Neurogenesis Research Articles

Objective To investigate the effect of Hes1 upregulation by using an adonoviral vector containing mouse Hes1 gene in adult hippocampal neurogenesis following traumatic brain injury (TBI), a Morris water maze (MWM) test was employed to investigate the spatial learning and memory capacity of adult mice following injury. Methods One hundred and sixty mice were randomly allocated into four groups: sham-PBS group, sham-PBS-TBI group, Ad5-enhanced green fluorescent protein (EGFP)-TBI group, Ad5-Hes1-TBI group. The TBI model mouse was subjected to lateral fluid percussion injury of (202±2) kPa using a pre-calibrated fluid percussion injury device. Then, Ad5-mRNA and PBS were stereotaetic injected into the hippocampus of the adult C57BL/6 mice and their expressions in the hippocampus were detected. Western blotting and real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) methods were employed to detect the expression level of Hes1 on day 3 following TBI. We performed BrdU or DCX immunofluorescence staining on day 3 or 7 post TBI, to investigate the effect of Hes1 upregulation in adult hippocampal neurogenesis following TBI. Results FQ-PCR and Western blotting analysis suggested that Hes1 was up-regulated in overexpression group at mRNA (1.87±0.13 vs. 0.97±0.13, P=0.025) on day 3 post TBI and protein level; Immunofluorescence staining showed that a significant decrease in the total number of BrdU (+ ) and DCX (+ ) cells from the animals with Ad5-mHes1 treated on day 3 or 7 post injury. Morris water maze (MWM) test confirmed that Hes1 overexpression did not lead to a statistically significant change in EL and the target quadrant (P=0.062). Conclusion These results strongly suggested that increased expression of Hes1 may inhibit adult neurogenesis in DG of hippocampus after TBI and did not lead to a statistically significant change in the spatial learning and memory capacity of adult mice following injury. Key words: Hes1; Adult neurogenesis; Traumatic brain injury; Morris water maze

Objective To observe the effect of maternal separation(MS)on the expression of glucocorticoid receptor(GR)and doublecortin(DCX)in hippocampus and prefrontal cortex of young mice. Methods Fifteen pregnant mice were randomly divided into 5 groups: the experimental group(3 d, 7 d, 14 d, 21 d)and the control group, n=3 in each group. Neonatal mice in experimental group were separated from mother for 3 h once a day, and the mice in control group were caged with mother without any processing after birth. All mice were weaned in postanal day 23. Separating female and male mice, and the male mice were killed and the brains were taken in postanal day 42. The expression and distribution of GR and DCX in hippocampus and prefrontal cortex were determined by immunohistochemical staining and Image J image analysis technique. Results The average optical density values of GR positive cells in hippocampus and prefrontal cortex, the average optical density values of DCX positive cells in hippocampal dentate gyrus subgranular zone in 3 d, 7 d, 14 d and 21 d group were(GR in hippocampus: 3 d((0.332±0.054)OD/μm2, 7 d(0.258±0.045)OD/μm2, 14 d(0.197±0.043)OD/μm2, 21 d(0.164±0.053)OD/μm2), (GR in prefrontal cortex: 3 d(0.356±0.043)OD/μm2, 7 d(0.278±0.041)OD/μm2, 14 d(0.220±0.039)OD/μm2, 21 d(0.157±0.034)OD/μm2)and(DCX in hippocampus: 3 d(0.193±0.020)OD/μm2, 7 d(0.146±0.033)OD/μm2, 14 d(0.110±0.032)OD/μm2, 21 d(0.060±0.017)OD/μm2)were lower than those in control group, which showed a decreasing trend with the increase of seperation time, and the average optical density values in 7 d, 14 d and 21 d group were obviously lower than those in control group(P<0.05). The average optical density values had statistical significance among the experimental groups(P <0.05). Conclusion MS can cause the decrease of GR in hippocampus and prefrontal cortex and reduce neurogenesis in the hippocampal dentate gyrus subgranular zone in young mice. It shows that the longer the seperation time, the greater the effect on hypothalamic-pituitary-adrenal(HPA) axis and neurogenesis. Key words: Maternal separation; Hippocampus; Prefrontal cortex; Glucocorticoid receptor; Doublecortin

リハビリテーションが神経保護・神経新生を増幅する

The primary cilium is a non-motile sensory antenna protruding from the surface of nearly all cells of the body, able to mediate the cellular response to extracellular signals. Although many of its functions remain to be clarified, it has been recently shown a role in neurogenesis [1]. In this study we evaluated the presence of the primary cilium in neurons isolated from the human fetal nucleus basalis of Meynert (hfnbM), a basal forebrain region crucially involved in the cholinergic transmission required for learning and memory. The hfnbM cells are characterized by the expression of cholinergic markers, such as choline acetyl transferase (ChAT) and also express the primary cilium, which, in basal conditions, was detected in the 17% of cells. It is known that nerve growth factor (NGF) supports survival, maintenance, connectivity and function of the brain cholinergic neurons. Indeed, we demonstrated that hfnbM cells respond to NGF in terms of proliferation, neurite formation and ChAT expression. Interestingly, NGF exposure significantly increased the percentage of ciliated cells (34.9%±1.8%). Given the known adverse effect of systemic chronic inflammation in the pathogenesis of neurodegenerative diseases, such as Alzheimer’s disease, characterized by the loss of nbM neurons, we exposed our cells to tumor necrosis factor-α (TNF-α). We observed that TNF-α significantly reduced the number of ciliated cells (4.3%±2%). Our results strongly suggest for the first time that primary cilia may be involved in the NGF-driven maturation of human nbM cholinergic neurons and suggest that the deleterious effects of neuroinflammation may be linked to an altered formation of the primary cilium.

Brain-derived neurotrophic factor (BDNF) is a potential marker both for the presence of psychiatric illnesses and for changes in clinical status, particularly mood disorders. Particularly intriguing are the increases in BDNF associated with neurogenesis and clinical improvement. Investigators conducted the first “transdiagnostic” study of BDNF in 236 consecutively admitted psychiatric inpatients (mean age, 45; 57% female) and …

Inflammatory demyelinating diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE) are often followed by cognitive deficits associated with the neuronal injury, synaptic loss and altered neurogenesis within the hippocampus. Changes depend on the genetic and epigenetic factors that ensure the cellular and environmental homeostasis and regulate the interactions of immunocompetent, glial and neural cells. Owing to high impact of stress proteins on these processes, in this study we compared the protein content of interleukin-6, transforming growth factor-β1, metallothioneins I/II (MTs) and glycoprotein 96 (gp96) in the hippocampus of DA and AO rats that differ in the susceptibility to the induction of EAE, and tested the relationship of MTs and gp96 to granule neurons, glial cells and neural progenitors in different subfields of dentate gyrus. Rats were immunized with bovine brain homogenate emulsified in complete Freund's adjuvant or only with CFA. The data showed that acute attack of EAE in DA rats was followed by accumulation of IL-6, TGF-β1 and MTs proteins, by increased expression of MTs in molecular and granular cell layer, by reduced expression of gp96/granular cell, by apoptosis and by microgliosis with appearance of Iba-1+ cells, co-expressing MT I/II and gp96. Furthermore, in subgranular zone (SGZ) of DA rats an augmented number of GFAP+ precursors, but decreased number of doublecortin (DCX)+ neuroblasts and immature NeuN+ neurons were found, implying that in DA rats the neurogenesis was delayed or reduced. Besides, in SGZ of both strains several DCX+ and NeuN+ cells co-expressing gp96 and MT I/II were found.

Mammalian cortical development is a multifaceted process that is under the control of precise transcriptional programs. During embryonic neurogenesis, neural progenitor cells undergo defined steps of differentiation to generate functional neurons at distinct stages of development. It is becoming increasingly clear that epigenetic mechanisms, including histone modifications, DNA methylation, chromatin remodeling and noncoding RNAs, play critical roles in specifying and maintaining cell-fates during neurogenesis. Furthermore, these mechanisms function in concert with each other and with sequence-specific transcription factors, emphasizing the collaboration between genetic and epigenetic mechanisms in driving neuronal fate. In this chapter, a comprehensive overview is provided of the epigenetic layers that underlie neurogenesis, along with prospective for future challenges in this exciting field. Keywords: histones; chromatin; post-translational modification of histones; DNA methylation; noncoding RNA; epigenetics; corticogenesis; neural progenitors; neurons

Objective To investigate the protective effect of hydrogen sulfide (H2S) on chronic unpredictable mild stress (CUMS)-induced damage in hippocampus of rats and explore potential mechanisms. Methods 40 SD rats were divided into four groups, including control, CUMS, CUMS co-treated with NaHS (1.68 mg/kg×14 d, ip) and CUMS co-treated with NaHS (5.6 mg/kg×14 d, ip) groups.After treatment with CUMS for 4 weeks, arrangement and morphology of hippocampal neuron were examined by HE staining, apoptosis of hippocampal neurons were measured by Tunel assay. Klotho expression was detected by ELISA. Meanwhile, the generation of H2S in the hippocampus was measured by spectrophotometry and the neurogenesis of hippocampus was detected by Brdu staining. Results The arrangement and morphology of CA3 hippocampal cells were disturbed and the neurogenesis in hippocampal DG region were inhibited in the CUMS group compared with control group.Moreover, the CUMS rats showed increased loss of hippocampal neurons(1.151±0.041, P<0.01), and the expression of klotho(0.910±0.032) and generation of H2S((0.445±0.025)nmol·mg-1·min-1) in CUMS rats were decreased in contrast to the control((0.621±0.019)nmol·mg-1·min-1, P<0.05). The sparse neuron and inhibited neurogenesis by CUMS in hippocampus of rats were improved by NaHS administration, and the loss of hippocampal neurons in CUMS + 1.68 mg/kg NaHS (1.032±0.023) or CUMS + 5.60 mg/kg NaHS(1.045±0.038) were decreased in contrast to the CUMS rats(P<0.01). Compared with CUMS group, the expression of klotho in CUMS + 1.68 mg/kg NaHS group(1.045±0.021)or CUMS + 5.6 mg/kg NaHS group(1.046±0.076) was up-regulated(P<0.05) and the generation of H2S in CUMS + 1.68 mg/kg NaHS group((0.582±0.008)nmol·mg-1·min-1)or CUMS + 5.6 mg/kg NaHS group((0.585±0.029)nmol·mg-1·min-1) was increased(all P<0.05). Conclusion H2S can antagonize the neural injury-induced by chronic stress probably by upregulating the expression of klotho protein, facilitating the production of H2S and promoting neurogenesis in hippocampus. Key words: Hydrogen sulfide; Chronic stress; Damage of hippocampus; Klotho; Neurogensis

Objective To investigate the effect of chronic stress on hippocampal neurogenesis. Methods Chronic unpredictable mild stress(CUMS) was used as animal model to provoke a decrease of neurogenesis in hippocampus. Simultaneously, hippocampal neurogenesis was monitored by assessing cell proliferation, survival, and differentiation. All rats were divided into control group, 14d CUMS group, 28d CUMS group. Results The cell proliferation in 14d CUMS group(2254.17±164.41) or 28d CUMS(1900.33±104.10) group were decreased contrast to the control (2919.50±188.80) (P 0.05). Conclusion These results suggest that chronic stress decreases cell proliferation and survival, but does not affect the phenotype of newborn cells in the hippocampus. Key words: Chronic unpredictable mild stress; Neural stem cell; Hippocampus

Current concepts of the mechanism of depressive illness have shifted from neurotransmitters to defects in nerve-cell growth (neurogenesis) in

The Zfp423 gene encodes a 30-Zn-finger transcription factor that acts as a scaffold for the assembly of complex transcriptional and cellular machineries regulating neural development. While null Zfp423 mutants feature a sharp decrease in the total number of cerebellar Purkinje cells (PCs), the underlying mechanisms remain unclear. Mutations of the human homolog ZNF423 have been identified in patients carrying cerebellar vermis hypoplasia (CVH) or Joubert Syndrome (JS), associated with other signs of classical ciliopathy outside the central nervous system. To further characterize the role of ZFP423 in cerebellar neurogenesis, we have performed morphological, cellular and molecular studies on two mutant mouse lines carrying allelic in-frame deletions of Zfp423. While both lines exhibit cerebellar hypoplasia, considerable differences are observed between the two mutants, with respect to neural progenitor differentiation, cell survival and morphogenesis. The results of this in vivo and in vitro structure-function analysis point to domain- and context-specific roles played by ZFP423 in different aspects of cerebellar development, and contribute to our understanding of its role as a disease / modifier gene in JS, CVH and other ciliopathies.

Cell surface heparan sulfate proteoglycans as novel markers of human neural stem cell fate determination

Aging is an inevitable physiological process that leads to the dysfunction of various tissues, and these changes may contribute to certain diseases, and ultimately death. Recent research has discovered biological pathways that promote aging. This review focuses on Wnt signaling, Wnt is a highly conserved secreted signaling molecule that plays an essential role in the development and function of various tissues, and is a notable factor that regulates aging. Although Wnt signaling influences aging in various tissues, its effects are particularly prominent in neuronal tissue and skeletal muscle. In neuronal tissue, neurogenesis is attenuated by the downregulation of Wnt signaling with aging. Skeletal muscle can also become weaker with aging, in a process known as sarcopenia. A notable cause of sarcopenia is the myogenic-to-fibrogenic trans-differentiation of satellite cells by excessive upregulation of Wnt signaling with aging, resulting in the impaired regenerative capacity of aged skeletal muscle. However, exercise is very useful for preventing the age-related alterations in neuronal tissue and skeletal muscle. Upregulation of Wnt signaling is implicated in the positive effects of exercise, resulting in the activation of neurogenesis in adult neuronal tissue and myogenesis in mature skeletal muscle. Although more investigations are required to thoroughly understand age-related changes and their biological mechanisms in a variety of tissues, this review proposes exercise as a useful therapy for the elderly, to prevent the negative effects of aging and maintain their quality of life.

Chicken ovalbumin upstream promoter-transcription factors (COUP-TFs) are the orphan receptors of the steroid/thyroid hormone receptor superfamily. These factors include COUP-TFⅠ and COUP-TF Ⅱ, which play critical roles in embryonic development, organogenesis, neurogenesis and cellular differentiation. Many studies showed that COUP-TFs were also involved in the development of embryonic eye. More attention has been paid to the issue that mutations of COUP-TFs genes lead to phenotypes of coloboma, small eyes, optic atrophy, eye retardation, strabismus, and amblyopia. However, the mechanisms of COUP-TFs regulating the development of embryonic eye are not clear. The origin, molecular struture, classification, biological functions, mechanisms of regulating the target genes transcription and development of embryonic eye of COUP-TFs were reviewed. Key words: COUP transcription factorⅠ; COUP transcription factor Ⅱ; Development of embryonic eye; Retinal development

To identify novel lncRNAs involved in cerebellar neurogenesis using neuronal specific Nbs1-deficient (Nbs1(CNS-del)) mouse model. Microarray analysis was performed to identify differentially expressed lncRNAs between Nbs1(CNS-ctr) and Nbs1(CNS-del) mice. Expression profiles of lncRNA Gm15577 and coding gene Negr1 in mice, primary cerebellar culture and cell lines were measured using RT-qPCR. Subcellular fractionation was performed to determine the subcellular localization of Gm15577. Gm15577 was specifically expressed in mice cerebellum in a developmentally regulated manner, which could be abolished upon Nbs1-deficiency. Gm15577 was located in the intronic region of Negr1 in a reversed orientation. Gm15577 modulated the RNA expression of Negr1, Shh and β-catenin. NEGR1 had a distinct expression pattern between normal and medulloblastoma patients. Gm15577 may modulate cerebellar granule cell proliferation and differentiation by targeting Negr1, and their dysfunctions or abnormal expression may be related to tumorigenesis of medulloblastoma.

Vascular endothelial growth factor (VEGF) have multiple protective effect on the nervous system which related to angiogenesis, neurogenesis, directly neurotrophic protection and antiapoptotic mechanisms .The study of the nervous system of VEGF focus on tumors, trauma, stroke, autoimmune diseases and neurodegenerative diseases.The study of VEGF related to epileptic seizures is relatively rare.This paper is to make a review about the neuroprotective effect of VEGF on epileptic seizure. Key words: Vascular endothelial growth factor; Epilepsy; Neuroprotective effect

Objective To evaluate the relieving effects of vanillin sinffing on depression-like behaviors in depressed rats and to explore the possible underlying mechanism. Methods Depression animal model established by chronic unpredictable medium intensity stress combined with isolation and destroy the olfactory bulb. The depressed rats were divided randomly into vanillin inhalation group, fluoxetine hydrochloride group, depression model group, olfactory bulbectomy with the vanillin inhalation treatment group and sham-operated group. Nervous behavioral changes had been observed at different time after the administration of 5 weeks. The concentration of brain derived neurotrophic factor(BDNF) in the brain homogenate and the positive expression of BDNF in hippocampus had been also measured. Results Two weeks after the intervention, the immobility time of vanillin group((12.78±7.50)s) was lower than that of the model group((57.33±32.16)s)(P<0.05). The consumption of saccharose in vanillin group((52.88±25.18)g) was higher than that of model group((37.40±19.33)g)(P<0.05). BDNF of the brain homogenate in vanillin group (0.54±0.13) was significantly increased compared with model group (0.36±0.06) (P<0.01). When compared with the OBX group (0.40±0.06), similar result was obtained. Immunohistochemistry and the average density of image analysis revealed that the expression of BNDF of hippocampal CA3 in vanillin group (0.40±0.03)was significantly increased compared with model group (0.25±0.04) and OBX group(0.28±0.03)(P<0.01). Conclusion Vanillin inhalation significantly relieves depression-like behaviors in depression rats .The possible mechanism may increase hippocampal neurogenesis by raising brain derived neurotrophic factor in brain. Key words: Vanillin; Olfactory pathway; Depressive disorder; Brain derived neurotrophic factor

Objective To investigate the expression of survivin after traumatic brain injury(TBI);and the relationship between the up- regulation of survivin and endogenous neurogenesis. Further to demonstrate the role of increased survivin to promote the adult neurogenesis, and detect the possible mechanism in this process.Finally to find the approach that can promote restoration of nervous function after TBI. Methods A-dult male C57BL/6 mice, total n= 80, were randomly divided into sham- operation group and TBI group. Mice in TBI and sham- operation group were sacrificed at 12 hours, 1, 2, 5, 7 and 14 days post TBI and sham- operation(n= 6 for each point), and hippocampus tissues from the ipsilateral hemispheres were carried out for Western blotting.Double- label immunofluorescence staining was adopted to detect survivin expression in difference kinds of cells in the hippocampus(n= 4). Results The up- regulation of survivin protein starting at day 1(42 003.15, P<0.05)and lasting to day 7, peaking at day 2(90 403.34, P<0.01). The number of survivin+, Brd U+ and doublecortin(DCX+) cells in subgranular zone(SGZ) of ipsilateral hippocampus was significantly increased after TBI by immunofluorescence staining. The results also revealed that the majority of survivin+ cells were BrdU+ cells,and a part of survivin+ cells were DCX+ cells in SGZ of dentate gyrus(DG)in the hippocampus. Conclusion Survivin gene was activated follow brain injury. The expression of survivin protein were increased in the hippocampus after TBI. Increased survivin protein is expressed in neural stem cells and immature neurons in ipsilateral hippocampus after TBI, which correlate to the proliferation of neurogenic cell in SGZ of hippocampus. Key words: Survivin; Traumatic brain injury; Hippocampus; Adult neurogenesis

Objective To explore the effect of neural stem cells (NSCs) transplantation on neurogenesis in an alzheimer'disease mouse model and its related mechanism. Methods A total of 16 12-month-old aPP/PS1 double transgenic aD mice were randomly divided into two groups: NSC group (receiving NSCs transplantation in the bilateral hippocampi, n=8) and PBS group as the negative control group (receiving an equal quantity of 0.01M/L phosphate buffer saline, n=8). another 8 wild type mice without any treatment were selected as the positive control group (Wt group). at five weeks after transplantation, the expressions of doublecortin (DCX) and nestin in the hippocampal dentate gyrus (DG) and subgranular zone (SGZ) were analyzed by immunofluorescence staining, the number of positive cells in these regions were counted by confocal microscopy, and Morris water maze (MWM) test was used to assess cognitive function in all mice. Results NSC group showed the enhanced spatial learning and memory ability in Morris water maze (MWM) as compared to PBS group, but it was still lower than that in Wt mice (both P 0.05). Conclusions NSCs transplantation can promote endogenous neurogenesis via the increased expression of DCX- and Nestin-positive cells in the hippocampal DG/SGZ in aD mice, which improves the cognitive abilities in aD mice in some extent. Key words: Alzheimer disease; Stem cells transplantation

To explore the effect of whole brain irradiation (WBI) on neurogenesis in hippocampus and its relationship with histone acetylation. A signal dose of 30Gy 4MeV electron beam was offered to male Sprague-Dawley rats (150 - 200 g). At Days 7 and 30, immunohistochemistry and Western blot were used to analyze the effects of WBI on neurogenesis and the expression of acetyl-H3 and histone deacetylase 1 (HDAC1) in hippocampus. Finally trichostatin A (TSA), a HDAC1 inhibitor, was used to verify whether H3 acetylation was associated with neurogenesis impairment. Immunofluorescence showed that, at Day 7 post-irradiation, the number of BrdU + NeuN + cells reduced by 67% (P < 0. 01) and it approached zero at Day 30 (P < 0. 01). Meanwhile, a significant decrease of HDAC1-dependent H3 acetylation was observed. Western blot showed 30% (P <0. 05) and 61% (P < 0. 01) reductions in H3 acetylation at Days 7 and 30 post-irradiation respectively. These results were further confirmed by immunofluorescent staining. Also HDAC1 levels significantly increased in a time-dependent manner at Days 7 and 30 post-irradiation. And TSA rescued neurogenesis impairment after WBI. Radiation-induced HDAC1-dependent H3 acetylation decline is associated with long-term neurogenesis impairment in dentate gyrus.