Expression of vimentin and glial fibrillary acidic protein in central nervous system development of rats

Objective: To investigate the distribution and contents of vimentin(Vim) and glial fibrillary acidic protein(GFAP) immunoreactivities in the central nervous system(CNS)of normal newborn, adult and aged rats.Methods: In this study, thirty healthy and normal Sprague–Dawley rats were simply classified into three groups: Newborn(7 days aged), adult(5 months aged) and aged(24 months aged) rats. Brains and spinal cord were dissected and cut into frozen sections. The expression of Vim and GFAP in CNS were detected by confocal immunofluorescence.Results: In each group, Vim was expressed in all the regions of CNS including the hippocampal, cerebral cortex, the third ventricle and spinal cord, and the expression was highest in neuron-like cell of newborn rats, while Vim was mainly expressed in cell bodies in adult and aged rats. GFAP was expressed in all the regions of CNS including the hippocampal, cerebral cortex, the third ventricle and spinal cord, and the expression was in astrocytes of aged rats. In the third ventricle, Vim was detected in all groups, and only observed in neuron-like cells of newborn. Meanwhile, the GFAP expression showed no significant differences between adult and aged rats in this region. The co-localization of Vim and GFAP were mainly observed in hippocampus and cerebral cortex of newborn,but this co-localization was found in the third ventricle of the rats in all groups.Conclusion: Our data demonstrate for the first time that the expression of Vim and GFAP in the rat's CNS during development. This data may provide a foundation for the further mechanistic studies of these two main intermediate filaments during development of CNS.

The role of microtubule-associated protein 1B in axonal growth and neuronal migration in the central nervous system

In this review, we discuss the role of microtubule-associated protein 1 B （MAP1B） and its phosphorylation in axonal development and regeneration in the central nervous system. MAP1B exhibits similar functions during axonal development and regeneration. MAP1B and phosphorylated MAPIB in neurons and axons maintain a dynamic balance between cytoskeletal components, and regulate the stability and interaction of microtubules and actin to promote axonal growth, neural connectivity and regeneration in the central nervous system.

The role of the Rho/ROCK signaling pathway in inhibiting axonal regeneration in the central nervous system

The Rho/Rho-associated coiled-coil containing protein kinase（Rho/ROCK） pathway is a major signaling pathway in the central nervous system, transducing inhibitory signals to block regeneration. After central nervous system damage, the main cause of impaired regeneration is the presence of factors that strongly inhibit regeneration in the surrounding microenvironment. These factors signal through the Rho/ROCK signaling pathway to inhibit regeneration. Therefore, a thorough understanding of the Rho/ROCK signaling pathway is crucial for advancing studies on regeneration and repair of the injured central nervous system.

Cell Replication and Angiogenesis in Central Nervous System Tumors and Their Relationship with the Expression of Tissue Prolactin and Hyperprolactinemia

This study aimed to assess the effect of intracellular prolactin (ICPRL) and hyperprolactinemia on cell replication, using an immunohistochemical (IHC) technique for Ki-67 and Mcm-2, and angiogenesis, using IHC for endoglin CD-105, in central nervous system (CNS) tumors. This cross-sectional study included 79 cases of surgically excised primary CNS tumors of neuroepithelial origin (41.8% of all cases: 10.2% astrocytomas, 24% glioblastomas and 7.6% oligodendrogliomas) and meningeal origin (58.2% of all cases). Ki-67 and Mcm-2 indexes were calculated as a percentage of marked cells. The medians for Ki-67 and Mcm-2 indexes were significantly lower in meningiomas than in glioblastomas (p S = 0.60) replication markers. There were no significant differences in vascular density between the different histological types. Immunohistochemistry for ICPRL was positive in 45.6% of the tumors. Serum prolactin (PRL) was elevated in 30.6% of the cases. Multiple regression analysis revealed no important correlation of ICPRL and serum PRL on Ki-67 and Mcm-2 indexes or vascular density. The analysis of the combined impact of ICPRL and serum PRL variables revealed a trend towards an increase in microvessel density in tumor tissue and a significant increase in cell replication markers (p = 0.009 for Ki-67 and p = 0.05 for Mcm-2). PRL in tumor tissue may be one of the modulating factors of cell proliferation in the CNS.

Lactate metabolism in neurodegenerative diseases

Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological conditions.The Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous system.Moreover,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease development.This review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.

Bromocriptine protects perilesional spinal cord neurons from lipotoxicity after spinal cord injury

Recent studies have revealed that lipid droplets accumulate in neurons after brain injury and evoke lipotoxicity,damaging the neurons.However,how lipids are metabolized by spinal cord neurons after spinal cord injury remains unclear.Herein,we investigated lipid metabolism by spinal cord neurons after spinal cord injury and identified lipid-lowering compounds to treat spinal cord injury.We found that lipid droplets accumulated in perilesional spinal cord neurons after spinal cord injury in mice.Lipid droplet accumulation could be induced by myelin debris in HT22 cells.Myelin debris degradation by phospholipase led to massive free fatty acid production,which increased lipid droplet synthesis,β-oxidation,and oxidative phosphorylation.Excessive oxidative phosphorylation increased reactive oxygen species generation,which led to increased lipid peroxidation and HT22 cell apoptosis.Bromocriptine was identified as a lipid-lowering compound that inhibited phosphorylation of cytosolic phospholipase A2 by reducing the phosphorylation of extracellular signal-regulated kinases 1/2 in the mitogen-activated protein kinase pathway,thereby inhibiting myelin debris degradation by cytosolic phospholipase A2 and alleviating lipid droplet accumulation in myelin debris-treated HT22 cells.Motor function,lipid droplet accumulation in spinal cord neurons and neuronal survival were all improved in bromocriptine-treated mice after spinal cord injury.The results suggest that bromocriptine can protect neurons from lipotoxic damage after spinal cord injury via the extracellular signal-regulated kinases 1/2-cytosolic phospholipase A2 pathway.

Amyloid precursor protein and growth-associated protein 43 expression in brain white matter and spinal cord tissues in a rat model of experimental autoimmune encephalomyelitis

Studies have demonstrated that amyloid precursor protein （APP） expression increases in multiple sclerosis tissues during acutely and chronically active stages. To determine the relationship between axonal injury and regeneration in multiple sclerosis, an animal model of experimental autoimmune encephalomyelitis was induced using different doses of myelin basic protein peptide. APP and growth-associated protein 43 （GAP-43）, which is considered a specific marker of neural regeneration, were assessed by western blot analysis. Expression of APP and GAP-43, as well as the correlation between these two proteins, in brain white matter and spinal cord tissues of experimental autoimmune encephalomyelitis rats at different pathological stages was analyzed. Results showed that APP and GAP-43 expression increased during the acute stage and decreased during remission, with a positive correlation between APP and GAP-43 expression in brain white matter and spinal cord tissues. These results suggest that APP and GAP-43 could provide nutritional and protective effects on damaged neurons.

Role of CAST-Drp1 Pathway in Retinal Neuron-Regulated Necrosis in Experimental Glaucoma

Objective Numerous studies have indicated that excitatory amino acid toxicity,such as glutamate toxicity,is involved in glaucoma.In addition,excessive glutamate can lead to an intracellular calcium overload,resulting in regulated necrosis.Our previous studies have found that the calpastatin(CAST)-calpain pathway plays an important role in retinal neuron-regulated necrosis after glutamate injury.Although inhibition of the calpain pathway can decrease regulated necrosis,necrotic cells remain.It has been suggested that there are other molecules that participate in retinal neuron-regulated necrosis.CAST is an important regulator of dynamin-related protein 1(Drp1)-mediated mitochondrial defects.Thus,the aim of this study was to determine whether the CAST-Drp1 pathway may be an underlying signaling axis in neuron-regulated necrosis.Methods Using cultured retinal neurons and in an in-vivo glaucoma model induced by glutamate overload,members of the CAST-Drp1 pathway were assessed by immunofluorescence,Western blotting,Phos-tagTM SDS-PAGE,and co-immunoprecipitation assays.Moreover,the black and white box test was performed on the rats.Results We found that more retinal neuron-regulated necrosis and Drp1 activation as well as lower CAST levels were present in the glutamate-induced glaucoma model.Rats with glutamate-induced glaucoma exhibited impaired visual function.We also observed retinal neuron-regulated necrosis and Drp1 activity decreased,and impaired vision recovered after CAST active peptide application,indicating that the CAST-Drp1 pathway plays a critical role in retinal neuron-regulated necrosis and visual function.Conclusion The results of this study indicate that the CAST-Drp1 pathway protects against retinal neuron-regulated necrosis,which may expand the therapeutic targets for the treatment of neurodegenerative disorders involving dysfunction of glutamate metabolism,such as glaucoma.

Immortalized hippocampal astrocytes from 3xTg-AD mice,a new model to study disease-related astrocytic dysfunction:a comparative review

Alzheimer's disease(AD)is characterized by complex etiology,long-lasting pathogenesis,and celltype-specific alterations.Currently,there is no cure for AD,emphasizing the urgent need for a comprehensive understanding of cell-specific pathology.Astrocytes,principal homeostatic cells of the central nervous system,are key players in the pathogenesis of neurodegenerative diseases,including AD.Cellular models greatly facilitate the investigation of cell-specific pathological alterations and the dissection of molecular mechanisms and pathways.Tumor-derived and immortalized astrocytic cell lines,alongside the emerging technology of adult induced pluripotent stem cells,are widely used to study cellular dysfunction in AD.Surprisingly,no stable cell lines were available from genetic mouse AD models.Recently,we established immortalized hippocampal astroglial cell lines from amyloid-βprecursor protein/presenilin-1/Tau triple-transgenic(3xTg)-AD mice(denominated as wild type(WT)-and 3Tg-iAstro cells)using retrovirus-mediated transduction of simian virus 40 large T-antigen and propagation without clonal selection,thereby maintaining natural heterogeneity of primary cultures.Several groups have successfully used 3Tg-iAstro cells for single-cell and omics approaches to study astrocytic AD-related alterations of calcium signaling,mitochondrial dysfunctions,disproteostasis,altered homeostatic and signaling support to neurons,and blood-brain barrier models.Here we provide a comparative overview of the most used models to study astrocytes in vitro,such as primary culture,tumor-derived cell lines,immortalized astroglial cell lines,and induced pluripotent stem cell-derived astrocytes.We conclude that immortalized WT-and 3Tg-iAstro cells provide a noncompetitive but complementary,low-cost,easy-to-handle,and versatile cellular model for dissection of astrocyte-specific AD-related alterations and preclinical drug discovery.

Electroacupuncture improves learning and memory functions in a rat cerebral ischemia/reperfusion injury model through PI3K/Akt signaling pathway activation

Electroacupuncture has been widely used to treat cognitive impairment after cerebral ischemia,but the underlying mechanism has not yet been fully elucidated.Studies have shown that autophagy plays an important role in the formation and development of cognitive impairment,and the phosphoinositide 3-kinase(PI3K)/Akt signaling pathway plays an important role in autophagy regulation.To investigate the role played by the PI3K/Akt signaling pathway in the electroacupuncture treatment of cerebral ischemia/reperfusion rat models,we first established a rat model of cerebral ischemia/reperfusion through the occlusion of the middle cerebral artery using the suture method.Starting at 2 hours after modeling,electroacupuncture was delivered at the Shenting(GV24)and Baihui(GV20)acupoints,with a dilatational wave(1-20 Hz frequency,2 mA intensity,6 V peak voltage),for 30 minutes/day over 8 consecutive days.Our results showed that electroacupuncture reduced the infarct volume in a rat model of cerebral ischemia/reperfusion injury,increased the mRNA expression levels of the PI3K/Akt signaling pathwayrelated factors Beclin-1,mammalian target of rapamycin(mTOR),and PI3K,increased the protein expression levels of phosphorylated Akt,Beclin-1,PI3K,and mTOR in the ischemic cerebral cortex,and simultaneously reduced p53 mRNA and protein expression levels.In the Morris water maze test,the latency to find the hidden platform was significantly shortened among rats subjected to electroacupuncture stimulation compared with rats without electroacupuncture stimulation.In the spatial probe test,the number of times that a rat crossed the target quadrant was increased in rats subjected to electroacupuncture stimulation compared with rats without electroacupuncture stimulation.Electroacupuncture stimulation applied to the Shenting(GV24)and Baihui(GV20)acupoints activated the PI3K/Akt signaling pathway and improved rat learning and memory impairment.This study was approved by the Animal Ethics Committee of the First Affiliated Hospital of Henan University of Traditional Chinese Medicine,China(approval No.8150150901)on March 10,2016.

Mechanism underlying treatment of ischemic stroke using acupuncture:transmission and regulation

The inflammatory response after cerebral ischemia/reperfusion is an important cause of neurological damage and repair.After cerebral ischemia/reperfusion,microglia are activated,and a large number of circulating inflammatory cells infiltrate the affected area.This leads to the secretion of inflammatory mediators and an inflammatory cascade that eventually causes secondary brain damage,including neuron necrosis,blood-brain barrier destruction,cerebral edema,and an oxidative stress response.Activation of inflammatory signaling pathways plays a key role in the pathological process of ischemic stroke.Increasing evidence suggests that acupuncture can reduce the inflammatory response after cerebral ischemia/reperfusion and promote repair of the injured nervous system.Acupuncture can not only inhibit the activation and infiltration of inflammatory cells,but can also regulate the expression of inflammation-related cytokines,balance the effects of pro-inflammatory and anti-inflammatory factors,and interfere with inflammatory signaling pathways.Therefore,it is important to study the transmission and regulatory mechanism of inflammatory signaling pathways after acupuncture treatment for cerebral ischemia/reperfusion injury to provide a theoretical basis for clinical treatment of this type of injury using acupuncture.Our review summarizes the overall conditions of inflammatory cells,mediators,and pathways after cerebral ischemia/reperfusion,and discusses the possible synergistic intervention of acupuncture in the inflammatory signaling pathway network to provide a foundation to explore the multiple molecular mechanisms by which acupuncture promotes nerve function restoration.

Atorvastatin combined with low-dose dexamethasone for vascular endothelial cell dysfunction induced by chronic subdural hematoma

Atorvastatin has been shown to be a safe and effective non-surgical treatment option for patients with chronic subdural hematoma.However,treatment with atorvastatin is not effective in some patients,who must undergo further surgical treatment.Dexamethasone has anti-inflammatory and immunomodulatory effects,and low dosages are safe and effective for the treatment of many diseases,such as ankylosing spondylitis and community-acquired pneumonia.However,the effects of atorvastatin and low-dose dexamethasone for the treatment of chronic subdural hematoma remain poorly understood.Hematoma samples of patients with chronic subdural hematoma admitted to the General Hospital of Tianjin Medical University of China were collected and diluted in endothelial cell medium at 1:1 as the hematoma group.Atorvastatin,dexamethasone,or their combination was added to the culture medium.The main results were as follows:hopping probe ion conductance microscopy and permeability detection revealed that the best dosages to improve endothelial cell permeability were 0.1μM atorvastatin and 0.1μM dexamethasone.Atorvastatin,dexamethasone,or their combination could markedly improve the recovery of injured endothelial cells.Mice subcutaneously injected with diluted hematoma solution and then treated with atorvastatin,dexamethasone,or their combination exhibited varying levels of rescue of endothelial cell function.Hopping probe ion conductance microscopy,western blot assay,and polymerase chain reaction to evaluate the status of human cerebral endothelial cell status and expression level of tight junction protein indicated that atorvastatin,dexamethasone,or their combination could reduce subcutaneous vascular leakage caused by hematoma fluid.Moreover,the curative effect of the combined treatment was significantly better than that of either single treatment.Expression of Krüppel-like factor 2 protein in human cerebral endothelial cells was significantly increased,as was expression of the tight junction protein and vascular permeability marker vascular endothelial cadherin in each treatment group compared with the hematoma stimulation group.Hematoma fluid in patients with chronic subdural hematoma may damage vascular endothelial cells.However,atorvastatin combined with low-dose dexamethasone could rescue endothelial cell dysfunction by increasing the expression of tight junction proteins after hematoma injury.The effect of combining atorvastatin with low-dose dexamethasone was better than that of atorvastatin alone.Increased expression of Krüppel-like factor 2 may play an important role in the treatment of chronic subdural hematoma.The animal protocols were approved by the Animal Care and Use Committee of Tianjin Medical University of China on July 31,2016(approval No.IRB2016-YX-036).The study regarding human hematoma samples was approved by the Ethics Committee of Tianjin Medical University of China on July 31,2018(approval No.IRB2018-088-01).

Enriched environment enhances histone acetylation of NMDA receptor in the hippocampus and improves cognitive dysfunction in aged mice

The mechanisms of age-associated memory impairment may be associated with glutamate receptor function and chromatin modification.To observe the effect of an enriched environment on the cognitive function of mice with age-associated memory impairment,3-monthold C57BL/6 male mice("young"mice)were raised in a standard environment,while 24-month-old C57BL/6 male mice with memory impairment("age-associated memory impairment"mice)were raised in either a standard environment or an enriched environment.The enriched environment included a variety of stimuli involving movement and sensation.A water maze test was then used to measure cognitive function in the mice.Furthermore,quantitative real-time polymerase chain reaction and western blot assays were used to detect right hippocampal GluN2B mRNA as well as protein expression of GluN2B and CREB binding protein in all mice.In addition,chromatin immunoprecipitation was used to measure the extent of histone acetylation of the hippocampal GluN2B gene promoters.Compared with the young mice,the water maze performance of age-associated memory impairment mice in the standard environment was significantly decreased.In addition,there were significantly lower levels of total histone acetylation and expression of CREB binding protein in the hippocampus of age-associated memory impairment mice in the standard environment compared with the young mice.There were also significantly lower levels of histone acetylation,protein expression,and mRNA expression of GluN2B in the hippocampus of these mice.In contrast,in the age-associated memory impairment mice with the enriched environment intervention,the water maze performance and molecular biological indexes were significantly improved.These data confirm that an enriched environment can improve cognitive dysfunction in age-associated memory impairment mice,and suggest that the mechanisms may be related to the increased expression of CREB binding protein and the increased degree of total histone acetylation in the hippocampus of age-associated memory impairment mice,which may cause the increase of histone acetylation of GluN2B gene promoter and the enhancement of GluN2B mRNA transcription and protein expression in hippocampus.The animal experiment was approved by the Animal Ethics Committee of Yangzhou University,China(approval No.20170312001)in March 2017.

Melatonin ameliorates microvessel abnormalities in the cerebral cortex and hippocampus in a rat model of Alzheimer’s disease

Melatonin can attenuate cardiac microvascular ischemia/reperfusion injury,but it remains unclear whether melatonin can also ameliorate cerebral microvascular abnormalities.Rat models of Alzheimer’s disease were established by six intracerebroventricular injections of amyloidbeta 1–42,administered once every other day.Melatonin(30 mg/kg)was intraperitoneally administered for 13 successive days,with the first dose given 24 hours prior to the first administration of amyloid-beta 1–42.Melatonin ameliorated learning and memory impairments in the Morris water maze test,improved the morphology of microvessels in the cerebral cortex and hippocampus,increased microvessel density,alleviated pathological injuries of cerebral neurons,and decreased the expression of vascular endothelial growth factor and vascular endothelial growth factor receptors 1 and 2.These findings suggest that melatonin can improve microvessel abnormalities in the cerebral cortex and hippocampus by lowering the expression of vascular endothelial growth factor and its receptors,thereby improving the cognitive function of patients with Alzheimer’s disease.This study was approved by the Animal Care and Use Committee of Jinzhou Medical University,China(approval No.2019015)on December 6,2018.

Human amniotic epithelial cells express specific markers of nerve cells and migrate along the nerve fibers in the corpus callosum

Human amniotic epithelial cells were isolated from a piece of fresh amnion. Using immunocytochemical methods, we investigated the expression of neuronal phenotypes （microtubule-associated protein-2, glial fibrillary acidic protein and nestin） in human amniotic epithelial cells. The conditioned medium of human amniotic epithelial cells promoted the growth and proliferation of rat glial cells cultured in vitro, and this effect was dose-dependent. Human amniotic epithelial cells were further transplanted into the corpus striatum of healthy adult rats and the grafted cells could integrate with the host and migrate 1 2 mm along the nerve fibers in corpus callosum. Our experimental findings indicate that human amniotic epithelial cells may be a new kind of seed cells for use in neurograft.

All roads lead to Rome-a review of the potential mechanisms by which exerkines exhibit neuroprotective effects in Alzheimer’s disease

Age-related neurodegenerative disorders such as Alzheimer’s disease(AD)have become a critical public health issue due to the significantly extended human lifespan,leading to considerable economic and social burdens.Traditional therapies for AD such as medicine and surgery remain ineffective,impractical,and expensive.Many studies have shown that a variety of bioactive substances released by physical exercise(called“exerkines”)help to maintain and improve the normal functions of the brain in terms of cognition,emotion,and psychomotor coordination.Increasing evidence suggests that exerkines may exert beneficial effects in AD as well.This review summarizes the neuroprotective effects of exerkines in AD,focusing on the underlying molecular mechanism and the dynamic expression of exerkines after physical exercise.The findings described in this review will help direct research into novel targets for the treatment of AD and develop customized exercise therapy for individuals of different ages,genders,and health conditions.

Astrocyte in prion disease: a double-edged sword

Prion diseases are infectious protein misfolding disorders of the central nervous system that result from misfolding of the cellular prion protein(PrPC)into the pathologic isoform PrPSc.Pathologic hallmarks of prion disease are depositions of pathological prion protein PrPSc,neuronal loss,spongiform degeneration and astrogliosis in the brain.Prion diseases affect human and animals,there is no effective therapy,and they invariably remain fatal.For a long time,neuronal loss was considered the sole reason for neurodegeneration in prion pathogenesis,and the contribution of non-neuronal cells like microglia and astrocytes was considered less important.Recent evidence suggests that neurodegeneration during prion pathogenesis is a consequence of a complex interplay between neuronal and non-neuronal cells in the brain,but the exact role of these non-neuronal cells during prion pathology is still elusive.Astrocytes are non-neuronal cells that regulate brain homeostasis under physiological conditions.However,astrocytes can deposit PrPSc aggregates and propagate prions in prion-infected brains.Additionally,sub-populations of reactive astrocytes that include neurotrophic and neurotoxic species have been identified,differentially expressed in the brain during prion infection.Revealing the exact role of astrocytes in prion disease is hampered by the lack of in vitro models of prion-infected astrocytes.Recently,we established a murine astrocyte cell line persistently infected with mouse-adapted prions,and showed how such astrocytes differentially process various prion strains.Considering the complexity of the role of astrocytes in prion pathogenesis,we need more in vitro and in vivo models for exploring the contribution of sub-populations of reactive astrocytes,their differential regulation of signaling cascades,and the interaction with neurons and microglia during prion pathogenesis.This will help to establish novel in vivo models and define new therapeutic targets against prion diseases.In this review,we will discuss the complex role of astrocytes in prion disease,the existing experimental resources,the challenges to analyze the contribution of astrocytes in prion disease pathogenesis,and future strategies to improve the understanding of their role in prion disease.

Cloning and bioinformatical analysis of the N-terminus of the sonic hedgehog gene

The sonic hedgehog protein not only plays a key role in early embryonic development, but also has essential effects on the adult nervous system, including neural stem cell proliferation, differentiation migration and neuronal axon guidance. The N-terminal fragment of sonic hedgehog is the key functional element in this process. Therefore, this study aimed to clone and analyze the N-terminal fragment of the sonic hedgehog gene. Total RNA was extracted from the notochord of a Sprague-Dawley rat at embryonic day 9 and the N-terminal fragment of sonic hedgehog was amplified by nested reverse transcription-PCR. The N-terminal fragment of the sonic hedgehog gene was successfully cloned. The secondary and tertiary structures of the N-terminal fragment of the sonic hedgehog protein were predicted using Jpred and Phyre online.

Neural differentiation of choroid plexus epithelial cells:role of human traumatic cerebrospinal fluid

As the key producer of cerebrospinal fluid（CSF）,the choroid plexus（CP） provides a unique protective system in the central nervous system.CSF components are not invariable and they can change based on the pathological conditions of the central nervous system.The purpose of the present study was to assess the effects of non-traumatic and traumatic CSF on the differentiation of multipotent stem-like cells of CP into the neural and/or glial cells.CP epithelial cells were isolated from adult male rats and treated with human non-traumatic and traumatic CSF.Alterations in m RNA expression of Nestin and microtubule-associated protein（MAP2）,as the specific markers of neurogenesis,and astrocyte marker glial fibrillary acidic protein（GFAP） in cultured CP epithelial cells were evaluated using quantitative real-time PCR.The data revealed that treatment with CSF（non-traumatic and traumatic） led to increase in m RNA expression levels of MAP2 and GFAP.Moreover,the expression of Nestin decreased in CP epithelial cells treated with non-traumatic CSF,while treatment with traumatic CSF significantly increased its m RNA level compared to the cells cultured only in DMEM/F12 as control.It seems that CP epithelial cells contain multipotent stem-like cells which are inducible under pathological conditions including exposure to traumatic CSF because of its compositions.

Distinct pathogenic mechanisms of various RARS1 mutations in Pelizaeus-Merzbacher-like disease

Mutations of the genes encoding aminoacyl-tRNA synthetases are highly associated with various central nervous system disorders.Recurrent mutations,including c.5A>G,p.D2G;c.1367C>T,p.S456L;c.1535G>A,p.R512Q and c.1846_1847del,p.Y616Lfs*6 of RARS1 gene,which encodes two forms of human cytoplasmic arginyl-tRNA synthetase(hArgRS),are linked to Pelizaeus-Merzbacher-like disease(PMLD)with unclear pathogenesis.Among these mutations,c.5A>G is the most extensively reported mutation,leading to a p.D2G mutation in the N-terminal extension of the long-form hArgRS.Here,we showed the detrimental effects of R512Q substitution andΔC mutations on the structure and function of hArgRS,while the most frequent mutation c.5A>G,p.D2G acted in a different manner without impairing hArgRS activity.The nucleotide substitution c.5A>G reduced translation of hArgRS mRNA,and an upstream open reading frame contributed to the suppressed translation of the downstream main ORF.Taken together,our results elucidated distinct pathogenic mechanisms of various RARS1 mutations in PMLD.