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1.
Nat Commun ; 15(1): 2337, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491015

RESUMO

We show that lattice dislocations of topological iron-based superconductors such as FeTe1-xSex will intrinsically trap non-Abelian Majorana quasiparticles, in the absence of any external magnetic field. Our theory is motivated by the recent experimental observations of normal-state weak topology and surface magnetism that coexist with superconductivity in FeTe1-xSex, the combination of which naturally achieves an emergent second-order topological superconductivity in a two-dimensional subsystem spanned by screw or edge dislocations. This exemplifies a new embedded higher-order topological phase in class D, where Majorana zero modes appear around the "corners" of a low-dimensional embedded subsystem, instead of those of the full crystal. A nested domain wall theory is developed to understand the origin of these defect Majorana zero modes. When the surface magnetism is absent, we further find that s± pairing symmetry itself is capable of inducing a different type of class-DIII embedded higher-order topology with defect-bound Majorana Kramers pairs. We also provide detailed discussions on the real-world material candidates for our proposals, including FeTe1-xSex, LiFeAs, ß-PdBi2, and heterostructures of bismuth, etc. Our work establishes lattice defects as a new venue to achieve high-temperature topological quantum information processing.

2.
IEEE J Biomed Health Inform ; 28(4): 2362-2372, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38265898

RESUMO

As a pivotal post-transcriptional modification of RNA, N6-methyladenosine (m6A) has a substantial influence on gene expression modulation and cellular fate determination. Although a variety of computational models have been developed to accurately identify potential m6A modification sites, few of them are capable of interpreting the identification process with insights gained from consensus knowledge. To overcome this problem, we propose a deep learning model, namely M6A-DCR, by discovering consensus regions for interpretable identification of m6A modification sites. In particular, M6A-DCR first constructs an instance graph for each RNA sequence by integrating specific positions and types of nucleotides. The discovery of consensus regions is then formulated as a graph clustering problem in light of aggregating all instance graphs. After that, M6A-DCR adopts a motif-aware graph reconstruction optimization process to learn high-quality embeddings of input RNA sequences, thus achieving the identification of m6A modification sites in an end-to-end manner. Experimental results demonstrate the superior performance of M6A-DCR by comparing it with several state-of-the-art identification models. The consideration of consensus regions empowers our model to make interpretable predictions at the motif level. The analysis of cross validation through different species and tissues further verifies the consistency between the identification results of M6A-DCR and the evolutionary relationships among species.


Assuntos
Adenosina , RNA , Humanos , Metilação , Consenso , RNA/genética , RNA/metabolismo , Adenosina/genética , Adenosina/metabolismo
3.
Nat Commun ; 14(1): 7119, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37932274

RESUMO

Over the last decade, the possibility of realizing topological superconductivity (TSC) has generated much excitement. TSC can be created in electronic systems where the topological and superconducting orders coexist, motivating the continued exploration of candidate material platforms to this end. Here, we use molecular beam epitaxy (MBE) to synthesize heterostructures that host emergent interfacial superconductivity when a non-superconducting antiferromagnet (FeTe) is interfaced with a topological insulator (TI) (Bi, Sb)2Te3. By performing in-vacuo angle-resolved photoemission spectroscopy (ARPES) and ex-situ electrical transport measurements, we find that the superconducting transition temperature and the upper critical magnetic field are suppressed when the chemical potential approaches the Dirac point. We provide evidence to show that the observed interfacial superconductivity and its chemical potential dependence is the result of the competition between the Ruderman-Kittel-Kasuya-Yosida-type ferromagnetic coupling mediated by Dirac surface states and antiferromagnetic exchange couplings that generate the bicollinear antiferromagnetic order in the FeTe layer.

4.
Brief Bioinform ; 24(1)2023 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-36562706

RESUMO

As microRNAs (miRNAs) are involved in many essential biological processes, their abnormal expressions can serve as biomarkers and prognostic indicators to prevent the development of complex diseases, thus providing accurate early detection and prognostic evaluation. Although a number of computational methods have been proposed to predict miRNA-disease associations (MDAs) for further experimental verification, their performance is limited primarily by the inadequacy of exploiting lower order patterns characterizing known MDAs to identify missing ones from MDA networks. Hence, in this work, we present a novel prediction model, namely HiSCMDA, by incorporating higher order network structures for improved performance of MDA prediction. To this end, HiSCMDA first integrates miRNA similarity network, disease similarity network and MDA network to preserve the advantages of all these networks. After that, it identifies overlapping functional modules from the integrated network by predefining several higher order connectivity patterns of interest. Last, a path-based scoring function is designed to infer potential MDAs based on network paths across related functional modules. HiSCMDA yields the best performance across all datasets and evaluation metrics in the cross-validation and independent validation experiments. Furthermore, in the case studies, 49 and 50 out of the top 50 miRNAs, respectively, predicted for colon neoplasms and lung neoplasms have been validated by well-established databases. Experimental results show that rich higher order organizational structures exposed in the MDA network gain new insight into the MDA prediction based on higher order connectivity patterns.


Assuntos
Neoplasias do Colo , Neoplasias Pulmonares , MicroRNAs , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Biologia Computacional/métodos , Neoplasias Pulmonares/genética , Bases de Dados Factuais , Algoritmos , Predisposição Genética para Doença
5.
BMC Bioinformatics ; 23(1): 516, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36456957

RESUMO

BACKGROUND: Drug repositioning is a very important task that provides critical information for exploring the potential efficacy of drugs. Yet developing computational models that can effectively predict drug-disease associations (DDAs) is still a challenging task. Previous studies suggest that the accuracy of DDA prediction can be improved by integrating different types of biological features. But how to conduct an effective integration remains a challenging problem for accurately discovering new indications for approved drugs. METHODS: In this paper, we propose a novel meta-path based graph representation learning model, namely RLFDDA, to predict potential DDAs on heterogeneous biological networks. RLFDDA first calculates drug-drug similarities and disease-disease similarities as the intrinsic biological features of drugs and diseases. A heterogeneous network is then constructed by integrating DDAs, disease-protein associations and drug-protein associations. With such a network, RLFDDA adopts a meta-path random walk model to learn the latent representations of drugs and diseases, which are concatenated to construct joint representations of drug-disease associations. As the last step, we employ the random forest classifier to predict potential DDAs with their joint representations. RESULTS: To demonstrate the effectiveness of RLFDDA, we have conducted a series of experiments on two benchmark datasets by following a ten-fold cross-validation scheme. The results show that RLFDDA yields the best performance in terms of AUC and F1-score when compared with several state-of-the-art DDAs prediction models. We have also conducted a case study on two common diseases, i.e., paclitaxel and lung tumors, and found that 7 out of top-10 diseases and 8 out of top-10 drugs have already been validated for paclitaxel and lung tumors respectively with literature evidence. Hence, the promising performance of RLFDDA may provide a new perspective for novel DDAs discovery over heterogeneous networks.


Assuntos
Aprendizagem , Neoplasias Pulmonares , Humanos , Benchmarking , Descoberta de Drogas , Paclitaxel
6.
Phys Rev Lett ; 129(27): 277001, 2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36638298

RESUMO

In this Letter, we establish a new theoretical paradigm for vortex Majorana physics in the recently discovered topological iron-based superconductors (TFeSCs). While TFeSCs are widely accepted as an exemplar of topological insulators (TIs) with intrinsic s-wave superconductivity, our theory implies that such a common belief could be oversimplified. Our main finding is that the normal-state bulk Dirac nodes, usually ignored in TI-based vortex Majorana theories for TFeSCs, will play a key role of determining the vortex state topology. In particular, the interplay between TI and Dirac nodal bands will lead to multiple competing topological phases for a superconducting vortex line in TFeSCs, including an unprecedented hybrid topological vortex state that carries both Majorana bound states and a gapless dispersion. Remarkably, this exotic hybrid vortex phase generally exists in the vortex phase diagram for our minimal model for TFeSCs and is directly relevant to TFeSC candidates such as LiFeAs. When the fourfold rotation symmetry is broken by vortex-line tilting or curving, the hybrid vortex gets topologically trivialized and becomes Majorana free, which could explain the puzzle of ubiquitous trivial vortices observed in LiFeAs. The origin of the Majorana signal in other TFeSC candidates such as FeTe_{x}Se_{1-x} and CaKFe_{4}As_{4} is also interpreted within our theory framework. Our theory sheds new light on theoretically understanding and experimentally engineering Majorana physics in high-temperature iron-based systems.

7.
Cancers (Basel) ; 13(9)2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33925568

RESUMO

Identification of drug-target interactions (DTIs) is a significant step in the drug discovery or repositioning process. Compared with the time-consuming and labor-intensive in vivo experimental methods, the computational models can provide high-quality DTI candidates in an instant. In this study, we propose a novel method called LGDTI to predict DTIs based on large-scale graph representation learning. LGDTI can capture the local and global structural information of the graph. Specifically, the first-order neighbor information of nodes can be aggregated by the graph convolutional network (GCN); on the other hand, the high-order neighbor information of nodes can be learned by the graph embedding method called DeepWalk. Finally, the two kinds of feature are fed into the random forest classifier to train and predict potential DTIs. The results show that our method obtained area under the receiver operating characteristic curve (AUROC) of 0.9455 and area under the precision-recall curve (AUPR) of 0.9491 under 5-fold cross-validation. Moreover, we compare the presented method with some existing state-of-the-art methods. These results imply that LGDTI can efficiently and robustly capture undiscovered DTIs. Moreover, the proposed model is expected to bring new inspiration and provide novel perspectives to relevant researchers.

8.
J Gastrointest Surg ; 24(2): 320-329, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30617773

RESUMO

BACKGROUND: The incidence of hepatocellular carcinoma (HCC) in non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Higher perioperative risks may be anticipated due to underlying steatohepatitis, while long-term outcomes after liver resection are unknown. We sought to investigate outcomes after liver resection for NAFLD-HCC versus hepatitis B virus (HBV)-HCC using propensity score matching (PSM). METHODS: Consecutive patients who underwent liver resection for HCC between 2003 and 2014 were identified from a multicenter database. Patients with NAFLD-HCC were matched one-to-one to patients with HBV-HCC. RESULTS: Among 1483 patients identified, 96 (6.5%) had NAFLD-HCC and 1387 (93.5%) had HBV-HCC. Patients with NAFLD-HCC were older (median age 57 vs. 50 years), more often overweight (50.0% vs. 37.5%), less often to have cirrhosis (30.2% vs. 72.5%) and liver dysfunction (Child-Pugh B: 4.2% vs. 10.7%), had larger tumor size (median 7.2 vs. 6.2 cm) yet had better tumor differentiation (27.1% vs. 17.6%) compared with patients with HBV-HCC (all P < 0.05). Perioperative mortality and morbidity were comparable between the two groups (1.0% vs. 1.4% and 20.8% vs. 23.2%, both P > 0.05). No differences were noted in median OS and RFS among patient with NAFLD-HCC versus HBV-HCC before or after PSM. CONCLUSION: While patients with NAFLD-HCC had different clinical characteristics than patients with HBV-HCC, liver resection resulted in similar perioperative outcomes and comparable OS and RFS among patients with NAFLD-HCC and HBV-HCC.


Assuntos
Carcinoma Hepatocelular/cirurgia , Hepatectomia , Hepatite B Crônica/complicações , Neoplasias Hepáticas/cirurgia , Hepatopatia Gordurosa não Alcoólica/complicações , Adulto , Idoso , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/patologia , Feminino , Hepatectomia/efeitos adversos , Humanos , Cirrose Hepática/complicações , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Pontuação de Propensão , Fatores de Risco , Taxa de Sobrevida , Carga Tumoral
9.
Neurosci Bull ; 35(3): 507-518, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30796753

RESUMO

Myasthenia gravis (MG) is a prototypical antibody-mediated neurological autoimmune disease with the involvement of humoral immune responses in its pathogenesis. T follicular helper (Tfh) cells have been implicated in many autoimmune diseases. However, whether and how Tfh cells are involved in MG remain unclear. Here, we established and studied a widely-used and approved animal model of human MG, the rat model with acetylcholine receptor alpha (AChRα) subunit (R-AChR97-116)-induced experimental autoimmune myasthenia gravis (EAMG). This model presented mild body-weight loss 10 days after the first immunization (representing the early stage of disease) and more obvious clinical manifestations and body-weight loss 7 days after the second immunization (representing the late stage of disease). AChR-specific pre-Tfh cells and mature Tfh cells were detected in these two stages, respectively. In co-cultures of Tfh cells and B cells, the number of IgG2b-secreting B cells and the level of anti-AChR antibodies in the supernatant were higher in the cultures containing EAMG-derived Tfh cells. In immunohistochemistry and immunofluorescence assays, a substantial number of CD4+/Bcl-6+ T cells and a greater number of larger germinal centers were observed in lymph node tissues resected from EAMG rats. Based on these results, we hypothesize that an AChR-specific Tfh cell-mediated humoral immune response contributes to the development of EAMG.


Assuntos
Imunidade Humoral , Miastenia Gravis Autoimune Experimental/imunologia , Receptores Colinérgicos/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Linfócitos B/imunologia , Modelos Animais de Doenças , Feminino , Linfonodos/imunologia , Subunidades Proteicas/imunologia , Proteínas Proto-Oncogênicas c-bcl-6/imunologia , Ratos Endogâmicos Lew , Receptor Cross-Talk
11.
Clin Immunol ; 173: 109-116, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27664932

RESUMO

MicroRNA 182 has been found to have a distinct contribution in the clonal expansion of activated- and functioning of specialized-helper T cells. In this study we knocked down microRNA 182 in vivo and induced experimental autoimmune encephalomyelitis (EAE) to determine the influences of microRNA 182 in the Treg cells functional specialization through Foxo1 dependent pathway in the peripheral lymphoid organs. Down-regulation of microRNA 182 significantly increased the proportions of Foxp3+ T cells in the peripheral lymph nodes and spleen. In vivo study verified a positive correlation between microRNA 182 levels and symptom severity of EAE, and a negative correlation between microRNA 182 and the transcriptional factor Foxp3. In vitro polarization study also confirmed the contribution of Foxo1 in microRNA 182 mediated down-regulation of Foxp3+ T cells. Together, our results provide evidence that during the development of EAE, microRNA 182 repressed Treg cells differentiation through the Foxo1 dependent pathway.


Assuntos
Encefalomielite Autoimune Experimental/imunologia , Proteína Forkhead Box O1/imunologia , MicroRNAs/imunologia , Linfócitos T Reguladores/imunologia , Animais , Diferenciação Celular , Feminino , Linfonodos/citologia , Camundongos Endogâmicos C57BL , Baço/citologia , Linfócitos T Reguladores/fisiologia
12.
Curr Neurovasc Res ; 10(2): 103-11, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23469950

RESUMO

Angiogenesis is associated with improved neurologic recovery after cerebral ischemia. Human bone marrow mesenchymal stem cells (hMSCs) have been successfully used to treat ischemic stroke and were shown to induce the expression of a number of neurotrophic factors including VEGF, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) in a rat middle cerebral artery occlusion (MCAO) ischemia model. In this study, we aimed to understand the mechanism underlying the improvement of neurological function following hMSCs transplantation into MCAO rats. We established a rat MCAO model and used immunofluorescence to evaluate α-tubulin expression in the hippocampus. We used RT-PCR to determine the expression of Ang-1 and Ang-2 mRNAs after transplantation of hMSCs into MCAO rats. We showed a significant decrease in α-tubulin expression in rats with cerebral ischemia, suggesting that α-tubulin is a protective protein in cerebral ischemia Transplantation of hMSCs significantly upregulated α-tubulin levels in the hippocampus. Transplantation of hMSCs also resulted in a significant upregulation of Ang-1 and Ang-2 mRNAs in MCAO rats. Ang-2 expression was upregulated earlier than Ang-1, suggesting that (1) transplantation of hMSCs promotes angiogenesis and that (2) Ang-2 may be an initiator of angiogenesis. Our results provide a theoretical basis for the therapeutic use of hMSCs in cerebral ischemia.


Assuntos
Angiopoietina-1/biossíntese , Angiopoietina-2/biossíntese , Isquemia Encefálica/cirurgia , Transplante de Células-Tronco Mesenquimais , Tubulina (Proteína)/biossíntese , Animais , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Imunofluorescência , Humanos , Microscopia Confocal , Ratos , Ratos Wistar , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/cirurgia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
13.
Cancer Biol Ther ; 12(7): 610-6, 2011 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-21785272

RESUMO

The relationship between IL-17A and cancer, whether beneficial or antagonistic, continues to be a controversial issue. In this study, effects of IL-17A on lung adenocarcinoma were investigated using lung cancer cell lines, 95D and 95C. In the presence or absence of IL-17A, cell proliferation and VEGF secretion were detected. Effects of IL-17A on capillary networks and process of angiogenesis were also evaluated. In vivo, the level of IL-17A was assayed in the serum of lung adenocarcinoma patients. At the same time, slices of adenocarcinoma tissue were analyzed for expression of IL-17A, its receptor (IL-17RA), VEGF, CD4(+)-IL-17A+ cells and CD8(+)-IL-17A+ cells by immunohistochemistry and immunofluorescence assays. IL-17A did not have effect on the proliferation of 95D or 95C cells, however, the elevated expression of VEGF in supernatant of 95D or 95C cells was found to be IL-17A concentration-dependent. Supernatants from 95D or 95C cells treated with IL-17A could obviously facilitate angiogenesis, compared with IL-17A absence group (P < 0.01). Higher levels of IL-17A were detected in serum of patients with lung adenocarcinoma than healthy controls (P < 0.001). Higher positive expressions of IL-17A, IL-17RA and VEGF were confirmed in lung adenocarcinoma lesion tissues compared to pericancerous normal tissues (P < 0.001). Tnc17 cells, as well as Th17 cells were found in adenocarcinoma tissue, indicating a potential role of these cells in disease. In summary, IL-17A might affect lung adenocarcinoma by promoting angiogenesis, while the role of Tnc17 cells or Th17 cells remains to be elucidated.


Assuntos
Adenocarcinoma/metabolismo , Interleucina-17/metabolismo , Neoplasias Pulmonares/metabolismo , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Adenocarcinoma de Pulmão , Adulto , Idoso , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Feminino , Humanos , Interleucina-17/sangue , Interleucina-17/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Neovascularização Patológica/induzido quimicamente , Receptores de Interleucina-17/metabolismo , Valores de Referência , Fator A de Crescimento do Endotélio Vascular/metabolismo
14.
Neurosci Lett ; 497(2): 128-33, 2011 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-21539896

RESUMO

The aim of this present study is to evaluate the therapeutic effect of co-transplantation of neuregulin-1-transfected Schwann cells (SCs) and bone marrow stromal cells (BMSCs) on a rat model of spinal cord hemi-section injuries (Brown-Séquard syndrome), which is relevant to human clinical spinal cord injury. Both in vivo and in vitro data we received demonstrated that co-transplantation BMSCs with NRG1-transfected SCs reduced the size of cystic cavities, promoted axonal regeneration and hind limb functional recovery in comparison with SCs or BMSCs transplantation alone or together, and this treatment could provide important insights into potential therapies of spinal cord hemi-section injuries.


Assuntos
Células da Medula Óssea/fisiologia , Transplante de Medula Óssea/métodos , Neuregulina-1/genética , Células de Schwann/transplante , Traumatismos da Medula Espinal/terapia , Animais , Cistos/patologia , Cistos/terapia , Modelos Animais de Doenças , Feminino , Masculino , Neuregulina-1/fisiologia , Ratos , Ratos Wistar , Células de Schwann/fisiologia , Traumatismos da Medula Espinal/patologia , Células Estromais/fisiologia , Células Estromais/transplante , Síndrome , Transfecção/métodos
15.
Eur J Immunol ; 39(3): 800-9, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19283707

RESUMO

In addition to their capacity to differentiate, BM stromal cells (BMSC) have immunosuppressive qualities that make them strong candidates for use in cell therapy against human autoimmune diseases. We studied the immunoregulatory activities of BMSC on experimental autoimmune myasthenia gravis (EAMG) in vitro and in vivo. Intravenous administration of syngenic BMSC to EAMG-model rats on the day of their second immunization was effective in ameliorating the pathological features of the disease. In vitro, the proliferative ability of T cells or B cells from EAMG rats was inhibited when they were cocultured with BMSC at proper ratios. This inhibitory effect was at least partially dependent on the secretion of IDO. We also determined that the development of EAMG is accompanied by an imbalance among the Th1, Th2, Th17, and Treg cell subsets, and that this can be corrected by the administration of BMSC, which leads to an increase of Th2 (IL-4) and Treg (Foxp3) cells, and a reduction of Th1 (IFN-gamma) and Th17 (IL-17) cells, through an IDO-dependent mechanism. These results provide further insights into the pathogenesis of MG, EAMG, and other immune-mediated diseases, and support a potential role for BMSC in their treatment.


Assuntos
Células da Medula Óssea/imunologia , Citocinas/imunologia , Indolamina-Pirrol 2,3,-Dioxigenase/imunologia , Miastenia Gravis Autoimune Experimental/imunologia , Células Estromais/imunologia , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Células da Medula Óssea/metabolismo , Citocinas/biossíntese , Feminino , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Miastenia Gravis Autoimune Experimental/induzido quimicamente , Miastenia Gravis Autoimune Experimental/metabolismo , Peptídeos/farmacologia , Ratos , Ratos Endogâmicos Lew , Células Estromais/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo
16.
J Neuroimmunol ; 207(1-2): 83-91, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19174310

RESUMO

Bone marrow stromal cells (BMSCs) are strong candidates for cell therapy against human autoimmune diseases. Intravenous administration of syngenic BMSCs to EAMG-model rats effectively ameliorated the disease, partially through a TGF-beta-dependent mechanism. The proliferative ability of T or B cells from EAMG rats was inhibited by BMSCs at proper cocultured ratios. And the imbalance of Th1, Th2, Th17 and Treg cell subsets accompanied with the development of EAMG was corrected by the administration of BMSCs. These results provide further insights into the pathogenesis of MG, EAMG, and other immune-mediated diseases, and support a potential role for BMSCs in their treatment.


Assuntos
Transplante de Medula Óssea/métodos , Miastenia Gravis Autoimune Experimental/cirurgia , Células Estromais/transplante , Linfócitos T Auxiliares-Indutores/metabolismo , Linfócitos T Reguladores/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Peso Corporal , Proliferação de Células , Técnicas de Cocultura/métodos , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Imunoglobulinas/metabolismo , Miastenia Gravis Autoimune Experimental/imunologia , Peptídeos/imunologia , Ratos , Ratos Endogâmicos Lew , Receptores Colinérgicos/imunologia , Células Estromais/imunologia , Linfócitos T Auxiliares-Indutores/classificação , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Reguladores/imunologia , Fatores de Tempo , Fator de Crescimento Transformador beta/imunologia
17.
Neurosci Lett ; 445(1): 117-21, 2008 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-18782604

RESUMO

To determine whether the receptor for advanced glycation endproducts (RAGE) contributes to cerebral ischemia, we evaluated RAGE expression in human cerebral ischemia and a model of permanent middle cerebral artery occlusion (pMCAO) in rats. Biopsy specimens were obtained from 12 patients with unilateral cerebral infarction. For the pMCAO model, the middle cerebral artery (MCA) of Sprague-Dawley (SD) rats was permanently occluded. Immunohistochemistry and Western blotting were used to measure RAGE expression in the ischemic hemisphere relative to the normal hemisphere. PC12 cells subjected to oxygen and glucose deprivation (OGD) were used to evaluate the role of RAGE in cell injury. As expected, cerebral ischemia patients expressed elevated levels of RAGE in the ischemic hemisphere. In 1 and 2 days pMCAO rats, levels of RAGE were higher in the ischemic hemisphere relative to the non-ischemic hemisphere, and expression was primarily located in the penumbra of the ischemic hemisphere. In PC12 cells, levels of RAGE increased after 7h of OGD culture. Notably, blockade of RAGE with a selective RAGE antibody in vitro reduced the cytotoxicity caused by OGD. The present data suggest that RAGE is up-regulated in human cerebral ischemia and pMCAO rats, suggesting a role for RAGE in brain ischemia.


Assuntos
Isquemia Encefálica/patologia , Córtex Cerebral/metabolismo , Infarto da Artéria Cerebral Média/patologia , Receptores Imunológicos/metabolismo , Regulação para Cima/fisiologia , Adulto , Idoso , Animais , Isquemia Encefálica/complicações , Contagem de Células , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Células PC12 , Ratos , Ratos Sprague-Dawley , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/genética , Fatores de Tempo
18.
Zhonghua Gan Zang Bing Za Zhi ; 15(9): 681-4, 2007 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-17903371

RESUMO

OBJECTIVE: To investigate the differentiation of bone marrow mesenchymal stem cells (BMSCs) and the effects of BMSCs on the proliferation of cirrhotic fat-storing cells (CFSC) and hepatocytes in vitro. METHODS: BMSCs and hepatocytes were isolated and harvested from the bone marrow and livers of rats. A co-culture system was set up by transwell inserts in which the two chambers were separated by a semipermeable membrane. BMSCs labeled with PKH26 were cultured with hepatocytes/CFSC in the co-culture system and also in a cell-cell direct contact culture system. Anti-albumin and anti-smooth muscle alpha-actin (alpha-SMA) antibodies were tested by using fluorescence immunocytochemistry. BMSCs and hepatocytes/CFSC cultured alone served as controls. The proliferation level of hepatocytes in the co-culture system was measured. CFSC were cultured with the conditional medium of BMSCs, and their quantities were measured microscopically. RESULTS: Expression of albumin was observed in the hepatocytes of the two culture systems after they were cultured for 72 h but the albumin levels were higher in the cell-cell direct contact culture system (P<0.01). As compared to the controls, the number of hepatocytes was larger in the co-culture system (P<0.01). No expression of alpha-SMA in CFSC was observed in either culture system. The proliferation of CFSC was inhibited by the conditional medium of BMSCs. The longer the time of the co-culturing the more significant was the CFSC growth suppression (P<0.01). CONCLUSIONS: BMSCs can be induced into hepatocytes by a local micro-environment formed by hepatocytes. BMSCs may promote proliferation of hepatocytes and inhibit proliferation of CFSC.


Assuntos
Células da Medula Óssea/citologia , Proliferação de Células , Hepatócitos/citologia , Cirrose Hepática Experimental , Células-Tronco Mesenquimais/citologia , Animais , Diferenciação Celular , Células Cultivadas , Técnicas de Cocultura , Feminino , Cirrose Hepática Experimental/metabolismo , Gravidez , Ratos , Ratos Sprague-Dawley
19.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 23(2): 106-9, 2007 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-17286899

RESUMO

AIM: To explore the synergistic effect of MBP 68-86 and 87-99, on the inhibition of experimental autoimmune encephalomyelitis (EAE) in Lewis rat by nasal administration. METHODS: Three different MBP peptides(MBP 68-86, 87-99, and the non-encephalitogenic peptide 110-128) were synthesized and administrated nasally to Lewis rat on day-11, -10, -9, -8 and -7 prior to immunization with the guinea pig MBP (gp-MBP)+CFA, which was used to induce EAE. The protective effect on Lewis rat from EAE by the MBP peptides was evaluated. RESULTS: Protection was achieved with the encephalitogenic peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP 110-128. Neither MBP 68-86 nor 87-99 used alone conferred complete protection to gp-MBP-induced EAE. In contrast, nasal administration of a mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even at lower dosage than being used alone. Rats tolerized with MBP 68-86+87-99 nasally showed decreased T cell responses to MBP, reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays. Rats tolerized with MBP 68-86+87-99 also had abrogated MBP-reactive IFN-gamma and TNF-alpha mRNA expression in lymph node cells compared to rats receiving MBP 110-128 nasally, while similar low levels of MBP-reactive TGF-beta and IL-4 mRNA expressing cells were observed in the two groups. CONCLUSION: Nasal administration of encephalitogenic MBP peptides can induce antigen-specific T cell tolerance and confer incomplete protection to gp-MBP-induced EAE, and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms are proposed to be responsible for tolerance development after nasal peptide administration.


Assuntos
Administração Intranasal , Encefalomielite Autoimune Experimental/tratamento farmacológico , Proteína Básica da Mielina/uso terapêutico , Fragmentos de Peptídeos/uso terapêutico , Animais , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Hibridização In Situ , Interferon gama/genética , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Proteína Básica da Mielina/administração & dosagem , Proteína Básica da Mielina/farmacologia , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/farmacologia , Ratos , Ratos Endogâmicos Lew , Fator de Necrose Tumoral alfa/genética
20.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 23(1): 52-5, 2007 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-17210108

RESUMO

AIM: To investigate the therapeutic effect of bone marrow stromal cells (BMSCs) transplantation on experimental autoimmune neuritis (EAN) and study the possible mechanism. METHODS: EAN model was established by immunizing Lewis rats with P(0)180-199 peptide and complete Freund's adjuvant (CFA). In the therapy group, BMSCs (2x10(6) cells/rat) were marked with fluorochrome PKH26 and injected into the rats' caudal vein 10 d after immunization. The therapeutic effect of BMSC transplantation on EAN rats was investigated by clinical assessment, immunohistochemical staining, and ELISA, respectively. RESULTS: The injected BMSCs could migrate to the demyelinated nerve tissues, and the demyelination and inflammatory infiltration was relieved. The infiltration of CD4(+) and CD8(+) T cells and the sera level of IFN-gamma and TNF-alpha were decreased significantly (P<0.05), whereas IL-4 level in the supernatant of cultured lymphocytes was increased (P<0.05). CONCLUSION: Certain therapeutic effect of BMSC transplantation on EAN was observed. BMSCs could reverse the disbalance of Th1/Th2 cells by regulating the cytokine expression and could inhibit the activation and proliferation of T cells.


Assuntos
Células da Medula Óssea/citologia , Transplante de Medula Óssea/métodos , Neurite Autoimune Experimental/terapia , Células Estromais/citologia , Animais , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Neurite Autoimune Experimental/patologia , Distribuição Aleatória , Ratos , Nervo Isquiático/patologia , Neuropatia Ciática/patologia , Neuropatia Ciática/terapia
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