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1.
Zhonghua Gan Zang Bing Za Zhi ; 31(5): 509-517, 2023 May 20.
Artigo em Chinês | MEDLINE | ID: mdl-37365028

RESUMO

Objective: To study the construction of a prognostic model for hepatocellular carcinoma (HCC) based on pyroptosis-related genes (PRGs). Methods: HCC patient datasets were obtained from the Cancer Genome Atlas (TCGA) database, and a prognostic model was constructed by applying univariate Cox and least absolute shrinkages and selection operator (LASSO) regression analysis. According to the median risk score, HCC patients in the TCGA dataset were divided into high-risk and low-risk groups. Kaplan-Meier survival analysis, receiver operating characteristic (ROC) curves, univariate and multivariate Cox analysis, and nomograms were used to evaluate the predictive ability of the prognostic models. Functional enrichment analysis and immune infiltration analysis were performed on differentially expressed genes between the two groups. Finally, two HCC datasets (GSE76427 and GSE54236) from the Gene Expression Omnibus database were used to externally validate the prognostic value of the model. Univariate and multivariate Cox regression analysis or Wilcoxon tests were performed on the data. Results: A total of 366 HCC patients were included after screening the HCC patient dataset obtained from the TCGA database. A prognostic model related to HCC was established using univariate Cox regression analysis, LASSO regression analysis, and seven genes (CASP8, GPX4, GSDME, NLRC4, NLRP6, NOD2, and SCAF11). 366 cases were evenly divided into high-risk and low-risk groups based on the median risk score. Kaplan-Meier survival analysis showed that there were statistically significant differences in the survival time between patients in the high-risk and low-risk groups in the TCGA, GSE76427, and GSE54236 datasets (median overall survival time was 1 149 d vs. 2 131 d, 4.8 years vs. 6.3 years, and 20 months vs. 28 months, with P = 0.000 8, 0.034 0, and 0.0018, respectively). ROC curves showed good survival predictive value in both the TCGA dataset and two externally validated datasets. The areas under the ROC curves of 1, 2, and 3 years were 0.719, 0.65, and 0.657, respectively. Multivariate Cox regression analysis showed that the risk score of the prognostic model was an independent predictor of overall survival time in HCC patients. The risk model score accurately predicted the survival probability of HCC patients according to the established nomogram. Functional enrichment analysis and immune infiltration analysis showed that the immune status of the high-risk group was significantly decreased. Conclusion: The prognostic model constructed in this study based on seven PRGs accurately predicts the prognosis of HCC patients.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Prognóstico , Piroptose , Neoplasias Hepáticas/genética , Fatores de Risco
2.
J Dent Res ; 102(9): 1058-1068, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37387366

RESUMO

Bone defect (BD) caused by trauma, infection, congenital defects, or neoplasia is a major cause of physical limitation. Distraction osteogenesis (DO) is a highly effective procedure for bone regeneration, while the concrete mechanism remains unknown. In this study, canine DO and BD models of the mandible were established. The results of micro-computed tomography and histological staining revealed that DO led to an increased mineralized volume fraction and robust new bone formation; in contrast, BD demonstrated incomplete bone union. Mesenchymal stem cells (MSCs) from DO and BD calluses were isolated and identified. Compared with BD-MSCs, DO-MSCs were found to have a stronger osteogenic capability. Single-cell RNA sequencing analysis was further performed to comprehensively define cell differences between mandibular DO and BD calluses. Twenty-six clusters of cells representing 6 major cell populations were identified, including paired related homeobox 1-expressing MSCs (PRRX1+MSCs), endothelial cells (ECs), T cells, B cells, neutrophils, and macrophages. Interestingly, 2 subpopulations in PRRX1+MSCs in the DO group were found to express the marker of neural crest cells (NCCs) and were associated with the process of epithelial-mesenchymal transition. The immunofluorescence assay was performed to further corroborate these results in vivo and in vitro, experimentally validating that continuous distraction maintained the PRRX1+MSCs in an embryonic-like state. Finally, we used CRISPR/Cas9 to knock out (KO) PRRX1 in the context of DO, which significantly blunted the capability of jawbone regeneration, resulting in a diminished NCC-like program and reduction of new bone volume. In addition, the ability of osteogenesis, cell migration, and proliferation in cultured PRRX1KO MSCs was inhibited. Taken together, this study provides a novel, comprehensive atlas of the cell fates in the context of DO regeneration, and PRRX1+MSCs act essential roles.


Assuntos
Células-Tronco Mesenquimais , Osteogênese por Distração , Diferenciação Celular , Células Endoteliais , Osteogênese por Distração/métodos , Microtomografia por Raio-X , Osteogênese/genética , Regeneração Óssea , Mandíbula/cirurgia
3.
Eur Rev Med Pharmacol Sci ; 25(3): 1302-1310, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33629300

RESUMO

OBJECTIVE: The systemic immune-inflammation index (SII), an inexpensive and widely available hematologic marker of inflammation, has been linked to tumor progression, metastatic spread, and poor patient prognosis. The objective of this study is to explore the prognostic value of SII in patients with urinary system cancers (USCs). MATERIALS AND METHODS: A comprehensive literature search was conducted by searching the PubMed, EMBASE, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases from inception to May 10, 2020, to identify potential studies that assessed the prognostic role of the SII in USCs. The hazard ratio (HR) with a 95% confidence interval (CI) were used to evaluate the correlation between SII and overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS) in USCs patients. RESULTS: A total of 12 studies, including 2,693 USCs patients, were eventually included in the meta-analysis. Elevated SII index was significantly associated with poor OS (HR=1.28, 95% CI: 1.17-1.39, p<0.001), PFS (HR=1.51, 95% CI: 1.25-1.82, p<0.001) and CSS (HR=3.42, 95% CI: 1.49-7.91, p<0.001). Furthermore, subgroup analysis indicated that higher SII than a cutoff value could predict poor OS in renal cell carcinoma (HR=1.23, p<0.001), prostate carcinoma (HR=1.95, p<0.001), bladder carcinoma (HR=5.40, p<0.001), testicular cancer (HR=6.09, p<0.001) and upper tract urothelial carcinoma (HR=2.19, p<0.001). Besides, these associations did not vary significantly by tumor subtypes and stages of USCs, sample sizes, study types, cutoff value defining elevated NLR, treatment methods, and NOS scores. CONCLUSIONS: SII may serve as a useful prognostic indicator in USCs and contribute to prognosis evaluation and treatment strategy formulation. However, more well-designed studies are warranted to verify our findings.


Assuntos
Inflamação/diagnóstico , Neoplasias Renais/diagnóstico , Neoplasias da Próstata/diagnóstico , Neoplasias da Bexiga Urinária/diagnóstico , Humanos , Inflamação/imunologia , Neoplasias Renais/imunologia , Masculino , Prognóstico , Neoplasias da Próstata/imunologia , Neoplasias da Bexiga Urinária/imunologia
5.
Ann R Coll Surg Engl ; : 1-6, 2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30112938

RESUMO

Introduction We present our experiences using a modified surgical approach from the edge of the tragus for mandibular condyle fractures, to reduce the risk of postoperative complications and visible scars. Materials and methods Thirty-two patients presenting with mandibular condyle fractures were treated through a modified approach on the edge of the tragus. The age of the patients ranged from 6 to 62 years. All mandibular condyle fractures were fixed. The patients were asked to start open-mouth training one week postoperatively, undergoing a cone-beam computed tomography examination and clinical follow-up. Postoperative complications were evaluated after surgery. Results Mouth opening was normal (average 39.5 mm) in all the patients during the operation and the occlusion improved significantly compared with preoperatively. No cases of damaged facial nerves were observed during the final follow-up at six months and postoperative scars were less noticeable. Conclusions The modified surgical approach from the edge of the tragus for mandibular condyle fractures provides a good view of the operative field, reduces the risk of facial nerve damage and produces a less noticeable postoperative scar.

6.
Zhonghua Yi Xue Za Zhi ; 97(7): 535-539, 2017 Feb 21.
Artigo em Chinês | MEDLINE | ID: mdl-28260295

RESUMO

Objective: To estimate the immune response of HepG2/dendritic cell (DC) fusion cells vaccines against HepG2 cells in vitro. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donors by Ficoll-Hypaque density-gradient centrifugation.Then DC were obtain from PBMCs by culturing in medium containing granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 5 days.DC and HepG2 fusion cells were induced by polythyleneglycol (PEG). The fusion cells were examined under fluorescence microscope by labeling DCs and HepG2 with green and red fluorescein, respectively, and then the fusion rates were analyzed by flow cytometry.The capacity of fusion cells to secrete interleukin (IL)-12 and stimulate the proliferation of T lymphocyte was assessed by ELISA and Flow cytometry, respectively.ELISPOT was used to assess the interferon gamma (IFN-γ) produced by cytotoxicity T lymphocyte (CTL), and the specific killing ability of fusion cells induce-CTL targeting HepG2 was estimated. Results: The fusion rate of HepG2/DC was 54.5%, and the fusion cells expressed a higher levels of DC mature marker CD80 and costimulatory molecules CD83, CD86 and MHC-Ⅰ, MHC-Ⅱ molecules HLA-ABC and HLA-DR than those in immature DCs (P<0.01). HepG2/DC showed a greater capacity to secrete high level of IL-12 (P<0.05) and activate proliferation of lymphocytes in vitro, as compared with DCs alone and DCs mix HepG2 (P<0.01). The HepG2/DC -activated CTL generated higher IFN-γ level and had a specific killing ability against HepG2 cells at the effecter/target ratio 30∶1 (31.4%±2.4%) and 100∶1 (57.6%±7.3%) (P<0.01). Conclusions: HepG2/DC fusion cells could efficiently stimulate T lymphocytes to generate specific CTL targeting HepG2 cells.It might be a promising strategy of immunotherapy for HCC.


Assuntos
Vacinas Anticâncer/imunologia , Leucócitos Mononucleares , Comunicação Celular , Fusão Celular , Células Dendríticas , Fator Estimulador de Colônias de Granulócitos e Macrófagos , Células Hep G2 , Humanos , Imunoterapia , Interferon gama , Interleucina-12 , Interleucina-4
7.
Biomed Pharmacother ; 68(4): 455-61, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24721321

RESUMO

Development of a novel angiogenesis inhibitor will be essential for the improvement of therapeutics against cancer. Kallistatin had been recognized as an endogenous angiogenesis inhibitor. Here, we demonstrated kallistatin's strong anti-angiogenesis and anti-metastasis activity stimulated by breast cancer cells (MCF-7) and its mechanism of action in vitro. The anti-angiogenesis effect in vivo was evaluated by chicken chorioallantoic membrane (CAM) neovascularisation. Because of the underlying molecular mechanism of its anti-angiogenesis activity remains poorly understood. In this study, we examined whether the NF-κB signaling pathway was involved in the anti-angiogenesis and anti-metastasis activity of kallistatin. Kallistatin significantly inhibited TNF-α-induced nuclear factor-κB activation in a dose-dependent manner. Addition of kallistatin inhibited TNF-α induced IκBα degradation; phosphorylation of IκBα kinase (IKK), nuclear factor-κB-p65 protein; and nuclear translocation of p65/50. Meanwhile, we investigated the effects of kallistatin on the expression of vascular endothelial growth factor (VEGF) and other angiogenesis-related gene in human umbilical vein endothelial cells (HUVECs). We found that kallistatin decreased the expression of VEGF and some angiogenesis-related genes, which promoted angiogenesis in cancer. Taken together, we suggested that kallistatin would inhibit tumor angiogenesis via inhibition of the NF-κB signaling pathway and finally abrogate NF-κB-dependent gene expression. All the results revealed that kallistatin would have potential as a novel.


Assuntos
Inibidores da Angiogênese/farmacologia , NF-kappa B/antagonistas & inibidores , Neovascularização Patológica/tratamento farmacológico , Serpinas/farmacologia , Inibidores da Angiogênese/administração & dosagem , Animais , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Embrião de Galinha , Membrana Corioalantoide/irrigação sanguínea , Membrana Corioalantoide/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana , Humanos , Células MCF-7 , Masculino , Metástase Neoplásica/prevenção & controle , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Ratos , Ratos Sprague-Dawley , Serpinas/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/genética
8.
Genet Mol Res ; 13(1): 2107-19, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24615087

RESUMO

Recent evidence suggests that genetic variations in the insulin-like growth factor (IGF)-IGF receptor (IGFR)-IGF binding proteins (IGFBP) axis may impact an individual's susceptibility to lung and esophageal cancer, but individually published results are inconclusive. Our meta-analysis aimed at providing a more precise estimation of these associations. An extensive literature search was conducted for appropriate articles published before May 15th, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for each study and then pooled using a random effect model. Twelve case-control studies were included with a total of 2686 lung cancer patients, 771 esophageal cancer patients, and 5918 healthy controls. Our meta-analysis indicated that genetic variations in the IGF-IGFR-IGFBP axis may be associated with increased risk of lung and esophageal cancer, especially among Asian populations. Further subgroup analysis by gene type indicated that common polymorphisms in the IGF1/2, IGF-1R, and IGFBP-3/5 genes may be the main determinants for lung cancer risk, while IGF-1, IGF-1R, and IGFBP-1 genetic polymorphisms may increase the risk of esophageal cancer. The current meta-analysis suggests that genetic variations in the IGF-IGFR-IGFBP axis confer susceptibility to lung and esophageal cancer, especially among Asian populations. Common polymorphisms in the IGF-IGFR-IGFBP axis may serve as useful biomarkers for predicting the risk of lung and esophageal cancer.


Assuntos
Neoplasias Esofágicas/genética , Predisposição Genética para Doença , Variação Genética , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Neoplasias Pulmonares/genética , Receptores de Somatomedina/genética , Somatomedinas/genética , Estudos de Casos e Controles , Estudos de Associação Genética , Humanos , Razão de Chances , Viés de Publicação , Risco
10.
J Cell Sci ; 110 ( Pt 14): 1625-34, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9247196

RESUMO

Arachidonic acid is elevated in a variety of cell types in response to extracellular stimuli, and has been hypothesized to exert at least some of its intracellular actions via activation of protein kinase C. Here we show that arachidonic acid stimulates a unique pattern of translocation of the epsilon-isoform of protein kinase C in isolated adult rat cardiac myocytes. Using western blot analysis, the majority of epsilon-protein kinase C was found in a cytosolic fraction in unstimulated cells. Treatment with 50 microM arachidonic acid caused a transient increase of epsilon-protein kinase C in a membrane fraction within 1 minute, then after 5-20 minutes most was found in a filament/nuclear fraction. Immunofluorescence and confocal microscopy of the filament fraction revealed a striated staining pattern with epsilon-protein kinase C localized near the Z-line where actin filaments are anchored and where transverse tubules are closely apposed to the myofilaments. delta-Protein kinase C, another isoform highly expressed in these cells, did not redistribute significantly in response to arachidonic acid, but in response to phorbol ester displayed a predominantly nuclear localization. Arachidonic acid also stimulated phosphorylation of the thin filament protein, troponin I, consistent with a filament localization for activated PKC. The physiological relevance of these findings was supported by the observation that 50 microM arachidonic acid promoted a 2.3-fold enhancement of myocyte twitch amplitude, an effect that was significantly blocked by the protein kinase C antagonist chelerythrine. Moreover, the onset of this physiological response correlated in time with translocation of epsilon-protein kinase C to the filaments. The results suggest that arachidonic acid initiates a redistribution of epsilon-protein kinase C to myofilament structures at or near the Z-line where this isozyme would be strategically located to regulate myofilament function and excitation-contraction coupling.


Assuntos
Ácido Araquidônico/farmacologia , Isoenzimas/metabolismo , Miocárdio/enzimologia , Miofibrilas/enzimologia , Proteína Quinase C/metabolismo , Animais , Carcinógenos/farmacologia , Citoesqueleto/química , Feminino , Imunofluorescência , Proteínas dos Microfilamentos/metabolismo , Contração Muscular/efeitos dos fármacos , Miocárdio/química , Miocárdio/citologia , Miofibrilas/efeitos dos fármacos , Fosforilação , Proteína Quinase C-épsilon , Ratos , Ratos Sprague-Dawley , Acetato de Tetradecanoilforbol/farmacologia
11.
Biophys J ; 70(5): 2448-57, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-9172772

RESUMO

To test the responsiveness of living cells to the intracellular messenger diacylglycerol, we developed a prototype caged diacylglycerol compound, 3-O-(alpha-carboxyl-2,4-dinitrobenzyl)-1 ,2-dioctanoyl-rac-glycerol (designated alpha-carboxyl caged diC(8)), that produces dioctanoylglycerol (diC(8)) on photolysis. Alpha-Carboxyl caged diC(8) is biologically inert toward diacylglycerol kinase and protein kinase C in vitro and is readily incorporated into cardiac myocyte membranes, where it has no effect before irradiation. Exposure to near-UV light releases biologically active diC8 in good yield (quantum efficiency = 0.2). Here we examine a cellular response to controlled elevation of diC8 within single cardiac myocytes. Twitch amplitude was monitored in electrically stimulated myocytes, and a ramp increase in the concentration of diC(8) was generated by continuous irradiation of cells loaded with the caged compound. The myocyte response was biphasic with a positive inotropic phase (39% increase in twitch amplitude), followed by a large negative inotropic phase (>80% decrease). The time to peak inotropy for both phases depended on the light intensity, decreasing from 376 +/- 51 S to 44 +/- 5 s (positive phase) and 422 +/- 118 S to 51 +/- 9 S (negative phase) as the light intensity was increased eightfold. Both phases were inhibited by the protein kinase C inhibitor chelethyrine chloride. An increase in extracellular K+ from 5 mM to 20 mM to partially depolarize the cell membrane eliminated the positive inotropic phase, but the negative inotropic response was largely unaltered. The results reveal new features in the response of cardiac muscle to diacylglycerol, including a positive inotropic phase and a complex responsiveness to a simple linear increase in diacylglycerol. The effects of photoreleased diC(8) were similar to the effects of opiate agonists selective for kappa receptors, consistent with a major role for diacylglycerol in these responses.


Assuntos
Diglicerídeos/química , Diglicerídeos/metabolismo , Diglicerídeos/farmacologia , Coração/fisiologia , Miocárdio/metabolismo , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida , Trifosfato de Adenosina/metabolismo , Animais , Anti-Hipertensivos/farmacologia , Encéfalo/enzimologia , Células Cultivadas , Diacilglicerol Quinase , Diglicerídeos/síntese química , Diglicerídeos/farmacocinética , Ativação Enzimática , Feminino , Coração/efeitos dos fármacos , Ventrículos do Coração , Luz , Contração Miocárdica/efeitos dos fármacos , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Fotólise , Proteína Quinase C/metabolismo , Pirrolidinas/farmacologia , Ratos , Ratos Sprague-Dawley , Sistemas do Segundo Mensageiro
12.
Neuroscience ; 60(2): 325-36, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-8072687

RESUMO

Amplification of complementary DNA by the polymerase chain reaction and anti-peptide antibodies were used to characterize the expression of two alternatively spliced forms of a metabotropic glutamate receptor (mGluR1 alpha and mGluR1 beta) in the central nervous system of the rat. Polymerase chain reaction analysis showed that mGluR1 alpha was the predominate of the two forms in the cerebellum, diencephalon, mesencephalon, olfactory bulb and brainstem, while mGluR1 beta was the major form present in the hippocampus. Approximately equal amounts of the two receptors were expressed in the cerebral cortex, septum and striatum. Immunochemical analyses of the two receptors were conducted in the rat cerebellum and hippocampus. An mGluR1 alpha-specific antibody labelled a protein with a relative molecular weight of 146,000 on immunoblots of the hippocampus and cerebellum. Immunoblot analysis of the developmental expression of mGluR1 alpha in the hippocampus and cerebellum demonstrated that in both structures, the levels of mGluR1 alpha were at or near their maximum levels in the adult brain. In contrast, two mGluR1 beta-specific antibodies failed to detect mGluR1 beta on immunoblots of brain tissue, thus precluding an immunocytochemical analysis of this receptor. Although low levels of a higher-molecular weight protein, possibly a dimeric form of mGluR1 beta were seen with one of the mGluR1 beta-specific antibodies, we hypothesize that some of the mGluR1 beta present in brain tissue may undergo proteolytic cleavage of the carboxy terminus. Immunocytochemical analysis of mGluR1 alpha showed that very high levels of this receptor were expressed in Purkinje cell bodies and dendrites. In the granule cell layer, some Golgi neurons were immunostained. The granule cells were not labelled. In the hippocampus, mGluR1 alpha immunoreactivity was present in interneurons of the stratum oriens and the dentate hilar region. Double-labelling studies demonstrated that these interneurons were also immunopositive for the neuropeptide somatostatin. The presence of mGluR1 alpha in cells of the hippocampus that are associated with the release of somatostatin, suggest that this receptor could play a role in regulating hippocampal excitability in both normal and epileptic tissues.


Assuntos
Processamento Alternativo , Encéfalo/metabolismo , RNA Mensageiro/biossíntese , Receptores de Glutamato/biossíntese , Sequência de Aminoácidos , Animais , Anticorpos , Sequência de Bases , Encéfalo/citologia , Primers do DNA , DNA Complementar/metabolismo , Expressão Gênica , Immunoblotting , Imuno-Histoquímica , Dados de Sequência Molecular , Especificidade de Órgãos , Peptídeos/síntese química , Peptídeos/imunologia , Reação em Cadeia da Polimerase/métodos , Ratos , Ratos Wistar , Receptores de Glutamato/análise
13.
J Neurochem ; 61(1): 85-92, 1993 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8390570

RESUMO

A comparison of the pharmacological and physiological properties of the metabotropic glutamate 1 alpha and 1 beta receptors (mGluR1 alpha and mGluR1 beta) expressed in baby hamster kidney (BHK 570) cells was performed. The mGluR1 beta receptor is an alternatively spliced form of mGluR1 alpha with a modified carboxy terminus. Immunoblots of membranes from the two cell lines probed with receptor-specific antipeptide antibodies showed that mGluR1 alpha migrated with an M(r) = 154,000, whereas mGluR1 beta migrated with an M(r) = 96,000. Immunofluorescence imaging of receptors expressed in BHK 570 cells revealed that the mGluR1 alpha receptor was localized to patches along the plasmalemma and on intracellular membranes surrounding the nucleus, whereas mGluR1 beta was distributed diffusely throughout the cell. Agonist activation of the mGluR1 alpha and the mGluR1 beta receptors stimulated phosphoinositide hydrolysis. At both receptors, glutamate, quisqualate, and ibotenate were full agonists, whereas trans-(+)-1-aminocyclopentane-1,3-dicarboxylate appeared to act as a partial agonist. The stimulation of phosphoinositide hydrolysis by mGluR1 alpha showed pertussis toxin-sensitive and insensitive components, whereas the mGluR1 beta response displayed only the toxin-insensitive component. The mGluR1 alpha and mGluR1 beta receptors also increased intracellular calcium levels by inducing release from intracellular stores. These results indicate that the different carboxy terminal sequences of the two receptors directly influences G protein coupling and subcellular deposition of the receptor polypeptides and suggest that the two receptors may subserve different roles in the nervous system.


Assuntos
DNA Recombinante , Fosfatidilinositóis/metabolismo , Receptores de Glutamato/metabolismo , Animais , Especificidade de Anticorpos , Cálcio/metabolismo , Linhagem Celular Transformada , Eletroforese em Gel de Poliacrilamida , Imunofluorescência , Hidrólise , Immunoblotting , Membranas Intracelulares/metabolismo , Rim/citologia , Rim/metabolismo , Concentração Osmolar , Toxina Pertussis , Receptores de Glutamato/imunologia , Fatores de Virulência de Bordetella/farmacologia
14.
Science ; 259(5098): 1173-5, 1993 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-8382377

RESUMO

Ligand-gated ion channels gated by glutamate constitute the major excitatory neurotransmitter system in the mammalian brain. The functional modulation of GluR6, a kainate-activated glutamate receptor, by adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) was examined with receptors expressed in human embryonic kidney cells. Kainate-evoked currents underwent a rapid desensitization that was blocked by lectins. Kainate currents were potentiated by intracellular perfusion of PKA, and this potentiation was blocked by co-application of an inhibitory peptide. Site-directed mutagenesis was used to identify the site or sites of phosphorylation on GluR6. Although mutagenesis of two serine residues, Ser684 and Ser666, was required for complete abolition of the PKA-induced potentiation, Ser684 may be the preferred site of phosphorylation in native GluR6 receptor complexes. These results indicate that glutamate receptor function can be directly modulated by protein phosphorylation and suggest that a dynamic regulation of excitatory receptors could be associated with some forms of learning and memory in the mammalian brain.


Assuntos
Encéfalo/fisiologia , Ácido Caínico/farmacologia , Proteínas Quinases/metabolismo , Receptores de Glutamato/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Sítios de Ligação , Células Cultivadas , Concanavalina A/farmacologia , Potenciais Evocados/efeitos dos fármacos , Humanos , Rim , Cinética , Potenciais da Membrana/efeitos dos fármacos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oligodesoxirribonucleotídeos , Receptores de Glutamato/efeitos dos fármacos , Receptores de Glutamato/genética , Receptores de Ácido Caínico , Serina , Aglutininas do Germe de Trigo/farmacologia
15.
Int J Cancer ; 52(3): 444-50, 1992 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-1399121

RESUMO

Protein kinase C (PKC) is the target for a number of tumor promoters. The mechanism underlying the promoting effects of bile acids in colorectal cancer is not understood. We report that sodium deoxycholate (DOC) triggered activation of PKC in physiological conditions. The biphasic effects of DOC upon PKC activation were Ca(2+)-stimulated and did not require phosphatidylserine (PtdSer) as phospholipid co-factor. The optimal rate of activation was obtained at 0.4 mM DOC and reached approximately half the maximal rate of activation obtained in the presence of PtdSer. Similarly to PtdSer, DOC supported diacylglycerol- as well as phorbol-ester-mediated PKC activation. The reciprocal effects of PtdSer and DOC upon PKC in either 0.5 mM CaCl2 or 0.5 mM EGTA suggest that DOC interacts with the phospholipid-binding domain to elicit PKC activation. DOC-supported enzyme activation exhibited substrate specificity different from that of PtdSer-supported enzyme activation. All tested primary and secondary bile acids activated PKC to various extents, with DOC being the most potent. We suggest that amphipathic bile acids acting in a PtdSer-like manner provide the hydrophobic environment required for PKC activation. Treatment of 32P-labeled platelets and colonic cells HT29 Cl.19A with DOC enhanced the phosphorylation of endogenous substrates for PKC. Colonic cells responsive at 50 microM DOC, appeared to be 10-fold more sensitive than platelets. We suggest that direct or indirect activation of PKC by bile acids may account for the promoting effects of these non-phorbol-ester-type tumor promoters.


Assuntos
Ácidos e Sais Biliares/farmacologia , Plaquetas/enzimologia , Carcinógenos/farmacologia , Neoplasias do Colo/enzimologia , Proteína Quinase C/metabolismo , Cálcio/farmacologia , Ácido Desoxicólico/farmacologia , Ativação Enzimática , Humanos , Fosforilação , Acetato de Tetradecanoilforbol/farmacologia , Células Tumorais Cultivadas
16.
Biochem Biophys Res Commun ; 169(3): 933-40, 1990 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-2114110

RESUMO

Unlike unsaturated fatty acids, which almost fully activated purified brain protein kinase C in a phosphatidylserine- and Ca2(+)-free reaction, related methyl esters were poorly active in vitro. In contrast, methyl arachidonate was revealed to be as potent as arachidonic acid in activating protein kinase C in intact platelets. Arachidonic acid-mediated activation peaked at 20 s while methyl arachidonate-mediated activation plateaued at 2 min when both lipids were added at 50 microM. At concentrations higher than 0.3 mM, all tested unsaturated fatty acids and related methyl esters were weak activators of the enzyme, with the exception of linolenic acid and methyl linolenate which evoked strong enzyme activation. However, inhibitors of arachidonate metabolism blocked both arachidonic-acid and methyl-arachidonate-induced responses. At 5 microM arachidonic acid and methyl arachidonate, protein kinase C activation was due to a cyclooxygenase product(s) whereas at 50 microM the lipoxygenase pathway was mostly involved in the reaction. Therefore, arachidonic acid and its methyl ester activate protein kinase C in platelets mainly through action of their metabolites and eicosanoid synthesis. It is suggested that such indirect protein kinase C activation may account for the tumor-promoting activity of unsaturated fatty acids and related methyl esters.


Assuntos
Ácidos Araquidônicos/fisiologia , Plaquetas/metabolismo , Proteína Quinase C/metabolismo , Ácido 5,8,11,14-Eicosatetrainoico/farmacologia , Animais , Ácido Araquidônico , Aspirina/farmacologia , Plaquetas/enzimologia , Sistema Livre de Células , Ativação Enzimática , Ésteres , Técnicas In Vitro , Metilação , Fosfoproteínas/metabolismo , Ratos , Relação Estrutura-Atividade
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