Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nat Immunol ; 23(4): 605-618, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35352063

RESUMO

Autonomic nerves control organ function through the sympathetic and parasympathetic branches, which have opposite effects. In the bone marrow, sympathetic (adrenergic) nerves promote hematopoiesis; however, how parasympathetic (cholinergic) signals modulate hematopoiesis is unclear. Here, we show that B lymphocytes are an important source of acetylcholine, a neurotransmitter of the parasympathetic nervous system, which reduced hematopoiesis. Single-cell RNA sequencing identified nine clusters of cells that expressed the cholinergic α7 nicotinic receptor (Chrna7) in the bone marrow stem cell niche, including endothelial and mesenchymal stromal cells (MSCs). Deletion of B cell-derived acetylcholine resulted in the differential expression of various genes, including Cxcl12 in leptin receptor+ (LepR+) stromal cells. Pharmacologic inhibition of acetylcholine signaling increased the systemic supply of inflammatory myeloid cells in mice and humans with cardiovascular disease.


Assuntos
Acetilcolina , Hematopoese , Animais , Linfócitos B , Colinérgicos , Hematopoese/genética , Camundongos , Nicho de Células-Tronco
2.
Cell ; 169(3): 510-522.e20, 2017 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-28431249

RESUMO

Organ-specific functions of tissue-resident macrophages in the steady-state heart are unknown. Here, we show that cardiac macrophages facilitate electrical conduction through the distal atrioventricular node, where conducting cells densely intersperse with elongated macrophages expressing connexin 43. When coupled to spontaneously beating cardiomyocytes via connexin-43-containing gap junctions, cardiac macrophages have a negative resting membrane potential and depolarize in synchrony with cardiomyocytes. Conversely, macrophages render the resting membrane potential of cardiomyocytes more positive and, according to computational modeling, accelerate their repolarization. Photostimulation of channelrhodopsin-2-expressing macrophages improves atrioventricular conduction, whereas conditional deletion of connexin 43 in macrophages and congenital lack of macrophages delay atrioventricular conduction. In the Cd11bDTR mouse, macrophage ablation induces progressive atrioventricular block. These observations implicate macrophages in normal and aberrant cardiac conduction.


Assuntos
Sistema de Condução Cardíaco , Macrófagos/fisiologia , Animais , Conexina 43/metabolismo , Feminino , Átrios do Coração/citologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Miócitos Cardíacos/fisiologia
4.
Immunity ; 51(5): 899-914.e7, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31732166

RESUMO

Myocardial infarction, stroke, and sepsis trigger systemic inflammation and organism-wide complications that are difficult to manage. Here, we examined the contribution of macrophages residing in vital organs to the systemic response after these injuries. We generated a comprehensive catalog of changes in macrophage number, origin, and gene expression in the heart, brain, liver, kidney, and lung of mice with myocardial infarction, stroke, or sepsis. Predominantly fueled by heightened local proliferation, tissue macrophage numbers increased systemically. Macrophages in the same organ responded similarly to different injuries by altering expression of tissue-specific gene sets. Preceding myocardial infarction improved survival of subsequent pneumonia due to enhanced bacterial clearance, which was caused by IFNÉ£ priming of alveolar macrophages. Conversely, EGF receptor signaling in macrophages exacerbated inflammatory lung injury. Our data suggest that local injury activates macrophages in remote organs and that targeting macrophages could improve resilience against systemic complications following myocardial infarction, stroke, and sepsis.


Assuntos
Suscetibilidade a Doenças , Macrófagos/imunologia , Macrófagos/metabolismo , Animais , Biomarcadores , Contagem de Células , Suscetibilidade a Doenças/imunologia , Receptores ErbB/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Isquemia/etiologia , Isquemia/metabolismo , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/metabolismo , Camundongos , Células Musculares/imunologia , Células Musculares/metabolismo , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/metabolismo , Especificidade de Órgãos/genética , Especificidade de Órgãos/imunologia , Pneumonia/etiologia , Pneumonia/metabolismo , Pneumonia/patologia
5.
Trends Immunol ; 42(5): 368-371, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33832864

RESUMO

Like other tissues, joints contain resident macrophages, and their diversity is only beginning to be characterized. Based on the highlights of recent studies, we discuss where current challenges lie and propose new avenues for future research in the osteoarticular field.


Assuntos
Macrófagos , Humanos
6.
Circ Res ; 124(9): 1372-1385, 2019 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-30782088

RESUMO

RATIONALE: After a stroke, patients frequently experience altered systemic immunity resulting in peripheral immunosuppression and higher susceptibility to infections, which is at least partly attributed to lymphopenia. The mechanisms that profoundly change the systemic leukocyte repertoire after stroke are incompletely understood. Emerging evidence indicates that stroke alters hematopoietic output of the bone marrow. OBJECTIVE: To explore the mechanisms that lead to defects of B lymphopoiesis after ischemic stroke. METHODS AND RESULTS: We here report that ischemic stroke triggers brain-bone marrow communication via hormonal long-range signals that regulate hematopoietic B lineage decisions. Bone marrow fluorescence-activated cell sorter analyses and serial intravital microscopy indicate that transient middle cerebral artery occlusion in mice arrests B-cell development beginning at the pro-B-cell stage. This phenotype was not rescued in Myd88-/- and TLR4-/- mice with disrupted TLR (Toll-like receptor) signaling or after blockage of peripheral sympathetic nerves. Mechanistically, we identified stroke-induced glucocorticoid release as the main instigator of B lymphopoiesis defects. B-cell lineage-specific deletion of the GR (glucocorticoid receptor) in CD19-Cre loxP Nr3c1 mice attenuated lymphocytopenia after transient middle cerebral artery. In 20 patients with acute stroke, increased cortisol levels inversely correlated with blood lymphocyte numbers. CONCLUSIONS: Our data demonstrate that the hypothalamic-pituitary-adrenal axis mediates B lymphopoiesis defects after ischemic stroke.


Assuntos
Corticosteroides/sangue , Linfócitos B/metabolismo , Células da Medula Óssea/metabolismo , Linfopoese , Receptores de Glucocorticoides/sangue , Acidente Vascular Cerebral/sangue , Idoso , Animais , Linfócitos B/citologia , Medula Óssea/metabolismo , Células da Medula Óssea/citologia , Feminino , Humanos , Sistema Hipotálamo-Hipofisário/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Pessoa de Meia-Idade , Sistema Hipófise-Suprarrenal/fisiopatologia , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/fisiopatologia
7.
Circ Res ; 123(4): 415-427, 2018 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-29980569

RESUMO

RATIONALE: Inflammatory stress induced by exposure to bacterial lipopolysaccharide causes hematopoietic stem cell expansion in the bone marrow niche, generating a cellular immune response. As an integral component of the hematopoietic stem cell niche, the bone marrow vasculature regulates the production and release of blood leukocytes, which protect the host against infection but also fuel inflammatory diseases. OBJECTIVE: We aimed to develop imaging tools to explore vascular changes in the bone marrow niche during acute inflammation. METHODS AND RESULTS: Using the TLR (Toll-like receptor) ligand lipopolysaccharide as a prototypical danger signal, we applied multiparametric, multimodality and multiscale imaging to characterize how the bone marrow vasculature adapts when hematopoiesis boosts leukocyte supply. In response to lipopolysaccharide, ex vivo flow cytometry and histology showed vascular changes to the bone marrow niche. Specifically, proliferating endothelial cells gave rise to new vasculature in the bone marrow during hypoxic conditions. We studied these vascular changes with complementary intravital microscopy and positron emission tomography/magnetic resonance imaging. Fluorescence and positron emission tomography integrin αVß3 imaging signal increased during lipopolysaccharide-induced vascular remodeling. Vascular leakiness, quantified by albumin-based in vivo microscopy and magnetic resonance imaging, rose when neutrophils departed and hematopoietic stem and progenitor cells proliferated more vigorously. CONCLUSIONS: Introducing a tool set to image bone marrow either with cellular resolution or noninvasively within the entire skeleton, this work sheds light on angiogenic responses that accompany emergency hematopoiesis. Understanding and monitoring bone marrow vasculature may provide a key to unlock therapeutic targets regulating systemic inflammation.


Assuntos
Medula Óssea/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Tomografia por Emissão de Pósitrons/métodos , Nicho de Células-Tronco , Estresse Fisiológico , Animais , Medula Óssea/patologia , Células Progenitoras Endoteliais/citologia , Feminino , Inflamação/diagnóstico por imagem , Integrina alfaVbeta3/metabolismo , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Imagem Multimodal/métodos
8.
Circ Res ; 119(7): 853-64, 2016 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-27444755

RESUMO

RATIONALE: Macrophages reside in the healthy myocardium, participate in ischemic heart disease, and modulate myocardial infarction (MI) healing. Their origin and roles in post-MI remodeling of nonischemic remote myocardium, however, remain unclear. OBJECTIVE: This study investigated the number, origin, phenotype, and function of remote cardiac macrophages residing in the nonischemic myocardium in mice with chronic heart failure after coronary ligation. METHODS AND RESULTS: Eight weeks post MI, fate mapping and flow cytometry revealed that a 2.9-fold increase in remote macrophages results from both increased local macrophage proliferation and monocyte recruitment. Heart failure produced by extensive MI, through activation of the sympathetic nervous system, expanded medullary and extramedullary hematopoiesis. Circulating Ly6C(high) monocytes rose from 64±5 to 108±9 per microliter of blood (P<0.05). Cardiac monocyte recruitment declined in Ccr2(-/-) mice, reducing macrophage numbers in the failing myocardium. Mechanical strain of primary murine and human macrophage cultures promoted cell cycle entry, suggesting that the increased wall tension in post-MI heart failure stimulates local macrophage proliferation. Strained cells activated the mitogen-activated protein kinase pathway, whereas specific inhibitors of this pathway reduced macrophage proliferation in strained cell cultures and in the failing myocardium (P<0.05). Steady-state cardiac macrophages, monocyte-derived macrophages, and locally sourced macrophages isolated from failing myocardium expressed different genes in a pattern distinct from the M1/M2 macrophage polarization paradigm. In vivo silencing of endothelial cell adhesion molecules curbed post-MI monocyte recruitment to the remote myocardium and preserved ejection fraction (27.4±2.4 versus 19.1±2%; P<0.05). CONCLUSIONS: Myocardial failure is influenced by an altered myeloid cell repertoire.


Assuntos
Fenômenos Biomecânicos/fisiologia , Proliferação de Células/fisiologia , Insuficiência Cardíaca/patologia , Macrófagos/fisiologia , Miocárdio/citologia , Animais , Células Cultivadas , Doença Crônica , Feminino , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
9.
Nature ; 487(7407): 325-9, 2012 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-22763456

RESUMO

During progression of atherosclerosis, myeloid cells destabilize lipid-rich plaques in the arterial wall and cause their rupture, thus triggering myocardial infarction and stroke. Survivors of acute coronary syndromes have a high risk of recurrent events for unknown reasons. Here we show that the systemic response to ischaemic injury aggravates chronic atherosclerosis. After myocardial infarction or stroke, Apoe-/- mice developed larger atherosclerotic lesions with a more advanced morphology. This disease acceleration persisted over many weeks and was associated with markedly increased monocyte recruitment. Seeking the source of surplus monocytes in plaques, we found that myocardial infarction liberated haematopoietic stem and progenitor cells from bone marrow niches via sympathetic nervous system signalling. The progenitors then seeded the spleen, yielding a sustained boost in monocyte production. These observations provide new mechanistic insight into atherogenesis and provide a novel therapeutic opportunity to mitigate disease progression.


Assuntos
Aterosclerose/etiologia , Aterosclerose/patologia , Infarto do Miocárdio/complicações , Infarto do Miocárdio/patologia , Animais , Apolipoproteínas E/genética , Células-Tronco Hematopoéticas/citologia , Inflamação/complicações , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/citologia , Baço/citologia , Células-Tronco/citologia
10.
Circ Res ; 116(3): 407-17, 2015 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-25362208

RESUMO

RATIONALE: The mechanisms leading to an expanded neutrophil and monocyte supply after stroke are incompletely understood. OBJECTIVE: To test the hypothesis that transient middle cerebral artery occlusion (tMCAO) in mice leads to activation of hematopoietic bone marrow stem cells. METHODS AND RESULTS: Serial in vivo bioluminescence reporter gene imaging in mice with tMCAO revealed that bone marrow cell cycling peaked 4 days after stroke (P<0.05 versus pre tMCAO). Flow cytometry and cell cycle analysis showed activation of the entire hematopoietic tree, including myeloid progenitors. The cycling fraction of the most upstream hematopoietic stem cells increased from 3.34%±0.19% to 7.32%±0.52% after tMCAO (P<0.05). In vivo microscopy corroborated proliferation of adoptively transferred hematopoietic progenitors in the bone marrow of mice with stroke. The hematopoietic system's myeloid bias was reflected by increased expression of myeloid transcription factors, including PU.1 (P<0.05), and by a decline in lymphocyte precursors. In mice after tMCAO, tyrosine hydroxylase levels in sympathetic fibers and bone marrow noradrenaline levels rose (P<0.05, respectively), associated with a decrease of hematopoietic niche factors that promote stem cell quiescence. In mice with genetic deficiency of the ß3 adrenergic receptor, hematopoietic stem cells did not enter the cell cycle in increased numbers after tMCAO (naive control, 3.23±0.22; tMCAO, 3.74±0.33, P=0.51). CONCLUSIONS: Ischemic stroke activates hematopoietic stem cells via increased sympathetic tone, leading to a myeloid bias of hematopoiesis and higher bone marrow output of inflammatory Ly6C(high) monocytes and neutrophils.


Assuntos
Infarto da Artéria Cerebral Média/patologia , Células-Tronco Mesenquimais/fisiologia , Mielopoese , Fibras Adrenérgicas/metabolismo , Fibras Adrenérgicas/fisiologia , Animais , Medula Óssea/metabolismo , Medula Óssea/patologia , Ciclo Celular , Infarto da Artéria Cerebral Média/metabolismo , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Norepinefrina/metabolismo , Receptores Adrenérgicos beta 3/genética , Receptores Adrenérgicos beta 3/metabolismo , Nicho de Células-Tronco , Fatores de Transcrição/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo
11.
Circ Res ; 117(10): 835-45, 2015 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-26394773

RESUMO

RATIONALE: Local plaque macrophage proliferation and monocyte production in hematopoietic organs promote progression of atherosclerosis. Therefore, noninvasive imaging of proliferation could serve as a biomarker and monitor therapeutic intervention. OBJECTIVE: To explore (18)F-FLT positron emission tomography-computed tomography imaging of cell proliferation in atherosclerosis. METHODS AND RESULTS: (18)F-FLT positron emission tomography-computed tomography was performed in mice, rabbits, and humans with atherosclerosis. In apolipoprotein E knock out mice, increased (18)F-FLT signal was observed in atherosclerotic lesions, spleen, and bone marrow (standardized uptake values wild-type versus apolipoprotein E knock out mice, 0.05 ± 0.01 versus 0.17 ± 0.01, P<0.05 in aorta; 0.13 ± 0.01 versus 0.28 ± 0.02, P<0.05 in bone marrow; 0.06 ± 0.01 versus 0.22 ± 0.01, P<0.05 in spleen), corroborated by ex vivo scintillation counting and autoradiography. Flow cytometry confirmed significantly higher proliferation of macrophages in aortic lesions and hematopoietic stem and progenitor cells in the spleen and bone marrow in these mice. In addition, (18)F-FLT plaque signal correlated with the duration of high cholesterol diet (r(2)=0.33, P<0.05). Aortic (18)F-FLT uptake was reduced when cell proliferation was suppressed with fluorouracil in apolipoprotein E knock out mice (P<0.05). In rabbits, inflamed atherosclerotic vasculature with the highest (18)F-fluorodeoxyglucose uptake enriched (18)F-FLT. In patients with atherosclerosis, (18)F-FLT signal significantly increased in the inflamed carotid artery and in the aorta. CONCLUSIONS: (18)F-FLT positron emission tomography imaging may serve as an imaging biomarker for cell proliferation in plaque and hematopoietic activity in individuals with atherosclerosis.


Assuntos
Doenças da Aorta/diagnóstico , Aterosclerose/diagnóstico , Doenças das Artérias Carótidas/diagnóstico , Proliferação de Células , Células-Tronco Hematopoéticas , Macrófagos , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X , Animais , Aorta Torácica/diagnóstico por imagem , Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/genética , Doenças da Aorta/metabolismo , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/diagnóstico por imagem , Aterosclerose/genética , Aterosclerose/metabolismo , Medula Óssea/diagnóstico por imagem , Doenças das Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/genética , Doenças das Artérias Carótidas/metabolismo , Colesterol na Dieta , Didesoxinucleosídeos , Dieta Hiperlipídica , Modelos Animais de Doenças , Feminino , Fluordesoxiglucose F18 , Células-Tronco Hematopoéticas/diagnóstico por imagem , Humanos , Macrófagos/diagnóstico por imagem , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Imagem Multimodal , Placa Aterosclerótica , Valor Preditivo dos Testes , Coelhos , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Baço/diagnóstico por imagem , Fatores de Tempo
12.
Circulation ; 132(20): 1880-90, 2015 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-26358260

RESUMO

BACKGROUND: Myocardial infarction (MI) is an ischemic wound that recruits millions of leukocytes. MI-associated blood leukocytosis correlates inversely with patient survival, yet the signals driving heightened leukocyte production after MI remain incompletely understood. METHODS AND RESULTS: With the use of parabiosis surgery, this study shows that soluble danger signals, among them interleukin-1ß, increase bone marrow hematopoietic stem cell proliferation after MI. Data obtained in bone marrow reconstitution experiments reveal that interleukin-1ß enhances hematopoietic stem cell proliferation by both direct actions on hematopoietic cells and through modulation of the bone marrow's hematopoietic microenvironment. An antibody that neutralizes interleukin-1ß suppresses these effects. Anti-interleukin-1ß treatment dampens the post-MI increase in hematopoietic stem cell proliferation. Consequently, decreased leukocyte numbers in the blood and infarct reduce inflammation and diminish post-MI heart failure in ApoE(-/-) mice with atherosclerosis. CONCLUSIONS: The presented insight into post-MI bone marrow activation identifies a mechanistic target for muting inflammation in the ischemically damaged heart.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Interleucina-1beta/antagonistas & inibidores , Leucócitos/patologia , Infarto do Miocárdio/patologia , Infarto do Miocárdio/prevenção & controle , Animais , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Interleucina-1beta/metabolismo , Leucócitos/metabolismo , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Infarto do Miocárdio/metabolismo , Proteínas Recombinantes/administração & dosagem
13.
Circ Res ; 115(2): 284-95, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-24786973

RESUMO

RATIONALE: Macrophages populate the steady-state myocardium. Previously, all macrophages were thought to arise from monocytes; however, it emerged that, in several organs, tissue-resident macrophages may self-maintain through local proliferation. OBJECTIVE: Our aim was to study the contribution of monocytes to cardiac-resident macrophages in steady state, after macrophage depletion in CD11b(DTR/+) mice and in myocardial infarction. METHODS AND RESULTS: Using in vivo fate mapping and flow cytometry, we estimated that during steady state the heart macrophage population turns over in ≈1 month. To explore the source of cardiac-resident macrophages, we joined the circulation of mice using parabiosis. After 6 weeks, we observed blood monocyte chimerism of 35.3±3.4%, whereas heart macrophages showed a much lower chimerism of 2.7±0.5% (P<0.01). Macrophages self-renewed locally through proliferation: 2.1±0.3% incorporated bromodeoxyuridine 2 hours after a single injection, and 13.7±1.4% heart macrophages stained positive for the cell cycle marker Ki-67. The cells likely participate in defense against infection, because we found them to ingest fluorescently labeled bacteria. In ischemic myocardium, we observed that tissue-resident macrophages died locally, whereas some also migrated to hematopoietic organs. If the steady state was perturbed by coronary ligation or diphtheria toxin-induced macrophage depletion in CD11b(DTR/+) mice, blood monocytes replenished heart macrophages. However, in the chronic phase after myocardial infarction, macrophages residing in the infarct were again independent from the blood monocyte pool, returning to the steady-state situation. CONCLUSIONS: In this study, we show differential contribution of monocytes to heart macrophages during steady state, after macrophage depletion or in the acute and chronic phase after myocardial infarction. We found that macrophages participate in the immunosurveillance of myocardial tissue. These data correspond with previous studies on tissue-resident macrophages and raise important questions on the fate and function of macrophages during the development of heart failure.


Assuntos
Macrófagos/fisiologia , Monócitos/fisiologia , Infarto do Miocárdio/imunologia , Isquemia Miocárdica/imunologia , Miocárdio/imunologia , Transferência Adotiva , Animais , Apoptose/efeitos dos fármacos , Transplante de Medula Óssea , Receptor 1 de Quimiocina CX3C , Divisão Celular , Toxina Diftérica/toxicidade , Feminino , Genes Reporter , Humanos , Ativação de Macrófagos , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/patologia , Isquemia Miocárdica/patologia , Miocárdio/patologia , Parabiose , Fagocitose , Quimera por Radiação , Receptores de Quimiocinas/genética , Receptores de Quimiocinas/fisiologia
14.
Eur Heart J ; 36(23): 1478-88, 2015 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-24950695

RESUMO

BACKGROUND: Myocarditis is characterized by inflammatory cell infiltration of the heart and subsequent deterioration of cardiac function. Monocytes are the most prominent population of accumulating leucocytes. We investigated whether in vivo administration of nanoparticle-encapsulated siRNA targeting chemokine (C-C motif) receptor 2 (CCR2)-a chemokine receptor crucial for leucocyte migration in humans and mice--reduces inflammation in autoimmune myocarditis. METHODS AND RESULTS: In myocardium of patients with myocarditis, CCL2 mRNA levels and CCR2(+) cells increased (P < 0.05), motivating us to pursue CCR2 silencing. Flow cytometric analysis showed that siRNA silencing of CCR2 (siCCR2) reduced the number of Ly6C(high) monocytes in hearts of mice with acute autoimmune myocarditis by 69% (P < 0.05), corroborated by histological assessment. The nanoparticle-delivered siRNA was not only active in monocytes but also in bone marrow haematopoietic progenitor cells. Treatment with siCCR2 reduced the migration of bone marrow granulocyte macrophage progenitors into the blood. Cellular magnetic resonance imaging (MRI) after injection of macrophage-avid magnetic nanoparticles detected myocarditis and therapeutic effects of RNAi non-invasively. Mice with acute myocarditis showed enhanced macrophage MRI contrast, which was prevented by siCCR2 (P < 0.05). Follow-up MRI volumetry revealed that siCCR2 treatment improved ejection fraction (P < 0.05 vs. control siRNA-treated mice). CONCLUSION: This study highlights the importance of CCR2 in the pathogenesis of myocarditis. In addition, we show that siCCR2 affects leucocyte progenitor trafficking. The data also point to a novel therapeutic strategy for the treatment of myocarditis.


Assuntos
Doenças Autoimunes/terapia , Quimiocina CCL2/genética , Miocardite/terapia , RNA Interferente Pequeno/farmacologia , Adulto , Animais , Movimento Celular , Quimiocina CCL2/metabolismo , Feminino , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/fisiologia , Humanos , Angiografia por Ressonância Magnética , Masculino , Camundongos , Monócitos/metabolismo , Nanopartículas , Interferência de RNA/fisiologia
15.
Circulation ; 127(20): 2038-46, 2013 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-23616627

RESUMO

BACKGROUND: Exaggerated and prolonged inflammation after myocardial infarction (MI) accelerates left ventricular remodeling. Inflammatory pathways may present a therapeutic target to prevent post-MI heart failure. However, the appropriate magnitude and timing of interventions are largely unknown, in part because noninvasive monitoring tools are lacking. Here, we used nanoparticle-facilitated silencing of CCR2, the chemokine receptor that governs inflammatory Ly-6C(high) monocyte subset traffic, to reduce infarct inflammation in apolipoprotein E-deficient (apoE(-/-)) mice after MI. We used dual-target positron emission tomography/magnetic resonance imaging of transglutaminase factor XIII (FXIII) and myeloperoxidase (MPO) activity to monitor how monocyte subset-targeted RNAi altered infarct inflammation and healing. METHODS AND RESULTS: Flow cytometry, gene expression analysis, and histology revealed reduced monocyte numbers and enhanced resolution of inflammation in infarcted hearts of apoE(-/-) mice that were treated with nanoparticle-encapsulated siRNA. To follow extracellular matrix cross-linking noninvasively, we developed a fluorine-18-labeled positron emission tomography agent ((18)F-FXIII). Recruitment of MPO-rich inflammatory leukocytes was imaged with a molecular magnetic resonance imaging sensor of MPO activity (MPO-Gd). Positron emission tomography/magnetic resonance imaging detected anti-inflammatory effects of intravenous nanoparticle-facilitated siRNA therapy (75% decrease of MPO-Gd signal; P<0.05), whereas (18)F-FXIII positron emission tomography reflected unimpeded matrix cross-linking in the infarct. Silencing of CCR2 during the first week after MI improved ejection fraction on day 21 after MI from 29% to 35% (P<0.05). CONCLUSION: CCR2-targeted RNAi reduced recruitment of Ly-6C(high) monocytes, attenuated infarct inflammation, and curbed post-MI left ventricular remodeling.


Assuntos
Aterosclerose/terapia , Marcação de Genes/métodos , Monócitos/metabolismo , Infarto do Miocárdio/genética , Infarto do Miocárdio/terapia , Interferência de RNA/fisiologia , Receptores CCR2/genética , Cicatrização/genética , Sequência de Aminoácidos , Animais , Aterosclerose/genética , Aterosclerose/patologia , Feminino , Predisposição Genética para Doença , Terapia Genética/métodos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dados de Sequência Molecular , Monócitos/patologia , Infarto do Miocárdio/patologia , Distribuição Aleatória , Receptores CCR2/antagonistas & inibidores , Receptores CCR2/metabolismo
16.
Ann Rheum Dis ; 72(10): 1717-24, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23313810

RESUMO

OBJECTIVES: Nicotinamide phosphoribosyltransferase (NAMPT)/pre-B-cell colony-enhancing factor/visfatin exerts multiple functions and has been implicated in the pathogenesis of rheumatoid arthritis. To gain insight into its role in arthritis and given that NAMPT is identified as a novel mediator of innate immunity, we addressed the function of monocyte-derived NAMPT in experimental arthritis by selective gene knockdown in inflammatory monocytes. METHODS: siRNA uptake and NAMPT expression were determined in Ly6Chigh and Ly6Clow monocyte subsets following intravenous injection of siRNA against NAMPT (siNAMPT) or non-targeting siRNA (siCT) formulated with the DMAPAP cationic liposome into mice. Mice with established collagen-induced arthritis (CIA) were treated weekly after disease onset with siNAMPT or siCT and clinical features were assessed. T-helper cell frequencies, cytokine production and percentage of IL-6-producing Ly6Chigh monocytes were analysed. Using a co-culture system consisting of purified CD14 monocytes and autologous CD4 T cells, NAMPT and cytokine production, and the percentage of IL-17-producing CD4 T cells, were determined following transfection of CD14 monocytes with siCT or siNAMPT. RESULTS: On intravenous injection, siRNA was preferentially engulfed by Ly6Chigh monocytes, and siRNA-mediated silencing of NAMPT expression in Ly6Chigh monocytes inhibited CIA progression. This effect was associated with reduced IL-6 production by Ly6Chigh monocytes, reduced proportion of Th17 cells and autoantibody titers, and decreased activation and infiltration of monocytes/macrophages and neutrophils in arthritic joints. Moreover, NAMPT-RNAi-silenced CD14 monocytes were found to reduce the percentage of IL-17-producing CD4 T cells in vitro. CONCLUSIONS: Our results show that the expression of NAMPT in Ly6Chigh monocytes promotes many downstream effects involved in inflammatory arthritis and demonstrate the utility of targeting disease-causing genes, such as NAMPT, in Ly6Chigh monocytes for therapeutic intervention in arthritis.


Assuntos
Artrite Experimental/imunologia , Citocinas/imunologia , Monócitos/imunologia , Nicotinamida Fosforribosiltransferase/imunologia , Animais , Artrite Experimental/prevenção & controle , Linfócitos T CD4-Positivos/imunologia , Técnicas de Cocultura , Citocinas/biossíntese , Citocinas/genética , Inativação Gênica , Humanos , Imunomodulação/imunologia , Interleucina-6/biossíntese , Receptores de Lipopolissacarídeos/análise , Camundongos , Camundongos Endogâmicos DBA , Nicotinamida Fosforribosiltransferase/genética , RNA Interferente Pequeno/genética , Células Th17/imunologia
17.
Blood ; 116(18): 3505-16, 2010 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-20682854

RESUMO

Cells from the mononuclear phagocyte system (MPS) act as systemic and local amplifiers that contribute to the progression of chronic inflammatory disorders. Transforming growth factor-ß-activated kinase 1 (TAK1) is a pivotal upstream mitogen-activated protein kinase-kinase-kinase acting as a mediator of cytokine expression. It remains critical to determine in vivo the implication of TAK1 in controlling the innate immune system. Here, we describe a vehicle tailored to selectively deliver siRNAs into MPS cells after intravenous administration, and validate in vivo the potential of the RNAi-mediated TAK1 knock down for immunomodulation. In a mouse model of immune-mediated inflammatory disorder, we show that anti-TAK1 siRNA lipoplexes efficiently alleviate inflammation, severely impair the downstream c-Jun N-terminal kinase and nuclear factor-κB signaling pathways, and decrease the expression of proinflammatory mediators. Importantly, the systemic TAK1 gene silencing decreases the frequency of Th1 and Th17 cells, both mediating autoimmunity in experimental arthritis, demonstrating the immunomodulatory potential of TAK1. Finally, in vitro inhibition of TAK1 in myeloid cells decreases interferon-γ-producing T cells, suggesting that a delivery system able to target MPS cells and to silence TAK1 impacts on pathogenic T effector cells in autoimmunity.


Assuntos
MAP Quinase Quinase Quinases/genética , Células Mieloides/imunologia , Interferência de RNA , Células Th1/imunologia , Células Th17/imunologia , Animais , Artrite/terapia , Linhagem Celular , Inflamação/terapia , Proteínas Quinases JNK Ativadas por Mitógeno/imunologia , Lipopolissacarídeos/imunologia , MAP Quinase Quinase Quinases/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Quinases Ativadas por Mitógeno/imunologia , Monócitos/imunologia , NF-kappa B/imunologia , Fator de Necrose Tumoral alfa/imunologia
18.
Nat Cardiovasc Res ; 1(1): 28-44, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35747128

RESUMO

Abnormal hematopoiesis advances cardiovascular disease by generating excess inflammatory leukocytes that attack the arteries and the heart. The bone marrow niche regulates hematopoietic stem cell proliferation and hence the systemic leukocyte pool, but whether cardiovascular disease affects the hematopoietic organ's microvasculature is unknown. Here we show that hypertension, atherosclerosis and myocardial infarction (MI) instigate endothelial dysfunction, leakage, vascular fibrosis and angiogenesis in the bone marrow, altogether leading to overproduction of inflammatory myeloid cells and systemic leukocytosis. Limiting angiogenesis with endothelial deletion of Vegfr2 (encoding vascular endothelial growth factor (VEGF) receptor 2) curbed emergency hematopoiesis after MI. We noted that bone marrow endothelial cells assumed inflammatory transcriptional phenotypes in all examined stages of cardiovascular disease. Endothelial deletion of Il6 or Vcan (encoding versican), genes shown to be highly expressed in mice with atherosclerosis or MI, reduced hematopoiesis and systemic myeloid cell numbers in these conditions. Our findings establish that cardiovascular disease remodels the vascular bone marrow niche, stimulating hematopoiesis and production of inflammatory leukocytes.

19.
Arthritis Rheum ; 62(3): 765-70, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20187132

RESUMO

OBJECTIVE: RNA interference (RNAi) is a powerful tool for sequence-specific gene silencing, and interest in its application in human diseases is growing. Given the success of recent strategies for administering gene therapy in rheumatoid arthritis using recombinant vectors such as adeno-associated virus type 5 (rAAV5) for optimized intraarticular gene transfer, we undertook the present study to determine the feasibility of using rAAV5-mediated RNAi-based therapy in arthritis. METHODS: We developed rAAV5 vectors expressing short hairpin small interfering RNA (shRNA) against tumor necrosis factor alpha (TNFalpha) under H1 promoter, and carrying the enhanced green fluorescent protein (eGFP) reporter gene under cytomegalovirus promoter (rAAV5-shTNF). TNFalpha gene silencing was validated in vitro with mouse macrophages. Mice with collagen-induced arthritis were injected in the ankle and knee joints, at disease onset, with either rAAV5-shTNF or control rAAV5-eGFP vectors (5 x 10(9) particles). Arthritis severity was assessed clinically and histologically, and immunologic response was examined. Local and systemic transgene expression was monitored using quantitative reverse transcriptase-polymerase chain reaction, immunohistochemical analysis, and enzyme-linked immunosorbent assay. RESULTS: After a single injection of rAAV5-shTNF into inflamed joints, local TNFalpha gene silencing provided rapid and long-term suppression of arthritis progression and reduced joint damage compared with that observed in control groups. Treatment with rAAV5-shTNF was associated with decreased proliferation and interferon-gamma production by antigen-stimulated T cells from draining lymph nodes, and the potency of this treatment was similar to that observed with other treatment strategies targeting TNFalpha at the protein level, either locally or systemically. CONCLUSION: Our data present the first proof-of-concept for the application of rAAV5-mediated RNAi-based gene therapy for local blockade of inflammation in experimental arthritis.


Assuntos
Artrite Experimental/terapia , Interferência de RNA/fisiologia , RNA Interferente Pequeno/administração & dosagem , Fator de Necrose Tumoral alfa/genética , Animais , Dependovirus , Regulação para Baixo , Ensaio de Imunoadsorção Enzimática , Inativação Gênica/fisiologia , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Imuno-Histoquímica , Injeções Intra-Articulares , Camundongos , Fator de Necrose Tumoral alfa/metabolismo
20.
Arthritis Rheum ; 62(9): 2651-61, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20496421

RESUMO

OBJECTIVE: Glucocorticoid-induced leucine zipper (GILZ) is a glucocorticoid-induced protein, the reported molecular interactions of which suggest that it functions to inhibit inflammation. However, the role of endogenous GILZ in the regulation of inflammation in vivo has not been established. This study was undertaken to examine the expression and function of GILZ in vivo in collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA), and in RA synoviocytes. METHODS: GILZ expression was detected in mouse and human synovium by immunohistochemistry and in cultured cells by real-time polymerase chain reaction and permeabilization flow cytometry. GILZ function was assessed in vivo by small interfering RNA (siRNA) silencing using cationic liposome-encapsulated GILZ or control nontargeting siRNA and was assessed in vitro using transient overexpression. RESULTS: GILZ was readily detectable in the synovium of mice with CIA and was up-regulated by therapeutic doses of glucocorticoids. Depleting GILZ expression in vivo increased the clinical and histologic severity of CIA and increased synovial expression of tumor necrosis factor and interleukin-1 (IL-1), without affecting the levels of circulating cytokines or anticollagen antibodies. GILZ was highly expressed in the synovium of patients with active RA and in cultured RA synovial fibroblasts, and GILZ overexpression in synovial fibroblasts inhibited IL-6 and IL-8 release. CONCLUSION: Our findings indicate that GILZ functions as an endogenous inhibitor of chronic inflammation via effects on cytokine expression and suggest that local modulation of GILZ expression could be a beneficial therapeutic strategy.


Assuntos
Artrite Experimental/metabolismo , Glucocorticoides/fisiologia , Mediadores da Inflamação/fisiologia , Fatores de Transcrição/metabolismo , Animais , Artrite Experimental/tratamento farmacológico , Artrite Experimental/patologia , Células Cultivadas , Citocinas/metabolismo , Dexametasona/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Inativação Gênica , Glucocorticoides/farmacologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos DBA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/farmacologia , Membrana Sinovial/efeitos dos fármacos , Membrana Sinovial/metabolismo , Membrana Sinovial/patologia , Fatores de Transcrição/genética , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA