RESUMO
Cholesterol crystal embolism (CCE) implies immunothrombosis, tissue necrosis, and organ failure but no specific treatments are available. As CCE involves complement activation, we speculated that inhibitors of the C5a/C5aR axis would be sufficient to attenuate the consequences of CCE like that with systemic vasculitis. Cholesterol microcrystal injection into the kidney artery of wildtype mice initiated intra-kidney immunothrombosis within a few hours followed by a sudden drop of glomerular filtration rate and ischemic kidney necrosis after 24 hours. Genetic deficiency of either C3 or C5aR prevented immunothrombosis, glomerular filtration rate drop, and ischemic necrosis at 24 hours as did preemptive treatment with inhibitors of either C5a or C5aR. Delayed C5a blockade after crystal injection still resolved crystal clots and prevented all consequences. Thus, selective blockade of C5a or C5aR is sufficient to attenuate the consequences of established CCE and prospective inhibition in high-risk patients may be clinically feasible and safe.
RESUMO
ABSTRACT: Thrombotic microangiopathy (TMA) is characterized by immunothrombosis and life-threatening organ failure but the precise underlying mechanism driving its pathogenesis remains elusive. In this study, we hypothesized that gasdermin D (GSDMD), a pore-forming protein that serves as the final downstream effector of the pyroptosis/interleukin-1ß (IL-1ß) pathway, contributes to TMA and its consequences by amplifying neutrophil maturation and subsequent necrosis. Using a murine model of focal crystalline TMA, we found that Gsdmd deficiency ameliorated immunothrombosis, acute tissue injury, and failure. Gsdmd-/- mice exhibited a decrease in mature IL-1ß, as well as in neutrophil maturation, ß2-integrin activation, and recruitment to TMA lesions, in which they formed reduced neutrophil extracellular traps in both arteries and interstitial tissue. The GSDMD inhibitor disulfiram dose-dependently suppressed human neutrophil pyroptosis in response to cholesterol crystals. Experiments with GSDMD-deficient, human-induced, pluripotent stem cell-derived neutrophils confirmed the involvement of GSDMD in neutrophil ß2-integrin activation, maturation, and pyroptosis. Both prophylactic and therapeutic administration of disulfiram protected the mice from focal TMA, acute tissue injury, and failure. Our data identified GSDMD as a key mediator of focal crystalline TMA and its consequences, including ischemic tissue infarction and organ failure. GSDMD could potentially serve as a therapeutic target for the systemic forms of TMA.
Assuntos
Gasderminas , Neutrófilos , Proteínas de Ligação a Fosfato , Microangiopatias Trombóticas , Animais , Humanos , Camundongos , Antígenos CD18/metabolismo , Antígenos CD18/genética , Modelos Animais de Doenças , Armadilhas Extracelulares/metabolismo , Armadilhas Extracelulares/imunologia , Inflamação/patologia , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/patologia , Proteínas de Ligação a Fosfato/metabolismo , Proteínas de Ligação a Fosfato/genética , Piroptose , Microangiopatias Trombóticas/patologia , Microangiopatias Trombóticas/metabolismo , Microangiopatias Trombóticas/imunologia , Microangiopatias Trombóticas/etiologiaRESUMO
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease pathologically characterized by vascular necrosis with inflammation. During AAV development, activated neutrophils produce reactive oxygen species (ROS), leading to the aberrant formation of neutrophil extracellular traps (NETs) via NETosis and subsequent fibrinoid vascular necrosis. Nuclear factor-erythroid 2-related factor 2 (Nrf2) functions as an intracellular defense system to counteract oxidative stress by providing antioxidant properties. Herein, we explored the role of Nrf2 in the pathogenesis of AAV. The role and mechanism of Nrf2 in ANCA-stimulated neutrophils and subsequent endothelial injury were evaluated in vitro using Nrf2 genetic deletion and Nrf2 activator treatment. In corresponding in vivo studies, the role of Nrf2 in ANCA-transfer AAV and spontaneous AAV murine models was examined. Pharmacological activation of Nrf2 in vitro suppressed ANCA-induced NET formation via the inhibition of ROS. In contrast, NET formation was enhanced in Nrf2-deficient neutrophils. Furthermore, Nrf2 activation protected endothelial cells from ANC-induced NETs-mediated injury. In vivo, Nrf2 activation ameliorated glomerulonephritis in two AAV models by upregulating antioxidants and inhibiting ROS-mediated NETs. Furthermore, Nrf2 activation restrained the expansion of splenic immune cells, including T lymphocytes and limited the infiltration of Th17 cells into the kidney. In contrast, Nrf2 genetic deficiency exacerbated vasculitis in a spontaneous AAV model. Thus, the pathophysiological process in AAV may be downregulated by Nrf2 activation, potentially leading to a new therapeutic strategy by regulating NETosis.
Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Modelos Animais de Doenças , Armadilhas Extracelulares , Camundongos Knockout , Fator 2 Relacionado a NF-E2 , Neutrófilos , Peroxidase , Espécies Reativas de Oxigênio , Animais , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Armadilhas Extracelulares/imunologia , Armadilhas Extracelulares/metabolismo , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/imunologia , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/patologia , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/genética , Neutrófilos/imunologia , Neutrófilos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Peroxidase/metabolismo , Peroxidase/genética , Camundongos , Humanos , Estresse Oxidativo/imunologia , Camundongos Endogâmicos C57BL , Células Endoteliais/imunologia , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Glomerulonefrite/imunologia , Glomerulonefrite/patologia , Glomerulonefrite/genética , Glomerulonefrite/metabolismo , Glomerulonefrite/etiologia , Anticorpos Anticitoplasma de Neutrófilos/imunologia , Masculino , Rim/patologia , Rim/imunologia , Transdução de Sinais/imunologiaRESUMO
Complement inhibitors have been approved for several immune-mediated diseases and they are considered the next paradigm-shifting approach in the treatment of glomerulonephritis. The hierarchical organization of the complement system offers numerous molecular targets for therapeutic intervention. However, complement is an integral element of host defense and therefore complement inhibition can be associated with serious infectious complications. Here we give a closer look to the hierarchical complement system and how interfering with proximal versus distal or selective versus unselective molecular targets could determine efficacy and safety. Furthermore, we propose to consider the type of disease, immunological activity, and patient immunocompetence when stratifying patients, e.g., proximal/unselective targets for highly active and potentially fatal diseases while distal and selective targets may suit more chronic disease conditions with low or moderate disease activity requiring persistent complement blockade in patients with concomitant immunodeficiency. Certainly, there exists substantial promise for anti-complement therapeutics. However, balancing efficacy and safety will be key to establish powerful treatment effects with minimal adverse events, especially when complement blockade is continued over longer periods of time in chronic disorders.