Effects of GM1 administration on autoimmune diabetes modulation and cytokines expression, Nerve Growth Factor and TrkA receptor in NOD mice (non obese diabetic)

Orientador: Ricardo de Lima ZollnerDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias MedicasResumo: A linhagem de camundongos NOD (non obese diabetic) desenvolve espontaneamente diabetes mellitus tipo 1 (DM-1) com marcante similaridade ao observado em humanos, que se estabelece entre 12ª e 24ª semana de vida, com presença de autoanticorpos específicos contra antígenos pancreáticos. Grande parte das células encontradas são linfócitos T CD4+ e T CD8+ e, embora células NK, linfócitos B, células dendríticas e macrófagos também possam ser identificados nas lesões, o desenvolvimento da doença é primariamente dependente de linfócitos T CD4+ e CD8+ auto-reativos. A diferenciação e funcionamento de células ß são regulados por uma variedade de hormônios e fatores de crescimento, incluindo Nerve Growth Factor (NGF). Sabe-se que células-ß pancreáticas expressam receptores funcionais para NGF e esta neurotrofina induz modificações morfológicas e fisiológicas, incluindo estimulação da secreção de insulina. Estudos de terapias para o DM-1 baseadas na intervenção sobre o sistema imunológico revelam que estas podem ser estratégias promissoras para impedir a instalação e/ou evolução da doença. Neste contexto, investigamos os efeitos da administração de GM1 sobre a incidência do DM-1 e insulite em camundongos NOD, expressão de citocinas, NGF e seu receptor de alta afinidade TrkA. Nossos resultados sugerem que administração de GM1 na dose de 100mg/kg/dia em camundongos NOD fêmeas a partir da 4ª semana de vida é capaz de diminuir o índice de infiltrado inflamatório e conseqüentemente a expressão do diabetes, modulando negativamente o infiltrado inflamatório bem como a expressão gênica de citocinas pró-inflamatórias (IL-12, IFN-?, TNF-a e IL-1ß), além de aumentar a expressão gênica e protéica de NGF e TrkA, que pode atuar como regulador de sobrevivência da célula ß de maneira a inibir a apoptose desta célulaAbstract: The strain of NOD mice (non obese diabetic) spontaneously develops diabetes mellitus type 1 (DM-1) with strong similarity to the observed in humans. In this model, the diabetes manifestation occurs among 12th and 24th weeks of life, with presence of pancreas-specific autoantibodies. Great part of the cells are CD4+ and CD8+T cells, and even so NK cells, lymphocytes B, dendritics cells and macrophages also can be identified in the injuries, the development of the disease is essentially dependent of autoreactive CD4+ and CD8+ T cells. It was demonstrated that ? - pancreatic cells express NGF functional receptors and that this neurotrophin induces morphological and physiological modifications in pancreatic ? cells, including stimulation in insulin secretion. The inquiries of therapies for the DM-1 based on the intervention on the immune system disclose that these can be promising strategies to hinder the installation and/or evolution of the disease. In this context, we investigate the effect of GM1 administration on the incidence of DM-1 and insulitis in NOD mice, cytokines expression, NGF and its high affinity receptor TrkA. Our results suggest that administration of GM1 in the dose of 100mg/kg/dia in female NOD mice from 4ª week of life are capable to reduce the index of inflammatory infiltrated and consequently the expression of diabetes, down-modulating the inflammatory infiltrated as well as the gene expression of pro-inflammatory cytokines (IL-12, IFN-?, TNF-? and IL-1?), besides increasing the gene and protein expression of NGF and TrkA, that can act as regulating of ß cell - survival in way to inhibit apoptosis of this cellMestradoCiencias BasicasMestre em Clinica Medic

BRD4 inhibition enhances azacitidine efficacy in acute myeloid leukemia and myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell-based disorders characterized by ineffective hematopoiesis, increased genomic instability and a tendency to progress toward acute myeloid leukemia (AML). MDS and AML cells present genetic and epigenetic abnormalities and, due to the heterogeneity of thesemolecular alterations, the current treatment options remain unsatisfactory. Hypomethylating agents (HMA), especially azacitidine, are the mainstay of treatment for high-risk MDS patients and HMA are used in treating elderly AML. The aim of this study was to investigate the potential role of the epigenetic reader bromodomain-containing protein-4 (BRD4) in MDS and AML patients. We identified the upregulation of the short variant BRD4 in MDS and AML patients, which was associated with a worse outcome of MDS. Furthermore, the inhibition of BRD4 in vitro with JQ1 or shRNA induced leukemia cell apoptosis, especially when combined to azacitidine, and triggered the activation of the DNA damage response pathway. JQ1 and AZD6738 (a specific ATR inhibitor) also synergized to induce apoptosis in leukemia cells. Our results indicate that the BRD4-dependent transcriptional program is a defective pathway in MDS and AML pathogenesis and its inhibition induces apoptosis of leukemia cells, which is enhanced in combination with HMA or an ATR inhibitor9CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulonão tem2011/51959-

BRD4 Inhibition Enhances Azacitidine Efficacy in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell-based disorders characterized by ineffective hematopoiesis, increased genomic instability and a tendency to progress toward acute myeloid leukemia (AML). MDS and AML cells present genetic and epigenetic abnormalities and, due to the heterogeneity of these molecular alterations, the current treatment options remain unsatisfactory. Hypomethylating agents (HMA), especially azacitidine, are the mainstay of treatment for high-risk MDS patients and HMA are used in treating elderly AML. The aim of this study was to investigate the potential role of the epigenetic reader bromodomain-containing protein-4 (BRD4) in MDS and AML patients. We identified the upregulation of the short variant BRD4 in MDS and AML patients, which was associated with a worse outcome of MDS. Furthermore, the inhibition of BRD4 in vitro with JQ1 or shRNA induced leukemia cell apoptosis, especially when combined to azacitidine, and triggered the activation of the DNA damage response pathway. JQ1 and AZD6738 (a specific ATR inhibitor) also synergized to induce apoptosis in leukemia cells. Our results indicate that the BRD4-dependent transcriptional program is a defective pathway in MDS and AML pathogenesis and its inhibition induces apoptosis of leukemia cells, which is enhanced in combination with HMA or an ATR inhibitor

Specific immunotherapy : Effects on granulocytes from Apis Mellifera allergic patients

Orientador: Ricardo de Lima ZollnerTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: As reações alérgicas à ferroada de inseto resultam de resposta exacerbada do sistema imune, com produção de elevados níveis de anticorpos IgE alérgeno-específicos e padrão de citocinas Th2, envolvidas na diferenciação de linfócitos B específicos para aquele antígeno em células produtoras de IgE e recrutamento de células efetoras da resposta alérgica. Neste contexto, granulocitos são células efetoras importantes na fase tardia da resposta alérgica e estão envolvidos na patogênese de diferentes doenças. Eosinófilos e neutrófilos, especificamente, modulam a resposta imune por meio de diferentes mecanismos, como a secreçao de citocinas, quimiocinas e mediadores lipídicos. A IgE desempenha papel central na patogênese das doenças alérgicas, interagindo com dois receptores de membranas: alta afinidade FcsRI e baixa afinidade FcsRII (CD23). A ligação da IgE ao seu receptor em mastocitos e basófilos promove a liberação de mediadores inflamatórios, dentre eles, a histamina. A histamina além de induzir os sintomas agudos da reação alérgica, sustenta a reação inflamatória até a fase crônica, sendo estes efeitos mediados através da ativação de diferentes receptores (H1, H2, H3 e H4). Os fatores liberadores de histamina (HRF), particularmente, HRF-dependentes de IgE, induzem a liberação de histamina na fase tardia da resposta alérgica, permitindo a perpetuação dos eventos inflamatórios crônicos. Muitos estudos demonstram a eficácia da imunoterapia específica na dessensibilização e no desenvolvimento de tolerância em indivíduos com quadros graves de hipersensibilidade à ferroada de insetos, sobretudo da classe Hymenoptera. Com base nestas informações, foram objetivos do presente trabalho avaliar os efeitos modulatórios da imunoterapia sobre a expressão gênica dos receptores de histamina (H1, H2 e H4), HRF- IgE dependente e de fatores apoptóticos (Bcl-2 e BID) por RT-PCR, além da expressão gênica, através da técnica de PCR em tempo real de fatores de transcrição envolvidos na diferenciação de granulocitos como PU.1, C/EBPa, C/EBPpe GATA-1, receptores de alta (FcsRla e FcsRly) e baixa afinidade de IgE (CD23), cuja detecção protéica foi realizada por imunofluorescência e citometria de fluxo, respectivamente. Além disso, foram avaliados os níveis séricos de IgE específica, secreçao de RANTES e IL-8 nos sobrenadantes das culturas celulares e quantificação de granulocitos apoptóticos através da técnica de TÚNEL. Os granulocitos foram isolados de pacientes submetidos à imunoterapia específica ao veneno de abelha, em diferentes períodos do tratamento (Pré, 1, 3, 6, 12, 18 e 24 meses), após injeção subcutânea, e submetidas à cultura por 72 horas, com estimulo de 1 ng/mL veneno de abelha. Indivíduos não alérgicos foram estudados como grupo controle. De maneira geral, a imunoterapia específica ao veneno de abelha foi capaz de modular os elementos analisados, reduzindo significativamente a expressão dos mesmos ao final de 24 meses de tratamento. Não verificamos, apenas, modulação no número de granulocitos apoptóticos ao longo da imunoterapia. Nossos resultados inéditos fornecem informações adicionais sobre os efeitos da imunoterapia sobre granulocitos, reforçando as propriedades supressoras e tolerogênicas desta forma de tratamentoAbstract: Allergic reactions to insect stings results from a exacerbated response of the immune system, resulting in the production of high levels of allergen-specific IgE antibodies and Th2 cytokine pattern, which are involved in the differentiation process of B lymphocytes, specific for that antigen, into IgE producing cells and the recruitment of effector cells of allergic response. Eosinophils and neutrophils, specifically, modulate the immune response through different mechanisms, such as the secretion of cytokines, chemokines and lipid mediators. IgE plays a central role on allergic diseases pathogenesis, interacting with two membrane receptors: high affinity FcsRI and low affinity FcsRII (CD23). Biding of IgE with receptors on mast cells and eosinophils promotes the release of inflammatory mediators, among them, histamine. Histamine, besides inducing acute symptoms of allergic reaction, supports inflammatory response until its chronic stage; these effects are mediated through the activation of distinct receptors (H1, H2, H3 and H4). Histamine releasing factors (HRF), particularly, IgE dependent HRF, induce histamine release during the late phase of allergic response, allowing the perpetuation of chronic inflammatory events. In this context, many studies have demonstrated the efficacy of specific immunotherapy on desensitization and tolerance development in subjects with severe hypersensivity to insect stings, especially Hymenoptera. Based on all these information, the aim of the present study were to evaluate the modulating effects of immunotherapy on gene expression of histamine receptors (H1, H2 and H4), IgE dependent HRF and apoptotic factors (Bcl-2 and BID), through RT-PCR; in addition to gene expression, through real time PCR, transcriptional factors involved at granulocytes differentiation as of PU.1, C/EBPa, C/EBPp and GATA-1, and protein expression of high (FcsRIa e FcsRly)and low affinity (CD23) IgE receptors, assessed by immunofluorescence and flow cytometry, respectively. Serum levels of specific IgE were also assessed, along with RANTES and IL-8 secretion in cell culture supernatant and quantification of apoptotic granulocytes through TUNEL technique. Granulocytes were isolated from patients undergoing bee venom specific immunotherapy in different periods of treatment (Pre, 1, 3, 6, 12, 18 and 24 months), after subcutaneous injection, and cultured for 72 hours, with bee venom 1ng/ml_. Non allergic subjects were studied as control group. Overall, bee venom specific immunotherapy was able to modulate the analyzed elements, significantly reducing their expression at the end of 24 months of treatment. Modulation on the number of apoptotic granulocytes were not observed during immunotherapy. Our results provide additional information about the effects of immunotherapy over granulocytes, reinforcing the suppressor and tolerogenic properties of this treatmentDoutoradoCiencias BasicasDoutor em Clínica Médic

SEMA3A partially reverses VEGF effects through binding to neuropilin-1

Cross-talk between hematopoietic stem cells (HSCs) and bone marrow stromal cells (BMSCs) is essential for HSCs regulation and leukemogenesis. Studying bone marrow of myelodysplasia patients, a pre-leukemic condition, we found mRNA overexpression of vascular endothelial growth factor A (VEGFA) in CD34+ HSCs and semaphorin 3A (SEMA3A) in BMSCs. To better understand the role of VEGFA and SEMA3A in leukemogenesis, we recruited 30 myelodysplastic syndrome (MDS) patients, 29 acute myeloid leukemia (6 secondary to MDS) patients and 12 controls. We found higher VEGFA expression in de novo AML patients (without prior MDS) group (p = 0.0073) and higher SEMA3A expression in all BMSCs patient's samples compared to control group. We then overexpressed VEGFA in an acute myelogenous leukemia cell line, KG1 cells, and in normal CD34+ cells. This overexpression increased KG1 (p = 0.045) and CD34+ cell (p = 0.042) viability and KG1 (p = 0.042) and CD34+ cell (p = 0.047) proliferation. Moreover, KG1 and CD34+ cells overexpressing VEGFA also had increased proliferation when co-cultured with human marrow stromal HS5 cells (p = 0.045 and p = 0.02, respectively). However, co-culture of these transformed cells with HS5 cells overexpressing SEMA3A reduced KG1 (p = 0.004) and CD34+ (p = 0.009) proliferation. Co-culture of KG1 transformed cells with HS27 cells overexpressing SEMA3A reduced KG1 proliferation as well (p = 0.01). To investigate whether the dominant SEMA3A effect over VEGFA could be due to competition for neuropilin1 receptor (NRP1), we performed immunoprecipitation with anti-NRP1 antibody of cell extracts of co-cultured KG1 and HS5 cells, induced or not by VEGFA and SEMA3A recombinant proteins. Results showed a preferential association of NRP1 with SEMA3A, suggesting that SEMA3A can partially reverse the effects caused by the VEGFA preventing its binding with the NRP1 receptor. Since both hematopoietic cells, leukemic and normal, showed similar behavior, we suppose that the attempt to reversion of VEGF effects by SEMA3A is a homeostatic phenomenon in the hematopoietic niche. Finally, we conclude that VEGFA overexpression confers AML cell advantages and SEMA3A may partially reverse this effect; thus, SEMA3A protein combined with VEGFA inhibitors could be beneficial for AML treatment