RESUMO

Cumulative evidence has established that Interferon (IFN)-γ has both pathogenic and protective roles in Multiple Sclerosis and the animal model, Experimental Autoimmune Encephalomyelitis (EAE). However, the underlying mechanisms to the beneficial effects of IFN-γ are not well understood. In this study, we found that IFN-γ exerts therapeutic effects on chronic, relapsing-remitting, and chronic progressive EAE models. The frequency of regulatory T (Treg) cells in spinal cords from chronic EAE mice treated with IFN-γ was significantly increased with no effect on Th1 and Th17 cells. Consistently, depletion of FOXP3-expressing cells blocked the protective effects of IFN-γ, indicating that the therapeutic effect of IFN-γ depends on the presence of Treg cells. However, IFN-γ did not trigger direct in vitro differentiation of Treg cells. In vivo administration of blocking antibodies against either interleukin (IL)-10, transforming growth factor (TGF)-ß or program death (PD)-1, revealed that the protective effects of IFN-γ in EAE were also dependent on TGF-ß and PD-1, but not on IL-10, suggesting that IFN-γ might have an indirect role on Treg cells acting through antigen-presenting cells. Indeed, IFN-γ treatment increased the frequency of a subset of splenic CD11b+ myeloid cells expressing TGF-ß-Latency Associated Peptide (LAP) and program death ligand 1 (PD-L1) in a signal transducer and activator of transcription (STAT)-1-dependent manner. Furthermore, splenic CD11b+ cells from EAE mice preconditioned in vitro with IFN-γ and myelin oligodendrocyte glycoprotein (MOG) peptide exhibited a tolerogenic phenotype with the capability to induce conversion of naïve CD4+ T cells mediated by secretion of TGF-ß. Remarkably, adoptive transfer of splenic CD11b+ cells from IFN-γ-treated EAE mice into untreated recipient mice ameliorated clinical symptoms of EAE and limited central nervous system infiltration of mononuclear cells and effector helper T cells. These results reveal a novel cellular and molecular mechanism whereby IFN-γ promotes beneficial effects in EAE by endowing splenic CD11b+ myeloid cells with tolerogenic and therapeutic activities.

Assuntos

Antígeno CD11b , Encefalomielite Autoimune Experimental , Interferon gama , Camundongos Endogâmicos C57BL , Células Mieloides , Baço , Animais , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/tratamento farmacológico , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/patologia , Camundongos , Interferon gama/metabolismo , Células Mieloides/efeitos dos fármacos , Células Mieloides/imunologia , Células Mieloides/metabolismo , Baço/imunologia , Antígeno CD11b/metabolismo , Feminino , Glicoproteína Mielina-Oligodendrócito/toxicidade , Glicoproteína Mielina-Oligodendrócito/imunologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/efeitos dos fármacos , Fragmentos de Peptídeos/toxicidade , Fragmentos de Peptídeos/farmacologia , Fator de Crescimento Transformador beta/metabolismo , Receptor de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/imunologia , Fatores de Transcrição Forkhead/metabolismo , Modelos Animais de Doenças

RESUMO

ABSTRACT Introduction: Immune dysfunction and thrombocytopenia are common features in liver cirrhosis. Platelet transfusion is the most widely used therapeutic approach for thrombocytopenia when indicated. The transfused platelets are prone to lesions during their storage that empower their interaction with the recipient leucocyte. These interactions modulate the host immune response. The impact of platelet transfusion on the immune system in cirrhotic patients is little understood. Therefore, this study aims to investigate the impact of platelet transfusion on neutrophil function in cirrhotic patients. Methods: This prospective cohort study was implemented on 30 cirrhotic patients receiving platelet transfusion and 30 healthy individuals as a control group. EDTA blood samples were collected from cirrhotic patients before and after an elective platelet transfusion. Flowcytometric analysis of neutrophil functions (CD11b expression and PCN formation) was performed. Results: There was a significant increase in expression of CD11b on neutrophils and Frequency of platelet-complexed neutrophils (PCN) in patients with cirrhosis compared with controls. Platelet transfusion increased level of CD11b and the frequency of PCN even more. There was a significant positive correlation between change in PCN Frequency pefore and after transfusion and the change in expression of CDllb among cirrhotic patients. Conclusions: Elective platelet transfusion appears to increase level of PCN in cirrhotic patients, moreover, exacerbate the expression of activation marker CDllb on both neutrophils and PCN. More research and studies are needed to corroborate our preliminary findings.

RESUMO

The ß2 integrin CD11b/CD18, also known as complement receptor 3 (CR3), and the moonlighting protein aminopeptidase N (CD13), are two myeloid immune receptors with overlapping activities: adhesion, migration, phagocytosis of opsonized particles, and respiratory burst induction. Given their common functions, shared physical location, and the fact that some receptors can activate a selection of integrins, we hypothesized that CD13 could induce CR3 activation through an inside-out signaling mechanism and possibly have an influence on its membrane expression. We revealed that crosslinking CD13 on the surface of human macrophages not only activates CR3 but also influences its membrane expression. Both phenomena are affected by inhibitors of Src, PLCγ, Syk, and actin polymerization. Additionally, after only 10 min at 37 °C, cells with crosslinked CD13 start secreting pro-inflammatory cytokines like interferons type 1 and 2, IL-12p70, and IL-17a. We integrated our data with a bioinformatic analysis to confirm the connection between these receptors and to suggest the signaling cascade linking them. Our findings expand the list of features of CD13 by adding the activation of a different receptor via inside-out signaling. This opens the possibility of studying the joint contribution of CD13 and CR3 in contexts where either receptor has a recognized role, such as the progression of some leukemias.

Assuntos

Antígenos CD13 , Antígenos CD18 , Integrinas , Humanos , Antígenos CD18/metabolismo , Antígeno de Macrófago 1/metabolismo , Fagocitose/fisiologia

RESUMO

INTRODUCTION: Immune dysfunction and thrombocytopenia are common features in liver cirrhosis. Platelet transfusion is the most widely used therapeutic approach for thrombocytopenia when indicated. The transfused platelets are prone to lesions during their storage that empower their interaction with the recipient leucocyte. These interactions modulate the host immune response. The impact of platelet transfusion on the immune system in cirrhotic patients is little understood. Therefore, this study aims to investigate the impact of platelet transfusion on neutrophil function in cirrhotic patients. METHODS: This prospective cohort study was implemented on 30 cirrhotic patients receiving platelet transfusion and 30 healthy individuals as a control group. EDTA blood samples were collected from cirrhotic patients before and after an elective platelet transfusion. Flowcytometric analysis of neutrophil functions (CD11b expression and PCN formation) was performed. RESULTS: There was a significant increase in expression of CD11b on neutrophils and Frequency of platelet-complexed neutrophils (PCN) in patients with cirrhosis compared with controls. Platelet transfusion increased level of CD11b and the frequency of PCN even more. There was a significant positive correlation between change in PCN Frequency pefore and after transfusion and the change in expression of CD11b among cirrhotic patients. CONCLUSIONS: Elective platelet transfusion appears to increase level of PCN in cirrhotic patients, moreover, exacerbate the expression of activation marker CD11b on both neutrophils and PCN. More research and studies are needed to corroborate our preliminary findings.

RESUMO

Therapies to deep burn injuries remain a global challenge. Human amniotic membrane (hAM) is a biomaterial that has been increasingly explored by the field of regenerative medicine. A decellularized hAM (DhAM) can be used as scaffold for mesenchymal stromal cells (MSCs) to grow without the loss of their stemness potential, allowing its application as cell therapy for wound healing. In this work, we associated DhAM with adipose-derived MSCs (DhAM + AD-MSCs), as a therapy strategy for second-degree burns in a preclinical model. Animals with induced second-degree burns were divided into four groups: control, which consists of a non-adherent gauze; a synthetic commercial dressing as the positive control (Control+); DhAM; and DhAM plus rat AD-MSCs (DhAM + AD-MSCs), followed by detailed and long term analysis (5 weeks). The macroscopical analysis showed the healing improvement in the wound area after the DhAM + AD-MSC treatment. Histological analysis also showed no alteration in the animal organs and a regular epithelial progression in comparison to the control. This observation was also confirmed by the analysis of suprabasal layers in the neoepidermis with CK10, showing a stratified and differentiated epithelium, when compared to Control and Control+. A strong CD73 (ecto-5'-nucleotidase) labeling was observed in the first 2 weeks postburn in dermis and epidermis. The expression in dermis was stronger in the second week in the middle of the wound, when comparing the Control+ with DhAM + AD-MSCs (p= 0.0238). In the epidermis the expression of CD73 was increased in all regions when compared to the control. This data suggests the involvement of this protein on wound healing. A low CD11b labeling was observed in DhAM + AD-MSCs treatment group mainly in the last treatment week, in comparison to Control and Control+ (p< 0.0001), which indicates a reduction in the inflammatory process. MSCs through CD73 can release high concentrations of adenosine, an immunosuppressive molecule, suggesting that this could be the mechanism by which the inflammation was better modulated in the DhAM + AD-MSCs group. The results obtained with this preclinical model confirm the effectiveness and safety of this low-cost and highly available dressing for future clinical application as a therapy for burn treatments.

Assuntos

Queimaduras , Células-Tronco Mesenquimais , Humanos , Ratos , Animais , Âmnio/patologia , Células-Tronco Mesenquimais/metabolismo , Queimaduras/terapia , Queimaduras/metabolismo , Cicatrização , Diferenciação Celular

RESUMO

Aspergillus fumigatus (A. fumigatus) is an environmental fungus and a human pathogen. Neutrophils are critical effector cells during the fungal infections, and neutropenia is a risk factor for the development of pulmonary aspergillosis. Neutrophil extracellular traps (NETs) are released by neutrophils in response to A. fumigatus and inhibit the conidial germination. In this work, we observed that the receptors TLR2, TLR4, and Dectin-1 were dispensable for the A. fumigatus induced NET release. In contrast CD11b/CD18 was critical for the NET release in response to A. fumigatus conidia, and this required the CD11b I-domain-mediated recognition, whereas the blockade of the CD11b lectin domain did not affect the A. fumigatus induced NET release. A. fumigatus induced NET release relied on the activity of spleen tyrosine kinase (Syk), Src family kinase(s), and class IA PI3 kinase δ. Although A. fumigatus promoted histone citrullination, this process was dispensable for the NET release in response to A. fumigatus conidia. The A. fumigatus induced NET release required the reactive oxygen species generation by the NOX2 complex, in a downstream pathway requiring CD11b/CD18, Src kinase family activity, Syk and PI3K class IA δ. Our findings thus reveal the signaling pathways involved in the formation of NETs in response to A. fumigatus.

Assuntos

Aspergilose/imunologia , Aspergillus fumigatus/imunologia , DNA/imunologia , Armadilhas Extracelulares/imunologia , Histonas/química , Antígeno de Macrófago 1/metabolismo , Neutrófilos/imunologia , Proteína-Arginina Desiminase do Tipo 4/química , Aspergilose/metabolismo , Aspergilose/microbiologia , Aspergillus fumigatus/metabolismo , Antígeno CD11b/metabolismo , Antígenos CD18/metabolismo , Citrulinação , DNA/metabolismo , Armadilhas Extracelulares/microbiologia , Humanos , Antígeno de Macrófago 1/genética , Neutrófilos/microbiologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteína-Arginina Desiminase do Tipo 4/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Quinase Syk/metabolismo , Quinases da Família src/metabolismo

RESUMO

Glutamine (GLN) is the most abundant free amino acid in the body, and is considered as a conditionally essential amino acid under stress conditions, acting as an important modulator of the immune response. We here investigated the role of exogenous GLN treatment on leukocyte migration after the onset of endotoxemia and the intracellular mechanisms of GLN actions on neutrophils. Two in vivo models of endotoxemia caused by lipopolysaccharide of Escherichia coli (LPS) injection were carried out in male outbred Balb/C mice 2-3 months old, as follow: (1) LPS (50 µg/kg) was intravenously injected 1 h prior to intravenous injection of GLN (0.75 mg/kg) and samples were collected 2 h later to investigate the role of GLN on the acute lung inflammation; (2) LPS (1 mg/kg) was intraperitoneally injected 1 h prior to intravenous injection of GLN (0.75 mg/kg) and samples were collected 18 h later to measure the effects of GLN on local and later phases of inflammation in the peritoneum. Results showed that GLN administration reduced the number of neutrophils in the inflamed lungs, partially recovery of the reduced number of leukocytes in the blood; reduced adhesion molecules on lung endothelium and on circulating neutrophils. Moreover, GLN treatment diminished the number of neutrophils, levels of chemotactic cytokine CXCL2 in the inflamed peritoneum, and neutrophils collected from the peritoneum of GLN-treated mice presented lower levels of Rho, Rac, and JNK. Together, our data show novel mechanisms involved in the actions of GLN on neutrophils migration.

Assuntos

Movimento Celular/efeitos dos fármacos , Endotoxemia/tratamento farmacológico , Glutamina/administração & dosagem , Lipopolissacarídeos/toxicidade , Neutrófilos/efeitos dos fármacos , Peritônio/efeitos dos fármacos , Pneumonia/tratamento farmacológico , Animais , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Endotoxemia/induzido quimicamente , Endotoxemia/metabolismo , Endotoxemia/patologia , Regulação da Expressão Gênica , Glutamina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/metabolismo , Peritônio/metabolismo , Pneumonia/induzido quimicamente , Pneumonia/metabolismo , Pneumonia/patologia

RESUMO

BACKGROUND: Immunosenescence is a remodeling of the immune system, caused by aging, with changes in the function of neutrophils, lymphocytes, and Treg cells. OBJECTIVE: This study aimed to evaluate the expression of molecules CD11b, CD16 and CD64 (neutrophils), CD154 (T lymphocytes), CD40 (B lymphocytes), and to quantitatively analyze the Treg cell subpopulation. METHODS: 49 elderlies (≥60 years) and 49 adults (≤35 years) were studied. Flow cytometry was used to analyze the expression of surface molecules and the subpopulation of Treg cells, and the results between the groups were compared statistically by the t-test. RESULTS: There was a decreased significance in the expression of CD11b and CD40 in the elderly. CONCLUSION: Decreased CD11b expression can result in susceptibility to infectious diseases, and impairment of phagocytic capacity. Decreased CD40 expression can result in a decline in B lymphocyte activation. The other molecule studied presented alterations not significant, but compatible with the immunological changes in aging.

Assuntos

Antígeno CD11b/metabolismo , Antígenos CD40/metabolismo , Senescência Celular , Imunossenescência , Linfócitos/metabolismo , Neutrófilos/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Biomarcadores/metabolismo , Brasil , Antígeno CD11b/imunologia , Antígenos CD40/imunologia , Ligante de CD40/imunologia , Ligante de CD40/metabolismo , Estudos Transversais , Regulação para Baixo , Feminino , Citometria de Fluxo , Proteínas Ligadas por GPI/imunologia , Proteínas Ligadas por GPI/metabolismo , Humanos , Imunofenotipagem/métodos , Linfócitos/imunologia , Masculino , Pessoa de Meia-Idade , Neutrófilos/imunologia , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Adulto Jovem

RESUMO

The effect of physical activity on the immune system is still poorly understood in cases of systemic lupus erythematosus (SLE). Therefore, our aim was to investigate differences in the serum levels of cytokines (IL-2, IL-5, IL-6, IL-8, IL-10 and TNF-α) and the numbers of CD11b + and CXCR2 + neutrophils and lymphocytes in women with SLE undergoing drug treatment, without ( n = 9) or with ( n = 5) 4 months of kinesiotherapy. Parameters related to functional capacity were also analyzed. In the case of the patients who were not submitted to kinesiotherapy, there were reductions in the levels of IL-5, IL-6 and IL-10, and an increase in the number of CD11b + leukocytes, in addition to an increase in abdominal circumference after the monitoring time. Patients submitted to kinesiotherapy did not present changes in serum cytokines or in the numbers of CD11b + and CXCR2 + neutrophils and lymphocytes, but there were increases of flexibility and strength, as well as a reduction in pain sensation after the monitoring time. In conclusion, kinesiotherapy was able to increase flexibility and reduce pain in SLE patients without influencing immune parameters.

Assuntos

Antígeno CD11b/sangue , Interleucina-10/sangue , Cinesiologia Aplicada/métodos , Lúpus Eritematoso Sistêmico/terapia , Linfócitos/imunologia , Dor/prevenção & controle , Adulto , Exercício Físico , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Pessoa de Meia-Idade , Estudos Prospectivos , Receptores de Interleucina-8B/sangue

RESUMO

Bovine ruminal acidosis is of economic importance as it contributes to reduced milk and meat production. This phenomenon is mainly attributed to an overload of highly fermentable carbohydrate, resulting in increased d(-) lactic acid levels in serum and plasma. Ruminal acidosis correlates with elevated acute phase proteins in blood, along with neutrophil activation and infiltration into various tissues leading to laminitis and aseptic polysynovitis. Previous studies in bovine neutrophils indicated that d(-) lactic acid decreased expression of L-selectin and increased expression of CD11b to concentrations higher than 6 mM, suggesting a potential role in neutrophil adhesion onto endothelia. The two aims of this study were to evaluate whether d(-) lactic acid influenced neutrophil and endothelial adhesion and to trigger neutrophil extracellular trap (NET) production (NETosis) in exposed neutrophils. Exposure of bovine neutrophils to 5 mM d(-) lactic acid elevated NET release compared to unstimulated neutrophil negative controls. Moreover, this NET contains CD11b and histone H4 citrullinated, the latter was dependent on PAD4 activation, a critical enzyme in DNA decondensation and NETosis. Furthermore, NET formation was dependent on d(-) lactic acid plasma membrane transport through monocarboxylate transporter 1 (MCT1). d(-) lactic acid enhanced neutrophil adhesion onto endothelial sheets as demonstrated by in vitro neutrophil adhesion assays under continuous physiological flow conditions, indicating that cell adhesion was a NET- and a CD11b/ICAM-1-dependent process. Finally, d(-) lactic acid was demonstrated for the first time to trigger NETosis in a PAD4- and MCT1-dependent manner. Thus, d(-) lactic acid-mediated neutrophil activation may contribute to neutrophil-derived pro-inflammatory processes, such as aseptic laminitis and/or polysynovitis in animals suffering acute ruminal acidosis.