RESUMO
Reactive oxygen species (ROS) have been extensively studied in biology in the past years. This class of molecules can be derived from endogenous sources (e.g., phagocytic cells as neutrophils, eosinophils, monocytes, macrophages, and organelles as mitochondria and peroxisomes) and participate in physiological and pathological conditions. The beneficial and harmful effects of ROS depend on redox regulation, which establishes the balance between their production and the activity of antioxidant systems to prevent oxidative stress in vivo. Neutrophils are the immune effectors most well depicted with an intense oxidative burst in response to tissue inflammation. Several proteins and members of the galectin family are involved in this fine modulation of ROS production by neutrophils. Interestingly, studies have indicated that Galectin-1 (Gal-1) can up- or downregulate ROS production by neutrophils even when exposed to N-formyl-Met-Leu-Phe (fMLP) or Phorbol Myristate Acetate (PMA), both of which are potent neutrophil stimulants that trigger high levels of ROS production. Similarly, Galectin-3 (Gal-3) induces ROS in neutrophils from a sterile or nonsterile inflammatory environment, possibly creating a negative loop that could control ROS production. Besides, superoxide production is also induced by Galectin-8 (Gal-8) and Galectin-9 (Gal-9) in neutrophils but in a different manner. We describe herein the luminol and lucigenin-dependent chemiluminescence technique by using a luminometer as a method of assessment to measure ROS production by human neutrophils isolated and exposed to purified human recombinant Gal-1. The protocol described herein could be applied for the investigation of the role of other galectins in the modulation of ROS production by neutrophils.
Assuntos
Galectinas , Neutrófilos , Espécies Reativas de Oxigênio , Galectinas/genética , Galectinas/metabolismo , Galectinas/farmacologia , Humanos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Monocytes are key cells in the immune dysregulation observed during human immunodeficiency virus (HIV) infection. The events that take place specifically in monocytes may contribute to the systemic immune dysfunction characterized by excessive immune activation in infected individuals, which directly correlates with pathogenesis and progression of the disease. Here, we investigated the immune dysfunction in monocytes from untreated and treated HIV + patients and associated these findings with epigenetic changes. Monocytes from HIV patients showed dysfunctional ability of phagocytosis and killing, and exhibited dysregulated cytokines and reactive oxygen species production after M. tuberculosis challenge in vitro. In addition, we showed that the expression of enzymes responsible for epigenetic changes was altered during HIV infection and was more prominent in patients that had high levels of soluble CD163 (sCD163), a newly identified plasmatic HIV progression biomarker. Among the enzymes, histone acetyltransferase 1 (HAT1) was the best epigenetic biomarker correlated with HIV - sCD163 high patients. In conclusion, we confirmed that HIV impairs effector functions of monocytes and these alterations are associated with epigenetic changes that once identified could be used as targets in therapies aiming the reduction of the systemic activation state found in HIV patients.
Assuntos
Epigênese Genética , Infecções por HIV/genética , Infecções por HIV/imunologia , HIV-1/fisiologia , Monócitos/imunologia , Adolescente , Adulto , Idoso , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Progressão da Doença , Ativação Enzimática , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monócitos/metabolismo , Fagocitose/genética , Receptores de Superfície Celular/metabolismo , Adulto JovemRESUMO
Oreochromis niloticus bred in net cages were supplemented with cell wall of Saccharomyces cerevisiae (Sc) (0.3%) or chromium carbochelate (Cr) (18 mg/kg of feed) or in association (Sc + Cr), for 90 days. After this period, acute inflammation was induced in the swim bladder by inoculation of 3 × 10(8) CFU of inactivated Streptococcus agalactiae, and another group received 0.65% saline solution (control). Twelve, 24, and 48 h after stimulation, the inflammation was evaluated through total and differential counting of accumulated cells, and through leukocyte respiratory burst in the blood, cortisolemia, glycemia and serum lysozyme concentration. The results showed that there were greater total numbers of cells in the exudate of fish inoculated with inactivated bacterium than in those injected with saline solution, with predominance of lymphocytes, thrombocytes, macrophages and granulocytes. Tilapia supplemented with Cr presented increased total numbers of cells with significant accumulation of lymphocytes and reductions in cortisolemia and glycemia, but the different treatments did not have any influence on leukocyte respiratory burst or serum lysozyme concentration. Tilapia supplemented with Sc and the Cr + Sc association did not present significant changes to the variables evaluated, despite higher accumulation of lymphocytes in the inflammatory exudate from fish treated with Sc. The results indicate that tilapia bred in net cages and supplemented with Cr presented higher total accumulation of cells at the inflammatory focus, thus indicating an increase in the inflammatory response induced by the bacterium, probably due to the reduction in cortisolemia and higher glucose consumption. Thus, supplementation with Cr had beneficial action, which facilitated development of acute inflammation induced by the bacterium, but did not affect neither leukocyte respiratory burst in the blood nor serum lysozyme concentration.
Assuntos
Sacos Aéreos/microbiologia , Ciclídeos , Doenças dos Peixes/microbiologia , Infecções Respiratórias/veterinária , Infecções Estreptocócicas/veterinária , Streptococcus agalactiae/imunologia , Sacos Aéreos/imunologia , Animais , Glicemia/análise , Cromo/administração & dosagem , Cromo/imunologia , Doenças dos Peixes/imunologia , Hidrocortisona/sangue , Muramidase/sangue , Probióticos/farmacologia , Distribuição Aleatória , Explosão Respiratória/imunologia , Infecções Respiratórias/imunologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/prevenção & controle , Saccharomyces cerevisiae/imunologia , Infecções Estreptocócicas/imunologia , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/prevenção & controleRESUMO
Galectins are beta-galactoside-binding lectins involved in several biological processes and galectin-3 (Gal-3) is related to modulation of immune and inflammatory responses. This study aimed to evaluate the role of Gal-3 in the life span and biological functions of murine neutrophils during in vitro infection by virulent Toxoplasma gondii RH strain. Inflammatory peritoneal neutrophils (Nphi) from C57BL/6 wild-type (WT) and Gal-3 knockout (KO) mice were cultured in the presence or absence of parasites and analyzed for phosphatidylserine (PS) exposure and cell death using Annexin-V and propidium iodide staining, and cell viability by MTT assay. Cell toxicities determined by lactate dehydrogenase (LDH), degranulation by lysozyme release, and cytokine production were measured in Nphi culture supernatants. Phorbol myristate acetate (PMA)- or zymosan-dependent reactive oxygen species (ROS) were measured in Nphi cultures. Our results demonstrated that Gal-3 is involved in the increase of the viable Nphi number and the decrease of PS exposure and cell death following T. gondii infection. We also observed that Gal-3 downmodulates T. gondii-induced Nphi toxicity as well as Nphi degranulation regardless of infection. Furthermore, Gal-3 expression by Nphi was associated with increased levels of IL-10 in the beginning and decreased levels of TNF-alpha later on, regardless of parasite infection, as well as with decreased levels of IL-6 and increased IL-12 levels, following early parasite infection. Our results also showed that Gal-3 suppresses PMA- but not zymosan-induced ROS generation in Nphi following T. gondii infection. In conclusion, Gal-3 plays an important modulatory role by interfering in Nphi life span and activation during early T. gondii infection.
Assuntos
Galectina 3/imunologia , Regulação da Expressão Gênica/imunologia , Ativação de Neutrófilo/imunologia , Neutrófilos/imunologia , Toxoplasma/imunologia , Toxoplasmose/imunologia , Animais , Degranulação Celular/genética , Degranulação Celular/imunologia , Células Cultivadas , Citocinas/biossíntese , Citocinas/imunologia , Galectina 3/genética , Galectina 3/metabolismo , Regulação da Expressão Gênica/genética , Camundongos , Camundongos Knockout , Ativação de Neutrófilo/genética , Neutrófilos/metabolismo , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo , Toxoplasma/metabolismo , Toxoplasmose/genética , Toxoplasmose/metabolismoRESUMO
To determine the relation between neutrophil function and the clinical characteristics of systemic lupus erythematosus (SLE), the superoxide anion (O2-) production by neutrophils, mediated by FcgammaR and FcgammaR/CR cooperation, was studied in 64 SLE patients classified according to their prevalent clinical manifestations. Three clinically distinct patterns were designated: (1) manifestations associated with the occurrence of cytotoxic antibodies (SLE-I group); (2) manifestations associated with circulating immune complexes (IC; SLE-II group), and (3) manifestations associated with IC and cytotoxic antibodies (SLE-III group). O2- production was evaluated by a lucigenin-dependent chemiluminescent assay in neutrophils stimulated with IC-IgG opsonized or not with complement. No difference in O2- production was observed when neutrophil responses from healthy controls were compared to the unclassified patients. However, when the SLE patient groups were considered, the following differences were observed: (1) SLE-I neutrophils showed lower O2- production mediated by the IgG receptor (FcgammaR) with the cooperation of complement receptors (FcgammaR/CR) than observed in the SLE-II, SLE-III, and healthy groups; (2) neutrophils from the SLE-II group showed a decreased [Formula: see text] production mediated by FcgammaR/CR compared to the SLE-III group, (3) SLE-III neutrophils produced more O(2)(-) than neutrophils from the SLE-II and control groups, and (4) CR showed inefficiency in mediating the O2- production by neutrophils from the SLE-I group. Comparative experiments on the kinetics of chemiluminescence (CL; Tmax and CLmax) disclosed differences only for the SLE-I group. Taken together, these results suggest that differences in oxidative metabolism of neutrophils mediated by FcgammaR/CR may reflect an acquired characteristic of disease associated with distinct clinical manifestations.
Assuntos
Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Neutrófilos/metabolismo , Superóxidos/metabolismo , Adulto , Idoso , Autoanticorpos/sangue , Feminino , Humanos , Cinética , Luminescência , Lúpus Eritematoso Sistêmico/epidemiologia , Masculino , Pessoa de Meia-Idade , Receptores de Complemento/metabolismo , Receptores de IgG/metabolismo , Estudos SoroepidemiológicosRESUMO
Os receptores para IgG (Fc'gama'R) fazem uma importante ligação entre as respostas imunes humoral e celular. Estes receptores medeiam várias respostas biológicas tais como: fagocitose, endocitose, captura e clearance de imunocomplexos, citotoxicidade e liberação de mediadores inflamatórios. Os Fc'gama'R humanos pertencem à superfamília das imunoglobulinas e três classes principais destes receptores são descritas, as quais apresentam várias isoformas. Estas moléculas diferem quanto à afinidade e especificidade para os isotipos de IgG, distribuição celular, sinalização intracelular e pesos moleculares. Além disso, o polimorfismo genético é responsável por variações entre os indivíduos. A diversidade estrutural e funcional dos Fc'gama'R faz destas moléculas importantes alvos para a imunoterapia. A ativação e desativação de células efetoras via Fc'gama'R pode ser explorada para o desenvolvimento de novas terapias para o câncer, doenças infecciosas e desordens auto-imunes. Esta revisão descreve detalhes estruturais e funcionais, relevância clínica e alguns usos terapêuticos dos Fc'gama'R