The methylcytosine dioxygenases TET proteins (TET1, TET2, and TET3) play important regulatory roles in neural function. In this study, we investigated the role of TET proteins in neuronal differentiation using Neuro2a cells as a model. We observed that knockdown of TET1, TET2 or TET3 promoted neuronal differentiation of Neuro2a cells, and their overexpression inhibited VPA (valproic acid)-induced neuronal differentiation, suggesting all three TET proteins negatively regulate neuronal differentiation of Neuro2a cells. Interestingly, the inducing activity of TET protein is independent of its enzymatic activity. Our previous studies have demonstrated that srGAP3 can negatively regulate neuronal differentiation of Neuro2a cells. Furthermore, we revealed that TET1 could positively regulate srGAP3 expression independent of its catalytic activity, and srGAP3 is required for TET-mediated neuronal differentiation of Neuro2a cells. The results presented here may facilitate better understanding of the role of TET proteins in neuronal differentiation, and provide a possible therapy target for neuroblastoma.
Animals ; Catalytic Domain ; Cell Differentiation ; drug effects ; physiology ; Cell Line, Tumor ; DNA-Binding Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Enzyme Inhibitors ; pharmacology ; GTPase-Activating Proteins ; genetics ; metabolism ; Immunohistochemistry ; Mice ; Microscopy, Fluorescence ; Neuroblastoma ; metabolism ; pathology ; Protein Isoforms ; antagonists & inhibitors ; genetics ; metabolism ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; metabolism ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; metabolism ; Valproic Acid ; pharmacology

OBJECTIVETo investigate the effects of α3 neuronal nicotinic acetylcholine receptor (nAChR) on apoptosis and p38 signal transduction pathway in SH-SY5Y cells and to assess the roles of α3 nAChR in the pathogenesis of Alzheimer's disease (AD).

METHODSThe levels of α3 nAChR mRNA and protein were measured by real-time PCR and Western blot, respectively, in SH-SY5Y cells transfected with α3 nAChR siRNA. The mRNA level of bcl-2 and bax was measured by the real-time PCR. The siRNA transfected SH-SY5Y cells and control were then treated with 10 µmol/L Aβ25-35 for another 48 h, and the change in apoptotic rate and the levels of p-p38 and p38 were measured by flow cytometry and Western blot. Subsequently these SH-SY5Y cells were exposed to a blocker of p38 protein, and the apoptotic rate was measured again.

RESULTSCompared to the controls, the expression of α3 nAChR at mRNA and protein levels in the SH-SY5Y cells transfected with α3 nAChR siRNA decreased by 95% and 86%, respectively; the mRNA levels of bax increased 2.11 times and that for bcl-2 decreased 0.53 times. The apoptotic rate was unaffected (3.40% ± 0.20%); but it increased after Aβ25-35 treatment (24.52% ± 1.59%); the level of p-p38 protein also increased by 178% in the α3 nAChR inhibited cells treated with Aβ25-35. Compared to controls, the Aβ25-35-treated SH-SY5Y cells and the Aβ25-35-treated and siRNA-transfected cells both showed a reduction in apoptosis after treatment with p38 blocker, especially in the former.

CONCLUSIONThe siRNA silencing of α3 nAChR mRNA may enhance the effect of Aβ25-35 on the cell apoptosis by increasing the levels of p38 protein and bax mRNA and decreasing the level of bcl-2 mRNA, which may play a role in the pathogenesis of AD.

Alzheimer Disease ; etiology ; Amyloid beta-Peptides ; metabolism ; Apoptosis ; Cell Line, Tumor ; Gene Silencing ; Humans ; Neuroblastoma ; metabolism ; pathology ; Peptide Fragments ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Receptors, Nicotinic ; genetics ; metabolism ; Signal Transduction ; Transfection ; bcl-2-Associated X Protein ; genetics ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVE: To construct dopamine D1 receptor (DRD1) expression interference vectors to study the role of DRD1 in nerve cells and lay a foundation for drug development in anti-convulsion. METHODS: Based on DRD1 gene sequence in GenBank, 10 interfere vectors of DRD1 were designed. Liposomal was used to transfect NG-108-15 and the transfect effect was assayed by GFP. With realtime PCR and Western blot, the DRD1 expression was detected. RESULTS: The 10 constructed interfere vectors transfected into NG-108-15 cells by liposomal method and inhibited DRD1 mRNA and protein expression. DRD1 mRNA expression in NG-108-15 cells transfected with pGPU6-GFP-Neo-si-DRD1-5 was the lowest whereas DRD1 protein expression in NG-108-15 cells transfected with pGPU6-GFP-Neo-si-DRD1-1, -2, -6, -7 was the lowest. CONCLUSION DRD1 expression interference vector is successfully constructed.
Animals ; Cell Line, Tumor ; Genetic Vectors ; Glioma ; pathology ; Hybrid Cells ; Liposomes ; metabolism ; Mice ; Neuroblastoma ; pathology ; RNA Interference ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Receptors, Dopamine D1 ; genetics ; metabolism ; Transfection

Age Factors ; Child ; Child, Preschool ; Ganglioneuroblastoma ; genetics ; metabolism ; pathology ; ultrastructure ; Ganglioneuroma ; genetics ; metabolism ; pathology ; ultrastructure ; Gene Amplification ; Gene Expression Regulation, Neoplastic ; Humans ; Infant ; N-Myc Proto-Oncogene Protein ; Neoplasm Staging ; Neuroblastoma ; genetics ; metabolism ; pathology ; ultrastructure ; Nuclear Proteins ; genetics ; metabolism ; Oncogene Proteins ; genetics ; metabolism ; Peripheral Nervous System Neoplasms ; classification ; genetics ; metabolism ; pathology ; ultrastructure ; Prognosis ; Proto-Oncogene Proteins c-myc ; metabolism ; Receptor, trkA ; metabolism ; S100 Proteins ; metabolism

OBJECTIVETo investigate the influence of inhibited α7 neuronal nicotinic acetylcholine receptor (nAChR) by small interference RNA (siRNA) in SH-SY5Y cells and to explore the connection of these changes with the β-amyloid precursor protein (APP) metabolism and the pathogenesis of Alzheimer's disease (AD).

METHODSThe siRNA of α7 nAChR was transfected into SH-SY5Y cells, and the expression of α7 nAChR and two subtypes of β-secretases (BACE1 and BACE2) at mRNA and protein levels was studied by real-time PCR and Western blot, respectively. The variation of Aβ(1-42) content was detected by ELISA.

RESULTSAs compared with controls, the expression of α7 nAChR at mRNA and protein levels in the SH-SY5Y cells transfected with the α7 nAChR siRNA were decreased by 84% and 79% (P < 0.01), respectively. The expressions of BACE1 mRNA and protein levels was increased by 527% and 71% (P < 0.01), respectively, while the expression of BACE2 decreased by 58% and 75% (P < 0.01), respectively. The Aβ(1-42) content increased by 208% (P < 0.01).

CONCLUSIONSAn inhibited α7 nAChR mRNA induced by siRNA may markedly stimulate the production of Aβ through the mechanism of increased expression of BACE1 and inhibited expression of BACE2, which may be related to the pathogenesis of AD.

Amyloid Precursor Protein Secretases ; genetics ; metabolism ; Amyloid beta-Peptides ; metabolism ; Aspartic Acid Endopeptidases ; genetics ; metabolism ; Cell Line, Tumor ; Humans ; Neuroblastoma ; metabolism ; pathology ; Peptide Fragments ; metabolism ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Receptors, Nicotinic ; genetics ; metabolism ; Transfection ; alpha7 Nicotinic Acetylcholine Receptor

OBJECTIVE: To explore the effects of nuclear protein-like transcription factor nuclear receptor subfamily 2 group E member 1 (NR2E1) on the growth, division, and proliferation of neuroblastoma cell line IMR32. METHODS: A NR2E1 shiRNA plasmid vector was constructed and transfected into neuroblastoma cell line IMR32 using lipofedamine™2000. Subsequent cell growth was measured by cell counting and the protein expression of somatic nuclear division was examined by immunofluorescent staining. RESULTS: At 48 h after the neuroblastoma cells IMR32 were transfected with NR2E1-shiRNA vector, the related nuclear division protein and the proliferation of the transfected cells IMR32 were remarkably depressed. CONCLUSION Cells division and proliferation of neuroblastoma cell line IMR32 is inhibited through transfection with the NR2E1-shiRNA plasmid vector.
Cell Division ; genetics ; physiology ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Neuroblastoma ; pathology ; RNA, Small Interfering ; genetics ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Transfection

OBJECTIVETo establish a tumor-bearing nude mouse model of human neuroblastoma in order to study the mechanisms of neuroblastoma invasion and metastasis, and to investigate potential therapeutic modalities in the experimental animal models.

METHODSA human neuroblastoma cell line was cultured in vitro. 1 x 10(7) cells undergoing exponential growth were collected in 0.1 ml of suspension and subcutaneously inoculated into the right flank next to the forelimb in nude mice. The biological characteristics of the developed tumors were observed, and histopathological and DNA microarray analyses were performed. The expressions of NSE in the subcutaneous tumor, metastatic tumor and the primary neuroblastoma tumor tissues from a pediatric patient were analyzed by immunohistochemistry.

RESULTSTumors successfully grew in 36 out of 48 injected mice, with a total tumor-formation rate of 75.0%. Metastasis occurred in 10 cases, and the metastatic rate was 20.8%. Tumors in five injected mice grew locally without metastasis. These tumors had large volume and the tumor weight reached up to half of the body weight of the host animal. Four mice exhibited systemic metastasis without tumor growth at the primary inoculation site. There were six mice with locally growing tumor accompanied by metastasis.

CONCLUSIONWe have successfully established a human neuroblastoma xenograft model in nude mice with high tumor growth and metastatic rates. This model depicting the natural cell growth, local infiltration and distant metastasis characteristics of human neuroblastoma, providing an ideal animal model for in vivo studies of neuroblastoma. In addition, the results of this study indicate the heterogeneous nature of neuroblastoma, it may play an important role in metastasis of this tumor.

Animals ; Cell Line, Tumor ; Child, Preschool ; Disease Models, Animal ; Female ; Gene Expression Profiling ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; secondary ; Male ; Mice ; Mice, Nude ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Neoplasm Transplantation ; Neuroblastoma ; genetics ; metabolism ; pathology ; secondary ; Phosphopyruvate Hydratase ; metabolism ; Tumor Burden

OBJECTIVETo investigate the influence of APP(SWE) on the expression of neuronal acetylcholine receptors (nAChRs) and its relationship with Alzheimer's disease (AD).

METHODSAPP(SWE), carried the Swedish family AD double mutants, were transfected into SH-SY5Y cells and primary cultured neurons from rat brains to build a cellular model of AD. The mRNA levels of APP and nAChRs, and the protein levels of total APP, αAPPs and nAChRs in the cultured cells were measured using real-time PCR and Western blot, respectively. The numbers of α3 nAChR were determined by receptor-[³H]epibatidine binding assay.

RESULTSIncreased expressions of Swedish 670/671 APP at mRNA and protein levels, and down-regulation of αAPPs were observed in both of the cultured neuronal cells transfected with APP(SWE). A significant increase of α7 nAChR expression at protein and mRNA levels was detected in the APP(SWE) transfected SH-SY5Y cells. On the other hand, after transfection with APP(SWE), the expressions of α3 nAChR at protein and mRNA levels in SH-SY5Y cells, and α4 nAChR at mRNA level in primary cultured neurons were inhibited. In addition, the numbers of receptor binding sites were deceased in SH-SY5Y cells overexpressing with APP(SWE).

CONCLUSIONOverexpression of APP(SWE) can decrease αAPPs and modify nAChRs by increasing expression of α7 nAChR and decreasing α3 and α4 nAChRs, which might play an important role in the pathogenesis of AD.

Alzheimer Disease ; genetics ; Amyloid Precursor Protein Secretases ; secretion ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; physiology ; Animals ; Brain Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cells, Cultured ; Cerebral Cortex ; cytology ; metabolism ; Down-Regulation ; Humans ; Neuroblastoma ; metabolism ; pathology ; Neurons ; cytology ; metabolism ; Plasmids ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Nicotinic ; genetics ; metabolism ; Transfection ; alpha7 Nicotinic Acetylcholine Receptor

Down syndrome critical region 1 (DSCR1), an oxidative stress-response gene, interacts with calcineurin and represses its phosphatase activity. Recently it was shown that hydrogen peroxide inactivates calcineurin by proteolytic cleavage. Based on these facts, we investigated whether oxidative stress affects DSCR1-mediated inactivation of calcineurin. We determined that overexpression of DSCR1 leads to increased proteolytic cleavage of calcineurin. Convertsely, knockdown of DSCR1 abolished calcineurin cleavage upon treatment with hydrogen peroxide. The PXIIXT motif in the COOH-terminus of DSCR1 is responsible for both binding and cleavage of calcineurin. The knockdown of overexpressed DSCR1 in DS fibroblast cells also abrogated calcineurin proteolysis by hydrogen peroxide. These results suggest that DSCR1 has the ability to inactivate calcineurin by inducing proteolytic cleavage of calcineurin upon oxidative stress.
Adenoviridae/genetics ; Adult ; Animals ; Calcineurin/antagonists & inhibitors/*metabolism ; Cells, Cultured ; Chromatin Immunoprecipitation ; Down Syndrome/*metabolism/pathology ; Fibroblasts/metabolism/pathology ; Humans ; Hydrogen Peroxide/pharmacology ; Immunoglobulin G/immunology ; Intracellular Signaling Peptides and Proteins/*physiology ; Male ; Mice ; Mice, Inbred ICR ; Muscle Proteins/*physiology ; Neuroblastoma/genetics/metabolism/pathology ; Neurons/cytology/metabolism ; Oxidants/pharmacology ; Oxidative Stress ; Peptide Fragments/immunology ; RNA, Messenger/genetics/metabolism ; RNA, Small Interfering/pharmacology ; Rabbits ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/pathology ; Young Adult

OBJECTIVESTo investigate the neuroprotective function of alpha 3 nicotinic acetylcholine receptor (nAChR) by inhibiting the gene expression in human neuroblastoma (SH-SY5Y) cells using small interference RNA (siRNA).

METHODSThe siRNA coding oligonucleotide sequences targeting alpha 3 nAChR were designed and synthesized. The annealed product was cloned into pSilencer 3.1-H1 neo vector. The recombinant alpha 3 nAChR pSilencer 3.1-H1 neo vector was transfected into the SH-SY5Y cells. The stable clones were screened by G418 medium, and the levels of alpha 3 nAChR mRNA and protein were monitored by using real-time PCR and Western blotting, respectively. After the SH-SY5Y cells with siRNA treatment were exposed to 1 micromol/L Abeta(1-42), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide], SOD, GSH-px and the lipid peroxidation were measured by spectrophotometry.

RESULTSCompared with the controls, the expression levels of mRNA and protein in the stable SH-SY5Y clone cells transfected with the recombinant alpha 3 nAChR pSilencer 3.1-H1 neo vector were decreased with inhibitory efficiency of 98% and 66%, respectively, the MTT reduction decreased; the product of lipid peroxidation was increased and the activities of SOD and GSH-px were decreased. Biologically, the gene expression inhibition of alpha 3 nAChR enhanced the toxicity induced by Abeta in SH-SY5Y cells.

CONCLUSIONSThe expression inhibition of alpha 3 nAChR as a result of recombinant alpha 3 nAChR siRNA can induce oxidative stress and improve the toxicity of Abeta on SH-SY5Y cells, indicating that alpha 3 nAChR may play a significant neuroprotective role in the pathogenesis of Alzheimer disease.

Amyloid beta-Peptides ; pharmacology ; Cell Line, Tumor ; Cell Membrane ; drug effects ; Gene Expression Regulation ; drug effects ; Humans ; Neuroblastoma ; pathology ; Oxidation-Reduction ; drug effects ; Peptide Fragments ; pharmacology ; RNA Interference ; immunology ; RNA, Small Interfering ; pharmacology ; Receptors, Nicotinic ; drug effects ; genetics ; metabolism ; Superoxide Dismutase ; antagonists & inhibitors ; genetics ; metabolism