐response habits in adulthood

Exposure to alcohol during early central nervous system development has been shown variously to affect aspects of physiological and behavioural development. In extreme cases, this can extend to craniofacial defects, severe developmental delay and mental retardation. At more moderate levels, subtle differences in brain morphology and behaviour have been observed. One clear effect of developmental alcohol exposure is an increase in the propensity to develop alcoholism and other addictions. The mechanisms by which this occurs, however, are not currently understood. In this study, we tested the hypothesis that adult zebrafish chronically exposed to moderate levels of ethanol during early brain ontogenesis would show an increase in conditioned place preference for alcohol and an increased propensity towards habit formation, a key component of drug addiction in humans. We found support for both of these hypotheses and found that the exposed fish had changes in mRNA expression patterns for dopamine receptor, nicotinic acetylcholine receptor and μ-opioid receptor encoding genes. Collectively, these data show an explicit link between the increased proclivity for addiction and addiction-related behaviour following exposure to ethanol during early brain development and alterations in the neural circuits underlying habit learning.

High‐resolution genomic copy number profiling of primary intraocular lymphoma by single nucleotide polymorphism microarrays

Primary intraocular lymphoma (PIOL) is a rare lymphoma. Because of difficulties in obtaining tissue samples, little is known about the disease's genetic features. In order to clarify these features, we carried out single nucleotide polymorphism array karyotyping of IOL using genomic DNA extracted from vitreous fluid. We analyzed 33 samples of IOLs consisting of 16 PIOLs, 12 IOLs with a central nervous system (CNS) lesion at diagnosis (IOCNSL), and five secondary IOLs following systemic lymphoma. All were B-cell type. We identified recurrent copy number (CN) gain regions in PIOLs, most frequently on chromosome 1q followed by 18q and 19q. Chromosome 6q was the most frequent loss region. Although these CN gain regions of PIOL were in common with those of IOCNSL, loss of 6q22.33 containing PTPRK and 9p21.3 containing CDKN2A were more frequently deleted in IOCNSL. Large CN loss in 6q was detected in three of four PIOL patients who had early CNS development and short survival periods, whereas long-term survivors did not have such deletions. There was a correlation between gain of the IL-10 gene located on 1q and intravitreal interleukin-10 concentration, which was higher in IOL than in benign uveitis. The results suggest that IOCNSL is a highly malignant form of PIOL that infiltrates into the CNS at an early stage. They also indicate that genetic differences between PIOL and primary CNS lymphoma need to be clarified.

Effect of severe neonatal seizures on prepulse inhibition and hippocampal volume of rats tested in early adulthood

Several lines of evidence indicate that the risk of developing schizophrenia is significantly enhanced following postnatal exposure to environmental insults occurring during the critical periods of early central nervous system development. The hippocampus is a brain structure that has been associated with the neuropathology of schizophrenia. Neonatal epileptic seizures in rat pups can affect the construction of hippocampal networks. Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). The aim of the present study was to investigate if prolonged epileptic seizures, occurring during postnatal brain development, alter prepulse inhibition (PPI) response of acoustic startle reflex and hippocampal volume of rats tested later in life (post-pubertal phase). Pilocarpine-induced status epilepticus (SE) was induced in postnatal days (PNDs) 7–9 in rat pups. On PND56, the animals were tested in the acoustic startle/PPI paradigm. Hippocampal volume was measured in histological brain slices using the Cavalieri's principle. Dorsal and ventral hippocampi were measured bilaterally. Our results demonstrate that animals subjected to SE presented deficits in PPI when tested in adulthood. Dorsal hippocampal volume was reduced in rats that experienced severe neonatal seizures.

Expression and Functional Characterization of Xhmg-at-hook Genes in Xenopus laevis

High Mobility Group A proteins (HMGA1 and HMGA2) are architectural nuclear factors involved in development, cell differentiation, and cancer formation and progression. Here we report the cloning, developmental expression and functional analysis of a new multi-AT-hook factor in Xenopus laevis (XHMG-AT-hook) that exists in three different isoforms. Xhmg-at-hook1 and 3 isoforms, but not isoform 2, are expressed throughout the entire development of Xenopus, both in the maternal and zygotic phase. Localized transcripts are present in the animal pole in the early maternal phase; during the zygotic phase, mRNA can be detected in the developing central nervous system (CNS), including the eye, and in the neural crest. We show evidence that XHMG-AT-hook proteins differ from typical HMGA proteins in terms of their properties in DNA binding and in protein/protein interaction. Finally, we provide evidence that they are involved in early CNS development and in neural crest differentiation.