Loss-of-function variants in CSDE1 have been strongly linked to neuropsychiatric disorders, yet the precise role of CSDE1 in neurogenesis remains elusive. In this study, we demonstrate that knockout of Csde1 during cortical development in mice results in impaired neural progenitor proliferation, leading to abnormal cortical lamination and embryonic lethality. Transcriptomic analysis revealed that Csde1 upregulates the transcription of genes involved in the cell cycle network. Applying a dual thymidine-labelling approach, we further revealed prolonged cell cycle durations of neuronal progenitors in Csde1-knockout mice, with a notable extension of the G1 phase. Intersection with CLIP-seq data demonstrated that Csde1 binds to the 3' untranslated region (UTR) of mRNA transcripts encoding cell cycle genes. Particularly, we uncovered that Csde1 directly binds to the 3' UTR of mRNA transcripts encoding Cdk6, a pivotal gene in regulating the transition from the G1 to S phases of the cell cycle, thereby maintaining its stability. Collectively, this study elucidates Csde1 as a novel regulator of Cdk6, sheds new light on its critical roles in orchestrating brain development, and underscores how mutations in Csde1 may contribute to the pathogenesis of neuropsychiatric disorders.
Animals ; Neurogenesis/genetics* ; Cell Cycle/genetics* ; Mice, Knockout ; Mice ; Neural Stem Cells/metabolism* ; DNA-Binding Proteins/metabolism* ; Cyclin-Dependent Kinase 6/genetics* ; Cell Proliferation ; 3' Untranslated Regions ; Cerebral Cortex/embryology* ; RNA-Binding Proteins ; Mice, Inbred C57BL

Neuroligins (NLs) are postsynaptic cell-adhesion proteins that play important roles in synapse formation and the excitatory-inhibitory balance. They have been associated with autism in both human genetic and animal model studies, and affect synaptic connections and synaptic plasticity in several brain regions. Yet current research mainly focuses on pyramidal neurons, while the function of NLs in interneurons remains to be understood. To explore the functional difference among NLs in the subtype-specific synapse formation of both pyramidal neurons and interneurons, we performed viral-mediated shRNA knockdown of NLs in cultured rat cortical neurons and examined the synapses in the two major types of neurons. Our results showed that in both types of neurons, NL1 and NL3 were involved in excitatory synapse formation, and NL2 in GABAergic synapse formation. Interestingly, NL1 affected GABAergic synapse formation more specifically than NL3, and NL2 affected excitatory synapse density preferentially in pyramidal neurons. In summary, our results demonstrated that different NLs play distinct roles in regulating the development and balance of excitatory and inhibitory synapses in pyramidal neurons and interneurons.
Animals ; Cell Adhesion Molecules, Neuronal ; physiology ; Cells, Cultured ; Cerebral Cortex ; embryology ; physiology ; GABAergic Neurons ; physiology ; Interneurons ; physiology ; Membrane Proteins ; physiology ; Nerve Tissue Proteins ; physiology ; Protein Isoforms ; physiology ; Pyramidal Cells ; physiology ; Rats, Sprague-Dawley ; Synapses ; physiology

The expansion and folding of the cerebral cortex occur during brain development and are critical factors that influence cognitive ability and sensorimotor skills. The disruption of cortical growth and folding may cause neurological disorders, resulting in severe intellectual disability and intractable epilepsy in humans. Therefore, understanding the mechanism that regulates cortical growth and folding will be crucial in deciphering the key steps of brain development and finding new therapeutic targets for the congenital anomalies of the cerebral cortex. This review will start with a brief introduction describing the anatomy of the brain cortex, followed by a description of our understanding of the proliferation, differentiation, and migration of neural progenitors and important genes and molecules that are involved in these processes. Finally, various types of disorders that develop due to malformation of the cerebral cortex will be discussed.
Brain ; Cerebral Cortex ; Drug Resistant Epilepsy ; Embryology ; Humans ; Intellectual Disability ; Malformations of Cortical Development ; Nervous System Diseases

In the present study, we examined the effect of oxygen glucose deprivation (OGD) post-conditioning (PostC) on neural cell apoptosis in OGD-PostC model and the protective effect on primary cortical neurons against OGD injury in vitro. Four-h OGD was induced by OGD by using a specialized and humidified chamber. To initiate OGD, culture medium was replaced with de-oxygenated and glucose-free extracellular solution-Locke's medium. After OGD treatment for 4 h, cells were then allowed to recover for 6 h or 20 h. Then lactate dehydrogenase (LDH) release assay, Western blotting and flow cytometry were used to detect cell death, protein levels and apoptotic cells, respectively. For the PostC treatment, three cycles of 15-min OGD, followed by 15 min normal cultivation, were applied immediately after injurious 4-h OGD. Cells were then allowed to recover for 6 h or 20 h, and cell death was assessed by LDH release assay. Apoptotic cells were flow cytometrically evaluated after 4-h OGD, followed by re-oxygenation for 20 h (O4/R20). In addition, Western blotting was used to examine the expression of heat-shock protein 70 (HSP70), Bcl-2 and Bax. The ratio of Bcl-2 expression was (0.44±0.08)% and (0.76±0.10)%, and that of Bax expression was (0.51±0.05)% and (0.39±0.04)%, and that of HSP70 was (0.42±0.031)% and (0.72±0.045)% respectively in OGD group and PostC group. After O4/R6, the rate of neuron death in PostC group and OGD groups was (28.96±3.03)% and (37.02±4.47)%, respectively. Therefore, the PostC treatment could up-regulate the expression of HSP70 and Bcl-2, but down-regulate Bax expression. As compared with OGD group, OGD-induced neuron death and apoptosis were significantly decreased in PostC group (P<0.05). These findings suggest that PostC inhibited OGD-induced neuron death. This neuro-protective effect is likely achieved by anti-apoptotic mechanisms and is associated with over-expression of HSP70.
Animals ; Apoptosis ; drug effects ; Blotting, Western ; Cell Hypoxia ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; blood supply ; cytology ; embryology ; Flow Cytometry ; Glucose ; pharmacology ; HSP70 Heat-Shock Proteins ; metabolism ; Ischemic Postconditioning ; methods ; Neurons ; cytology ; drug effects ; metabolism ; Oxygen ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; prevention & control ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo study the insular development of small for gestational age (SGA) infants.

METHODSThe insular area and circle were measured by cerebral ultrasonography in 92 SGA infants. The results were compared with those from 109 appropriate for gestational age (AGA) infants.

RESULTSThe insular area and circle were positively correlated with the birth weight and gestational age in SGA infants. The insular area in SGA infants with a gestational age of either >37 weeks (451 +/- 92 mm2 vs 516 +/- 116 mm2; p<0.01) or < or = 34 weeks (248 +/- 78 mm2 vs 314 +/- 80 mm2; p<0.01) was significantly less than that in the AGA infants. The insular circle in SGA infants with a gestational age of >37 weeks was also significantly less than that in the AGA infants (92 +/- 11 mm vs 97 +/- 11 mm; p<0.05).

CONCLUSIONSThe insular development of SGA infants seems to be immature. The insular development may be assessed based on the insular area and circle measured by cerebral ultrasonography.

Birth Weight ; Cerebral Cortex ; embryology ; Echoencephalography ; Female ; Gestational Age ; Humans ; Infant, Newborn ; Infant, Small for Gestational Age ; Male

Bone morphogenic protein 4 (BMP4), a member of the TGF-beta superfamily, induced neural differentiation of neural stem cells (NSCs) grown in a medium containing basic fibroblast growth factor (bFGF). The Ras protein level and the activities of the downstream ERKs were increased by transfection of BMP4 or treatment with recombinant BMP4. The effects of BMP4, including activation of the Ras-ERK pathway and induction of the neuron marker beta-tubulin type III (Tuj1), were blocked by co-treatment of the BMP4 antagonist, noggin. The roles of the Ras-ERK pathway in neuronal differentiation by BMP4 were revealed by measuring the effect of the ERK pathway inhibition by dominant negative Ras or PD98059, the MEK specific inhibitor. BMP4 is a transcriptional target of Wnt/beta-catenin signaling, and both the mRNA and protein levels of BMP4 were increased by treatment of valproic acid (VPA), a chemical inhibitor of glycogen synthase kinase 3beta (GSK3beta) activating the Wnt/beta-catenin pathway. The BMP4- mimicking effects of VPA, activation of the Ras-ERK pathway and induction of Tuj1, also were blocked by noggin. These results indicate the potential therapeutic usage of VPA as a replacement for BMP4.
Animals ; Bone Morphogenetic Protein 4/genetics/*metabolism ; Cell Differentiation/drug effects ; Cells, Cultured ; Cerebral Cortex/cytology/embryology ; Extracellular Signal-Regulated MAP Kinases/*metabolism ; Neurons/*cytology ; Rats ; Rats, Sprague-Dawley ; Stem Cells/*cytology ; Up-Regulation/drug effects ; Valproic Acid/pharmacology ; beta Catenin/metabolism ; ras Proteins/genetics/metabolism

Extracellular signal-regulated kinase 1/2 (ERK1/2) pathway has been shown to be important for regulating cell proliferation and survival. The role of ERK1/2 signaling in the survival and growth of neural stem cells (NSCs) has not been addressed adequately. In this work, we aimed to provide evidence that proliferation of NSCs in vitro is controlled via ERK1/2-dependent pathway. NSCs were isolated from embryonic day 14.5 (E14.5) cortex of mouse forebrain. Cells were harvested at the desired times (1 d, 3 d and 5 d) and the total protein was extracted and analyzed by Western blot. It was observed that ERK1/2 was activated during the proliferation of NSCs. In addition, mitogen-activated protein kinase kinase (MEK) inhibitor PD98059, which directly prohibited ERK1/2 phosphorylation, inhibited the formation of neurospheres, and this inhibitory effect was dose-dependent. After treatment with 20 mumol/L PD98059, the growth of NSCs was also inhibited with time-dependence. These data indicate that ERK1/2 is essential for the proliferation of NSCs derived from mouse embryonic cortex.
Animals ; Cell Proliferation ; Cerebral Cortex ; cytology ; embryology ; Flavonoids ; pharmacology ; Mice ; Mitogen-Activated Protein Kinase 3 ; physiology ; Neural Stem Cells ; cytology ; Phosphorylation ; Protein Kinase Inhibitors ; pharmacology

Cytoplasmic Cu/Zn superoxide dismutase (SOD1) is an antioxidant enzyme that converts superoxide to hydrogen peroxide in cells. Its spatial distribution matches that of superoxide production, allowing it to protect cells from oxidative stress. SOD1 deficiencies result in embryonic lethality and a wide range of pathologies in mice, but little is known about normal SOD1 protein expression in developing embryos. In this study, the expression pattern of SOD1 was investigated in post-implantation mouse embryos and extraembryonic tissues, including placenta, using Western blotting and immunohistochemical analyses. SOD1 was detected in embryos and extraembryonic tissues from embryonic day (ED) 8.5 to 18.5. The signal in embryos was observed at the lowest level on ED 9.5-11.5, and the highest level on ED 17.5-18.5, while levels remained constant in the surrounding extraembryonic tissues during all developmental stages examined. Immunohistochemical analysis of SOD1 expression on ED 13.5-18.5 revealed its ubiquitous distribution throughout developing organs. In particular, high levels of SOD1 expression were observed in the ependymal epithelium of the choroid plexus, ganglia, sensory cells of the olfactory and vestibulocochlear epithelia, blood cells and vessels, hepatocytes and hematopoietic cells of the liver, lymph nodes, osteogenic tissues, and skin. Thus, SOD1 is highly expressed at late stages of embryonic development in a cell- and tissue-specific manner, and can function as an important antioxidant enzyme during organogenesis in mouse embryos.
Animals ; Cerebral Cortex/embryology/enzymology ; Copulation ; Cytoplasm/*enzymology ; Embryonic Development/*physiology ; Female ; Immunohistochemistry ; Lung/embryology/enzymology ; Male ; Mice ; Mice, Inbred ICR ; Organogenesis/*physiology ; Pregnancy ; Stomach/embryology/enzymology ; Superoxide Dismutase/deficiency/genetics/*metabolism

OBJECTIVETo investigate the protective effects of icaritin (ICT) on apoptosis of primarily cultured rat neurons induced by Abeta(25-35) peptide and its mechanism.

METHODSCortical neurons from rat embryonic cortical on d17 pregnancy were cultured in neural basal medium for 7 days. Icaritin (ICT) was pre-incubated for 24 h before adding Abeta(25-35) peptide and then the cells were incubated for 72 h. Neuroprotective effects of ICT were evaluated by MTT assay, LDH level in medium and cell morphological observation. Meanwhile, apoptosis was determined by JC-1 staining for mitochondria membrane potential (DeltaPsim) and AO/EB double staining for genetic damage of nucleoli in monolayer cells.

RESULTS0.1 micromol.L(-1) ICT pre-incubation for 24 h prevented rat neurons from Abeta(25-35) peptide induced apoptosis significantly as demonstrated by MTT, LDH assay and morphological observation. AO/EB double staining also indicated that ICT prevented neurons from apoptosis. JC-1 staining further showed that ICT prevented decreasing of mitochondrial DeltaPsim induced by Abeta(25-35) peptide.

CONCLUSIONICT could protect primarily cultured rat neurons from Abeta(25-35) peptide induced apoptosis.

Amyloid beta-Peptides ; toxicity ; Animals ; Apoptosis ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; embryology ; Drugs, Chinese Herbal ; pharmacology ; Flavonoids ; pharmacology ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study cortical neuron injury following recurrent epileptiform discharges induced by magnesium-free treatment in vitro.

METHODSCultured embryo cortical neurons were exposed to magnesium-free media for 3 h, then they were returned to regular media containing normal level magnesium. At different time after Mg(2+)-free treatment, trypan blue staining and determination of LDH activity were used to determine the cell viability, flow cytometry was applied to measure neuronal apoptosis, and MTT assay to study metabolic rate.

RESULTS(1) Neuronal morphology on light microscopy following Mg(2+)-free treatment showed that there were no prominent alterations. (2) At different time (6, 12, 72 h) after Mg(2+)-free treatment, neuronal viability by trypan blue staining and LDH activity showed modest changes compared with time-matched control in different culture days (6, 12, 17 d) (P > 0.05). (3) Cell apoptosis increased mildly at different time after Mg(2+)-free treatment in neurons cultured for different days, but the increase was not significant (P > 0.05). (4) Metabolic rate decreased at 6 h after Mg(2+)-free treatment (P < 0.05) in neurons cultured for 6 d, and was 86.4% of that of the control; while the rate at 24 h in neurons cultured for 12 d and 17 d also decreased (P < 0.05), being 78.7% and 70.9%, respectively, of that of the control.

CONCLUSIONSThese findings demonstrated that the injury occurred on cultured cortical neurons caused by magnesium-free-treatment-induced recurrent epileptiform discharges was mainly functional and relatively mature neurons displayed more severe and much later mitochondrial function impairment than immature neurons.

Animals ; Cerebral Cortex ; embryology ; Culture Media ; chemistry ; pharmacology ; Culture Techniques ; Magnesium ; pharmacology ; Neurons ; drug effects ; pathology ; Rats ; Rats, Wistar ; Seizures ; physiopathology