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Background: Glioblastoma represents the most frequently diagnosed malignant neoplasm within the central nervous system. Human glioblastoma cells can be phenotypically reprogrammed into neuron-like cells through the forced expression of NEUROG2 and SOXC factors. NEUROG2 serves as a pioneer factor, establishing an initial framework for this transformation. However, the specific role of SOXC factors has not been fully elucidated., Methods: In this study, we used ChIP-seq to determine the potential target gene of NGN2. RNA-seq has been used to evaluate the transcriptional change during NGN2-SOX11-mediated neuron reprogramming. Immunofluorescence was used to determine the neuron reprogramming efficacy and cell proliferation ability. ChIP-qPCR, Co-IP, and Western Blot were performed to investigate the mechanism., Results: Our findings reveal that SOXC factors, in contrast to their previously identified function as transcriptional activators, act as transcriptional repressors. They achieve this by recruiting TRIM28 to suppress the expression of ECT2, a RhoGEF. This suppression results in the differential regulation of RhoA, RAC1, and CDC42 activities throughout the reprogramming process. We further establish that small molecules targeting RhoA and its effectors can substitute for SOXC factors in facilitating the neuronal reprogramming of glioblastoma cells., Conclusion: These results underscore the pivotal role of SOXC factors' transcriptional repression and illuminate one of their specific downstream targets., (© 2024 The Author(s). CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

K V channel-interacting proteins (KChIP1-4) belong to a family of Ca 2+ -binding EF-hand proteins that are able to bind to the N-terminus of the K V 4 channel α-subunits. KChIPs are predominantly expressed in the brain and heart, where they contribute to the maintenance of the excitability of neurons and cardiomyocytes by modulating the fast inactivating-K V 4 currents. As the auxiliary subunit, KChIPs are critically involved in regulating the surface protein expression and gating properties of K V 4 channels. Mechanistically, KChIP1, KChIP2, and KChIP3 promote the translocation of K V 4 channels to the cell membrane, accelerate voltage-dependent activation, and slow the recovery rate of inactivation, which increases K V 4 currents. By contrast, KChIP4 suppresses K V 4 trafficking and eliminates the fast inactivation of K V 4 currents. In the heart, I Ks , I Ca,L , and I Na can also be regulated by KChIPs. I Ca,L and I Na are positively regulated by KChIP2, whereas I Ks is negatively regulated by KChIP2. Interestingly, KChIP3 is also known as downstream regulatory element antagonist modulator (DREAM) because it can bind directly to the downstream regulatory element (DRE) on the promoters of target genes that are implicated in the regulation of pain, memory, endocrine, immune, and inflammatory reactions. In addition, all the KChIPs can act as transcription factors to repress the expression of genes involved in circadian regulation. Altered expression of KChIPs has been implicated in the pathogenesis of several neurological and cardiovascular diseases. For example, KChIP2 is decreased in failing hearts, while loss of KChIP2 leads to increased susceptibility to arrhythmias. KChIP3 is increased in Alzheimer's disease and amyotrophic lateral sclerosis, but decreased in epilepsy and Huntington's disease. In the present review, we summarize the progress of recent studies regarding the structural properties, physiological functions, and pathological roles of KChIPs in both health and disease. We also summarize the small-molecule compounds that regulate the function of KChIPs. This review will provide an overview and update of the regulatory mechanism of the KChIP family and the progress of targeted drug research as a reference for researchers in related fields.

A holy grail of regenerative medicine is to replenish the cells that are lost due to disease. The adult mammalian central nervous system (CNS) has, however, largely lost such a regenerative ability. An emerging strategy for the generation of new neurons is through glia-to-neuron (GtN) conversion in vivo, mainly accomplished by the regulation of fate-determining factors. When inhibited, PTBP1, a factor involved in RNA biology, was reported to induce rapid and efficient GtN conversion in multiple regions of the adult CNS. Remarkably, PTBP1 inhibition was also claimed to greatly improve behaviors of mice with neurological diseases or aging. These phenomenal claims, if confirmed, would constitute a significant advancement in regenerative medicine. Unfortunately, neither GtN conversion nor therapeutic potential via PTBP1 inhibition was validated by the results of multiple subsequent replication studies with stringent methods. Here we review these controversial studies and conclude with recommendations for examining GtN conversion in vivo and future investigations of PTBP1.

In vivo cell fate conversions have emerged as potential regeneration-based therapeutics for injury and disease. Recent studies reported that ectopic expression or knockdown of certain factors can convert resident astrocytes into functional neurons with high efficiency, region specificity, and precise connectivity. However, using stringent lineage tracing in the mouse brain, we show that the presumed astrocyte-converted neurons are actually endogenous neurons. AAV-mediated co-expression of NEUROD1 and a reporter specifically and efficiently induces reporter-labeled neurons. However, these neurons cannot be traced retrospectively to quiescent or reactive astrocytes using lineage-mapping strategies. Instead, through a retrograde labeling approach, our results reveal that endogenous neurons are the source for these viral-reporter-labeled neurons. Similarly, despite efficient knockdown of PTBP1 in vivo, genetically traced resident astrocytes were not converted into neurons. Together, our results highlight the requirement of lineage-tracing strategies, which should be broadly applied to studies of cell fate conversions in vivo., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Two previously undescribed flavonols with phenylpropanoid or benzyl substitution, named alangsine A (1), and alangsine B (2), together with four known compounds (3-6) were isolated from the leaves of Alangium chinense. Alangsine A was a racemic mixture, which was further separated into two enantiomers via high-performance liquid chromatography on a chiral column. The absolute configurations of the enantiomer pairs were deduced from the circular dichroism (CD) spectra. The activity of the isolated compounds towards neuronal excitability was examined., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Two new phthalideisoquinoline hemiacetal alkaloid derivatives, named corybensines A and B (1 and 2), and four known alkaloids (3-6) were isolated from the bulbs of Corydalis decumbens. Their structures were characterized by analysis of 1D/2D NMR and ECD data, quantum chemical ECD calculations, and X-ray diffraction analysis. Among them, compound 2 represents the first naturally occurring phthalideisoquinoline hemiacetal alkaloid derivative with a 2-pyrrolidinone moiety. The activity of the isolated compounds towards neuronal excitability was examined., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020. Published by Elsevier B.V.)

Eight new alkaloids, including five isoquinoline alkaloids, a benzoazepine alkaloid, two isoindole alkaloids, and three synthetic alkaloids firstly obtained from the natural sources, together with three known ones were isolated from the bulbs of Corydalis decumbens. The structures were determined by analysis of their spectroscopic data and single-crystal X-ray diffraction. This is the first report of isoindole alkaloid and benzoazepine alkaloid from the genus Corydalis. Full NMR data for 9-11 are reported here for the first time. Moreover, the ability to modulate neuronal Ca 2+ mobilization of the isolated alkaloids was tested in primary cultured neocortical neurons. Compound 7 inhibited spontaneous Ca 2+ oscillations in primary neocortical neuron cultures at low micromolar concentrations., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Diabetes can result in pathological changes to enteric nervous system. Our aim was to test the dynamic changes of enteric neurons and identify the role of enteric glial cells (EGCs) in regulating enteric neuron expression in diabetic rats., Methods: A single injection of streptozotocin (STZ) was used to establish diabetic rats. Animals were randomly distributed into diabetic 1-, 4-, 8-, and 16-week groups, as well as age-matched control groups. The PGP9.5- and glial fibrillary acidic protein (GFAP)-immunopositive cells were quantified by immunohistochemistry. The protein levels of PGP9.5, ChAT, nNOS, S-100β, and c-fos were determined by western blotting. The levels of nerve growth factor (NGF), neurotrophin 3 (NT-3), and glial cell-derived neurotrophic factor (GDNF) were tested by ELISA., Key Results: An increase in blood glucose and a decrease in body weight were observed following STZ administration. PGP9.5 expression did not change in the diabetic ileum. However, ChAT increased after 16 weeks, and nNOS decreased after 8 and 16 weeks in the ilea of diabetic rats. The absence of degeneration of enteric neurons during the acute stage of the disease could be the consequence of the up-regulation of GFAP, S-100β, and c-fos. Moreover, the content of NGF, NT-3, and GDNF in the ileum increased by varying degrees after 1 and/or 4 weeks of diabetes. Using 2 co-culture models of EGCs and SH-SY5Y cells in a high glucose condition, the supportive role of EGCs was further confirmed., Conclusions & Inferences: Enteric glial cell activation can protect enteric neurons from damage due to diabetes in the acute stage of the disease, in part via the promotion of neurotrophin release., (© 2018 John Wiley & Sons Ltd.)

Neurons are postmitotic. Once lost because of injury or degeneration, they do not regenerate in most regions of the mammalian central nervous system. Recent advancements nevertheless clearly reveal that new neurons can be reprogrammed from non-neuronal cells, especially glial cells, in the adult mammalian brain and spinal cord. Here, we give a brief overview concerning cell fate reprogramming in vivo and then focus on the underlying molecular and cellular mechanisms. Specifically, we critically review the cellular sources and the reprogramming factors for in vivo neuronal conversion. Influences of environmental cues and the challenges ahead are also discussed. The ability of inducing new neurons from an abundant and broadly distributed non-neuronal cell source brings new perspectives regarding regeneration-based therapies for traumatic brain and spinal cord injuries and degenerative diseases.

Pro-neural transcription factors and small molecules can induce the reprogramming of fibroblasts into functional neurons; however, the immediate-early molecular events that catalyze this conversion have not been well defined. We previously demonstrated that neurogenin 2 (NEUROG2), forskolin (F), and dorsomorphin (D) can reprogram fibroblasts into functional neurons with high efficiency. Here, we used this model to define the genetic and epigenetic events that initiate an acquisition of neuronal identity. We demonstrate that NEUROG2 is a pioneer factor, FD enhances chromatin accessibility and H3K27 acetylation, and synergistic transcription activated by these factors is essential to successful reprogramming. CREB1 promotes neuron survival and acts with NEUROG2 to upregulate SOX4, which co-activates NEUROD1 and NEUROD4. In addition, SOX4 targets SWI/SNF subunits and SOX4 knockdown results in extensive loss of open chromatin and abolishes reprogramming. Applying these insights, adult human glioblastoma cell and skin fibroblast reprogramming can be improved using SOX4 or chromatin-modifying chemicals., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Adult-generated dentate granule neurons have emerged as major contributors to hippocampal plasticity. New neurons are generated from neural stem cells through a complex sequence of proliferation, differentiation, and maturation steps. Development of the new neuron is dependent on the precise temporal activity of transcription factors, which coordinate the expression of stage-specific genetic programs. Here, we review current knowledge in transcription factor-mediated regulation of mammalian neural stem cells and neurogenesis and will discuss potential mechanisms of how transcription factor networks, on one hand, allow for precise execution of the developmental sequence and, on the other hand, allow for adaptation of the rate and timing of adult neurogenesis in response to complex stimuli. Understanding transcription factor-mediated control of neuronal development will provide new insights into the mechanisms underlying neurogenesis-dependent plasticity in health and disease., (Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.)

Aim: Appoptosin (SLC25A38) is a pro-apoptotic protein, which is upregulated in Alzheimer's disease (AD) brains and plays an important role in promoting the pathological progress of AD. The aim of this study was to investigate the effects of curcumin from the rhizome of Curcuma longa on appoptosin-induced apoptosis in SH-SY5Y cells., Methods: SH-SY5Y cells were pretreated with curcumin, then transfected with appoptosin or vector. The apoptotic cells were detected with Annexin V staining analysis by flow cytometry. The expression of cleaved caspase-3, appoptosin, heme oxygenase-1 (HO-1) was examined using Western blotting. Intracellular level of ROS was measured with DCFH-DA staining by flow cytometry analysis. Mitochondrial membrane potential (ΔΨm) was detected with JC-1 staining under a fluorescence microscope and quantified by fluorescence ratio detection.Overexpression of appoptosin in SH-SY5Y cells markedly increased cell apoptosis accompanied by reduced HO-1 expression, increased intracellular heme level, ROS overproduction and ΔΨm impairment. Treatment of SH-SY5Y cells with curcumin (2.5-20 μmol/L) for 24 h did not significantly affect their viability. However, pretreatment with curcumin (2.5-20 μmol/L) dose-dependently attenuated all above-mentioned pathological changes in appoptosin-transfected SH-SY5Y cells., Results: Overexpression of appoptosin in SH-SY5Y cells markedly increased cell apoptosis accompanied by reduced HO-1 expression, increased intracellular heme level, ROS overproduction and ΔΨm impairment. Treatment of SH-SY5Y cells with curcumin (2.5-20 μmol/L) for 24 h did not significantly affect their viability. However, pretreatment with curcumin (2.5-20 μmol/L) dose-dependently attenuated all above-mentioned pathological changes in appoptosin-transfected SH-SY5Y cells., Conclusion: Curcumin inhibits appoptosin-induced apoptosis in SH-SY5Y cells by upregulating the expression of HO-1, reducing the production of intracellular heme and ROS, and preventing the ΔΨm loss.

Spinal cord injury (SCI) leads to irreversible neuronal loss and glial scar formation, which ultimately result in persistent neurological dysfunction. Cellular regeneration could be an ideal approach to replenish the lost cells and repair the damage. However, the adult spinal cord has limited ability to produce new neurons. Here we show that resident astrocytes can be converted to doublecortin (DCX)-positive neuroblasts by a single transcription factor, SOX2, in the injured adult spinal cord. Importantly, these induced neuroblasts can mature into synapse-forming neurons in vivo. Neuronal maturation is further promoted by treatment with a histone deacetylase inhibitor, valproic acid (VPA). The results of this study indicate that in situ reprogramming of endogenous astrocytes to neurons might be a potential strategy for cellular regeneration after SCI.

Transcription factors play key roles in the formation of a multilayered cerebral cortex consisting of neurons and glial cells. Krüppel-like factor 4 (KLF4) is expressed in neural stem cells and controls axonal regeneration. Its dysregulation leads to hydrocephalus in postnatal mouse brains. Here, we further show that KLF4 regulates neurogenesis and radial migration of neurons in the developing cerebral cortex. Neural progenitors with constitutive expression of KLF4 fail to migrate and develop into mature neurons but, rather, form cells with a glial identity. Notably, the JAK-STAT pathway is altered by KLF4, with increased phosphorylation of STAT3 at tyrosine 705. Blocking STAT3 activation with a dominant negative form can rescue the migration defect induced by constitutive KLF4 expression. Furthermore, downregulation of endogenous KLF4 significantly promotes radial migration and the transition of newly born migrating neurons from multipolar to bipolar morphology. Together, these results suggest that precise regulation of KLF4 expression is critical to neuronal differentiation and migration during the formation of a cerebral cortex.

Cyproheptadine (CPH) is a histamine- and serotonin-receptor antagonist, and its effects are observed recently in the modulation of multiple intracellular signals. In this study, we used cortical neurons and HEK-293 cells transfected with Kv2.1 α-subunit to address whether CPH modify neural voltage-gated K(+) channels by a mechanism independent of its serotonergic and histaminergic properties. Our results demonstrate that intracellularly delivered CPH increased the I(K) by reducing the activity of protein kinas A (PKA). Inhibition of G(i) eliminated the CPH-induced effect on both the I(K) and PKA. Blocking of 5-HT-, M-, D(2)-, H(1)- or H(2)-type GPCR receptors with relevant antagonists did not eliminate the CPH-induced effect on the I(K). Antagonists of the sigma-1 receptor, however, blocked the effect of CPH. Moreover, the inhibition of sigma-1 by siRNA knockdown significantly reduced the CPH-induced effect on the I(K). On the contrary, sigma-1 receptor agonist mimicked the effects of CPH on the induction of I(K). A ligand-receptor binding assay indicated that CPH bound to the sigma-1 receptor. Similar effect of CPH were obtained from HEK-293 cells transfected with the α-subunit of Kv2.1. In overall, we reveal for the first time that CPH enhances the I(K) by modulating activity of PKA, and that the associated activation of the sigma-1 receptor/G(i)-protein pathway might be involved. Our findings illustrate an uncharacterized effect of CPH on neuron excitability through the I(K), which is independent of histamine H(1) and serotonin receptors.

Kruppel-like factor 4 (KLF4) is involved in self-renewal of embryonic stem cells and reprogramming of somatic cells to pluripotency. However, its role in lineage-committed stem cells remains largely unknown. Here, we show that KLF4 is expressed in neural stem cells (NSCs) and is down-regulated during neuronal differentiation. Unexpectedly, enhanced expression of KLF4 reduces self-renewal of cultured NSCs and inhibits proliferation of subventricular neural precursors in transgenic mice. Mice with increased KLF4 in NSCs and NSCs-derived ependymal cells developed hydrocephalus-like characteristics, including enlarged ventricles, thinned cortex, agenesis of the corpus callosum, and significantly reduced subcommissural organ. These characteristics were accompanied by elevation of GFAP expression and astrocyte hypertrophy. The ventricular cilia, vital for cerebrospinal fluid flow, are also disrupted in the mutant mice. These results indicate that down-regulation of KLF4 is critical for neural development and its dysregulation may lead to hydrocephalus.

Carbon monoxide (CO)-induced delayed neuron damage is the serious complication, but the underlying mechanisms are poorly understood. This study was designed to investigate the time-dependent changes of the lipid peroxidation (malondialdehyde, MDA) and antioxidative status (glutathione, GSH; glutathione peroxidase, GSH-Px; glutathione reductase, GR; and anti-reactive oxygen species anti-ROS) in nerve tissues for the possible mechanisms exploration. Adult rats were treated with CO by peritoneal injection, and sacrificed after day 0, 1, 3, 7, 14 and 21 of treatment. The results showed that the step-down latency progressively shortened while the numbers of error increased. Comparing with the level of day 0, MDA levels in serum, cerebral cortex and hippocampus significantly increased on day 1, 3 and 7. The level of GSH increased firstly but then decreased. The activities of GR, GSH-Px, and anti-ROS decreased in serum, cerebral cortex and hippocampus of rats after day 1, 3, 7, 14 and 21. Thus, we concluded that CO-mediated delayed neuron damage might be associated with elevation of lipid peroxidation and reduction of antioxidative status. The time-dependent changes of lipid peroxidation and antioxidative status in serum, cerebral cortex and hippocampus, at least in part, are involved in the toxic effects of CO poisoning on neuron.

Neurogenesis persists in the adult brain and can be regulated by a plethora of external stimuli, such as learning, memory, exercise, environment and stress. Although newly generated neurons are able to migrate and preferentially incorporate into the neural network, how these cells are molecularly regulated and whether they are required for any normal brain function are unresolved questions. The adult neural stem cell pool is composed of orphan nuclear receptor TLX-positive cells. Here, using genetic approaches in mice, we demonstrate that TLX (also called NR2E1) regulates adult neural stem cell proliferation in a cell-autonomous manner by controlling a defined genetic network implicated in cell proliferation and growth. Consequently, specific removal of TLX from the adult mouse brain through inducible recombination results in a significant reduction of stem cell proliferation and a marked decrement in spatial learning. In contrast, the resulting suppression of adult neurogenesis does not affect contextual fear conditioning, locomotion or diurnal rhythmic activities, indicating a more selective contribution of newly generated neurons to specific cognitive functions.

Brain tissue engineering in the postinjury brain represents a promising option for cellular replacement and rescue, providing a cell scaffold for either transplanted or resident cells. In this article, a hyaluronic acid (HA)-poly-D-lysine (PDL) copolymer hydrogel with an open porous structure and viscoelastic properties similar to neural tissue has been developed for brain tissue engineering. The chemicophysical properties of the hydrogel with HA:PDL ratios of 10:1, 5:1, and 4:1 were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectrometry. Neural cells cultured in the hydrogel were studied by phase-contrast microscope and SEM. The incorporation of PDL peptides into the HA-PDL hydrogel allowed for the modulation of neuronal cell adhesion and neural network formation. Macrophages and multinucleated foreign body giant cells found at the site of implantation of the hydrogel in the rat brain within the first weeks postimplantation decreased in numbers after 6 weeks, consistent with the host response to inert implants in numerous tissues. Of importance was the infiltration of the hydrogel by glial fibrillary acidic protein-positive cells-reactive astrocytes-by immunohistochemistry and the contiguity between the hydrogel and the surrounding tissue demonstrated by SEM. These findings indicated the compatibility of this hydrogel with brain tissue. Collectively, the results demonstrate the promise of an HA-PDL hydrogel as a scaffold material for the repair of defects in the brain.

Glial fibrillary acidic protein (GFAP) is a member of the family of intermediate filament structural proteins and is found predominantly in astrocytes of the central nervous system (CNS). To assess the function of GFAP, we created GFAP-null mice using gene targeting in embryonic stem cells. The GFAP-null mice have normal development and fertility, and show no gross alterations in behavior or CNS morphology. Astrocytes are present in the CNS of the mutant mice, but contain a severely reduced number of intermediate filaments. Since astrocyte processes contact synapses and may modulate synaptic function, we examined whether the GFAP-null mice were altered in long-term potentiation in the CA1 region of the hippocampus. The GFAP-null mice displayed enhanced long-term potentiation of both population spike amplitude and excitatory post-synaptic potential slope compared to control mice. These data suggest that GFAP is important for astrocyte-neuronal interactions, and that astrocyte processes play a vital role in modulating synaptic efficacy in the CNS. These mice therefore represent a direct demonstration that a primary defect in astrocytes influences neuronal physiology.