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AIM:To investigate the effect of doublecortin-like kinase 1(DCLK1)on the biological properties of gastric cancer stem cells,and to explore its possible mechanism.METHODS:Serum-free suspension culture of gastric cancer stem cells and targeted inhibition of DCLK1 activity in gastric cancer stem cells with DCLK1 inhibitor DCLK1-IN-1 were performed.The expression levels of DCLK1,stemness-related proteins(SOX2 and OCT4),proliferation-related pro-teins(cyclin D1 and c-MYC),drug resistance-related proteins(ABCG2 and TOP2A),epithelial-mesenchymal transition-related proteins(E-cadherin,vimentin and Snail),and PI3K/AKT/mTOR signaling pathway-related proteins in gastric cancer stem cells were examined by Western blot.The effects of DCLK1 on viability and drug resistance of gastric cancer stem cells were determined by CCK-8 assay,and the effects of DCLK1 on self-renewal of gastric cancer stem cells were de-termined by methylcellulose spheroid-forming assay.Wound-healing and Transwell assays were performed to assess the ef-fect of DCLK1 on the migration and invasion of gastric cancer stem cells.RESULTS:The expression levels of DCLK1 and stemness-related proteins SOX2 and OCT4 in gastric cancer stem cells were significantly higher than those in parental cells(P<0.01).The proliferation,drug resistance,migration and invasion of gastric cancer stem cells in DCLK1 inhibi-tion group were significantly lower than those in Sphere cell group(P<0.01).The expression levels of proliferation-related proteins(c-MYC and cyclin D1)and drug resistance-related proteins(TOP2A and ABCG2)were down-regulated,the ex-pression of epithelial marker E-cadherin was up-regulated,the expression of mesenchymal markers vimentin and Snail was down-regulated,and the expression levels of PI3K/AKT/mTOR signaling pathway-related proteins and their phosphoryla-tion levels were reduced in DCLK1 inhibition group(P<0.05).CONCLUSION:DCLK1 is highly expressed in gastric cancer stem cells,which may be involved in the proliferation,drug resistance and invasion of gastric cancer stem cells by regulating PI3K/AKT/mTOR signaling pathway.It suggests that DCLK1 can be used as a potential target for gastric cancer stem cells.
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Objective To investigate the effects of doublecortin-like kinase 1 (DCLK1) on the malignant biological behaviors, such as proliferation, migration, and invasion, of A549 cell line and their corresponding mechanisms. Methods DCLK1-overexpressing A549 cell lines were established through lentiviral infection, and DCLK1 expression was validated by using RT-PCR and Western blot analysis. Proliferation ability was assessed with CCK-8 and plate cloning assays, and migration and invasion abilities were examined with Transwell assays. The pathway regulated by DCLK1 in lung adenocarcinoma was analyzed on the basis of the TCGA lung adenocarcinoma cohort with pathway enrichment analysis and verified through Western blot analysis. Results DCLK1 overexpression in A549 cells promoted cell proliferation, migration, and invasion. The inhibition of the FAK/PI3K/AKT/mTOR signaling pathway impaired the DCLK1-mediated malignant behavior of A549 cells. Conclusion DCLK1 promotes the malignant behavior of A549 cells through the activation of the FAK/PI3K/AKT/mTOR signaling pathway.
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@#Objective To investigate the value of receiver operating curve human papilloma virus(HPV)-DNA typing combined with serum neutrophil lymphocyte ratio(NLR)and bicorticoid kinase 1(DCLK1)levels in the early diagnosis of cervical cancer.Methods A total of 120 patients with early cervical cancer diagnosed in our obstetrics and gynecology department from August 2018 to June 2022 were randomly included as cervical cancer group,and 120 patients with benign lesions were included as benign group.The level of DCLK1 was detected by ELISA;NLR was detected by automatic blood cell analyzer;HPV subtypes in cervical secretions were detected by HPV genotyping gene chip detection system;the cut-off values of serum NLR and DCLK1 levels in the diagnosis of cervical cancer were analyzed by using the receiver operator curve(ROC);four table method was applied to analyze the diagnostic value of HPV-DNA typing,serum NLR,DCLK1 levels alone and in combination for cervical cancer.Results Compared with benign group,the levels of serum NLR and DCLK1 in cervical cancer group were obviously higher(P<0.05).The positive rate of HR-HPV in cervical cancer group was obviously higher than that in benign group(P<0.05).The ROC curve was drawn with serum NLR and DCLK1 levels as test variables,the results showed that the AUC of serum NLR and DCLK1 predicting early cervical cancer was 0.724 and 0.718,respectively,and the cut-off value was 3.08 and 3.32,respectively.HPV-DNA typing combined with serum NLR and DCLK1 detected 18 false positives and 17 false negatives,Kappa value was 0.725,which was consistent with pathological results.The sensitivity,negative predictive value and accuracy of HPV-DNA typing combined with serum NLR and DCLK1 levels in the diagnosis of early cervical cancer were obviously higher than those of HPV-DNA typing,serum NLR and DCLK1 levels alone(P<0.05).Conclusion The results of HPV-DNA typing combined with NLR and DCLK1 in the diagnosis of early cervical cancer are highly consistent with the pathological results,and the sensitivity and accuracy are obviously improved.
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OBJECTIVE@#To investigate the mechanism by which doublecortin promotes the recovery of cytoskeleton in arginine vasopressin (AVP) neurons in rats with electrical lesions of the pituitary stalk (PEL).@*METHODS@#Thirty-two SD rats were randomized into PEL group with electrical lesions of the pituitary stalk through the floor of the skull base (=25) and sham operation group (=7), and the daily water consumption (DWC), daily urine volume (DUV) and urine specific gravity (USG) of the rats were recorded. Four rats on day 1 and 7 rats on each of days 3, 7 and 14 after PEL as well as the sham-operated rats were sacrificed for detection of the expressions of β-Tubulin (Tuj1), doublecortin and caspase- 3 in the AVP neurons of the supraoptic nucleus using immunofluorescence assay and Western blotting.@*RESULTS@#After PEL, the rats exhibited a typical triphasic pattern of diabetes insipidus, with the postoperative days 1-2 as the phase one, days 3-5 as the phase two, and days 6-14 as the phase three. Immunofluorescent results indicated the repair of the AVP neurons evidenced by significantly increased doublecortin expressions in the AVP neurons following PEL; similarly, the expression of Tuj1 also increased progressively after PEL, reaching the peak level on day 7 after PEL. The apoptotic rates of the AVP neurons exhibited a reverse pattern of variation, peaking on postoperative day 3 followed by progressive reduction till day 14. Western blotting showed that the expressions of c-Jun and p-c-Jun were up-regulated significantly on day 3 ( < 0.05) and 7 ( < 0.01) after PEL, while an upregulated p-JNK expression was detected only on day 3 ( < 0.05), as was consistent with the time-courses of neuronal recovery and apoptosis after PEL.@*CONCLUSIONS@#JNK/c-Jun pathway is activated after PEL to induce apoptosis of AVP neurons in the acute phase and to promote the repair of neuronal cytoskeleton by up-regulation of doublecortin and Tuj1 expressions.
Subject(s)
Animals , Rats , Apoptosis , Arginine Vasopressin , Pharmacology , Cytoskeleton , Metabolism , MAP Kinase Signaling System , Neurons , Cell Biology , Pituitary Gland , Cell Biology , Wounds and Injuries , Proto-Oncogene Proteins c-jun , Metabolism , Random Allocation , Rats, Sprague-Dawley , Regeneration , Tubulin , MetabolismABSTRACT
OBJECTIVE: To observe the effect of "Huayu Tongluo"(Blood-stasis Dispersing and Meridian-collateral Dredging) moxibustion on the delayed memory and expression of Nestin and Doublecortin (DCX) proteins in the hippocampus in vascular dementia (VD) rats in the view of neurogenesis produced by intracerebral transplantation of neural stem cells (NSCs) and endothelial progenitor cells (EPCs). METHODS: Healthy male Wistar rats were randomized into control group, VD model group,NSCs+EPCs group and NSCs+EPCs moxibustion group. The VD model was established by using a modified 2-vessels occlusion method, and neurogenesis was produced by transplantation of NSCs+EPCs (2×106cell/10 µL) into the lateral ventricle for rats of the NSCs+EPCs groups 3 days after successful VD-modeling. Moxibustion was applied to "Dazhui" (GV 14), "Baihui" (GV 20) and "Shenting" (GV 24) once daily for 21 days with an interval of one day between every two 7 days. The Morris Water Maze was used to test the rat's delayed memory ability before and 24 h after the treatment. The expression of Nestin and DCX proteins in the hippocampus tissues was detected using double-labeled immunofluorescence technique. RESULTS: Following modeling, Morris Water Maze tests showed that the average escape latency of location navigation task was significantly prolonged in VD rats(P<0.008)and the times of target platform crossing (spatial probing task) within 120 s were remarkably reduced in VD rats (P<0.008). Compared with pre-treatment in the same one group, the escape latency of NSCs+EPCs and NSCs+EPCs moxibustion groups were considerably reduced (P<0.05), and the average times of target platform crossing of the NSCs+EPCs moxibustion group were markedly increased(P<0.05). The effect of NSCs+EPCs moxibustion was evidently superior to that of simple NSCs+EPCs in shortening the escape latency (P<0.008). The expression levels of Nestin protein were significantly higher in the NSCs+EPCs moxibustion group after 1 and 3 period treatment than those in the NSCs+EPCs group (P<0.05).. CONCLUSION: Moxibustion intervention is able to improve the delayed memory in VD rats, which may be related to its effect in up-regulating the expression of hippocampal Nestin and DCX proteins within 15 days via accelerating neurogenesis.
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Objective To investigate the neurodevelopmental toxicity of ACR by studying the expression of DCX and GAP-43 in the hippocampal dentate gyrus of rats after maternal exposure to acrylamide. Methods Pregnant rats were randomly divided into low-dose ACR(4.5 mg/kg),medium-dose(9 mg/kg),high dose groups(18 mg/kg)and the control group(0 mg/kg),8 in each group,and were exposed to toxicant from gestation-al day 15 to postnatal day 13. All rats and their pups were killed on postnatal day 14. ABC immunohistochemistry was used to detect the expression of GFAP in the hippocampus of mother rats and offspring. Results Compared with the control group,the expression of DCX and GAP-43 in hippocampus dentate gyrus of the pregnant rats in middle and high dose groups was significantly decreased(P < 0.05). Conclusion ACR may interfere with the growth and development of neurons by reducing the expression of DCX and GAP-43.
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Objective To investigate the effect of quetiapine (QUE) on the memory and doublecortin (DCX) expression in the hippocampus of C57BL/6 mice with cuprizone (CPZ)-induced schizophrenia in C57BL/ 6 mice.Methods 1% dimethyl sulfoxide (DMSO) was used as a vehicle to dissolve QUE.Three group of mice,16 in each of three groups,were treated with vehicle (control group),0.2% CPZ alone (CPZ group) or 0.2% CPZ combined with 10 mg· kg-1 · d-1 QUE (QUE+CPZ group) for six weeks,respectively.Spatial working memory was evaluated by Y-type maze test 24 hours after the completion of the treatment period.The number of DCX positivenew neurons was calculated by immunofluorescence staining assay.The expression of Notch1 and Hes1 mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR) assay.Results (1) Y-maze test:CPZ group achieved a much lower percentage of correct alternation than control group ((22.70±6.70) % vs (57.69 ±6.70)%) in Y-maze test (P<0.05).The percentage of correct alternation in CPZ + QUE group ((54.69± 10.06) %) was significantly increased compared with CPZ group (P<0.01).CPZ mice exhibited significant spatial working memory impairment.(2) Immunofluorescence staining:the number of DCX-positive cells in the hippocampus of the CPZ group (6342.85± 1801.72) was significantly decreased compared with that in control group (19428.57±2507.13) (P<0.01),and it was reversed by QUE intervention (15928.57±2049.97).(3) RT-PCR:the Notch1 and Hes1 mRNA expression in CPZ group were significant lower than that in sham and CPZ + QUE group,(Notch1 (0.97±0.29) vs (0.23±0.20),P<0.01);Hes1 (1.00±0.41) vs (0.38±0.30),P<0.01),and there was no significant difference between sham group and CPZ + QUE group.Conclusion QUE is helpful to relieve CPZ-induced cognitive impairment and decreases expression of DCX in hippocampal,which may be related with activation of Notch1 pathway.
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Objective: To examine the plasmic expression level of doublecortinlike kinase 1 (DCLK1) in patients with colorectal cancer and explore its diagnostic value through comparing with carcinoembryonic antigen (CEA). Methods: The plasma samples were obtained from 78 patients with colorectal cancer before surgical operation and 48 healthy volunteers. The plasmic expression levels of DCLK1 and CEA were examined by enzyme-linked immunosorbent assay (ELISA). The sensitivity, specificity and accuracy of DCLK1 and CEA alone as well as in combination for diagnosis of colorectal cancer were compared. The relationships of the plasmic expression levels of DCLK1 and CEA with the clinicopathological features were analyzed. Results: The plasmic expression levels of DCLK1 and CEA in patients with colorectal cancer were both higher than those in the healthy volunteers (both P < 0.01). The sensitivity and accuracy of DCLK1 for diagnosis of colorectal cancer were both higher than those of CEA. The combination of DCLK1 and CEA could further improve the sensitivity and accuracy of diagnosis. The plasmic expression level of DCLK1 had a significant impact on TNM staging, degree of differentiation, lymph node metastasis and vascular invasion (all P < 0.01). Conclusion: Plasmic DCLK1 is expected to become a novel tumor biomarker for diagnosis of colorectal cancer, and it is associated with the grade of malignancy.
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ObjectiveTo investigate the effects of maternal thyroid dysfunction during pregnancy caused by iodine deficiency of different degrees on doublecortin ( DCX ) and synaptophysin ( p38 ) expressions in fetal brain.Methods Wistar female rats were randomly divided into four groups:adequate iodine ( AI),mild iodine deficiency ( MiID ),moderate iodine deficiency ( MoID ),and severe iodine deficiency ( SID ),according to the total daily iodine supply( fed on an iodine deficient diet with different dosages of KI added in drinking water).Three months later the rats were mated.Serum TSH and thyroid hormones were determined in maternal rats on gestational day 20 using chemiluminescent immunoassay.The iodine contents in urine and histological changes of thyroid gland were observed in pregnant rats.The mRNA and protein levels of DCX and synaptophysin ( p38 ) were analyzed in fetal brain by using real time quantitative RT-PCR and western blotting respectively.Results( 1 ) Iodine contents in urine of pregnant rats were reduced with the decrease of their iodine supply.Compared with group AI,serum TSH was significantly increased [ ( 2.95 ± 1.70 vs 1.31 ± 0.55 ) mU/L,P < 0.05 ],and both TT4 and FT4 were significantly decreased [ ( 14.3±4.1 vs 28.4±19.3 ) nmol/L,P<0.05 ] and [ ( 10.8±3.6 vs 20.2±8.0) pmol/L,P<0.01 ] in pregnant rats of SID group.Whereas,a slight rise in TSH,and a mild decline in both TT4and FT4 were found in MoID and MiID groups.However,there were no significant changes in TT3 and FT3 levels among these four groups.( 2 )Histological characteristics of thyroid gland in pregnant rats showed a typical goiter with small follicular hyperplasia and lack of colloid in SID group,moderate follicular hyperplasia with decreased colloid in MoID group; but mild cellular hyperplasia without decrease in follicular size and colloid in MiID group.( 3 ) The mRNA levels of DCX were increased in fetal brains of three iodine deficiency groups compared with AI group,but a statistical significance was found in MoID group.The protein levels of DCX in all experiment groups were significantly increased.Both mRNA and protein expressions of synaptophysin ( p38 )were significantly down-regulated in three iodine deficiency groups.Conclusions Maternal thyroid dysfunction caused by iodine deficiency,even by mild or moderate iodine deficiency,may lead to retardation of fetal neuronal and synaptic growth.
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New neuron formation in the adult brain extends our knowledge and incorporates a novel dimension about brain plasticity. Adult neurogenesis is a complex process regulated by different factors within the niche, where adult neural stem cells reside, proliferate and differentiate. Neural stem cell together with astrocytes and endothelial cells form the principle components of this complex niche. Other molecular factors that regulate adult neurogenesis are the neuro-transmitters (GABA, glutamate, serotonin, dopamine); hormones (prolactin, growth hormone, estrogens and melatonin); growth factors (FGF, EGF, VEGF) and neurotrophins (BDNF, NT3). All of them regulate different aspects of the neurogenic process. Behavioral regulators that influence new neuron formation in the adult brain include physical activity, complex stimulatory environment best known as enrichment environment, and social interaction. Voluntary physical activity with free access to the running wheel increases the number of proliferating cells, while the complex stimulatory environment provided by enriched environment preferentially influences survival of newborn cells. In addition, social interaction has a positive influence on the new neuron formation in the dentate gyrus (DG). Although adult hippocampal neurogenesis is positively regulated by the aforementioned factors, there are different conditions with negative influence on this process. Some of these conditions are stress exposure and sleep deprivation. Both conditions are present in neuropsychiatric diseases such as depression, anxiety and schizophrenia. Thus, stress and sleep deprivation impair adult hippocampal neurogenesis. Alteration of the neurogenic process following stress occurs due to the high levels of glucocorticoid receptors within the hippocampus and because exposure to stress causes the increase in glucocorticoid levels. Preclinical studies have shown that exposure to different classes of stressors affect hippocampal neurogenesis. Prolonged exposure to stressors (chronic mild stress), predatory odor, foot shock, acute force swimming and psychosocial stress not only affect mature neuronal plasticity but also hippocampal neurogenesis. Although there is information about the effects of stress on adult neurogenesis, the mechanism by which stress causes inhibition of hippocampal neurogenesis remains unclear. Recent work showed that exposure to stress increases the pro-inflammatory cytokine interleukin-1 β (IL-1 β) in several brain areas. Also, administration of IL-1β exerts stress-like effects including down-regulation of hippocampal brain derived neurotrophic factor (BDNF). Additionally, inhibition of the receptor for IL-1β prevents stress-like effects. Moreover, the suppression of cell proliferation is mediated by direct actions of IL-1 β on IL-1RI receptors localized on precursor cells. These findings support that IL-1 β is a critical mediator of the antineurogenic effect caused by acute and chronic stress. However, IL-1 β is not the unique mediator of stress that could be involved in the alteration of adult hippocampal neurogenesis. Recently it was reported that the decrease in cell proliferation concomitantly occurs with an increase of IL6 and TNFα levels. Preclinical studies have suggested that adult hippocampal neurogenesis is not a sole cause of depression or the sole mechanism of treatment efficacy, but it is likely an important contributor to this complex disorder. In order to revert the effects of stress on adult hippocampal neurogenesis, different therapies have been used, for example: electroconvulsive therapy (ECT), exercise, complex stimulatory environment and antidepressant drugs. Although the most rapid induction of neurogenesis is seen with ECT application, most studies have been done with antidepressant drugs. The effects of antidepressants are time-dependent as highest therapeutic effects are observed within the time course of weeks. Different types of antidepressants (serotonin and norepinephrine reuptake inhibitors, monoamine oxidase inhibitors and atypical antidepressants) have been used to study their influence on the neurogenic process. Despite that serotonin reuptake inhibitors are the most prescribed treatments for major depression and that the therapeutic effects of antidepressants require chronic treatment, the mechanisms by which these drugs exert their effects on hippocampal neurogenesis are still unknown. Although serotonin reuptake inhibitors are very fast in increasing serotonin levels, the antidepressant action is delayed possibly because of the induction of structural or functional changes that possibly need longer time (2-4 weeks). In this regard, one of the actions of antidepressants is the regulation of adult hippocampal neurogenesis, a process that is consistent with the delayed onset of therapeutic effects of antidepressants. Fluoxetine is one of the antidepressants more used to study its influence on adult neurogenesis. Fluoxetine targets amplifying neural progenitors by increasing the rate of symmetric divisions without altering the division of stem-like cells in the DG. Considering previous classification based on the temporal protein markers expression, the neural progenitors targeted by fluoxetine correspond to type 2a, 2b and type 3. In addition, the increase in new neurons caused by fluoxetine is due to the expansion of neural progenitors. In addition to cell proliferation, the neurogenic process also involves a maturation step, which is associated with the expression of doublecortin, a protein that binds to microtubules and that is expressed along the cytoplasm of the cell. Further maturation of immature neurons such as dendrite maturation, is controlled independently of the regulation of precursor cell proliferation. Thus, micro-regulatory events influence the course of adult hippocampal neurogenesis. Here, fluoxetine also affects dendrite maturation and functional integration of new neurons. Chronic fluoxetine treatment modifies dendrite morphology increasing dendrite arborisation and favors synaptic plasticity of newborn granule cells. Also, chronic administration of fluoxetine causes behavioral improvement, an effect that was blocked when neurogenesis was ablated by X-ray irradiation. Other important factor that influences the effect of antidepressants on adult neurogenesis is the genetic background. Then antidepressants induced behavioral improvement depending on the genetic background of the mouse strain used. Preclinical studies in mice have revealed different actions of antidepressants on adult hippocampal neurogenesis. However, studies in humans are scarce and deserve greater attention to discover the correlation between preclinical and clinical studies. Recent work in human brains shows contradictory evidences about the regulation of neuronal development by antidepressants. These evidences are in the same line as recent published work in which it was demonstrated that the effects of ADs are age-dependent. Altogether, multiple evidences indicate that antidepressants affect several aspects of the neurogenic process. Therefore, chronic treatment is necessary for the antidepressant-dependent regulation of adult hippocampal neurogenesis. In addition, it has been shown that antidepressants act through different pathways involving both neurogenesis-dependent and neurogenesis-independent actions. Although there is an important increase in the adult hippocampal neurogenesis field, it is necessary to increase the number of studies performed in human beings to correlate the preclinical findings with clinical studies to address the role of adult neurogenesis in neuropsychiatric disorders.
El hallazgo de la formación de nuevas neuronas en el giro dentado (GD) del hipocampo amplió el conocimiento acerca de la plasticidad del encéfalo. En este sentido, la neurogénesis es un proceso que involucra diferentes eventos celulares tales como: la división de las células madre, la proliferación de los neuroblastos, la migración y la sobrevivencia celular, así como la maduración dendrítica, la elongación axonal y la integración de las neuronas nuevas a los circuitos neuronales existentes. En conjunto, todas estas etapas causan cambios estructurales y funcionales en el cerebro. Por lo tanto, la formación de neuronas es un proceso regulado de manera fina por diferentes factores entre los que se incluyen: el nicho; algunos neurotransmisores como la serotonina, la dopamina, el glutamato y el GABA; factores de crecimiento como el factor de crecimiento de fibroblastos, el factor de crecimiento epidermal y el factor de crecimiento vascular endotelial (FGF, EGF y VEGF, por sus siglas en inglés); neurotrofinas como el factor neurotrópico derivado del cerebro y por la neurotrofina 3 (BDNF y NT3, por sus siglas en inglés). Aunado a la existencia de factores que favorecen la neurogénesis hipocámpica, también hay factores que influyen de manera negativa en la formación de neuronas. Entre éstos se encuentra el estrés, el cual se relaciona con algunas enfermedades neuropsiquiátricas como la depresión y la ansiedad. A este respecto, estudios preclínicos han revelado que la aplicación de diferentes tipos de estresores puede afectar la plasticidad neuronal al inducir alteraciones morfológicas y funcionales en el hipocampo, así como afectar el proceso neurogénico. Las alteraciones causadas por el estrés se han relacionado con un aumento considerable y sostenido de los niveles de glucocorticoides. Esto último afecta el proceso neurogénico debido a que el hipocampo es una estructura cerebral que expresa niveles altos de receptores para estas hormonas. Al ser activados de forma persistente, los receptores a glucocorticoides causan una alteración en la neuroplasticidad hipocámpica. De tal modo y considerando lo anterior, teorías recientes han asociado un fallo en la formación de neuronas en el hipocampo con algunos trastornos psiquiátricos como la demencia, la esquizofrenia y la depresión. No esta del todo elucidado el mecanismo a través del cual el estrés altera el proceso neurogénico. Sin embargo, trabajos recientes han revelado que la exposición a estrés causa un aumento en los niveles de ciertas citocinas proinflamatorias, tales como la interleucina-1 β (IL-1 β). El aumento en los niveles de esta citocina provoca un efecto tipo depresivo y una disminución en los niveles del BDNF, así como una alteración en la formación de nuevas neuronas. Estos hallazgos apoyan la idea de que la IL-1 β es un mediador crítico del efecto antineurogénico causado por el estrés crónico y agudo. Sin embargo, la IL-1 β no es la única citocina asociada con las alteraciones en el proceso neurogénico, ya que recientemente se reportó que la disminución en la proliferación celular causada por el estrés ocurre de manera paralela con el aumento en la expresión de los mensajeros de la IL-6 y del TNF-α. Una manera de contrarrestar los efectos del estrés sobre la plasticidad neuronal es a través de la administración de fármacos antidepresivos. Diversos trabajos han mostrado que el tratamiento crónico con este tipo de fármacos revierte las alteraciones en la neurogénesis hipocámpica y en la plasticidad neuronal causadas por el estrés. Finalmente, aun cuando existen evidencias del papel que desempeña la neurogénesis en modelos animales de algunas enfermedades neuropsiquiátricas y de la forma en que los fármacos antidepresivos favorecen la formación de neuronas, es importante contar con más estudios en humanos que permitan corroborar los hallazgos que se han obtenido en los estudios preclínicos. De algún modo todos los reportes apuntan a que los fármacos antidepresivos pueden actuar por mecanismos independientes o dependientes de la neurogénesis hipocámpica.
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The hippocampus makes new memories and is involved in mental cognition, and the hippocampal dentate gyrus (DG) is critical because neurogenesis, which occurs throughout life, occurs in the DG. We observed the differentiation of neuroblasts into mature neurons (granule cells) in the DG of C57BL/6 mice at various early postnatal (P) ages: P1, P7, P14, and P21 using doublecortin (DCX) immunohistochemistry (IHC) for neuroblasts and calbindin D-28k (CB) IHC for granule cells. DCX-positive cells decreased in the DG with age; however, CB+ cells increased over time. At P1, DCX and CB double-labeled (DCX+CB+) cells were scattered throughout the DG. At P7, DCX+CB+ cells (about 92% of CB+ cells) were seen only in the granule cell layer (GCL) of the dorsal blade. At P14, DCX+CB+ cells (about 66% of CB+ cells) were found in the lower half of the GCL of both blades. In contrast, at P21, about 18% of CB+ cells were DCX+CB+ cells, and they were mainly located only in the subgranular zone of the DG. These results suggest that the developmental pattern of DCX+CB+ cells changes with time in the early postnatal stages.
Subject(s)
Animals , Mice , S100 Calcium Binding Protein G , Cognition , Dentate Gyrus , Hippocampus , Immunohistochemistry , Neurogenesis , NeuronsABSTRACT
We observed how the hypothyroid state affects diabetic states and modifies cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG). For this, 0.03% methimazole, an anti-thyroid drug, was administered to 7-week-old, pre-diabetic Zucker diabetic fatty (ZDF) rats by drinking water for 5 weeks, and the animals were sacrificed at 12 weeks of age. At this age, corticosterone levels were significantly increased in the ZDF rats compared to those in the control (Zucker lean control, ZLC) rats. Methimazole (methi) treatment in the ZDF rats (ZDF-methi rats) significantly decreased corticosterone levels and diabetes-induced hypertrophy of adrenal glands. In the DG, Ki67 (a marker for cell proliferation)- and doublecortin (DCX, a marker for neuronal progenitors)-immunoreactive cells were much lower in the ZDF rats than those in the ZLC rats. However, in ZDF-methi rats, numbers of Ki67- and DCX-immunoreactive cells were similar to those in the ZLC rats. These suggest that methi significantly reduces diabetes-induced hypertrophy of the adrenal gland and alleviates the diabetes-induced reduction of cell proliferation and neuronal progenitors in the DG.
Subject(s)
Animals , Rats , Adrenal Glands , Cell Proliferation , Corticosterone , Dentate Gyrus , Drinking Water , Hypertrophy , Hypothyroidism , Methimazole , NeuronsABSTRACT
Neurogenesis in the adult brain occurs continuously throughout life. The main olfactory bulb (MOB) is the first central relay of the olfactory system. We examined proliferation of newly generated cells in each layer of the gerbil MOB after 5 min of transient cerebral ischemia using doublecortin (DCX), a marker of neuronal progenitors. Many DCX immunoreactive neuroblasts were found in the all layers of the MOBs of control and ischemia groups. Ten to 15 days after ischemia/reperfusion, no difference in numbers of DCX immunoreactive neuroblasts was found in the MOB. Thirty days after ischemia/reperfusion, significant increase of DCX immunoreactive cells was observed in all layers of ischemic MOB. This result indicates that neuroblasts increase in the MOB from 30 days after transient cerebral ischemia in gerbils.
Subject(s)
Adult , Humans , Brain , Gerbillinae , Ischemia , Ischemic Attack, Transient , Neurogenesis , Neurons , Olfactory BulbABSTRACT
Doublecortin (DCX), a microtubule-associated protein, expresses specifically in neuronal precursors and used as a marker for neuronal precursors and neurogenesis. In the present study, we observed differences in DCX immunoreactivity and its protein levels in the main olfactory bulb (MOB) of young adult, middle-aged and aged dogs. In the young adult dog, DCX-immunoreactive cells with well-stained processes were detected in the MOB. DCX immunoreactive cells were decreased in the MOB of middle-aged dog. In the aged dog, DCX immunoreactive cells were more decreased compared to that in the MOB of middle-aged dog. DCX protein level in the dog MOB was also significantly decreased with age. These results suggest that reductions of DCX immunoreactivity and protein levels in the aged MOB may be involved in some neural deficits related to olfactory impairment in the aged dog.
Subject(s)
Aged , Animals , Dogs , Humans , Young Adult , Aging , Neurogenesis , Neurons , Olfactory BulbABSTRACT
We examined the effects of steptozotocin (STZ)-induced type 1 diabetes on cell proliferation and neuroblasts in the subgranular zone of the hippocampal dentate gyrus (SZDG) of male Wistar rats. Change in memory function was also investigated using the passive avoidance test. In the SZDG, Ki67 (a marker for cell proliferation) positive nuclei were significantly decreased at 2 and 3 weeks and slightly decreased at 4 weeks after STZ treatment. Doublecortin (DCX, a marker for neuronal differentiation)-immunoreactive (+) neuroblasts with tertiary dendrites were significantly decreased in the STZ-treated group compared to those in the vehicle-treated group. However, DCX+ neuroblasts without tertiary dendrites were abundant at 4 weeks after STZ treatment. In addition, retention latency time in STZ-treated group was similar to that of vehicle-treated group at 2 and 3 weeks after STZ treatment. However, the retention latency time was significantly decreased at 4 weeks after STZ treatment. These results suggest that STZ significantly reduced cell proliferation and neuroblasts at 2~3 weeks after STZ treatment, but not at 4 weeks after STZ treatment although memory impairment was detected at 4 weeks after STZ treatment. The gradual reduction of DCX+ neuroblasts with tertiary dendrites may be associated with the impairment of hippocampus-related memory function.
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Humans , Male , Cell Proliferation , Dendrites , Dentate Gyrus , Memory , Neurons , Rats, Wistar , Retention, Psychology , StreptozocinABSTRACT
Mesenchymal stem cells (MSCs) secrete bioactive factors that exert diverse responses in vivo. In the present study, we explored mechanism how MSCs may lead to higher functional recovery in the animal stroke model. Bone marrow-derived MSCs were transplanted into the brain parenchyma 3 days after induction of stroke by occluding middle cerebral artery for 2 h. Stoke induced proliferation of resident neural stem cells in subventricular zone. However, most of new born cells underwent cell death and had a limited impact on functional recovery after stroke. Transplantation of MSCs enhanced proliferation of endogenous neural stem cells while suppressing the cell death of newly generated cells. Thereby, newborn cells migrated toward ischemic territory and differentiated in ischemic boundaries into doublecortin+ neuroblasts at higher rates in animals with MSCs compared to control group. The present study indicates that therapeutic effects of MSCs are at least partly ascribed to dual functions of MSCs by enhancing endogenous neurogenesis and protecting newborn cells from deleterious environment. The results reinforce the prospects of clinical application using MSCs in the treatment of neurological disorders.
Subject(s)
Animals , Male , Rats , Cell Differentiation/physiology , Cell Proliferation , Cell Survival , Disease Models, Animal , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/physiology , Models, Biological , Neurons/physiology , Rats, Sprague-Dawley , Stroke/pathologySubject(s)
Humans , Animals , Rats , Pilocarpine , Epilepsy, Temporal Lobe/chemically induced , Neurogenesis , Rats, Wistar , Models, AnimalABSTRACT
Voluntary running is known to dramatically increase the cell proliferation and neurogenesis in the dentate gyrus of the adult mouse hippocampus. However, it is crucial to realize that adding excitatory neurons could result in serious maladaptive outcomes for hippocampal circuit function. To investigate the response of mature granule cells on the increase of cell proliferation during voluntary running, we investigated the temporal change of calbindin-D28k (a marker for mature granule cells) using immunohistochemistry during voluntary running with upregulated neurogenesis. By using immunohistochemsitry for Ki-67 and doublecortin (DCX), we observed that the cell proliferation and differentiation of granule cells increased at 1 week of voluntary running. We found that, at 6 weeks of voluntary running, the cell proliferation and differentiation of granule cells returned to sedentary control levels. On the other hand, calbindin-D28k immunoreactivity decreased in the granular cell layer of the dentate gyrus and CA3 region of hippocampus after 1 week of voluntary running. At 6 weeks of voluntary running, the density of the calbindin-D28k in the granular cell layer and CA3 region was returned to the sedentary control level. These results demonstrate that the cell proliferation and differentiation are increased at early point of voluntary running, and the granule cell activity in the dentate gyrus is temporally changed for response to the increase of cell proliferation and differentiation during voluntary running.
Subject(s)
Adult , Animals , Humans , Mice , Calbindin 1 , Cell Proliferation , Dentate Gyrus , Hand , Hippocampus , Immunohistochemistry , Neurogenesis , Neurons , RunningABSTRACT
Stress induces degeneration of brain structures and functions. Particularly, hippocampus is sensitive to stressful stimulations. In the present study, the change of synaptic related molecules in the mouse dentate gyrus was examined with immunohistochemistry after restraint stress. We subjected mice to restraint stress for 6 h per day for 4 days. As a result, the number of Ki-67, a marker for proliferation, and doublecortin (DCX), a marker for neurogenesis, immunoreactive cells was decreased in the stress group. On the other hand, the intensity of calbindinD-28k, a marker of pre-existing granule cells, immunoreactivity was increased in the granule cell layer after 4 days restraint stress. As well as, the immunoreactivity of synaptic related molecules, postsynaptic density-95 (PSD-95), growth association protein-43 (GAP-43) and beta-NADPH-d reactivity were increased in the inner molecular layer of dentate gyrus after 4 days restraint stress. In conclusion, this study shows that repeated restraint stress suppresses neurogenesis in dentate gyrus and strengthens synaptic plasticity of existing granule cells.
Subject(s)
Animals , Mice , Brain , Dentate Gyrus , Hand , Hippocampus , Immunohistochemistry , Neurogenesis , PlasticsABSTRACT
The neuronal migration disorders, X-linked lissencephaly syndrome (XLIS) and subcortical band heterotopia (SBH), also called "double cortex", have been linked to missense, nonsense, aberrant splicing, deletion, and insertion mutations in doublecortin (DCX) in families and sporadic cases. Most DCX mutations identified to date are located in two evolutionarily conserved domains. We performed mutation analysis of DCX in two Korean patients with SBH. The SBH patients had mild to moderate developmental delays, drug-resistant generalized seizures, and diffuse thick SBH upon brain MRI. Sequence analysis of the DCX coding region in Patient 1 revealed a c.386 C>T change in exon 3. The sequence variation results in a serine to leucine amino acid change at position 129 (S129L), which has not been found in other family members of Patient 1 or in a large panel of 120 control X-chromosomes. We report here a novel c.386 C>T mutation of DCX that is responsible for SBH.