Emerging Role of HMGB1 in the Pathogenesis of Schistosomiasis Liver Fibrosis

In chronic schistosomiasis, liver fibrosis is linked to portal hypertension, which is a condition associated with high mortality and morbidity. High mobility group box 1 (HMGB1) was originally described as a nuclear protein that functions as a structural co-factor in transcriptional regulation. However, HMGB1 can also be secreted into the extracellular milieu under appropriate signal stimulation. Extracellular HMGB1 acts as a multifunctional cytokine that contributes to infection, injury, inflammation, and immune responses by binding to specific cell-surface receptors. HMGB1 is involved in fibrotic diseases. From a clinical perspective, HMGB1 inhibition may represent a promising therapeutic approach for treating tissue fibrosis. In this study, we demonstrate elevated levels of HMGB1 in the sera in experimental mice or in patients with schistosomiasis. Using immunohistochemistry, we demonstrated that HMGB1 trafficking in the hepatocytes of mice suffering from acute schistosomiasis was inhibited by Glycyrrhizin, a well-known HMGB1 direct inhibitor, as well as by DIC, a novel and potential anti-HMGB1 compound. HMGB1 inhibition led to significant downregulation of IL-6, IL4, IL-5, IL-13, IL-17A, which are involved in the exacerbation of the immune response and liver fibrogenesis. Importantly, infected mice that were treated with DIC or GZR to inhibit HMGB1 pro-inflammatory activity showed a significant increase in survival and a reduction of over 50% in the area of liver fibrosis. Taken together, our findings indicate that HMGB1 is a key mediator of schistosomotic granuloma formation and liver fibrosis and may represent an outstanding target for the treatment of schistosomiasis

Papel das células dendríticas na modulação de mioblastos humanos

Made available in DSpace on 2015-11-04T13:36:12Z (GMT). No. of bitstreams: 2 leandro_alves_ioc_mest_2014.pdf: 112755376 bytes, checksum: b2de2958661b65ce907ca9c107efa88b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2015-04-14Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, BrasilExistem diversas doenças crônico degenerativas que afetam diretamente a capacidade contrátil e força muscular da musculatura esquelética e/ou cardíaca, sejam elas doenças de cunho inflamatório ou genético. Dentre elas, podemos destacar as distrofias musculares e a miopatias inflamatórias (MI), que além da fraqueza progressiva e perda da resistência dos músculos esqueléticos, exibem importante infiltração inflamatória. A infiltração inflamatória gera danos secundários ao tecido muscular, agravando a doença com a perda da força muscular. A histopatologia do músculo lesionado é caracterizada pela presença de células inflamatórias, tais como linfócitos T, macrófagos e células dendríticas (DC). Em diversas MI, as DC são encontradas circundando fibras musculares lesionadas ou não ou mesmo invadindo fibras necróticas e não necróticas. Esta propriedade ilustra a importância da interação entre as DC e as células musculares e que exercem potencial papel na progressão das doenças musculares degenerativas. Além disso, as DC são células chave na indução da resposta imune adaptativa assim como na integração das respostas inata e específica. Entretanto a interação existente entre as DC e os mioblastos, células responsáveis pela regeneração do tecido muscular, ainda não foi claramente determinada. O objetivo desse estudo é, portanto, determinar se há interação entre as DC e mioblastos, e também que alterações morfológicas e funcionais ocorre nos mioblastos após a interação Para responder o objetivo do trabalho realizamos co-cultivos in vitro de mioblastos e DC. Para tal utilizamos DC imaturas (iDC), cultivadas apenas com meio de cultura, e DC ativadas (actDC), cultivadas ativadas por LPS. Por microscopia de luz e eletrônica observamos que as iDC e actDC aderem aos mioblastos, principalmente às actDC. Nós observamos por microscopia óptica e eletrônica que as DC aderem firmemente aos mioblastos nos estágios de proliferação e diferenciação. No estágio de diferenciação, o co-cultivo com iDC e actDC observamos que as miofibras formadas foram mais finas e desorganizadas, principalmente com actDC. Além disso também observamos a diminuição na formação de miotubos e diminuição na de myoD e miogenina, com diferenças mais pronunciadas no co-cultivo com actDC. No estágio de proliferação o cocultivo com iDC e actDC aumentou a marcação de mioblastos BrdU+, principalmente no co-cultivo com actDC. A expressão de fibronectina, caderina e laminina no co-cultivo não foi alterado. Entretanto no estágio de diferenciação, observamos por imunofluorescência, que a marcação para aactinina, b-catenina e laminina não foi alterada. Fato interessante foi a indoleamina 2,3 dioxigenase (IDO), uma enzima que degrada o aminoácido triptofano e promove imunotolerância foi observada marcação nos mioblastos. Quando realizamos o co-cultivo, principalmente com actDC, houve aumento na expressão de IDO nas células musculares tanto no estágio de proliferação como no de diferenciação. Analisamos que houve diminuição na capacidade de migração dos mioblastos no cocultivo com iDC e actDC, e que a diferença é pronunciada com actDC. Por fim, houve aumento na liberação de citocinas e aumento na expressão de HLA-ABC e HLA-DR no co-cultivo com actDC. Nos dados sugerem que o co-cultivo de DC e mioblastos alteram os mioblastos e que essa mudança indica uma contribuição das DC na evolução das MIThere are several chronic degenerative diseases that are either inflammatory diseases or genetic diseases which directly affect the contractile capacity and muscle strength in skeletal muscle and / or the heart. It is possible to highlight the muscular dystrophies and inflammatory myopathies (IM), which have clinical symptoms such as progressive weakness and loss of skeletal muscle strength and the exhibition of significant inflammatory infiltration. Inflammatory infiltration generates secondary muscle tissue damage and exacerbates the progression of the disease and muscle weakness. The sick muscle histopathology is characterized by the presence of inflammatory cells such as T lymphocytes, macrophages and dendritic cells (DC). In several IM, DC are found surrounding or even invading necrotic and non-necrotic muscle fibers and this facet illustrates the importance of the interaction between the aforementioned cells and the potential in the progression of degenerative muscle diseases. Furthermore, DC cells are key for the induction of the adaptive immune response as well as the integration of innate and specific responses. However the interaction between DCs and myoblasts, the cells which are responsible for muscle tissue regeneration, has not been clearly determined. Therefore, the aim of this study is to determine whether there is interaction between DCs and myoblasts and also any morphological and functional changes that occur in the myoblasts as a result of the interaction. In order to answer our question, we designed an in vitro co-culture of myoblasts plus DCs. We used immature DCs (iDC) cultured with medium only and activated DCs (actDC) cultured with medium and LPS. We observed by optical and electron microscopy that DCs have a tight adhesion with myoblasts in the proliferation or differentiation phases. Upon the co-culturing of iDC and actDC in the differentiation phase, we observed that the myofibers formed were thinner and more disorganized, especially in the actDC co-culture. In addition, we also observed a decrease in myotube formation, and a decrease in myoD and myogenin expression in the co-cultures of iDC and actDC. Furthermore, the aforementioned decreases in formation and expression were more pronounced in the actDC co-culture. During myoblast proliferation the co-culturing of iDC and actDC increased the staining in myoblasts for BrdU, especially in myoblasts from the actDC co-culture. In addition, the expression of fibronectin, cadherin and laminin in the co-cultures did not change. However, during myoblast differentiation, we observed via immunoflourescence that the staining of α-actinin, β-catenin, and laminin was unaltered in the different co-cultures. Interestingly, indoleamine 2,3 dioxigenase (IDO), an enzyme that degrades the essential amino acid tryptophan and promotes immune tolerance, was found to be expressed in myoblasts. Moreover, this expression was increased during co-culture, in both the proliferation and differentiation phases. We also analyzed the myoblasts migration ability and observed that myoblast migration is decreased during co-culture. The decrease in migration was greater in the actDC co-culture than the iDC. Finally, there was a greater release of cytokines and increased expression of HLA-ABC and HLA-DR in the co-culture with actDC. In conclusion, our data suggests that the use of co-culture changes the myoblast profile and indicates that DCs can contribute to IM evolution

Evaluation of the effect of neutralizing anti-IFN-α antibodies produced in one SLE patient vaccinated with IFN-K on myotubes atrophy induced by type I interferon

International audienc

Activated dendritic cells modulate proliferation and differentiation of human myoblasts

International audienceIdiopathic Inflammatory Myopathies (IIMs) are a heterogeneous group of autoimmune diseases affecting skeletal muscle tissue homeostasis. They are characterized by muscle weakness and inflammatory infiltration with tissue damage. Amongst the cells in the muscle inflammatory infiltration, dendritic cells (DCs) are potent antigen-presenting and key components in autoimmunity exhibiting an increased activation in inflamed tissues. Since, the IIMs are characterized by the focal necrosis/regeneration and muscle atrophy, we hypothesized that DCs may play a role in these processes. Due to the absence of a reliable in vivo model for IIMs, we first performed co-culture experiments with immature DCs (iDC) or LPS-activated DCs (actDC) and proliferating myoblasts or differentiating myotubes. We demonstrated that both iDC or actDCs tightly interact with myoblasts and myotubes, increased myoblast proliferation and migration, but inhibited myotube differentiation. We also observed that actDCs increased HLA-ABC, HLA-DR, VLA-5, and VLA-6 expression and induced cytokine secretion on myoblasts. In an in vivo regeneration model, the co-injection of human myoblasts and DCs enhanced human myoblast migration, whereas the absolute number of human myofibres was unchanged. In conclusion, we suggest that in the early stages of myositis, DCs may play a crucial role in inducing muscle-damage through cell-cell contact and inflammatory cytokine secretion, leading to muscle regeneration impairment

Activated dendritic cells modulate proliferation and differentiation of human myoblasts

Submitted by Sandra Infurna ([email protected]) on 2018-08-30T11:27:17Z No. of bitstreams: 1 ingo_riederer_etal_IOC_2018.pdf: 4869218 bytes, checksum: 5c2cc86e5c212e47523493aa9299d736 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-08-30T11:40:38Z (GMT) No. of bitstreams: 1 ingo_riederer_etal_IOC_2018.pdf: 4869218 bytes, checksum: 5c2cc86e5c212e47523493aa9299d736 (MD5)Made available in DSpace on 2018-08-30T11:40:38Z (GMT). No. of bitstreams: 1 ingo_riederer_etal_IOC_2018.pdf: 4869218 bytes, checksum: 5c2cc86e5c212e47523493aa9299d736 (MD5) Previous issue date: 2018Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Rio de Janeiro, RJ, Brasil / Sorbonne Université. Institut fr Myologie. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Immunology-Immunopathology-Immunotherapy. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Immunology-Immunopathology-Immunotherapy. Paris, France.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação. Rio de Janeiro, RJ, Brasil.Sorbonne Université. Institut de Myologie. Paris, France.Sorbonne Université. Institut de Myologie. Paris, France.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Rio de Janeiro, RJ, Brasil.Idiopathic Inflammatory Myopathies (IIMs) are a heterogeneous group of autoimmune diseases affecting skeletal muscle tissue homeostasis. They are characterized by muscle weakness and inflammatory infiltration with tissue damage. Amongst the cells in the muscle inflammatory infiltration, dendritic cells (DCs) are potent antigen-presenting and key components in autoimmunity exhibiting an increased activation in inflamed tissues. Since, the IIMs are characterized by the focal necrosis/regeneration and muscle atrophy, we hypothesized that DCs may play a role in these processes. Due to the absence of a reliable in vivo model for IIMs, we first performed co-culture experiments with immature DCs (iDC) or LPS-activated DCs (actDC) and proliferating myoblasts or differentiating myotubes. We demonstrated that both iDC or actDCs tightly interact with myoblasts and myotubes, increased myoblast proliferation and migration, but inhibited myotube differentiation. We also observed that actDCs increased HLA-ABC, HLA-DR, VLA-5, and VLA-6 expression and induced cytokine secretion on myoblasts. In an in vivo regeneration model, the co-injection of human myoblasts and DCs enhanced human myoblast migration, whereas the absolute number of human myofibres was unchanged. In conclusion, we suggest that in the early stages of myositis, DCs may play a crucial role in inducing muscle-damage through cell-cell contact and inflammatory cytokine secretion, leading to muscle regeneration impairment

JAK inhibitor improves type I interferon induced damage: proof of concept in dermatomyositis

International audienceDermatomyositis is an acquired auto-immune disease characterized by skin lesions and muscle-specific pathological features such as perifascicular muscle fibre atrophy and vasculopathy. Dermatomyositis patients display an upregulation of type I interferon-inducible genes in muscle fibres, endothelial cells, skin and peripheral blood. However, the effect of type I interferon on muscle tissue has not yet been determined. Our aim was to study the pathogenicity of type I interferon in vitro and to evaluate the efficacy of the type I interferon pathway blockade for therapeutic purposes. The activation of type I interferon in differentiating myoblasts abolished myotube formation with reduced myogenin expression while in differentiated myotubes, we observed a reduction in surface area and an upregulation of atrophy-associated genes. In vitro endothelial cells exposure to type I interferon disrupted vascular network organization. All the pathogenic effects observed in vitro were abolished by ruxolitinib. Finally, four refractory dermatomyositis patients were treated with ruxolitinib and improvement ensued in skin lesions, muscle weakness and a reduced serum type I interferon levels and interferon-inducbile genes scores. We propose JAK inhibition as a mechanism-based treatment for dermatomyositis, a finding that is relevant for the design of future clinical trials targeting dermatomyositis