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1.
Genes (Basel) ; 15(5)2024 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-38790160

RESUMO

Pituitary neuroendocrine tumors (PitNET) are known to be variably infiltrated by different immune cells. Nonetheless, their role in pituitary oncogenesis has only begun to be unveiled. The immune microenvironment could determine the biological and clinical behavior of a neoplasm and may have prognostic implications. To evaluate the expression of immune-related genes and to correlate such expression with the presence of infiltrating immune cells in forty-two PitNETs of different lineages, we performed whole transcriptome analysis and RT-qPCR. Deconvolution analysis was carried out to infer the immune cell types present in each tumor and the presence of immune cells was confirmed by immunofluorescence. We found characteristic expression profiles of immune-related genes including those encoding interleukins and chemokines for each tumor lineage. Genes such as IL4-I1, IL-36A, TIRAP, IL-17REL, and CCL5 were upregulated in all PitNETS, whereas IL34, IL20RA, and IL-2RB characterize the NR5A1-, TBX19-, and POU1F1-derived tumors, respectively. Transcriptome deconvolution analysis showed that M2 macrophages, CD4+ T cells, CD8+ T cells, NK cells, and neutrophils can potentially infiltrate PitNET. Furthermore, CD4+ and CD8+ T cells and NK cells infiltration was validated by immunofluorescence. Expression of CCL18, IL-5RA, and HLA-B as well as macrophage tumor infiltration could identify patients who can potentially benefit from treatment with immune checkpoint inhibitors.


Assuntos
Tumores Neuroendócrinos , Neoplasias Hipofisárias , Transcriptoma , Microambiente Tumoral , Humanos , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/imunologia , Neoplasias Hipofisárias/patologia , Microambiente Tumoral/imunologia , Microambiente Tumoral/genética , Tumores Neuroendócrinos/genética , Tumores Neuroendócrinos/imunologia , Tumores Neuroendócrinos/patologia , Regulação Neoplásica da Expressão Gênica , Perfilação da Expressão Gênica/métodos , Masculino , Feminino , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Pessoa de Meia-Idade , Adulto
2.
Brain Sci ; 13(10)2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37891811

RESUMO

Seizure-mediated oxidative stress is a crucial mechanism in the pathophysiology of epilepsy. This study evaluated the antioxidant effects of daytime-restricted feeding (DRF) and the role of the Nrf2 signaling pathway in a lithium-pilocarpine model seizure model that induces status epilepticus (SE). We performed a lipoperoxidation assay and dihydroethidium fluorescence to measure oxidative stress markers in the hippocampus (malondialdehyde and reactive oxygen species). The protein content of Nrf2 and its downstream protein SOD2 was evaluated using Western blotting. The cellular distribution of the Nrf2 and SOD2 proteins in the pyramidal cell layer of both the CA1 and CA3 hippocampal subfields and astrocytes (GFAP marker) were quantified using immunofluorescence and immunohistochemistry, respectively. Our results indicate that DRF reduced the malondialdehyde levels and the production of reactive oxygen species. Furthermore, a significant increase in Nrf2 and SOD2 protein content was observed in animals subjected to restrictive diet. In addition, DRF increased the relative intensity of the Nrf2 fluorescence in the perinuclear and nuclear compartments of pyramidal neurons in the CA1 subfield. Nrf2 immunoreactivity and the astrocyte marker GFAP also increased their colocalization under DRF conditions. Additionally, SOD2 immunoreactivity was increased in CA1 pyramidal neurons but not in the CA3 region. Our findings suggest that DRF partially prevents oxidative stress by increasing the Nrf2 transcriptional factor and the SOD2 enzyme during the development of SE.

3.
Int J Mol Sci ; 24(5)2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36902214

RESUMO

Acral melanoma (AM) is the most common melanoma in non-Caucasian populations, yet it remains largely understudied. As AM lacks the UV-radiation mutational signatures that characterize other cutaneous melanomas, it is considered devoid of immunogenicity and is rarely included in clinical trials assessing novel immunotherapeutic regimes aiming to recover the antitumor function of immune cells. We studied a Mexican cohort of melanoma patients from the Mexican Institute of Social Security (IMSS) (n = 38) and found an overrepresentation of AM (73.9%). We developed a multiparametric immunofluorescence technique coupled with a machine learning image analysis to evaluate the presence of conventional type 1 dendritic cells (cDC1) and CD8 T cells in the stroma of melanoma, two of the most relevant immune cell types for antitumor responses. We observed that both cell types infiltrate AM at similar and even higher levels than other cutaneous melanomas. Both melanoma types harbored programmed cell death protein 1 (PD-1+) CD8 T cells and PD-1 ligand (PD-L1+) cDC1s. Despite this, CD8 T cells appeared to preserve their effector function and expanding capacity as they expressed interferon-γ (IFN-γ) and KI-67. The density of cDC1s and CD8 T cells significantly decreased in advanced stage III and IV melanomas, supporting these cells' capacity to control tumor progression. These data also argue that AM could respond to anti-PD-1-PD-L1 immunotherapy.


Assuntos
Linfócitos T CD8-Positivos , Células Dendríticas , Linfócitos do Interstício Tumoral , Melanoma , Neoplasias Cutâneas , Pele , Humanos , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Melanoma/imunologia , Melanoma/patologia , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Células Dendríticas/imunologia , Linfócitos do Interstício Tumoral/imunologia , Raios Ultravioleta , Exposição à Radiação , Pele/efeitos da radiação , Melanoma Maligno Cutâneo
4.
J Oncol ; 2022: 9775736, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36276271

RESUMO

Melanoma is the deadliest form of skin cancer. Due to its high mutation rates, melanoma is a convenient model to study antitumor immune responses. Dendritic cells (DCs) play a key role in activating cytotoxic CD8+ T lymphocytes and directing them to kill tumor cells. Although there is evidence that DCs infiltrate melanomas, information about the profile of these cells, their activity states, and potential antitumor function remains unclear, particularly for conventional DCs type 1 (cDC1). Approaches to profiling tumor-infiltrating DCs are hindered by their diversity and the high number of signals that can affect their state of activation. Multiplexed immunofluorescence (mIF) allows the simultaneous analysis of multiple markers, but image-based analysis is time-consuming and often inconsistent among analysts. In this work, we evaluated several machine learning (ML) algorithms and established a workflow of nine-parameter image analysis that allowed us to study cDC1s in a reproducible and accessible manner. Using this workflow, we compared melanoma samples between disease-free and metastatic patients at diagnosis. We observed that cDC1s are more abundant in the tumor infiltrate of the former. Furthermore, cDC1s in disease-free patients exhibit an expression profile more congruent with an activator function: CD40highPD-L1low CD86+IL-12+. Although disease-free patients were also enriched with CD40-PD-L1+ cDC1s, these cells were also more compatible with an activator phenotype. The opposite was true for metastatic patients at diagnosis who were enriched for cDC1s with a more tolerogenic phenotype (CD40lowPD-L1highCD86-IL-12-IDO+). ML-based workflows like the one developed here can be used to analyze complex phenotypes of other immune cells and can be brought to laboratories with standard expertise and computer capacity.

5.
Eur J Histochem ; 66(1)2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35174683

RESUMO

Desmoplastic stroma (DS) and the epithelial-to-mesenchymal transition (EMT) play a key role in pancreatic ductal adenocarcinoma (PDAC) progression. To date, however, the combined expression of DS and EMT markers, and their association with variations in survival within each clinical stage and degree of tumor differentiation is unknown. The purpose of this study was to investigate the association between expression of DS and EMT markers and survival variability in patients diagnosed with PDAC. We examined the expression levels of DS markers alpha smooth muscle actin (α-SMA), fibronectin, and vimentin, and the EMT markers epithelial cell adhesion molecule (EPCAM), pan-cytokeratin, and vimentin, by immunohistochemistry using a tissue microarray of a retrospective cohort of 25 patients with PDAC. The results were examined for association with survival by clinical stage and by degree of tumor differentiation. High DS markers expression -α-SMA, fibronectin, and vimentin- was associated with decreased survival at intermediate and advanced clinical stages (p=0.006-0.03), as well as with both poorly and moderately differentiated tumor grades (p=0.01-0.02). Interestingly, the same pattern was observed for EMT markers, i.e., EPCAM, pan-cytokeratin, and vimentin (p=0.00008-0.03). High expression of DS and EMT markers within each clinical stage and degree of tumor differentiation was associated with lower PDAC survival. Evaluation of these markers may have a prognostic impact on survival time variation in patients with PDAC.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Biomarcadores Tumorais/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Transição Epitelial-Mesenquimal/fisiologia , Humanos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Prognóstico , Estudos Retrospectivos
6.
Pharmaceuticals (Basel) ; 14(8)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34451912

RESUMO

Cancer is the second leading cause of death, after cardiovascular diseases. Different strategies have been developed to treat cancer; however, chemotherapy with cytotoxic agents is still the most widely used treatment approach. Nevertheless, drug resistance to available chemotherapeutic agents is still a serious problem, and the development of new active compounds remains a constant need. Taking advantage of the molecular hybridization approach, in the present work we designed, synthesized, and tested the cytotoxic activity of two hybrid compounds and seven derivatives based on the structure of combretastatin A-4 and 2,3-diphenyl-2H-indazole. Practical modifications of reported synthetic protocols for 2-pheny-2H-indazole and 2,3-dipheny-2H-indazole derivatives under microwave irradiation were implemented. The cytotoxicity assays showed that our designed hybrid compounds possess strong activity, especially compound 5, which resulted even better than the reference drug cisplatin against HeLa and SK-LU-1 cells (IC50 of 0.16 and 6.63 µM, respectively), and it had similar potency to the reference drug imatinib against K562 cells. Additionally, in silico and in vitro studies strongly suggest tubulin as the molecular target for hybrid compound 5.

7.
Front Immunol ; 12: 668369, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34220814

RESUMO

In cutaneous T cell lymphoma (CTCL), a dominant Th2 profile associated with disease progression has been proposed. Moreover, although the production and regulation of IL-4 expression during the early stages of the disease may have important implications in later stages, these processes are poorly understood. Here, we demonstrate the presence of TOX+ CD4+ T cells that produce IL-4+ in early-stage skin lesions of CTCL patients and reveal a complex mechanism by which the NLRP3 receptor promotes a Th2 response by controlling IL-4 production. Unassembled NLRP3 is able to translocate to the nucleus of malignant CD4+ T cells, where it binds to the human il-4 promoter. Accordingly, IL-4 expression is decreased by knocking down and increased by promoting the nuclear localization of NLRP3. We describe a positive feedback loop in which IL-4 inhibits NLRP3 inflammasome assembly, thereby further increasing its production. IL-4 induced a potentially malignant phenotype measured based on TOX expression and proliferation. This mechanism of IL-4 regulation mediated by NLRP3 is amplified in late-stage CTCL associated with disease progression. These results indicate that NLRP3 might be a key regulator of IL-4 expression in TOX+ CD4+ T cells of CTCL patients and that this mechanism might have important implications in the progression of the disease.


Assuntos
Linfócitos T CD4-Positivos/metabolismo , Interleucina-4/metabolismo , Linfócitos do Interstício Tumoral/metabolismo , Linfoma Cutâneo de Células T/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neoplasias Cutâneas/metabolismo , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células , Citotoxicidade Imunológica , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Interleucina-4/genética , Células Jurkat , Linfócitos do Interstício Tumoral/imunologia , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/imunologia , México , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Fenótipo , Transdução de Sinais , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia
8.
Cancers (Basel) ; 13(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067089

RESUMO

We previously reported that triple-negative breast cancer (BRCA) cells overexpress the cytokines GM-CSF, G-CSF, MCP-1, and RANTES, and when monocytes were 3-D co-cultured with them, M1-like macrophages were generated with the ability to induce aggressive features in luminal BRCA cell lines. These include upregulation of mesenchymal and stemness markers and invasion. In this study, we stimulated peripheral blood monocytes with the four cytokines and confirmed their capacity to generate protumoral M1-like macrophages. Using the METABRIC BRCA database, we observed that GM-CSF, MCP-1, and RANTES are associated with triple-negative BRCA and reduced overall survival, particularly in patients under 55 years of age. We propose an extended M1-like macrophage proinflammatory signature connected with these three cytokines. We found that the extended M1-like macrophage signature coexists with monocyte/macrophage, Th1 immune response, and immunosuppressive signatures, and all are enriched in claudin-low BRCA samples, and correlate with reduced patient overall survival. Furthermore, we observed that all these signatures are also present in mesenchymal carcinomas of the colon (COAD) and bladder (BLCA). The claudin-low tumor subtype has an adverse clinical outcome and remains poorly understood. This study places M1 macrophages as potential protumoral drivers in already established cancers, and as potential contributors to claudin-low aggressiveness and poor prognosis.

9.
Int J Mol Sci ; 21(14)2020 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-32664691

RESUMO

The Retinoblastoma protein (pRb) is a key cell cycle regulator conserved in a wide variety of organisms. Experimental analysis of pRb's functions in animals and plants has revealed that this protein participates in cell proliferation and differentiation processes. In addition, pRb in animals and its orthologs in plants (RBR), are part of highly conserved protein complexes which suggest the possibility that analogies exist not only between functions carried out by pRb orthologs themselves, but also in the structure and roles of the protein networks where these proteins are involved. Here, we present examples of pRb/RBR participation in cell cycle control, cell differentiation, and in the regulation of epigenetic changes and chromatin remodeling machinery, highlighting the similarities that exist between the composition of such networks in plants and animals.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Montagem e Desmontagem da Cromatina , Epigênese Genética , Proteínas de Plantas/fisiologia , Proteína do Retinoblastoma/fisiologia , Animais , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/fisiologia , Ciclo Celular/genética , Proteínas de Ciclo Celular/química , Diferenciação Celular/genética , Dano ao DNA , Genes de Plantas , Genes do Retinoblastoma , Homeostase , Mamíferos/genética , Mamíferos/metabolismo , Modelos Moleculares , Família Multigênica , Complexos Multiproteicos , Proteínas de Neoplasias/química , Proteínas de Neoplasias/fisiologia , Proteínas de Plantas/química , Plantas/genética , Plantas/metabolismo , Conformação Proteica , Domínios Proteicos , Processamento de Proteína Pós-Traducional , Proteína do Retinoblastoma/química , Especificidade da Espécie , Células-Tronco/metabolismo
10.
Tuberculosis (Edinb) ; 115: 42-48, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30948175

RESUMO

Tuberculosis (TB) is the most prevalent infectious disease worldwide, with no fully effective vaccine yet available. Considering that BCG strains devoid of the BCG1416c or BCG1419c genes afforded protection in mice versus highly virulent M. tuberculosis challenge, or in chronic infection models compared to BCG, respectively, we hypothesized that a synergistic effect of these strains might occur and provide enhanced protection against TB. Herein, we evaluated this hypothesis throughout an experimental design approach, where different combinations of these strains were tested for their capacity to induce cytokines in vitro, compared to individual strains. Our results show that mixed-infection of murine macrophages using these strains significantly decreases induction of TNF-α, IL-1ß, IL-6 but increases IL-4 induction compared with individual strains. These results suggest the existence of interaction effects during infection, which reduce induction of pro-inflammatory cytokines, even though individual intracellular replication is not altered when strains are combined. This is the first report of the evaluation of a potential whole-live combined vaccine against tuberculosis, which paradoxically seems to reduce production of pro-inflammatory cytokines while induces IL-4, leading us to further hypothesize that this combination might contribute as a therapeutic vaccine to reduce inflammation in severe TB cases.


Assuntos
Interleucinas/metabolismo , Macrófagos/microbiologia , Mycobacterium bovis/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Vacina BCG , Interações Hospedeiro-Patógeno , Interleucina-1beta/metabolismo , Interleucina-4/metabolismo , Interleucina-6/metabolismo , Camundongos , Mutação/fisiologia , Mycobacterium bovis/genética , Mycobacterium tuberculosis/genética , Tuberculose/metabolismo , Tuberculose/prevenção & controle
11.
Methods Mol Biol ; 1932: 175-185, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30701500

RESUMO

microRNAs are noncoding RNAs of 20-24 nucleotides (nt) in length that act as repressors of genes and are important in key developmental processes in the entire life cycle of plants. To determine the function of a microRNA, the first step is to resolve its expression pattern; this can be achieved by in situ hybridization, RNA blot assays, or quantitative PCR. However, the study of the expression of a MIR gene is straightforward with the use of reporter proteins such as ß-D-glucuronidase (GUS), GFP, or mCherry. To do this, it is necessary to clone the promoter region of the MIR gene and place it upstream of the reporter gene; in this way the activity of the promoter will be a direct reflection of the expression of the MIR gene. Here, we indicate step by step how to make transcriptional fusion constructs from the cloning of a promoter region of a MIR gene fused to the classical reporter proteins GUS and mCherry, the latter with codon optimization for better expression in Arabidopsis thaliana. This method is particularly useful to dissect the promoter region of a MIR gene and to find its expression pattern in a tissue and developmental specific manner.


Assuntos
Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/genética , MicroRNAs/genética , RNA de Plantas/genética , Proteínas Recombinantes de Fusão/genética , Clonagem Molecular , Genes de Plantas/genética , Genes Reporter/genética , Glucuronidase/genética , Regiões Promotoras Genéticas/genética , Transcrição Gênica/genética
12.
Nutrients ; 10(11)2018 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-30423806

RESUMO

It has been widely described that chronic intake of fructose causes metabolic alterations which can be associated with brain function impairment. In this study, we evaluated the effects of fructose intake on the sleep⁻wake cycle, locomotion, and neurochemical parameters in Wistar rats. The experimental group was fed with 10% fructose in drinking water for five weeks. After treatment, metabolic indicators were quantified in blood. Electroencephalographic recordings were used to evaluate the sleep architecture and the spectral power of frequency bands. Likewise, the locomotor activity and the concentrations of orexin A and monoamines were estimated. Our results show that fructose diet significantly increased the blood levels of glucose, cholesterol, and triglycerides. Fructose modified the sleep⁻wake cycle of rats, increasing the waking duration and conversely decreasing the non-rapid eye movement sleep. Furthermore, these effects were accompanied by increases of the spectral power at different frequency bands. Chronic consumption of fructose caused a slight increase in the locomotor activity as well as an increase of orexin A and dopamine levels in the hypothalamus and brainstem. Specifically, immunoreactivity for orexin A was increased in the ventral tegmental area after the intake of fructose. Our study suggests that fructose induces metabolic changes and stimulates the activity of orexinergic and dopaminergic neurons, which may be responsible for alterations of the sleep⁻wake cycle.


Assuntos
Encéfalo/efeitos dos fármacos , Açúcares da Dieta/farmacologia , Dopamina/metabolismo , Comportamento Alimentar , Frutose/farmacologia , Orexinas/metabolismo , Sono/efeitos dos fármacos , Animais , Glicemia/metabolismo , Encéfalo/citologia , Encéfalo/metabolismo , Tronco Encefálico/efeitos dos fármacos , Tronco Encefálico/metabolismo , Dieta , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Lipídeos/sangue , Locomoção/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Ratos Wistar , Fases do Sono/efeitos dos fármacos , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismo , Vigília/efeitos dos fármacos
13.
Funct Plant Biol ; 44(8): 751-760, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32480604

RESUMO

The central or lytic vacuole is the largest intracellular organelle in plant cells, but we know unacceptably little about the mechanisms regulating its function in vivo. The underlying reasons are related to difficulties in accessing this organelle without disrupting the cellular integrity and to the dynamic morphology of the vacuole, which lacks a defined structure. Among such morphological changes, vacuolar convolution is probably the most commonly observed event, reflected in the (reversible) transformation of a large central vacuole into a structure consisting of interconnected bubbles of a smaller size. Such behaviour is observed in plant cells subjected to hyperosmotic stress but also takes place in physiological conditions (e.g. during stomatal closure). Although vacuolar convolution is a relatively common phenomenon in plants, studies aimed at elucidating its execution mechanisms are rather scarce. In the present review, we analyse the available evidence on the participation of the cellular cytoskeleton and ion transporters in vacuolar morphology dynamics, putting special emphasis on the available evidence of the role played by phosphatidylinositol 3,5-bisphosphate in this process.

14.
Front Immunol ; 7: 666, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28111575

RESUMO

Pediatric oncology, notably childhood acute lymphoblastic leukemia (ALL), is currently one of the health-leading concerns worldwide and a biomedical priority. Decreasing overall leukemia mortality in children requires a comprehensive understanding of its pathobiology. It is becoming clear that malignant cell-to-niche intercommunication and microenvironmental signals that control early cell fate decisions are critical for tumor progression. We show here that the mesenchymal stromal cell component of ALL bone marrow (BM) differ from its normal counterpart in a number of functional properties and may have a key role during leukemic development. A decreased proliferation potential, contrasting with the strong ability of producing pro-inflammatory cytokines and an aberrantly loss of CXCL12 and SCF, suggest that leukemic lymphoid niches in ALL BM are unique and may exclude normal hematopoiesis. Cell competence ex vivo assays within tridimensional coculture structures indicated a growth advantage of leukemic precursor cells and their niche remodeling ability by CXCL12 reduction, resulting in leukemic cell progression at the expense of normal niche-associated lymphopoiesis.

15.
Biochim Biophys Acta ; 1833(7): 1787-97, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23352808

RESUMO

Genetically encoded calcium ion (Ca(2+)) indicators have become very useful and widely used tools for Ca(2+) imaging, not only in cellular models, but also in living organisms. However, the in vivo and in situ characterization of these indicators is tedious and time consuming, and it does not provide information regarding the suitability of an indicator for particular experimental environments. Thus, initial in vitro evaluation of these tools is typically performed to determine their properties. In this review, we examined the properties of dynamic range, affinity, selectivity, and kinetics for Ca(2+) indicators. Commonly used strategies for evaluating these properties are presented. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.


Assuntos
Sinalização do Cálcio/genética , Cálcio/metabolismo , Genes Reporter/genética , Indicadores e Reagentes/metabolismo , Proteínas Luminescentes/genética , Animais , Humanos , Indicadores e Reagentes/análise , Proteínas Luminescentes/metabolismo
16.
Plant Cell Physiol ; 53(10): 1768-75, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22942251

RESUMO

Hypersensitive cell death is known to involve dynamic remodeling of intracellular structures that uses energy released during ATP hydrolysis. However, the relationship between intracellular structural changes and ATP levels during hypersensitive cell death remains unclear. Here, to visualize ATP dynamics directly in real time in individual living plant cells, we applied a genetically encoded Förster resonance energy transfer (FRET)-based fluorescent ATP indicator, ATeam1.03-nD/nA, for plant cells. Intracellular ATP levels increased approximately 3 h after inoculation with the avirulent strain DC3000/avrRpm1 of Pseudomonas syringae pv. tomato (Pst), which was accompanied by the simultaneous disappearance of transvacuolar strands and appearance of bulb-like structures within the vacuolar lumen. Approximately 5 h after bacterial inoculation, the bulb-like structures disappeared and ATP levels drastically decreased. After another 2 h, the large central vacuole was disrupted. In contrast, no apparent changes in intracellular ATP levels were observed in the leaves inoculated with the virulent strain Pst DC3000. The Pst DC3000/avrRpm1-induced hypersensitive cell death was strongly suppressed by inhibiting ATP synthesis after oligomycin A application within 4 h after bacterial inoculation. When the inhibitor was applied 7 h after bacterial inoculation, cell death was unaffected. These observations show that changes in intracellular ATP levels correlate with intracellular morphological changes during hypersensitive cell death, and that ATP is required just before vacuolar rupture in response to bacterial infection.


Assuntos
Trifosfato de Adenosina/análise , Trifosfato de Adenosina/metabolismo , Arabidopsis/citologia , Citosol/metabolismo , Microscopia de Fluorescência/métodos , Folhas de Planta/microbiologia , Pseudomonas syringae/patogenicidade , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/microbiologia , Morte Celular , Resistência à Doença , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/análise , Oligomicinas/farmacologia , Doenças das Plantas/microbiologia , Folhas de Planta/citologia , Folhas de Planta/efeitos dos fármacos , Plantas Geneticamente Modificadas , Pseudomonas syringae/genética , Análise de Célula Única/métodos , Vacúolos/metabolismo
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