RESUMO
In this paper, LINC00839 expression in gastric cancer (GC) was confirmed by real-time quantitative PCR. The function of LINC00839 in GC was detected by loss of function assays. Luciferase assays was performed to confirm the interaction between LINC00839 and miR-1236-3p. Then we investigated the regulatory effect of LINC00839 on miR-1236-3p. The results confirmed that the expression level of LINC00839 in GC was significantly up-regulated. LINC00839 could promote GC cell proliferation, mobility, and invasion. The detection of luciferase reporter gene confirmed that LINC000839 could bind to the binding site of miR-1236-3p. Our findings suggest that LINC00839 promotes GC progression through sponging miR-1236-3p.
Assuntos
MicroRNAs , RNA Longo não Codificante , Neoplasias Gástricas , Linhagem Celular Tumoral , Proliferação de Células/genética , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismoRESUMO
Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is associated with an increased risk of graft failure and severe graft-versus-host disease (GVHD). Recent studies have shown that mesenchymal stromal cells (MSCs) display potent immunosuppressive effects and can support normal hematopoiesis. In a multi-center trial, we co-transplanted culture-expanded donor-derived bone marrow MSCs (BM-MSCs) into 35 children with severe aplastic anemia (SAA) undergoing haplo-HSCT. All 35 patients (100%) achieved hematopoietic reconstitution and showed sustained full donor chimerism. The median time for myeloid engraftment was 14 days (range 10-22 days), while that for platelet engraftment was 18 days (range 9-36 days). The incidence of grade II-IV acute GVHD and chronic GVHD was 25.71 and 22.86%, respectively. The overall survival rate was 85.71% with a median of 22 months (range 3.5-37 months). The combined transplantation of haploidentical HSCs and BM-MSCs into children with SAA without an HLA-identical sibling donor is relatively safe and may represent an effective new therapy to improve survival rates and reduce the risk of graft failure.
Assuntos
Anemia Aplástica/mortalidade , Anemia Aplástica/terapia , Transplante de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Mesenquimais , Doadores de Tecidos , Doença Aguda , Adolescente , Aloenxertos , Anemia Aplástica/sangue , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Doença Enxerto-Hospedeiro/sangue , Doença Enxerto-Hospedeiro/mortalidade , Humanos , Incidência , Masculino , Índice de Gravidade de Doença , Taxa de Sobrevida , Quimeras de Transplante/sangueRESUMO
As a "living fossil" that is used to understand the evolutionary history of seed plants, Ginkgo biloba is a well-known multipurpose tree with edible seeds, medicinal properties, and ornamental value, but little is known about its genetic diversity. Microsatellite, or simple sequence repeat (SSR), markers have proven to be powerful tools for genetic studies of plants. In this study, we isolated 30 novel polymorphic microsatellite loci in G. biloba using 454 pyrosequencing. The characteristics of these loci were tested with 48 cultivars. The number of alleles (NA) per locus ranged from two to seven. The observed (HO) and expected (HE) heterozygosities ranged from 0.000 to 0.750 and from 0.021 to 0.792, with an average of 0.326 and 0.443, respectively. In terms of genetic diversity in the Ginkgo population, NA was 3.300, NE was 2.090, I was 0.782, HO was 0.326, and HE was 0.443. These polymorphic SSRs will be useful for the assessment of population genetic diversity and resource conservation of G. biloba.
Assuntos
Ginkgo biloba/genética , Repetições de Microssatélites/genética , Variação Genética/genética , Genética Populacional , Polimorfismo Genético/genética , Análise de Sequência de DNA/métodosRESUMO
In this study, we aimed to explore the associations between HLA-A\B\DRB1 polymorphisms and the risks of vulvar lichen sclerosus (VLS) or squamous cell hyperplasia of the vulva (SCHV) in Han Chinese women. We enrolled 76 Han Chinese women with VLS (Group A), 74 with SCHV (Group B), and 66 healthy women (control group) in this study. Polymerase chain reaction amplification with sequence specific primers (PCR-SSP) was used to determine HLA-A\B\DRB1 polymorphisms. Compared with the control group, HLA-A*11, -B*15, and -DRB1*12 were present at a higher frequency in groups A and B, while HLA-B*13 was present at a higher frequency in group A. Fewer women in group A carried HLA-A*31, -DRB1*01, and -DRB1*03 genotypes and fewer women in group B carried HLA-B*40 and -DRB1*03 genotypes. Significant differences were found between group B and the control group for HLA-A*11, -B*15, -B*40, and -DRB1*03, and between group A and the control group for HLA-B*15 and -DRB1*12. The HLA-A*11, HLA-B*13, HLA-B*15, and HLA-DRB1*12 genotypes were associated with a higher risk of VLS, while the HLA-A*31, HLA-DRB1*01, and HLA-DRB1*03 genotypes were associated with a lower risk of VLS. In addition, carrying HLA-A*11, HLA-B*15, HLA-B*35, and HLA-DRB1*12 genotypes, and carrying HLA-B*40 and HLA-DRB1*03 genotypes were found to be risk or protective factors for SCHV, respectively.
Assuntos
Antígenos HLA-A/genética , Antígenos HLA-B/genética , Cadeias HLA-DRB1/genética , Hiperplasia/genética , Polimorfismo Genético , Vulva/patologia , Líquen Escleroso Vulvar/genética , Adulto , Alelos , Estudos de Casos e Controles , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Pessoa de Meia-Idade , Fatores de Risco , Líquen Escleroso Vulvar/diagnósticoRESUMO
Ginkgo biloba is considered to be a living fossil that can be used to understand the ancient evolutionary history of gymnosperms, but little attention has been given to the study of its population genetics, molecular phylogeography, and genetic resources assessment. Chloroplast simple sequence repeat (cpSSR) markers are powerful tools for genetic studies of plants. In this study, a total of 30 perfect cpSSRs of Ginkgo were identified and characterized, including di-, tri, tetra-, penta-, and hexanucleotide repeats. Fifteen of 21 designed primer pairs were successfully amplified to yield specific polymerase chain reaction products from 16 Ginkgo cultivars. Polymorphic cpSSRs were further applied to determine the genetic variation of 116 individuals in 5 populations of G. biloba. The results showed that 24 and 76% genetic variation existed within and among populations of this species, respectively. These polymorphic and monomorphic cpSSR markers can be used to trace the origin and evolutionary history of Ginkgo.
Assuntos
Cloroplastos/genética , Ginkgo biloba/genética , Repetições de Microssatélites/genética , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , Frequência do Gene/genética , Loci Gênicos , Genética Populacional , Genoma de Cloroplastos/genética , HaploidiaRESUMO
1. The purpose of this study was to evaluate the effects of supplementing diets with three types of fermented Ginkgo-leaves (FGL) on growth, antioxidant capacity, intestinal morphology and microbial ecology in broiler chicks. 2. A total of 300 d-old broilers were randomly allocated to 4 dietary treatments with 6 replications of 10 birds each. Birds were fed on basal diets (Control) or basal diets supplemented with 0.5% FGL with Candida utilis (CF group), Aspergillus niger (AF group) or their combined fermentation (CAF group), respectively, for a 42 d feeding trial. 3. AF and CAF supplementation improved body weight gain (BWG) (22-42 d) and feed conversion ratio (22-42 d and 1-42 d). Concentrations of serum α-tocopherol in CAF group, as well as hepatic α-tocopherol in the three FGL groups were increased, while hepatic reactive oxygen species (ROS) levels were greatly decreased in group AF and CAF. Chickens in AF and CAF groups had decreased hepatic protein carbonyls and malondialdehyde (MDA), as well as jejunal and ileal protein carbonyls. The total superoxide dismutase (T-SOD) activities and glutathione (GSH) of both jejunum and ileum of the CAF group were higher than the other groups. 4. Duodenal and jejunal villous height of birds fed on the AF and CAF diets were increased, while jejunal crypt depth (CD) was decreased. Furthermore, birds fed on AF and CAF supplemented diets had increased ileal lactobacilli populations. Decreased ileal and caecal Escherichia coli and Salmonellas populations was found for the birds fed on CAF supplemented diets. 5. The present study may indicate that the improved feed efficiency and intestinal functions in the group supplemented with AF and CAF are directly connected with the improved antioxidant capacity and intestinal microbial ecology.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Aspergillus niger/química , Candida/química , Galinhas/crescimento & desenvolvimento , Galinhas/metabolismo , Ginkgo biloba/química , Ração Animal/análise , Animais , Antioxidantes/metabolismo , Galinhas/anatomia & histologia , Galinhas/microbiologia , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Fermentação , Intestinos/anatomia & histologia , Intestinos/microbiologia , Masculino , Folhas de Planta/química , Distribuição Aleatória , Aumento de Peso/efeitos dos fármacosRESUMO
The regulative sequence (2273 bp) of the chalcone synthase gene promoter of biloba was cloned by genomic walking. A 2273-bp promoter 5' upstream translation start site of GbCHS was cloned and designated as GbCHSP. pBI121+CHSP:GUS and pBI121-35S:GUS were constructed and transformed into tobacco by LBA4404. We found that GbCHSP could drive transient expression of GUS in tobacco and differentially expressed in root, stem and leaf tissues of this plant. GUS activity regulated by the CHSP promoter were located in tissues (apical meristems) at the growing points of roots and stems. pBI121+CHSP:GUS could be induced by wounding, copper, UV-B, abscisic acid, and ethephon treatments of transgenic seedlings. This activity was weakly inhibited by gibberellin. Deletion analysis of the CHSP promoter in transgenic tobacco showed that CHSP1 complete promoter conferred a GUS expression and activity similar to that of 35 S(CaMV). GUS activity dropped dramatically when there were CHSP4, CHSP5 constructs and was almost totally absent when the CHSP6 construct was present. We conclude that the upstream sequence -1548 to -306 of GbCHSP is the main region for transcriptional regulation of the CHS gene and that it is activated by hormone and stress factors in G. biloba. These results will help us to understand the transcriptional regulatory mechanisms involved in GbCHS expression and flavonoid accumulation in G. biloba.
Assuntos
Aciltransferases/genética , Ginkgo biloba/genética , Nicotiana/genética , Regiões Promotoras Genéticas , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Nicotiana/crescimento & desenvolvimentoRESUMO
Cultivar identification is a key step to avoid the formation of homonyms and synonyms of Ginkgo biloba. In this study, a new approach based on combinational utilization of polymorphic bands produced from 6 different random amplified polymorphic DNA (RAPD) primers was developed for identifying 42 Ginkgo cultivars, and a manual cultivar identification diagram that consisted of polymorphic bands produced from different RAPD primers was reported. To check the reliability and efficiency of the cultivar identification diagram, 5 randomly chosen cultivars were further tested, and the workability of the diagram was verified. This new approach will be very helpful for Ginkgo cultivar discrimination and protection, and will also be beneficial for the nursery industry for early identification of Ginkgo seedlings.
Assuntos
DNA de Plantas/química , DNA de Plantas/genética , Marcadores Genéticos/genética , Ginkgo biloba/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Primers do DNA/química , Genótipo , Reprodutibilidade dos TestesRESUMO
Aspergillus niger-fermented Ginkgo biloba leaves (FR) and its comparative effect with vitamin E (VE) and nonfermented (NF) Ginkgo leaves on growth, lipid metabolism, antioxidant capacity, and meat quality of broiler chicks were investigated. In total, 360 one-day-old broiler chicks were randomly allocated into 6 dietary treatments, which were then denoted as control group (basal diet), VE group (containing respectively 15 and 30 IU/kg of all-rac-α-tocopherol acetate in the starter and grower phase), NF group (containing respectively 0.35% and 0.7% NF in the starter and grower phase), and FR1, FR2, and FR3 groups containing respectively 0.2, 0.35, and 0.5% FR in the starter and 0.4, 0.7, and 1.0% FR in the grower phase. The results on performance showed that a significant (P < 0.05) reduction of feed:gain ratio of birds in the FR2 group (22-42 d and 1-42 d) was observed when compared with that of the control and NF groups. With dietary FR increasing, the serum α-tocopherol concentration increased linearly (P = 0.001). Compared with the control, broilers had higher (P < 0.05) serum high-density lipoprotein concentration, total superoxide dismutase activities, and total antioxidant capacity when they were provided with the FR2 and FR3 diet. Whereas the low-density lipoprotein and triglyceride concentrations were lower (P < 0.05 or P < 0.01) in broilers from FR2 or FR3 groups. As the dietary FR increased, abdominal fat (P = 0.002) and muscle malondialdehyde (P = 0.001) concentrations decreased. Furthermore, 24-h pH, 24-h drip loss, and cooking loss were greatly improved (P < 0.05) as the levels of FR increased. Birds fed with FR had a lower (P < 0.05) C16:0 and C18:0 concentrations but a greater (P = 0.001) concentration of C18:2, C18:3, and C20:4 than that of the control. In conclusion, FR can improve the growth performance and lipid metabolism of broilers with decreased abdominal fat deposition. Also, the antioxidant capacity and meat quality improving effects observed in broilers fed FR products might result from the increased retention of α-tocopherol and reduction in lipid peroxidation, as evidenced by the decrease in malondialdehyde and the increase in total superoxide dismutase activities.
Assuntos
Ginkgo biloba/metabolismo , Carne/normas , Extratos Vegetais/farmacologia , Folhas de Planta/química , Gordura Abdominal/efeitos dos fármacos , Gordura Abdominal/fisiologia , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antioxidantes/metabolismo , Galinhas/sangue , Galinhas/crescimento & desenvolvimento , Galinhas/metabolismo , Dieta/veterinária , Fermentação , Metabolismo dos Lipídeos , Peroxidação de Lipídeos/efeitos dos fármacos , Extratos Vegetais/químicaRESUMO
We examined the effect of polymorphisms in the endothelial nitric oxide synthase gene on the risk for essential hypertension in a Han Chinese population through a meta-analysis of data from 15 studies. Associations between increased risk for essential hypertension and 4b/a were obtained in a dominant model and allele contrast (aa + ab vs bb: odds ratio (OR)(FE) = 1.26, 95% confidence interval (CI) = 1.10-1.44; a vs b allele: OR(FE) = 1.23, 95%CI: 1.09-1.40). Four studies with sample sizes over 500 produced similar results. No evidence of publication bias was found. Also, no significant heterogeneity was observed among these studies. When we examined the G894T polymorphism, we found a marginally significant association for allele contrast and the recessive model when all the eligible studies were pooled together. However, there was no evidence for a significant association after the exclusion of two studies deviating from Hardy-Weinberg equilibrium in the control group. Heterogeneity among studies was observed. Results of cumulative and recursive cumulative meta-analysis indicated that more studies are needed to objectively determine the effects of these two polymorphisms.
Assuntos
Hipertensão/genética , Óxido Nítrico Sintase Tipo III/genética , Polimorfismo Genético/genética , Adulto , Idoso , Povo Asiático/genética , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Gap junctions represent a ubiquitous and integral part of multicellular organisms, providing the only conduit for direct exchange of nutrients, messengers and ions between neighboring cells. However, at the molecular level we have limited knowledge of their endogenous permeants and selectivity features. By probing the accessibility of systematically substituted cysteine residues to thiol blockers (a technique called SCAM), we have identified the pore-lining residues of a gap junction channel composed of Cx32. Analysis of 45 sites in perfused Xenopus oocyte pairs defined M3 as the major pore-lining helix, with M2 (open state) or M1 (closed state) also contributing to the wider cytoplasmic opening of the channel. Additional mapping of a close association between M3 and M4 allowed the helices of the low resolution map (Unger et al., 1999. Science. 283:1176-1180) to be tentatively assigned to the connexin transmembrane domains. Contrary to previous conceptions of the gap junction channel, the residues lining the pore are largely hydrophobic. This indicates that the selective permeabilities of this unique channel class may result from novel mechanisms, including complex van der Waals interactions of permeants with the pore wall, rather than mechanisms involving fixed charges or chelation chemistry as reported for other ion channels.
Assuntos
Aminoácidos/genética , Conexinas/química , Conexinas/genética , Junções Comunicantes/química , Sequência de Aminoácidos , Substituição de Aminoácidos , Aminoácidos/análise , Animais , Cisteína/genética , Junções Comunicantes/fisiologia , Potenciais da Membrana/fisiologia , Dados de Sequência Molecular , Mutagênese , Oócitos/fisiologia , Estrutura Terciária de Proteína , Ratos , Relação Estrutura-Atividade , Xenopus , Proteína beta-1 de Junções ComunicantesRESUMO
OBJECTIVE: This study aims to explore the biological function of maternally expressed gene 3 (MEG3) in liver cancer and the potential mechanism of phosphatidylinositide 3-kinases/protein kinase B (PI3K/AKT) pathway in regulating proliferation and invasion of hepatoma cells. PATIENTS AND METHODS: Quantitative Real-time polymerase chain reaction (qRT-PCR) was applied to examine the level of MEG3 in 72 pairs of liver cancer tissues and corresponding adjacent tissues. Expression levels of MEG3 and AP1G1 in hepatocellular carcinoma cell lines including SMMC-7721 and BEL-7402 were detected. After transfection of MEG3-siRNA or AP1G1 overexpression plasmid, the proliferative and invasive abilities of hepatoma cells were detected through cell counting kit-8 (CCK-8) and cell invasion assay. The effects of MEG3 and AP1G1 on the cell cycle of hepatoma cell lines were examined using flow cytometry. Western blot was conducted to estimate the changes in the protein levels of AP1G1, p-PI3K, p-AKT and VEGF before and after transfection. RESULTS: The level of MEG3 in hepatoma cancer tissues and cell lines was significantly reduced, especially in patients with advanced liver cancer. Knockdown of MEG3 significantly promoted proliferation and invasion of hepatoma cells, but accelerated cell cycle. Western blot analysis revealed that knockdown of MEG3 reduced the level of AP1G1 and activated the PI3K/AKT pathway. In addition, rescue experiments demonstrated that overexpression of AP1G1 partially reversed the promotive effect of lowly-expressed MEG3 on cell proliferation and invasion, suggesting that low expression of MEG3 may activate PI3K/AKT pathway by inhibiting AP1G1 expression. CONCLUSIONS: Low expression of MEG3 could promote the proliferative and invasive abilities of hepatoma cells and accelerate cell cycle. The mechanism may be related to the inhibition of AP1G1 expression and activation of PI3K/AKT pathway.
Assuntos
Complexo 1 de Proteínas Adaptadoras/metabolismo , Neoplasias Hepáticas/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Longo não Codificante/metabolismo , Complexo 1 de Proteínas Adaptadoras/genética , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Ligação Proteica , Interferência de RNA , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/genética , RNA Interferente Pequeno/metabolismo , Transdução de SinaisRESUMO
OBJECTIVE: To elucidate the effect of cyclooxygenase 2 (COX-2) on cisplatin resistance of NSCLC and its molecular mechanisms, with special attention to its pro-EMT (epithelial-mesenchymal transition) properties. MATERIALS AND METHODS: COX-2 levels were compared in two NSCLC cell lines, A549 and H460, by qPCR (quantitative Polymerase Chain Reaction) and Western blot. Cytotoxicity of cisplatin was also determined in the two cell lines using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The expression of EMT-related proteins and activation of AKT (protein kinase B) signaling were detected in H460 cells with ectopic COX-2 expression. RESULTS: Cisplatin-induced apoptosis was assessed in COX-2 overexpressing H460 cells by FACS. NS398, a COX-2 inhibitor, was also applied to determine EMT status and effect on cisplatin sensitivity in H460 cells. COX-2 levels were positively correlated with cisplatin resistance in both NSCLC cell lines tested. In response to COX-2 overexpression, EMT-related proteins, such as E-cadherin, were inhibited, while vimentin and N-cadherin were upregulated. The AKT signaling pathway was also activated in H460 cells. Ectopic expression of COX-2 potentiated cisplatin resistance of H460 cells, which was accompanied by decreased levels of apoptosis. Notably, NS398 effectively increased the cytotoxicity of cisplatin in A549 cells by inhibiting EMT and the AKT pathway. CONCLUSIONS: COX-2 might promote cisplatin resistance in NSCLC by promoting EMT through the AKT signaling pathway activation.
Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Ciclo-Oxigenase 2/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Transição Epitelial-Mesenquimal , Proteínas Proto-Oncogênicas c-akt/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Caderinas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Cisplatino/uso terapêutico , Ciclo-Oxigenase 2/genética , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Nitrobenzenos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologia , Vimentina/metabolismoRESUMO
Recently, we have reported that melittin, a major toxic peptide of the whole bee venom, plays a central role in production of local inflammation, nociception and hyperalgesia following the experimental honeybee's sting. However, the exact peripheral mechanisms underlying melittin-induced multiple pain-related behaviors are still less characterized. In the present study, we sought to investigate the potential roles of peripheral mitogen-activated protein kinases (MAPKs) in melittin-induced nociception and hyperalgesia by pre- and post-administration of three MAPK inhibitors, namely U0126 (1 mug, 10 mug) for extracellular signal-regulated kinase (ERK), SP600125 (10 mug, 100 mug) for c-Jun N-terminal kinase (JNK) and SB239063 (10 mug, 100 mug) for p38 MAPK, into the local inflamed area of one hind paw of rats. Both pre- and post-treatment with three drugs significantly suppressed the occurrence and maintenance of melittin-evoked persistent spontaneous nociception (PSN) and primary heat hyperalgesia, with little antinociceptive effect on mechanical hyperalgesia. In vehicle-treated group, ipsilateral injection of melittin produced no impact on thermal and mechanical sensitivity of the other hind paw, suggesting no occurrence of contralateral heat and mechanical hyperalgesia in the melittin test. In addition, local administration of each inhibitor into the contralateral hind paw exerted no significant influence on either PSN or heat/mechanical hyperalgesia tested in the primary injured hind paw, excluding the systemically pharmacological effects of the three drugs. Furthermore, local administration of the three compounds in naïve animals, respectively, did not change the basal pain sensitivity to either thermal or mechanical stimuli, suggesting lack of peripherally functional roles of the three MAPK subfamily members in normal pain sensitivity under the physiological state. Taken together, we conclude that activation of peripheral MAPKs, including ERK, JNK and p38, might contribute to the induction and maintenance of persistent ongoing pain and primary heat hyperalgesia in the melittin test. However, they are not likely to be involved in the processing of melittin-induced primary mechanical hyperalgesia, implicating a mechanistic separation between mechanical and thermal hyperalgesia in the periphery.
Assuntos
Hiperalgesia/induzido quimicamente , Hiperalgesia/enzimologia , Meliteno , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Limiar da Dor/efeitos dos fármacos , Análise de Variância , Animais , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Inibidores Enzimáticos/farmacologia , Lateralidade Funcional , Masculino , Medição da Dor , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacosRESUMO
The pore-lining residues of gap junction channels determine their permeability to ions and small cellular metabolites. These residues can be identified through systematic cysteine substitution and accessibility analysis, commonly known as SCAM (Substituted Cysteine Accessibility Method). However, application of this technique to intercellular channels is more complicated than for their transmembrane counterparts. We have utilized a novel dual-oocyte perfusion device to apply cysteine reagents to the cytoplasmic face of paired, voltage-clamped Xenopus oocytes. In this configuration, a large and irreversible cysteine reagent MBB (maliemidobutyryl biocytin, mw 537) was shown to readily traverse the gap junction pore and induce conductance changes upon reaction of accessible sites. Of the 11 reactive sites identified, 6 were located in M3, where they span the bilayer. They display a periodicity characteristic of the tilted helix that lines the pore in the gap junction structure of Unger et al. (1999). Access to several of the other sites was attributed to aqueous crevices between transmembrane helices. Reactive sites were slightly different than those identified for gap junction hemichannels (Zhou et al. 1997), suggesting that conformational changes occur upon docking.
Assuntos
Conexinas/metabolismo , Cisteína/metabolismo , Junções Comunicantes/metabolismo , Lisina/análogos & derivados , Sequência de Aminoácidos , Animais , Conexinas/genética , Junções Comunicantes/química , Junções Comunicantes/genética , Ativação do Canal Iônico/fisiologia , Lisina/química , Lisina/metabolismo , Maleimidas/química , Maleimidas/metabolismo , Modelos Moleculares , Oócitos/fisiologia , Técnicas de Patch-Clamp/instrumentação , Estrutura Secundária de Proteína , Ratos , Xenopus laevis , Proteína beta-1 de Junções ComunicantesRESUMO
The anterior cingulate cortex (ACC) has been demonstrated to play an important role in the affective dimension of pain. Although much evidence has pointed to an increased excitatory synaptic transmission in the ACC in some of the pathological pain state, the inhibitory synaptic transmission in this process has not been well studied. Also, the overall changes of excitatory and inhibitory synaptic transmission have not been comparatively studied in an animal model displaying both long-term persistent nociception and hyperalgesia. Here we used patch clamp recordings in ACC brain slices to observe the changes in synaptic transmission in a pain model induced by peripheral bee venom injection. First, we show that, comparing with those of naive and saline controlled rats, there was a significant increase in spike frequency in ACC neurons harvested from rats after 2 h period of peripheral persistent painful stimuli. Second, it is further shown that the frequency, amplitude and half-width were all increased in spontaneous excitatory post-synaptic currents (sEPSCs), while the amplitude of spontaneous inhibitory post-synaptic currents (sIPSCs) was decreased. The recordings of miniature post-synaptic currents demonstrate an increase in frequency of miniature excitatory post-synaptic currents (mEPSCs) and a decrease in both frequency and amplitude of miniature inhibitory post-synaptic currents (mIPSCs) in rats' ACC slice of bee venom treatment. Taken together, the present results demonstrate an unparalleled change between excitatory and inhibitory synaptic transmission in the ACC under a state of peripheral persistent nociception that might be underlying mechanisms of the excessive excitability of the ACC neurons. We propose that the painful stimuli when lasts or becomes persistent may cause a disruption of the balance between excitatory and inhibitory synaptic transmission that can contribute to the functional change in the ACC.
Assuntos
Giro do Cíngulo/patologia , Inibição Neural/fisiologia , Neurônios/patologia , Dor/patologia , Transmissão Sináptica/fisiologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Análise de Variância , Animais , Venenos de Abelha/efeitos adversos , Venenos de Abelha/farmacologia , Bicuculina/farmacologia , Biofísica/métodos , Modelos Animais de Doenças , Estimulação Elétrica/efeitos adversos , Estimulação Elétrica/métodos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas de Receptores de GABA-A/farmacologia , Masculino , Inibição Neural/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Dor/induzido quimicamente , Dor/fisiopatologia , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Sprague-Dawley , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologiaRESUMO
The molecular mechanisms controlling pH-sensitivity of gap junctions formed of two different connexins are yet to be determined. We used a proton-sensitive fluorophore and electrophysiological techniques to correlate changes in intracellular pH (pHi) with electrical coupling between connexin-expressing Xenopus oocytes. The pH sensitivities of alpha 3 (connexin46), alpha 2 (connexin38), and alpha 1 (connexin43) were studied when these proteins were expressed as: 1) nonjunctional hemichannels (for alpha 3 and alpha 2), 2) homotypic gap junctions, and 3) heterotypic gap junctions. We found that alpha 3 hemichannels are sensitive to changes in pHi within a physiological range (pKa = 7.13 +/- 0.03; Hill coefficient = 3.25 +/- 1.73; n = 8; mean +/- SEM); an even more alkaline pKa was obtained for alpha 2 hemichannels (pKa = 7.50 +/- 0.03; Hill coefficient = 3.22 +/- 0.66; n = 13). The pH sensitivity curves of alpha 2 and alpha 3 homotypic junctions were indistinguishable from those recorded from hemichannels of the same connexin. Based on a comparison of pKa values, both alpha 3 and alpha 2 gap junctions were more pHi-dependent than alpha 1. The pH sensitivity of alpha 2-containing heterotypic junctions could not be predicted from the behavior of the two connexons in the pair. When alpha 2 was paired with alpha 3, the pH sensitivity curve was similar to that obtained from alpha 2 homotypic pairs. Yet, pairing alpha 2 with alpha 1 shifted the curve similar to homotypic alpha 1 channels. Pairing alpha 2 with a less pH sensitive mutant of alpha 1 (M257) yielded the same curve as when alpha 1 was used. However, the pH sensitivity curve of alpha 3/alpha 1 channels was similar to alpha 3/alpha 3, while alpha 3/M257 was indistinguishable from alpha 3/alpha 1. Our results could not be consistently predicted by a probabilistic model of two independent gates in series. The data show that dissimilarities in the pH regulation of gap junctions are due to differences in the primary sequence of connexins. Moreover, we found that pH regulation is an intrinsic property of the hemichannels, but pH sensitivity is modified by the interactions between connexons. These interactions should provide a higher level of functional diversity to gap junctions that are formed by more than one connexin.