RESUMO
Zika virus (ZIKV) is an emergent arthropod-borne virus whose outbreak in Brazil has brought major public health problems. Infected individuals have different symptoms, including rash and pruritus, which can be relieved by the administration of antiallergics. In the case of pregnant women, ZIKV can cross the placenta and infect the fetus leading to congenital defects. We have identified that mast cells in the placentae of patients who had Zika during pregnancy can be infected. This led to our investigation on the possible role of mast cells during a ZIKV infection, using the HMC-1 cell line. We analyzed their permissiveness to infection, release of mediators and ultrastructural changes. Flow cytometry detection of ZIKV-NS1 expression 24 h post infection in 45.3% of cells showed that HMC-1 cells are permissive to ZIKV infection. Following infection, ß-hexosaminidase was measured in the supernatant of the cells with a notable release at 30 min. In addition, an increase in TNF-α, IL-6, IL-10 and VEGF levels were measured at 6 h and 24 h post infection. Lastly, different intracellular changes were observed in an ultrastructural analysis of infected cells. Our findings suggest that mast cells may represent an important source of mediators that can activate other immune cell types during a ZIKV infection, which has the potential to be a major contributor in the spread of the virus in cases of vertical transmission.
Assuntos
Citocinas/metabolismo , Mastócitos/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adulto , Brasil , Linhagem Celular , Feminino , Humanos , Imuno-Histoquímica , Transmissão Vertical de Doenças Infecciosas , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Mastócitos/patologia , Mastócitos/ultraestrutura , Mastócitos/virologia , Microscopia Eletrônica de Transmissão , Placenta/imunologia , Placenta/metabolismo , Placenta/virologia , Gravidez , Fator de Necrose Tumoral alfa/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Zika virus/patogenicidade , Infecção por Zika virus/enzimologia , Infecção por Zika virus/fisiopatologia , Infecção por Zika virus/transmissão , beta-N-Acetil-Hexosaminidases/metabolismoRESUMO
Mast cells play an essential role in different immunological phenomena including allergy and infectious diseases. Several bacteria induce mast cell activation leading to degranulation and the production of several cytokines and chemokines. However, mast cells also have different microbicidal activities such as phagocytosis and the release of DNA with embedded granular proteins known as Mast Cell Extracellular Traps (MCETs). Although previous reports indicate that extracellular bacteria are able to induce MCETs little is known if intracellular bacteria can induce these structures. In this work, we evaluated MCETs induction by the intracellular bacteria Listeria monocytogenes. We found that mast cells released DNA after stimulation with L. monocytogenes, and this DNA was complexed to histone and tryptase. Before extracellular DNA release, L. monocytogenes induced modifications to the mast cell nuclear envelope and DNA was detected outside the nucleus. L. monocytogenes stimulated mast cells to produce significant amounts of reactive oxygen species (ROS) and blocking NADPH oxidase diminished DNA release by mast cells. Finally, MCETs showed antimicrobial activity against L. monocytogenes that was partially blocked when ß-hexosaminidase activity was inhibited. These results show that L. monocytogenes induces mast cells to produce microbicidal MCETs, suggesting a role for mast cells in containing infection beyond the induction of inflammation.
Assuntos
Armadilhas Extracelulares/imunologia , Armadilhas Extracelulares/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Listeria monocytogenes/imunologia , Mastócitos/imunologia , Mastócitos/metabolismo , Linhagem Celular , DNA/metabolismo , Histonas/metabolismo , Humanos , Listeriose , Mastócitos/ultraestrutura , Membrana Nuclear/ultraestrutura , Fagocitose/imunologia , Espécies Reativas de Oxigênio/metabolismo , beta-N-Acetil-Hexosaminidases/metabolismoRESUMO
Megacolon is frequently observed in patients who develop the digestive form of Chagas disease. It is characterized by dilation of the rectum-sigmoid portion and thickening of the colon wall. Microscopically, the affected organ presents denervation, which has been considered as consequence of an inflammatory process that begins at the acute phase and persists in the chronic phase of infection. Inflammatory infiltrates are composed of lymphocytes, macrophages, natural killer cells, mast cells, and eosinophils. In this study, we hypothesized that mast cells producing tryptase could influence the migration and the activation of eosinophils at the site, thereby contributing to the immunopathology of the chronic phase. We seek evidence of interactions between mast cells and eosinophils through (1) evaluation of eosinophils, regarding the expression of PAR2, a tryptase receptor; (2) correlation analysis between densities of mast cells and eosinophils; and (3) ultrastructural studies. The electron microscopy studies revealed signs of activation of mast cells and eosinophils, as well as physical interaction between these cells. Immunohistochemistry and correlation analyses point to the participation of tryptase immunoreactive mast cells in the migration and/or survival of eosinophils at the affected organ.
Assuntos
Doença de Chagas/imunologia , Eosinófilos/imunologia , Mastócitos/imunologia , Trypanosoma cruzi/imunologia , Triptases/imunologia , Adulto , Idoso , Doença de Chagas/parasitologia , Colo/imunologia , Colo/parasitologia , Eosinófilos/ultraestrutura , Feminino , Humanos , Imuno-Histoquímica , Macrófagos/imunologia , Macrófagos/ultraestrutura , Masculino , Mastócitos/ultraestrutura , Pessoa de Meia-IdadeRESUMO
Mast cells are abundant in the skin and other peripheral tissues, where they are one of the first immune cells to make contact with invading pathogens. As a result of pathogen recognition, mast cells can be activated and release different preformed and de novo-synthesized mediators. Sporothrix schenckii is the fungus that causes sporotrichosis, a worldwide-distributed subcutaneous mycosis considered as an important emerging health problem. It remains unknown whether or not mast cells are activated by S. schenckii. Here, we investigated the in vitro response of mast cells to conidia of S. schenckii and their in vivo involvement in sporotrichosis. Mast cells became activated after interaction with conidia, releasing early response cytokines as TNF-α and IL-6. Although histamine release was not significantly stimulated by S. schenckii, we determined that conidia potentiate histamine secretion induced by compound 48/80. Furthermore, functional depletion of peritoneal mast cells before S. schenckii infection significantly reduced the severity of cutaneous lesions of the sporotrichosis. These data demonstrate that mast cells are important contributors in the host response to S. schenckii infection, suggesting a role of these cells in the progress of clinical manifestations in sporotrichosis.
Assuntos
Mastócitos/imunologia , Sporothrix/imunologia , Esporotricose/imunologia , Animais , Degranulação Celular/imunologia , Distribuição de Qui-Quadrado , Histamina/análise , Histamina/imunologia , Interleucina-6/imunologia , Masculino , Mastócitos/microbiologia , Mastócitos/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Ratos , Ratos Wistar , Esporos Fúngicos/imunologia , Esporotricose/microbiologia , Fator de Necrose Tumoral alfa/imunologia , p-Metoxi-N-metilfenetilamina/farmacologiaRESUMO
The current study examined the role of PLD2 in the maintenance of mast cell structure. Phospholipase D (PLD) catalyzes hydrolysis of phosphatidylcholine to produce choline and phosphatidic acid (PA). PLD has two isoforms, PLD1 and PLD2, which vary in expression and localization depending on the cell type. The mast cell line RBL-2H3 was transfected to overexpress catalytically active (PLD2CA) and inactive (PLD2CI) forms of PLD2. The results of this study show that PLD2CI cells have a distinct star-shaped morphology, whereas PLD2CA and RBL-2H3 cells are spindle shaped. In PLD2CI cells, the Golgi complex was also disorganized with dilated cisternae, and more Golgi-associated vesicles were present as compared with the PLD2CA and RBL-2H3 cells. Treatment with exogenous PA led to the restoration of the wild-type Golgi complex phenotype in PLD2CI cells. Conversely, treatment of RBL-2H3 and PLD2CA cells with 1% 1-Butanol led to a disruption of the Golgi complex. The distribution of acidic compartments, including secretory granules and lysosomes, was also modified in PLD2CI cells, where they concentrated in the perinuclear region. These results suggest that the PA produced by PLD2 plays an important role in regulating cell morphology in mast cells.
Assuntos
Mastócitos/citologia , Fosfolipase D/metabolismo , Animais , Linhagem Celular , Complexo de Golgi/enzimologia , Complexo de Golgi/ultraestrutura , Isoenzimas/genética , Isoenzimas/metabolismo , Lisossomos/enzimologia , Lisossomos/ultraestrutura , Mastócitos/enzimologia , Mastócitos/ultraestrutura , Ácidos Fosfatídicos/farmacologia , Fosfolipase D/genética , RNA Mensageiro/metabolismo , Ratos , Vesículas Secretórias/enzimologia , Vesículas Secretórias/ultraestruturaRESUMO
The aim of the present study was to determine whether dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one inhibit the activation of human leukemic LAD2 mast cells induced by compound 48/80 or the calcium ionophore A23187. LAD2 cells were preincubated in the presence of test drugs and then challenged with the secretagogues. This study provides the first evidence in favor of the view that dehydroleucodine and xanthatin inhibit the degranulation of LAD2 cells, thus acting as human mast cell stabilizers. These molecules could be effective in the treatment of human diseases associated with inappropriate mast cell activation.
Assuntos
Furanos/farmacologia , Lactonas/farmacologia , Mastócitos/metabolismo , Sesquiterpenos/farmacologia , Calcimicina/farmacologia , Ionóforos de Cálcio/farmacologia , Degranulação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Cinética , Leucemia de Mastócitos/metabolismo , Leucemia de Mastócitos/patologia , Mastócitos/fisiologia , Mastócitos/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , beta-N-Acetil-Hexosaminidases/metabolismo , p-Metoxi-N-metilfenetilamina/farmacologiaRESUMO
BACKGROUND: Mast cells have recently gained new importance as immunoregulatory cells that are involved in numerous pathological processes. One result of these processes is an increase in mast cell numbers at peripheral sites. This study was undertaken to determine the mast cell response in the peritoneal cavity and bone marrow during repopulation of the peritoneal cavity in rats. RESULTS: Two mast cell specific antibodies, mAb AA4 and mAb BGD6, were used to distinguish the committed mast cell precursor from more mature mast cells. The peritoneal cavity was depleted of mast cells using distilled water. Twelve hours after distilled water injection, very immature mast cells could be isolated from the blood and by 48 hours were present in the peritoneal cavity. At this same time the percentage of mast cells in mitosis increased fourfold. Mast cell depletion of the peritoneal cavity also reduced the total number of mast cells in the bone marrow, but increased the number of mast cell committed precursors. CONCLUSIONS: In response to mast cell depletion of the peritoneal cavity, a mast cell progenitor is released into the circulation and participates in repopulation of the peritoneal cavity, while the committed mast cell precursor is retained in the bone marrow.
Assuntos
Células da Medula Óssea/citologia , Linhagem da Célula , Mastócitos/citologia , Cavidade Peritoneal/citologia , Células-Tronco/citologia , Animais , Células da Medula Óssea/efeitos dos fármacos , Contagem de Células , Linhagem da Célula/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Separação Celular , Feminino , Separação Imunomagnética , Injeções Intraperitoneais , Masculino , Mastócitos/efeitos dos fármacos , Mastócitos/ultraestrutura , Mitose/efeitos dos fármacos , Ratos , Ratos Wistar , Células-Tronco/efeitos dos fármacos , Fatores de Tempo , Água/administração & dosagem , Água/farmacologiaRESUMO
The present study was designed to examine the effects of a sesquiterpene lactone isolated from Artemisia douglasiana Besser (dehydroleucodine), a xanthanolide sesquiterpene isolated from Xanthium cavanillesii Schouw (xanthatin) and a semisynthetic butenolide (3-benzyloxymethyl-5H-furan-2-one) on mast cell degranulation induced by compound 48/80. Peritoneal mast cells from male adult Sprague-Dawley rats were purified in Percoll, preincubated in the presence of test lactones (dehydroleucodine, xanthatin or 3-benzyloxymethyl-5H-furan-2-one) and then challenged with the mast cell activator compound 48/80 (10 microg/ml). Concentration-response and kinetic studies of mast cell serotonin release evoked by compound 48/80, evaluation of mast cell viability and morphology by light and electron microscopy, and comparative studies using ketotifen and sodium chromoglycate were carried out. Serotonin release studies, carried out together with morphological studies, showed the effectiveness of the above lactones to stabilize mast cells. The comparative study with ketotifen and sodium chromoglycate, well known mast cell stabilizers, showed the following order of potency dehydroleucodine=xanthatin>3-benzyloxymethyl-5H-furan-2-one> or =ketotifen/sodium chromoglycate to inhibit mast cell serotonin release induced by compound 48/80. The present study provides the first strong evidence in favour of the hypothesis that dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one inhibit compound 48/80-induced serotonin release from peritoneal mast cells, acting thus as mast cell stabilizers. Our findings may provide an insight into the design of novel pharmacological agents which may be used to regulate the mast cell response.
Assuntos
Antiulcerosos/farmacologia , Degranulação Celular/efeitos dos fármacos , Lactonas/farmacologia , Mastócitos/efeitos dos fármacos , p-Metoxi-N-metilfenetilamina/farmacologia , Animais , Antiulcerosos/química , Corantes/metabolismo , Relação Dose-Resposta a Droga , Processamento de Imagem Assistida por Computador , Lactonas/química , Masculino , Mastócitos/ultraestrutura , Estrutura Molecular , Peritônio/citologia , Ratos , Ratos Sprague-Dawley , Serotonina/metabolismo , Cloreto de Tolônio/metabolismoRESUMO
Hydroquinone (HQ) is naturally found in the diet, drugs, as an environmental contaminant and endogenously generated after benzene exposure. Considering that HQ alters the immune system and its several source of exposures in the environment, we hypothesized that prolonged exposure of HQ could affect the course of an immune-mediated inflammatory response. For this purpose, male Wistar rats were intraperitoneally exposed to vehicle or HQ once a day, for 22 days with a 2-day interval every 5 days. On day 10 after exposure with vehicle or HQ, animals were ovalbumin (OA)-sensitized and OA-aerosolized challenged on day 23. HQ exposure did not alter the number of circulating leukocytes but impaired allergic inflammation, evidenced by lower number of leukocytes in the bronchoalveolar lavage fluid 24h after OA-challenge. Reduced force contraction of ex vivo tracheal segments upon OA-challenge and impaired mesentery mast cell degranulation after in situ OA-challenge were also detected in tissues from HQ exposed animals. The OA-specificity on the decreased responses was corroborated by normal trachea contraction and mast cell degranulation in response to compound 48/80. In fact, lower levels of circulating OA-anaphylactic antibodies were found in HQ exposed rats, as assessed by passive cutaneous anaphylaxis assay. The reduced level of OA-anaphylactic antibody was not dependent on lower number or proliferation of lymphocytes. Nevertheless, lower expression of the co-stimulatory molecules CD6 and CD45R on OA-activated lymphocytes from HQ exposed rats indicate the interference of HQ exposure with signaling of the humoral response during allergic inflammation. Together, these data indicate specific effects of HQ exposure manifested during an immune host defense.
Assuntos
Alveolite Alérgica Extrínseca/patologia , Poluentes Ambientais/toxicidade , Hidroquinonas/toxicidade , Alveolite Alérgica Extrínseca/fisiopatologia , Animais , Antígenos CD/biossíntese , Antígenos de Diferenciação de Linfócitos T/biossíntese , Líquido da Lavagem Broncoalveolar/citologia , Degranulação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citometria de Fluxo , Antígenos Comuns de Leucócito/biossíntese , Contagem de Leucócitos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Masculino , Mastócitos/efeitos dos fármacos , Mastócitos/ultraestrutura , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Infiltração de Neutrófilos/efeitos dos fármacos , Ovalbumina/imunologia , Anafilaxia Cutânea Passiva/imunologia , Ratos , Ratos Wistar , Baço/efeitos dos fármacos , Baço/patologia , Traqueia/efeitos dos fármacos , Traqueia/fisiologiaRESUMO
Mast cells from two erythrinid species: Hoplias malabaricus and Hoplias lacerdae, were studied in several tissues throughout the body using light and electron microscopy. Mast cells were found in all organs studied, but were especially abundant in the gastrointestinal tract, and were always in association with connective tissue. These cells showed different characteristics between the two species studied, like varied morphology, anatomical distribution, density, basophilic/eosinophilic staining and heparin content. In H. malabaricus, the tissues fixed with Helly's solution contained mast cells that were basophilic, metachromatic and had heparin in their cytoplasmic granules, while the tissues fixed with Karnovsky's solution contained eosinophilic and orthochromatic mast cells in which heparin was not detected. In H. lacerdae, the use of both fixatives resulted in mast cells that were eosinophilic, orthochromatic, with no identifiable heparin content. Exclusively in H. malabaricus oesophagus, the mast cells were additionally seen among the epithelial cells. The ultrastructural studies performed in hindgut fixed with Karnovsky's solution revealed that the cytoplasmic granules seen in H. lacerdae mast cells were better preserved than in H. malabaricus mast cells. The latter had electron-lucent granules that were often merged, forming channels. The present study demonstrated that mast cells from two species belonging to the same genus or even mast cells from the same species but under different fixatives can present heterogeneous characteristics, possibly due to their functional properties or to their sensitivity to fixatives.