RESUMO
Acute respiratory distress syndrome (ARDS) is a uniform progression of overwhelming inflammation in lung tissue with extensive infiltration of inflammatory cells. Neutrophil apoptosis is thought to be a significant process in the control of the resolution phase of inflammation. It has been proved that 5-Aza-2'-deoxycytidine (Aza) can inhibit cancer by activating death-associated protein kinase 1 (DAPK1) to promote apoptosis. However, the effect of DAPK1 on neutrophil apoptosis is unclear, and research on the role of Aza in inflammation is lacking. Here, we investigated whether Aza can regulate DAPK1 expression to influence the fate of neutrophils in ARDS. In vitro, we stimulated neutrophil-like HL-60 (dHL-60) cells with different concentrations of Aza for different durations and used RNA interference to up- or downregulate DAPK1 expression. We observed that culturing dHL-60 cells with Aza increased apoptosis by inhibiting NF-κB activation to modulate the expression of Bcl-2 family proteins, which was closely related to the levels of DAPK1. In vivo, ARDS was evoked by intratracheal instillation of lipopolysaccharide (LPS; 3 mg/kg). One hour after LPS administration, mice were treated with Aza (1 mg/kg, i.p.). To inhibit DAPK1 expression, mice were intraperitoneally injected with a DAPK1 inhibitor. Aza treatment accelerated inflammatory resolution in LPS-induced ARDS by suppressing pulmonary edema, alleviating lung injury and decreasing the infiltration of inflammatory cells in bronchoalveolar lavage fluid (BALF). Moreover, Aza reduced the production of proinflammatory cytokines. However, administration of the DAPK1 inhibitor attenuated the protective effects of Aza. Similarly, the proapoptotic function of Aza was prevented when DAPK1 was inhibited either in vivo or in vitro. In summary, Aza promotes neutrophil apoptosis by activating DAPK1 to accelerate inflammatory resolution in LPS-induced ARDS. This study provides the first evidence that Aza prevents LPS-induced neutrophil survival by modulating DAPK1 expression.
Assuntos
Apoptose/efeitos dos fármacos , Proteínas Quinases Associadas com Morte Celular , Inflamação/metabolismo , Neutrófilos/efeitos dos fármacos , Síndrome do Desconforto Respiratório/metabolismo , Animais , Citocinas/metabolismo , Proteínas Quinases Associadas com Morte Celular/metabolismo , Proteínas Quinases Associadas com Morte Celular/farmacologia , Decitabina/metabolismo , Decitabina/farmacologia , Modelos Animais de Doenças , Células HL-60 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
AIMS: Systemic inflammation occurs commonly during many human disease settings and increases vascular permeability, leading to organ failure, and lethal outcomes. Lipocalin 10 (Lcn10), a poorly characterized member of the lipocalin family, is remarkably altered in the cardiovascular system of human patients with inflammatory conditions. Nonetheless, whether Lcn10 regulates inflammation-induced endothelial permeability remains unknown. METHODS AND RESULTS: Systemic inflammation models were induced using mice by injection of endotoxin lipopolysaccharide (LPS) or caecal ligation and puncture (CLP) surgery. We observed that the expression of Lcn10 was dynamically altered only in endothelial cells (ECs), but not in either fibroblasts or cardiomyocytes isolated from mouse hearts following the LPS challenge or CLP surgery. Using in vitro gain- and loss-of-function approaches and an in vivo global knockout mouse model, we discovered that Lcn10 negatively regulated endothelial permeability upon inflammatory stimuli. Loss of Lcn10 augmented vascular leakage, leading to severe organ damage and higher mortality following LPS challenge, compared to wild-type controls. By contrast, overexpression of Lcn10 in ECs displayed opposite effects. A mechanistic analysis revealed that both endogenous and exogenous elevation of Lcn10 in ECs could activate slingshot homologue 1 (Ssh1)-Cofilin signalling cascade, a key axis known to control actin filament dynamics. Accordingly, a reduced formation of stress fibre and increased generation of cortical actin band were exhibited in Lcn10-ECs, when compared to controls upon endotoxin insults. Furthermore, we identified that Lcn10 interacted with LDL receptor-related protein 2 (LRP2) in ECs, which acted as an upstream factor of the Ssh1-Confilin signalling. Finally, injection of recombinant Lcn10 protein into endotoxic mice showed therapeutic effects against inflammation-induced vascular leakage. CONCLUSION: This study identifies Lcn10 as a novel regulator of EC function and illustrates a new link in the Lcn10-LRP2-Ssh1 axis to controlling endothelial barrier integrity. Our findings may provide novel strategies for the treatment of inflammation-related diseases.
Assuntos
Células Endoteliais , Lipopolissacarídeos , Humanos , Animais , Camundongos , Células Endoteliais/metabolismo , Lipopolissacarídeos/farmacologia , Lipopolissacarídeos/metabolismo , Transdução de Sinais , Inflamação/prevenção & controle , Inflamação/metabolismo , Camundongos Knockout , Receptores de LDL/metabolismoRESUMO
ABSTRACT: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been spread around the world and is currently affecting global public health. Clinical evidence indicates that the elevated number of peripheral neutrophils and higher ratio of neutrophils-to-lymphocytes are correlated with severe outcomes in COVID-19 patients, suggesting the possible immunopathological role of neutrophils during SARS-CoV-2 infection. As an abundant innate immune cell type, neutrophils are well known for their contributions to antimicrobial defense. However, their dysfunction is also associated with different inflammatory signatures during the pathogenesis of infection. Herein, in this mini-review, we summarize the recent progress on the potential role of neutrophils during COVID-19-associated inflammatory responses. In particular, we highlight the interactions between neutrophils and viruses as well as the relationship of neutrophils with cytokine storm and thrombosis in COVID-19 patients. Lastly, we discuss the importance of neutrophils as potential therapeutic targets for COVID-19.
Assuntos
COVID-19/imunologia , COVID-19/virologia , Neutrófilos/virologia , SARS-CoV-2 , Animais , Síndrome da Liberação de Citocina , Citocinas/imunologia , Humanos , Sistema Imunitário , Imunidade Inata , Inflamação , Molécula 1 de Adesão Intercelular/imunologia , Linfócitos/imunologia , Camundongos , Neutrófilos/metabolismo , Moléculas com Motivos Associados a Patógenos/imunologia , TromboseRESUMO
The defective eradication of invading pathogens is a major cause of death in sepsis. As professional phagocytic cells, macrophages actively engulf/kill microorganisms and play essential roles in innate immune response against pathogens. Growth differentiation factor 3 (GDF3) was previously implicated as an important modulator of inflammatory response upon acute sterile injury. In this study, administration of recombinant GDF3 protein (rGDF3) either before or after CLP surgery remarkably improved mouse survival, along with significant reductions in bacterial load, plasma pro-inflammatory cytokine levels, and organ damage. Notably, our in vitro experiments revealed that rGDF3 treatment substantially promoted macrophage phagocytosis and intracellular killing of bacteria in a dose-dependent manner. Mechanistically, RNA-seq analysis results showed that CD5L, known to be regulated by liver X receptor α (LXRα), was the most significantly upregulated gene in rGDF3-treated macrophages. Furthermore, we observed that rGDF3 could promote LXRα nuclear translocation and thereby, augmented phagocytosis activity in macrophages, which was similar as LXRα agonist GW3965 did. By contrast, pre-treating macrophages with LXRα antagonist GSK2033 abolished beneficial effects of rGDF3 in macrophages. In addition, rGDF3 treatment failed to enhance bacteria uptake and killing in LXRα-knockout (KO) macrophages. Taken together, these results uncover that GDF3 may represent a novel mediator for controlling bacterial infection.
Assuntos
Fator 3 de Diferenciação de Crescimento/farmacologia , Receptores X do Fígado/imunologia , Macrófagos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Proteínas Recombinantes/farmacologia , Sepse/prevenção & controle , Animais , Benzoatos/farmacologia , Benzilaminas/farmacologia , Células Cultivadas , Citocinas/imunologia , Citocinas/metabolismo , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/imunologia , Perfilação da Expressão Gênica/métodos , Fator 3 de Diferenciação de Crescimento/administração & dosagem , Fator 3 de Diferenciação de Crescimento/genética , Fígado/efeitos dos fármacos , Fígado/imunologia , Fígado/microbiologia , Receptores X do Fígado/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fagocitose/imunologia , Células RAW 264.7 , Proteínas Recombinantes/administração & dosagem , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sepse/imunologia , Sepse/microbiologiaRESUMO
The activation of NLRP3 inflammasome and NF-κB pathway, associating with oxidativestress, have been implicated in the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). NecroX-5 has been reported to exhibit theeffectsofanti-oxidation and anti-stress in various diseases. However, the role of NecroX-5 in ALI has not been explicitly demonstrated. The aim of this study was to explore the therapeutic effects and potential mechanism action of NecroX-5 on ALI. Here, we found that NecroX-5 pretreatment dramatically diminished the levels of IL-1ß, IL-18 and ROS in in RAW264.7 cells challenged with LPS and ATP. Furthermore, NecroX-5 suppressed the activation of NLRP3 inflammasome and NF-κB signalpathway. In addition, NecroX-5 also inhibited the thioredoxin-interacting protein (TXNIP) expression. In vivo, NecroX-5 reduced the LPS-induced lung histopathological injury, the number of TUNEL-positive cells, lung wet/dry (W/D) ratio, levels of total protein and inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) in mice. Additionally, LPS-induced upregulation of myeloperoxidase (MPO), ROS production and malondialdehyde (MDA) were inhibited by NecroX-5 administration. Thus, our results demonstrate that NecroX-5 protects against LPS-induced ALI by inhibiting TXNIP/NLRP3 and NF-κB.
Assuntos
Anti-Inflamatórios/uso terapêutico , Proteínas de Transporte/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Pulmão/metabolismo , Síndrome do Desconforto Respiratório/tratamento farmacológico , Sulfonas/uso terapêutico , Tiorredoxinas/metabolismo , Animais , Proteínas de Transporte/genética , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Lipopolissacarídeos/imunologia , Pulmão/patologia , Masculino , Camundongos , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Peroxidase/metabolismo , Células RAW 264.7 , Síndrome do Desconforto Respiratório/imunologia , Transdução de Sinais , Tiorredoxinas/genéticaRESUMO
The timely resolution of pulmonary inflammation coordinated by endogenous pro-resolving mediators helps limit lung tissue injury, but few endogenous pro-resolving mediators that are normally operative during acute inflammation. The protective effects of BML-111 (5(S)-6(R)-7-trihydroxyheptanoic acid methyl ester), a potent commercially available anti-inflammatory and pro-resolving mediator, on ventilation-induced lung injury (VILI) have been extensively studied, but its characteristics as a pro-resolving mediator have not. Here, anesthetized Sprague-Dawley rats were ventilated with a high tidal volume (20â¯mL/kg, HVT) for 1â¯h and randomly allocated to recover for 6, 12, 24, 48, 72, 96 or 168â¯h; BML-111 was administered at the peak of inflammation to evaluate its pro-resolving effect on VILI. The one-hour HVT induced a maximal pulmonary inflammatory response at 12â¯h that was largely resolved by 72â¯h. BML-111 largely resolved the maximal inflammatory response at 48â¯h; the resolution interval (Ri) was shortened by 26â¯h. Similarly, HVT elicited a time course of changes in histopathology and pulmonary edema, and BML-111 alleviates these changes. Mechanistically, neutrophil apoptosis was significantly increased in BML-111-treated rats subjected to HVT. The apoptosis inhibitor z-VAD-fmk partially reversed the proapoptotic actions of BML-111 on neutrophil and the resolving effects of BML-111 on VILI but had no effect alone. Importantly, the HVT treatment activated the nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1) and NF-κB signaling pathways in the lung tissue, and BML-111 further induced Nrf2 and HO-1 expression but inhibited the NF-κB pathway. Intriguingly, when we inhibited the Nrf2/HO-1 pathway with the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX), Nrf2 expression was further increased, but the inhibitory effects of BML-111 on the NF-κB pathway and on the subsequent inflammatory response, and the proapoptotic actions on neutrophil were reversed. The results suggest that BML-111 promotes the resolution of HVT-induced inflammation to mitigate VILI in rats, perhaps by modulating the Nrf2/HO-1 and NF-κB pathways and subsequently increasing neutrophil apoptosis.
Assuntos
Ácidos Heptanoicos/uso terapêutico , Inflamação/tratamento farmacológico , Pulmão/efeitos dos fármacos , Neutrófilos/patologia , Lesão Pulmonar Induzida por Ventilação Mecânica/tratamento farmacológico , Animais , Apoptose , Células Cultivadas , Modelos Animais de Doenças , Heme Oxigenase-1/metabolismo , Humanos , Pulmão/patologia , Masculino , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Protoporfirinas/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
Sepsis is a syndrome of life-threatening organ dysfunction caused by dysregulated host responses to infection. Macrophage polarization is a key process involved in the pathogenesis of sepsis. Recent evidence has demonstrated that autophagy participates in the regulation of macrophage polarization in different phases of inflammation. Here, we investigated whether trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, promotes the macrophage M2 phenotype by enhancing autophagy to counteract excessive inflammation in a cecal ligation and puncture (CLP) mouse model. TSA stimulation increased the proportions of M2 marker (CD206, CD124 and CD23)-labeled RAW264.7 macrophages. Furthermore, with increasing TSA doses, autophagy was enhanced gradually. Interestingly, the autophagy activator rapamycin (Rap), also known as an mTOR inhibitor, unexpectedly decreased the proportions of M2 marker-labeled macrophages. However, TSA treatment reversed the Rap-induced decreases in CD206-labeled macrophages. Next, we stimulated different groups of RAW264.7 cells with the autophagy inhibitors MHY1485 or 3-methyladenine (3-MA). Inhibition of autophagy at any stage in the process suppressed TSA-induced macrophage M2 polarization, but the effect was not associated with mTOR activity. In vivo, TSA administration promoted peritoneal macrophage M2 polarization, increased LC3 II expression, attenuated sepsis-induced organ (lung, liver and kidney) injury, and altered systemic inflammatory cytokine secretion. However, 3-MA abolished the protective effects of TSA in CLP mice and decreased the number of M2 peritoneal macrophages. Therefore, TSA promotes the macrophage M2 phenotype by enhancing autophagy to reduce systemic inflammation and ultimately improves the survival of mice with polymicrobial sepsis.