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1.
Mol Med Rep ; 20(2): 939-950, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31173189

RESUMO

The dental follicle develops into the periodontal ligament, cementum and alveolar bone. Human dental follicle cells (hDFCs) are the precursor cells of periodontal development. Long non­coding RNAs (lncRNAs) have been revealed to be crucial factors that regulate a variety of biological processes; however, whether lncRNAs serve a role in human periodontal development remains unknown. Therefore, the present study used microarrays to detect the differentially expressed lncRNAs and mRNAs between hDFCs and human periodontal ligament cells (hPDLCs). A total of 845 lncRNAs and 1,012 mRNAs were identified to be differentially expressed in hDFCs and hPDLCs (fold change >2.0 or <­2.0; P<0.05). Microarray data were validated by reverse transcription­quantitative polymerase chain reaction. Bioinformatics analyses, including gene ontology, pathway analysis and coding­non­coding gene co­expression network analysis, were performed to determine the functions of the differentially expressed lncRNAs and mRNAs. Bioinformatics analysis identified that a number of pathways may be associated with periodontal development, including the p53 and calcium signaling pathways. This analysis also revealed a number of lncRNAs, including NR_033932, T152410, ENST00000512129, ENST00000540293, uc021sxs.1 and ENST00000609146, which may serve important roles in the biological process of hDFCs. In addition, the lncRNA termed maternally expressed 3 (MEG3) was identified to be differentially expressed in hDFCs by reverse transcription­quantitative polymerase chain reaction. The knockdown of MEG3 was associated with a reduction of pluripotency makers in hDFCs. In conclusion, for the first time, to the best of our knowledge, the current study determined the different expression profiles of lncRNAs and mRNAs between hDFCs and hPDLCs. The observations made may provide a solid foundation for further research into the molecular mechanisms of lncRNAs in human periodontal development.

2.
Int J Oncol ; 54(6): 1995-2004, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31081045

RESUMO

Harmine (HM) is a ß­carboline alkaloid found in multiple medicinal plants. It has been used in folk medicine for anticancer therapy; however, the molecular mechanism of HM on human breast cancer remains unclear. Transcriptional co­activator with PDZ­binding motif (TAZ), also known as WW domain­containing transcription regulator 1, serves an important role in the carcinogenesis and progression of breast cancer. The aim of the present study was to elucidate the potential anticancer activity and mechanism of HM in breast cancer, in vitro and in vivo. Cell proliferation was measured using a CCK­8 assay, apoptotic activity was detected by flow cytometry and DAPI staining, and cell migration was examined using a wound healing assay. The expression of proteins, including extracellular signal­regulate kinase (Erk), phosphorylated (p­) Erk, protein kinase B (Akt), p­Akt, B­cell lymphoma 2 (Bcl­2) and Bcl­2­associated X protein (Bax), were determined by western blotting. The mRNA expression of TAZ was detected using reverse transcription­quantitative polymerase chain reaction analysis. The expression of proteins in mouse tumor tissues were examined by immunohistochemistry. HM significantly suppressed cellular proliferation and migration, promoted apoptosis in vitro and inhibited tumor growth in vivo. In addition, HM significantly decreased the expression of TAZ, p­Erk, p­Akt and Bcl­2, but increased that of Bax. The overexpression of TAZ in breast cancer cells inhibited the antitumor effect of HM. In conclusion, HM was found to induce apoptosis and prevent the proliferation and migration of human breast cancer cell lines, possibly via the downregulation of TAZ.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Harmina/administração & dosagem , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Harmina/farmacologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Células MCF-7 , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Phytother Res ; 33(5): 1551-1561, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31066474

RESUMO

Aacacetin, a plant flavone has shown antitumor efficacy recently. However, its associated mechanisms are poorly known. We hypothesized that the muscarinic M3 receptor (M3 R), which is highly expressed in some cancer tissue, is related to the antitumor effect of acacetin in head and neck squamous cell carcinoma (HNSCC) cells. Our results showed that 12.5- to 200-µM acacetin inhibited cell viability in dose- and time-dependent manners in HNSCC cells, but a relative higher concentration was needed for oral adenoid cystic carcinoma cells. M3 R expression level was higher in HNSCC cells than that in adenoid cystic carcinoma cells. Flow cytometry and electron microscopy confirmed acacetin-induced cell apoptosis in 22B cells, a HNSCC cell line. Acacetin promoted mitochondrial cytochrome c release and caspase 9, 3 processing. Knocking down of M3 R expression by specific siRNA significantly prevented the acacetin-induced cell viability damage, cell apoptosis, and caspase 3 activation. Besides, M3 R was also involved in acacetin-induced elevation of reactive oxygen species and intracellular calcium ([Ca2+ ]i ). These data indicate that acacetin-induced cell apoptosis in HNSCC cells may through M3 R related calcium signaling and caspase 3 activation. Acacetin is a potent natural antitumor reagent especially for the tumor cells, which highly expressed M3 R.


Assuntos
Flavonas/química , Receptor Muscarínico M3/uso terapêutico , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transfecção
4.
Int J Nanomedicine ; 14: 205-214, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30636873

RESUMO

Background: Efficient and precise circulating tumor cells' (CTCs) capture and release with minimal effect on cell viability for CTCs' analysis are general requirements of CTCs' detection device in clinical application. However, these two essential factors are difficult to be achieved simultaneously. Methods: In order to reach the aforementioned goal, we integrated multiple strategies and technologies of staggered herringbone structure, nanowires' substrate, peptides, enzymatic release, specific cell staining, and gene sequencing into microfluidic device and the sandwich structure peptide-silicon nanowires' substrate was termed as Pe-SiNWS. Results: The Pe-SiNWS demonstrated excellent capture efficiency (95.6%) and high release efficiency (92.6%). The good purity (28.5%) and cell viability (93.5%) of CTCs could be obtained through specific capture and biological release by using Pe-SiNWS. The good purity of CTCs facilitated precise and quick biological analysis, and five types of KRAS mutation were detected in 16 pancreatic cancer patients but not in healthy donors. Conclusion: The results proved that the effective capture, minor damage release, and precise analysis of CTCs could be realized simultaneously by our novel strategy. The successful clinical application indicated that our work was anticipated to open up new opportunities for the design of CTC microfluidic device.


Assuntos
Separação Celular/métodos , Nanofios/química , Células Neoplásicas Circulantes/metabolismo , Neoplasias Pancreáticas/patologia , Fragmentos de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Silício/química , Estudos de Casos e Controles , Humanos , Dispositivos Lab-On-A-Chip , Mutação , Células Neoplásicas Circulantes/patologia , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/genética , Silício/metabolismo
5.
Front Genet ; 9: 555, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30510566

RESUMO

Cisplatin resistance is a major cause of treatment failure in advanced ovarian cancer. The limited evidence shows the paradoxical regulation of miR-205 on chemotherapy resistance in cancer. Herein, we found that miR-205-5p was enormously increased in cisplatin-resistant C13K ovarian cancer cells compared with its cisplatin-sensitive OV2008 parental cells using miRNA microarrays, which was further verified by quantitative PCR. Furthermore, we confirmed that inhibition of miR-205-5p upregulated PTEN and subsequently attenuated its downstream target p-AKT, which inversed C13K cells from cisplatin resistance to sensitivity. Our data suggest that miR-205-5p contributes to cisplatin resistance in C13K ovarian cancer cells may via targeting PTEN/AKT pathway.

6.
Biochem Biophys Res Commun ; 504(1): 1-5, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-29958884

RESUMO

Lung cancer is a common malignant tumor, the cancer stem cells (CSCs) were regarded responsible for the development of cancer tissue. The effects of amiloride on lung cancer stem cells and the possible mechanism were not much investigated. In this study, human NCI-H1975 lung CSCs were selected by flow cytometry, and the effects of amiloride at different concentrations (0, 12.5, 25, 50, and 100 µmol/L) were evaluated on proliferation, migration, invasion and apoptosis of CSCs using cell counting kit-8 and Transwell migration assays as well as flow cytometry. Wstern blot analysis was performed to investigate the effect of amiloride on the level of proteins in uPA system, NF-kB pathway, and PI3K-AKT-mTOR pathway in CSCs. As a result, we found that amiloride inhibited proliferation, migration and invasion of lung CSCs, and promoted apoptosis. Further, we found that amiloride decreased levels of target proteins in the uPA system, as well as the NF-kB and PI3K-AKT-mTOR pathways. These results indicated that amiloride could inhibit proliferation, migration and invasion of lung CSCs, and promotes apoptosis, these effects may be related to decreased levels of proteins in the uPA system, the NF-kB pathway, and the PI3K-AKT-mTOR pathway.

7.
Mol Med Rep ; 18(2): 1335-1344, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29845276

RESUMO

Three­dimensional printed (3DP) scaffolds have become an excellent resource in alveolar bone regeneration. However, selecting suitable printable materials remains a challenge. In the present study, 3DP scaffolds were fabricated using three different ratios of poly (ε­caprolactone) (PCL) and poly­lactic­co­glycolic acid (PLGA), which were 0.1PCL/0.9PLGA, 0.5PCL/0.5PLGA and 0.9PCL/0.1PLGA. The surface characteristics and degradative properties of the scaffolds, and the response of human periodontal ligament stem cells (hPDLSCs) on the scaffolds, were assessed to examine the preferable ratio of PCL and PLGA for alveolar bone regeneration. The results demonstrated that the increased proportion of PLGA markedly accelerated the degradation, smoothed the surface and increased the wettability of the hybrid scaffold. Furthermore, the flow cytometry and Cell Counting Kit­8 assay revealed that the adhesion and proliferation of hPDLSCs were markedlyincreased on the 0.5PCL/0.5PLGA and 0.1PCL/0.9PLGA scaffolds. Additionally, the alkaline phosphatase activity detection and reverse­transcription quantitative polymerase chain reaction demonstrated that the hPDLSCs on the 0.5PCL/0.5PLGA scaffold exhibited the best osteogenic capacity. Consequently, PCL/PLGA composite scaffolds may represent a candidate focus for future bone regeneration studies, and the 0.5PCL/0.5PLGA scaffold demonstrated the best bio­response from the hPDLSCs.


Assuntos
Diferenciação Celular , Ácido Láctico/química , Osteogênese , Ligamento Periodontal/metabolismo , Poliésteres/química , Ácido Poliglicólico/química , Impressão Tridimensional , Células-Tronco/metabolismo , Tecidos Suporte/química , Adolescente , Feminino , Humanos , Masculino , Ligamento Periodontal/citologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Células-Tronco/citologia
8.
Int J Mol Med ; 40(5): 1529-1536, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28949371

RESUMO

Hypoxia­inducible factor­1α (HIF­1α) is essential for regulating the osteogenic differentiation of periodontal ligament cells (PDLCs). The regulatory mechanism of HIF­1α transcription is still not clear. Recently, two long non­coding RNAs, HIF1A antisense RNA 1 (HIF1A­AS1) and HIF1A antisense RNA 2 (HIF1A­AS2), were found to regulate HIF­1α mRNA, but the regulatory mechanisms among HIF­1α, HIF1A­AS1 and HIF1A­AS2 have not been well studied. We hypothesized that HIF1A­AS1 and HIF1A­AS2 play important roles in the osteogenic differentiation of PDLCs by regulating HIF­1α. In the present study, we showed that expression levels of HIF1A­AS1, HIF1A­AS2, HIF­1α and osteogenic biomarkers were time­dependent under hypoxia. Even though both HIF1A­AS1 and HIF1A­AS2 were complementary to HIF­1α mRNA, only HIF1A­AS2 showed an inhibitory effect on HIF­1α in PDLCs. Moreover, HIF­1α had positive regulatory effects on HIF1A­AS1 and HIF1A­AS2. HIF­1α promoted the osteogenic differentiation of PDLCs, and HIF1A­AS2 had a negative effect on the osteogenic differentiation of PDLCs. Altogether, the present study revealed the complex relationships among HIF1A­AS1, HIF1A­AS2 and HIF­1α, as well as their roles in regulating the osteogenic differentiation of PDLCs. These findings provide a theoretical basis for promoting periodontal tissue regeneration and repair during orthodontic tooth movement.


Assuntos
Diferenciação Celular/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Osteogênese/genética , Ligamento Periodontal/citologia , RNA Antissenso/genética , Adulto , Hipóxia Celular , Células Cultivadas , Biologia Computacional/métodos , Expressão Gênica , Inativação Gênica , Humanos , Interferência de RNA , Adulto Jovem
9.
Neurosci Lett ; 638: 76-82, 2017 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-27939977

RESUMO

The effects of melatonin on spatial memory deficits in Alzheimer's disease (AD) have been thoroughly investigated. Our previous study demonstrated that melatonin rescues hippocampus-dependent spatial memory deficits by arresting hippocampal pathological progression in an animal model of AD, which occurs via the inhibition of GSK3ß and an increase in c-Fos. Based on the interaction between the amygdala and hippocampus, it is important to determine whether melatonin also improves amygdala-dependent emotional memory to understand the mechanism of melatonin amelioration of memory deficits in AD. The basolateral amygdala (BLA) is essential for the processing of emotions, including cued fear conditioning and anxiety. In the present study, we intraperitoneally injected Tg2576 mice with melatonin for 4 months and measured amygdala-dependent emotional memory using cued fear conditioning and a step-down passive avoidance test; the expression of c-Fos, Arc, phosphorylated CREB (pCREB) and other related genes were subsequently measured using Real-time polymerase chain reaction (RT-PCR) and Western blot in BLA. Our findings suggest that melatonin ameliorates amygdala-dependent emotional memory in AD via up-regulation of the pCREB/c-Fos pathway.


Assuntos
Tonsila do Cerebelo/fisiopatologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Emoções/efeitos dos fármacos , Melatonina/farmacologia , Transtornos da Memória/tratamento farmacológico , Memória/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Condicionamento Clássico , Sinais (Psicologia) , Medo/efeitos dos fármacos , Humanos , Melatonina/uso terapêutico , Transtornos da Memória/metabolismo , Transtornos da Memória/psicologia , Camundongos Transgênicos , Transdução de Sinais , Regulação para Cima
10.
Int J Nanomedicine ; 11: 2133-46, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27274239

RESUMO

Selection of the optimal chemotherapy regimen for an individual cancer patient is challenging. The existing chemosensitivity tests are costly, time-consuming, and not amenable to wide utilization within a clinic. This limitation might be addressed by the recently proposed use of circulating tumor cells (CTCs), which provide an opportunity to noninvasively monitor response to therapy. Over the past few decades, various techniques were developed to capture and recover CTCs, but these techniques were often limited by a capture and recovery performance tradeoff between high viability and high efficiency. In this work, we used anti-epithelial cell adhesion molecule coated aptamer-poly (N-isopropylacrylamide) functionalized silicon nanowire substrates to capture and release epithelial cell adhesion molecule-positive CTCs at 32°C and 4°C, respectively. Then, we applied the nuclease to digest the aptamer to release the captured CTCs (near or at the end of the polymer brush), which cannot be released by heating/cooling process. High viability and purity CTCs could be achieved by decreasing the heating/cooling cycles and enzymatic treatment rounds. Furthermore, the time-saving process is helpful to maintain the morphology and enhance vitality of the recovered CTCs and is beneficial to the subsequent cell culture in vitro. We validated the feasibility of chemosensitivity testing based on the recovered HCC827 cells using an adenosine triphosphate-tumor chemosensitivity assay, and the results suggested that our method can determine which agent and what concentration have the best chemosensitivity for the culturing recovered CTCs. So, the novel method capable of a highly effective capture and recovery of high viability CTCs will pave the way for chemosensitivity testing.


Assuntos
Resinas Acrílicas/química , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Nanofios/química , Células Neoplásicas Circulantes/patologia , Antineoplásicos/farmacologia , Aptâmeros de Peptídeos/química , Biotina/química , Linhagem Celular Tumoral , Células Cultivadas , Células Imobilizadas , Molécula de Adesão da Célula Epitelial/química , Molécula de Adesão da Célula Epitelial/metabolismo , Humanos , Células Neoplásicas Circulantes/metabolismo , Reprodutibilidade dos Testes , Silício/química
11.
Pharmacol Biochem Behav ; 117: 47-51, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24342459

RESUMO

Synaptic communication forms the basis of learning and memory. Disruptions of synaptic function and memory have been widely reported in many neurological diseases, such as dementia. Thus, restoration of impaired synaptic communication is a potential therapeutic approach for these diseases. In this study, we demonstrated that supplementation with berberine, a plant alkaloid with a long history of medicinal usage in Chinese medicine, effectively reverses the synaptic deficits induced by D-galactose. We also found that berberine rescued D-galactose-induced memory impairment and additionally rescued the mRNA and protein levels of Arc/Arg3.1, an important immediate early gene that is crucial for maintaining normal synaptic plasticity. Our study provides the first piece of evidence supporting the potential use of berberine in the treatment of neural diseases with synaptic/memory impairments.


Assuntos
Berberina/farmacologia , Proteínas do Citoesqueleto/metabolismo , Galactose/farmacologia , Transtornos da Memória/prevenção & controle , Proteínas do Tecido Nervoso/metabolismo , Sinapses/efeitos dos fármacos , Animais , Sequência de Bases , Primers do DNA , Masculino , Transtornos da Memória/induzido quimicamente , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
Mol Ther ; 21(12): 2247-57, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23922015

RESUMO

Deficits of protein phosphatase-2A (PP2A) play a crucial role in tau hyperphosphorylation, amyloid overproduction, and synaptic suppression of Alzheimer's disease (AD), in which PP2A is inactivated by the endogenously increased inhibitory protein, namely inhibitor-2 of PP2A (I2(PP2A)). Therefore, in vivo silencing I2(PP2A) may rescue PP2A and mitigate AD neurodegeneration. By infusion of lentivirus-shRNA targeting I2(PP2A) (LV-siI2(PP2A)) into hippocampus and frontal cortex of 11-month-old tg2576 mice, we demonstrated that expression of LV-siI2(PP2A) decreased remarkably the elevated I2(PP2A) in both mRNA and protein levels. Simultaneously, the PP2A activity was restored with the mechanisms involving reduction of the inhibitory binding of I2(PP2A) to PP2A catalytic subunit (PP2AC), repression of the inhibitory Leu309-demethylation and elevation of PP2AC. Silencing I2(PP2A) induced a long-lasting attenuation of amyloidogenesis in tg2576 mice with inhibition of amyloid precursor protein hyperphosphorylation and ß-secretase activity, whereas simultaneous inhibition of PP2A abolished the antiamyloidogenic effects of I2(PP2A) silencing. Finally, silencing I2(PP2A) could improve learning and memory of tg2576 mice with preservation of several memory-associated components. Our data reveal that targeting I2(PP2A) can efficiently rescue Aß toxicities and improve the memory deficits in tg2576 mice, suggesting that I2(PP2A) could be a promising target for potential AD therapies.


Assuntos
Doença de Alzheimer/terapia , Lentivirus/genética , Proteínas Oncogênicas/antagonistas & inibidores , Proteínas Oncogênicas/genética , Proteína Fosfatase 2/metabolismo , Interferência de RNA , Proteínas tau/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Domínio Catalítico , Linhagem Celular Tumoral , Modelos Animais de Doenças , Regulação da Expressão Gênica , Vetores Genéticos , Células HEK293 , Hipocampo/metabolismo , Humanos , Lentivirus/metabolismo , Camundongos , Camundongos Transgênicos , Terapia de Alvo Molecular , Proteína Fosfatase 2/química , RNA Interferente Pequeno/genética
13.
J Huazhong Univ Sci Technolog Med Sci ; 33(3): 368-374, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23771662

RESUMO

This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system (RAAS) and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy (STNx) were established. Animals were randomly divided into 4 groups: sham STNx group (control), STNx group, morning benazepril group (MB) and evening benazepril group (EB). Benazepril was intragastrically administered at a dose of 10 mg/kg/day at 07:00 and 19:00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light:dark cycle of 12:12 for 12 weeks. Systolic blood pressure (SBP), 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity (RA), angiotensin II (AngII) and aldosterone (Ald) by radioimmunoassay (RIA) and the mRNA expression profile of clock genes (bmal1, dbp and per2) by real-time PCR at 12 weeks. Our results showed that no significant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Ald and RA content of a day between the MB group and EB group. The expression peak of bmal1 mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.


Assuntos
Benzazepinas/administração & dosagem , Proteínas CLOCK/metabolismo , Hipertensão Renal/tratamento farmacológico , Hipertensão Renal/fisiopatologia , Rim/efeitos dos fármacos , Rim/fisiopatologia , Sistema Renina-Angiotensina/efeitos dos fármacos , Animais , Anti-Hipertensivos/administração & dosagem , Ritmo Circadiano , Cronoterapia Farmacológica , Perfilação da Expressão Gênica , Rim/cirurgia , Masculino , Nefrectomia , Ratos , Ratos Wistar , Resultado do Tratamento
14.
Neurobiol Aging ; 34(6): 1555-63, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23402899

RESUMO

The current therapies for Alzheimer's disease (AD) are merely palliative that cannot arrest the pathologic progression of the disease. Therefore, it is critical to develop treatments that can target the disease-modifying molecule(s). In the present study, we found that treatment of tg2576 mice with melatonin from 4-8 months of age did not improve the pathology or behavioral performance of the mice. However, remarkable attenuation of tau and ß-amyloid pathologies with memory improvement were observed when melatonin was supplied from the age of 8-12 months or 4-12 months of the mice; more importantly, the improvements were still significant when the mice survived to old age. We also found that the disease stage-specific alteration of glycogen synthase kinase-3ß (GSK-3ß) but not protein phosphatase-2A, was correlated with the alterations of the pathology and behavior, and the timely targeting of GSK-3ß was critical for the efficacy of melatonin. Our finding suggests that melatonin treatment only at proper timing could arrest AD by targeting the activated GSK-3ß, which provides primary evidence for the importance and strategy in developing disease-modifying interventions of AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Modelos Animais de Doenças , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Quinase 3 da Glicogênio Sintase/metabolismo , Melatonina/uso terapêutico , Transtornos da Memória/tratamento farmacológico , Doença de Alzheimer/enzimologia , Doença de Alzheimer/patologia , Animais , Glicogênio Sintase Quinase 3 beta , Humanos , Masculino , Melatonina/farmacologia , Transtornos da Memória/enzimologia , Transtornos da Memória/patologia , Camundongos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico
15.
Neurobiol Aging ; 33(2): 254-64, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20138402

RESUMO

A chronic neuron loss is the cardinal pathology in Alzheimer disease (AD), but it is still not understood why most neurons in AD brain do not accomplish apoptosis even though they are actually exposed to an environment with enriched proapoptotic factors. Protein phosphatase-2A inhibitor-2 (I(2)(PP2A)), an endogenous PP2A inhibitor, is significantly increased in AD brain, but the role of I(2)(PP2A) in AD-like neuron loss is elusive. Here, we show that I(2)(PP2A) regulates p53 and Akt correlatively. The mechanisms involve activated transcription and p38 MAPK activities. More importantly, we demonstrate that the simultaneous activation of Akt induced by I(2)(PP2A) counteracts the hyperactivated p53-induced cell apoptosis. Furthermore, I(2)(PP2A), p53 and Akt are all elevated in the brain of mouse model and AD patients. Our results suggest that the increased I(2)(PP2A) may trigger apoptosis by p53 upregulation, but due to simultaneous activation of Akt, the neurons are aborted from the apoptotic pathway. This finding contributes to the understanding of why most neurons in AD brain do not undergo apoptosis.


Assuntos
Apoptose/fisiologia , Chaperonas de Histonas/metabolismo , Neurônios/citologia , Neurônios/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Regulação da Expressão Gênica/fisiologia , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos
16.
Neurochem Res ; 36(2): 288-96, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21061060

RESUMO

Altered neurogenesis has been reported in Alzheimer disease (AD), the most common neurodegenerative disorder characterized with hyperphosphorylated tau and accumulation of ß-amyloid (Aß). Recent studies suggest that tau phosphorylation is essential for hippocampal neurogenesis, however, it is not known whether tau phosphorylation also play a role in neurogenesis of subventricular zone (SVZ), another main progenitor niche in the brain. Here, we examined the expression of phosphorylated tau (p-tau) in SVZ and analyzed the role of p-tau in adult SVZ neurogenesis. We found that the expression of p-tau increased during postnatal development and remains at a high level until adulthood, and the p-tau was colocalized with some SVZ neural precursors. However, up-regulating glycogen synthase kinase-3 (GSK-3), a crucial tau kinase, had no effect on SVZ neurogenesis in adult rat brain. The SVZ neurogenesis was also unaffected in tau knockout and human tau transgenic mice. These results suggest that tau phosphorylation and GSK-3 activation may not be essential for adult SVZ neurogenesis.


Assuntos
Encéfalo/anatomia & histologia , Quinase 3 da Glicogênio Sintase/metabolismo , Neurogênese/fisiologia , Nicho de Células-Tronco , Proteínas tau/metabolismo , Animais , Biomarcadores/metabolismo , Encéfalo/fisiologia , Glicogênio Sintase Quinase 3 beta , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Ratos , Ratos Sprague-Dawley , Proteínas tau/genética
17.
J Neurosci ; 30(10): 3839-48, 2010 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-20220019

RESUMO

Protein phosphatase 2A (PP2A) is indispensable in development, and deficits of PP2A and deterioration of neuronal axons have been observed in several neurodegenerative disorders, but the direct link between PP2A and the neuronal axon development is still missing. Here, we show that PP2A is essential for axon development in transfected rat brain and the dissociated hippocampal neurons. Upregulation of PP2A catalytic subunit (PP2Ac) not only promotes formation and elongation of the functional axons but also rescues axon retardation induced by PP2A inhibition. PP2A can dephosphorylate collapsin response mediator protein-2 (CRMP2) that implements the axon polarization, whereas constitutive expression of phosphomimic-CRMP2 abrogates the effect of PP2A upregulation. We also demonstrate that PP2Ac is enriched in the distal axon of the hippocampal neurons. Our results reveal a mechanistic link between PP2A and axonogenesis/axonopathy, suggesting that upregulation of PP2A may be a promising therapeutic for some neurodegenerative disorders.


Assuntos
Axônios/enzimologia , Proteínas do Tecido Nervoso/metabolismo , Neurogênese/fisiologia , Proteína Fosfatase 2/fisiologia , Substituição de Aminoácidos/genética , Animais , Axônios/metabolismo , Células Cultivadas , Regulação da Expressão Gênica no Desenvolvimento , Hipocampo/citologia , Hipocampo/enzimologia , Hipocampo/metabolismo , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Neuritos/enzimologia , Neuritos/metabolismo , Neurogênese/genética , Fosforilação/genética , Proteína Fosfatase 2/antagonistas & inibidores , Proteína Fosfatase 2/biossíntese , Proteína Fosfatase 2/genética , RNA Interferente Pequeno/fisiologia , Ratos
18.
Hippocampus ; 20(12): 1339-49, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19816983

RESUMO

An increased hippocampal neurogenesis has been observed in Alzheimer disease (AD), the most common neurodegenerative disorder characterized with accumulation of ß-amyloid (Aß) and hyperphosphorylated tau (p-tau). Studies in transgenic mouse models suggest that the amyloidosis suppresses adult neurogenesis. Although emerging evidence links tau to neurodevelopment, the direct data regarding tau phosphorylation in adult neurogenesis is missing. Here, we found that the immature neurons, identified by doublecortin (DCX) and neurogenic differentiation factor (neuroD), were only immunoreactive to p-tau but not to the non-p-tau in adult rat brain and human patients with AD, and the p-tau was coexpressed temporally and spatially with DCX and neuroD in the hippocampal dentate gyrus (DG) of the rat brains during postnatal development. A correlative increase of immature neuron markers and tau phosphorylation was induced in rat hippocampal DG by upregulating glycogen synthase kinase-3 (GSK-3), a crucial tau kinase, and the increased neurogenesis was due to an enhanced proliferation but not survival or differentiation of the newborn neurons. The hippocampal neurogenesis was severely impaired in tau knockout mice and activation of GSK-3 in these mice did not rescue the deficits. These results reveal an essential role of tau phosphorylation in adult hippocampal neurogenesis. It suggests that spatial/temporal manipulation of tau phosphorylation may be compensatory for the neuron loss in neurological disorders, including AD.


Assuntos
Hipocampo/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo , Proteínas tau/metabolismo , Análise de Variância , Animais , Western Blotting , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Fosforilação , Ratos , Ratos Sprague-Dawley
19.
J Alzheimers Dis ; 16(1): 39-47, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19158420

RESUMO

The autophagic lysosomal system contributes to the removal of cytosolic components, and abnormality of lysosomal proteases has been reported in the brain of patients with Alzheimer's disease (AD). However, the role of lysosome in tau degradation is still elusive. Here, we infused chloroquine, 3-methyladenine or rapamycin into rat hippocampus or the lateral ventricle to manipulate the autophagic activity and measured the levels of tau protein by Western blotting. We unexpectedly observed that the level of different tau species decreased upon inhibition of lysosomal proteases or macroautophagy by chloroquine or 3-methyladenine. Furthermore, induction of autophagic activity by rapamycin did not induce degradation of tau proteins. To explore the underlying mechanisms for the increased tau degradation induced by autophagic inhibition, we used MG-132, an inhibitor of proteasome and calpain. We found that simultaneous inhibition of proteasome and calpain by MG-132 prevented the chloroquine-induced tau degradation. Further studies demonstrated that the activity of calpain was elevated whereas the activity of proteasome was suppressed in response to inhibition of autophagy by 3-methyladenine or chloroquine. Our data suggest that the lysosomal autophagic system may not degrade tau in the normal adult rat brain and inhibition of autophagy may induce tau proteolysis through activating calpain.


Assuntos
Autofagia/fisiologia , Calpaína/metabolismo , Proteínas tau/metabolismo , Animais , Antibacterianos/farmacologia , Autofagia/efeitos dos fármacos , Western Blotting , Calpaína/antagonistas & inibidores , Cloroquina/farmacologia , Quimotripsina/metabolismo , Ativação Enzimática/fisiologia , Lisossomos/enzimologia , Masculino , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma , Ratos , Ratos Sprague-Dawley , Sirolimo/farmacologia , Tripsina/metabolismo
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