RESUMO
Pulmonary arterial hypertension (PAH) is a pulmonary vascular disease characterized by the progressive elevation of pulmonary arterial pressures. It is becoming increasingly apparent that inflammation contributes to the pathogenesis and progression of PAH. Several viruses are known to cause PAH, such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), human endogenous retrovirus K(HERV-K), and human immunodeficiency virus (HIV), in part due to acute and chronic inflammation. In this review, we discuss the connections between HERV-K, HIV, SARS-CoV-2, and PAH, to stimulate research regarding new therapeutic options and provide new targets for the treatment of the disease.
Assuntos
COVID-19 , Retrovirus Endógenos , Infecções por HIV , Hipertensão Arterial Pulmonar , Humanos , HIV , SARS-CoV-2 , Hipertensão Pulmonar Primária Familiar , InflamaçãoRESUMO
People living with HIV and who receive antiretroviral therapy have a significantly improved lifespan, compared to the early days without therapy. Unfortunately, persisting viral replication in the lungs sustains chronic inflammation, which may cause pulmonary vascular dysfunction and ultimate life-threatening Pulmonary Hypertension (PH). The mechanisms involved in the progression of HIV and PH remain unclear. The study of HIV-PH is limited due to the lack of tractable animal models that recapitulate infection and pathobiological aspects of PH. On one hand, mice with humanized immune systems (hu-mice) are highly relevant to HIV research but their suitability for HIV-PH research deserves investigation. On another hand, the Hypoxia-Sugen is a well-established model for experimental PH that combines hypoxia with the VEGF antagonist SU5416. To test the suitability of hu-mice, we combined HIV with either SU5416 or hypoxia. Using right heart catheterization, we found that combining HIV+SU5416 exacerbated PH. HIV infection increases human pro-inflammatory cytokines in the lungs, compared to uninfected mice. Histopathological examinations showed pulmonary vascular inflammation with arterial muscularization in HIV-PH. We also found an increase in endothelial-monocyte activating polypeptide II (EMAP II) when combining HIV+SU5416. Therefore, combinations of HIV with SU5416 or hypoxia recapitulate PH in hu-mice, creating well-suited models for infectious mechanistic pulmonary vascular research in small animals.
Assuntos
Infecções por HIV , Hipertensão Pulmonar , Hipertensão Arterial Pulmonar , Animais , Infecções por HIV/complicações , Humanos , Hipertensão Pulmonar/etiologia , Hipóxia/patologia , Sistema Imunitário/patologia , Inflamação/complicações , CamundongosRESUMO
Background and aims: TACE/ADAM17 is a membrane bound metalloprotease, which cleaves substrates involved in immune and inflammatory responses and plays a role in coronary artery disease (CAD). We measured TACE and its substrates in CAD patients to identify potential biomarkers within this molecular pathway with potential for acute coronary syndrome (ACS) and major adverse cardiovascular events (MACE) prediction. Methods: Blood samples were obtained from consecutive patients (n = 229) with coronary angiographic evidence of CAD admitted with ACS or electively. MACE were recorded after a median 3-year follow-up. Controls (n = 115) had a <10% CAD risk as per the HeartSCORE. TACE and TIMP3 protein and mRNA levels were measured by ELISA and RT-qPCR respectively. TACE substrates were measured using a multiplex proximity extension assay. Results: TACE mRNA and cell protein levels (p < 0.01) and TACE substrates LDLR (p = 0.006), TRANCE (p = 0.045), LAG-3 (p < 0.001) and ACE2 (p < 0.001) plasma levels were significantly higher in CAD patients versus controls. TACE inhibitor TIMP3 mRNA levels were significantly lower in CAD patients and tended to be lower in the ACS population (p < 0.05). TACE substrates TNFR1 (OR:3.237,CI:1.514-6.923,p = 0.002), HB-EGF (OR:0.484,CI:0.288-0.813,p = 0.006) and Ep-CAM (OR:0.555,CI:0.327-0.829,p = 0.004) accurately classified ACS patients with HB-EGF and Ep-CAM levels being lower compared to electively admitted patients. TNFR1 (OR:2.317,CI:1.377-3.898,p = 0.002) and TNFR2 (OR:1.902,CI:1.072-3.373,p = 0.028) were significantly higher on admission in those patients who developed MACE within 3 years. Conclusions: We demonstrate a possible role of TACE substrates LAG-3, HB-EGF and Ep-CAM in atherosclerotic plaque development and stability. We also underline the importance of measuring TNFR1 and TNFR2 earlier than previously appreciated for MACE prediction. We report an important role of TIMP3 in regulating TACE levels.
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The lung is the organ with the highest vascular density in the human body. It is therefore perceivable that the endothelium of the lung contributes significantly to the circulation of extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies. In addition to the endothelium, EVs may arise from alveolar macrophages, fibroblasts and epithelial cells. Because EVs harbor cargo molecules, such as miRNA, mRNA, and proteins, these intercellular communicators provide important insight into the health and disease condition of donor cells and may serve as useful biomarkers of lung disease processes. This comprehensive review focuses on what is currently known about the role of EVs as markers and mediators of lung pathologies including COPD, pulmonary hypertension, asthma, lung cancer and ALI/ARDS. We also explore the role EVs can potentially serve as therapeutics for these lung diseases when released from healthy progenitor cells, such as mesenchymal stem cells.
Assuntos
Comunicação Celular , Vesículas Extracelulares , Pneumopatias/fisiopatologia , Biomarcadores , Micropartículas Derivadas de Células , Exossomos , HumanosRESUMO
One current concept suggests that unchecked proliferation of clonally selected precursors of endothelial cells (ECs) contribute to severe pulmonary arterial hypertension (PAH). We hypothesized that clonally selected ECs expressing the progenitor marker CD117 promote severe occlusive pulmonary hypertension (PH). The remodelled pulmonary arteries of PAH patients harboured CD117+ ECs. Rat lung CD117+ ECs underwent four generations of clonal expansion to enrich hyperproliferative ECs. The resulting clonally enriched ECs behaved like ECs, as measured by in vitro and in vivo angiogenesis assays. The same primitive ECs showed a limited ability for mesenchymal lineage differentiation. Endothelial differentiation and function were enhanced by blocking TGF-ß signalling, promoting bone morphogenic protein (BMP) signalling. The transplantation of the EC clones caused arterio-occlusive PH in rats exposed to chronic hypoxia. These EC clones engrafted in the pulmonary arteries. Yet cessation of chronic hypoxia promoted lung cell apoptosis and resolution of vascular lesions. In conclusion, this is to the best of our knowledge, the first report that clonally enriched primitive ECs promote occlusive pulmonary arteriopathy and severe PH. These primitive EC clones further give rise to cells of endothelial and mesenchymal lineage as directed by BMP and TGF-ß signaling.
Assuntos
Arteriopatias Oclusivas/etiologia , Células Endoteliais/patologia , Hipertensão Pulmonar/etiologia , Hipóxia/patologia , Artéria Pulmonar/patologia , Animais , Apoptose , Arteriopatias Oclusivas/patologia , Proteínas Morfogenéticas Ósseas/fisiologia , Linhagem da Célula , Separação Celular , Células Cultivadas , Doença Crônica , Células Clonais , Células Endoteliais/química , Células Endoteliais/transplante , Citometria de Fluxo , Humanos , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/patologia , Hipóxia/complicações , Masculino , Mesoderma/citologia , Proteínas Proto-Oncogênicas c-kit/análise , Ratos , Ratos Sprague-Dawley , Receptor do Fator de Crescimento Transformador beta Tipo I/antagonistas & inibidores , Transdução de Sinais , Transcriptoma , Fator de Crescimento Transformador beta/fisiologiaRESUMO
In mice, the initial stage of nephrotoxic serum-induced nephritis (NTN) mimics antibody-mediated human glomerulonephritis. Local immune deposits generate tumor necrosis factor (TNF), which activates pro-inflammatory pathways in glomerular endothelial cells (GECs) and podocytes. Because TNF receptors mediate antibacterial defense, existing anti-TNF therapies can promote infection; however, we have previously demonstrated that different functional domains of TNF may have opposing effects. The TIP peptide mimics the lectin-like domain of TNF, and has been shown to blunt inflammation in acute lung injury without impairing TNF receptor-mediated antibacterial activity. We evaluated the impact of TIP peptide in NTN. Intraperitoneal administration of TIP peptide reduced inflammation, proteinuria, and blood urea nitrogen. The protective effect was blocked by the cyclooxygenase inhibitor indomethacin, indicating involvement of prostaglandins. Targeted glomerular delivery of TIP peptide improved pathology in moderate NTN and reduced mortality in severe NTN, indicating a local protective effect. We show that TIP peptide activates the epithelial sodium channel(ENaC), which is expressed by GEC, upon binding to the channel's α subunit. In vitro, TNF treatment of GEC activated pro-inflammatory pathways and decreased the generation of prostaglandin E2 and nitric oxide, which promote recovery from NTN. TIP peptide counteracted these effects. Despite the capacity of TIP peptide to activate ENaC, it did not increase mean arterial blood pressure in mice. In the later autologous phase of NTN, TIP peptide blunted the infiltration of Th17 cells. By countering the deleterious effects of TNF through direct actions in GEC, TIP peptide could provide a novel strategy to treat glomerular inflammation.
Assuntos
Canais Epiteliais de Sódio/metabolismo , Glomerulonefrite/tratamento farmacológico , Glomérulos Renais/efeitos dos fármacos , Peptídeos Cíclicos/administração & dosagem , Proteinúria/tratamento farmacológico , Animais , Nitrogênio da Ureia Sanguínea , Linhagem Celular , Dinoprostona/metabolismo , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Feminino , Glomerulonefrite/sangue , Glomerulonefrite/imunologia , Glomerulonefrite/patologia , Humanos , Injeções Intraperitoneais , Glomérulos Renais/citologia , Glomérulos Renais/patologia , Camundongos , Óxido Nítrico/metabolismo , Técnicas de Patch-Clamp , Cultura Primária de Células , Proteinúria/sangue , Proteinúria/imunologia , Proteinúria/patologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Células Th17/efeitos dos fármacos , Células Th17/imunologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Proapoptotic and monocyte chemotactic endothelial monocyte-activating protein 2 (EMAPII) is released extracellularly during cigarette smoke (CS) exposure. We have previously demonstrated that, when administered intratracheally during chronic CS exposures, neutralizing rat antibodies to EMAPII inhibited endothelial cell apoptosis and lung inflammation and reduced airspace enlargement in mice (DBA/2J strain). Here we report further preclinical evaluation of EMAPII targeting using rat anti-EMAPII antibodies via either nebulization or subcutaneous injection. Both treatment modalities efficiently ameliorated emphysema-like disease in two different strains of CS-exposed mice, DBA/2J and C57BL/6. Of relevance for clinical applicability, this treatment showed therapeutic and even curative potential when administered either during or following CS-induced emphysema development, respectively. In addition, a fully humanized neutralizing anti-EMAPII antibody administered subcutaneously to mice during CS exposure retained anti-apoptotic and anti-inflammatory effects similar to that of the parent rat antibody. Furthermore, humanized anti-EMAPII antibody treatment attenuated CS-induced autophagy and restored mammalian target of rapamycin signaling in the lungs of mice, despite ongoing CS exposure. Together, our results demonstrate that EMAPII secretion is involved in CS-induced lung inflammation and cell injury, including apoptosis and autophagy, and that a humanized EMAPII neutralizing antibody may have therapeutic potential in emphysema.
Assuntos
Anticorpos Neutralizantes/farmacologia , Lesão Pulmonar/tratamento farmacológico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Enfisema Pulmonar/tratamento farmacológico , Fumar/efeitos adversos , Animais , Autofagia/efeitos dos fármacos , Citocinas/efeitos dos fármacos , Lesão Pulmonar/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Proteínas de Neoplasias/efeitos dos fármacos , Pneumonia/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Enfisema Pulmonar/metabolismo , Proteínas de Ligação a RNA/efeitos dos fármacosRESUMO
It remains a mystery why HIV-associated end-organ pathologies persist in the era of combined antiretroviral therapy (ART). One possible mechanism is the continued production of HIV-encoded proteins in latently HIV-infected T cells and macrophages. The proapoptotic protein HIV-Nef persists in the blood of ART-treated patients within extracellular vesicles (EVs) and peripheral blood mononuclear cells. Here we demonstrate that HIV-Nef is present in cells and EVs isolated from BAL of patients on ART. We hypothesize that HIV-Nef persistence in the lung induces endothelial apoptosis leading to endothelial dysfunction and further pulmonary vascular pathologies. The presence of HIV-Nef in patients with HIV correlates with the surface expression of the proapoptotic endothelial-monocyte-activating polypeptide II (EMAPII), which was implicated in progression of pulmonary emphysema via mechanisms involving endothelial cell death. HIV-Nef protein induces EMAPII surface expression in human embryonic kidney 293T cells, T cells, and human and mouse lung endothelial cells. HIV-Nef packages itself into EVs and increases the amount of EVs secreted from Nef-expressing T cells and Nef-transfected human embryonic kidney 293T cells. EVs from BAL of HIV+ patients and Nef-transfected cells induce apoptosis in lung microvascular endothelial cells by upregulating EMAPII surface expression in a PAK2-dependent fashion. Transgenic expression of HIV-Nef in vascular endothelial-cadherin+ endothelial cells leads to lung rarefaction, characterized by reduced alveoli and overall increase in lung inspiratory capacity. These changes occur concomitantly with lung endothelial cell apoptosis. Together, these data suggest that HIV-Nef induces endothelial cell apoptosis via an EMAPII-dependent mechanism that is sufficient to cause pulmonary vascular pathologies even in the absence of inflammation.
Assuntos
Morte Celular/fisiologia , Células Endoteliais/virologia , Infecções por HIV/virologia , Produtos do Gene nef do Vírus da Imunodeficiência Humana/metabolismo , Animais , Apoptose/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , Citocinas/metabolismo , Células Endoteliais/metabolismo , Endotélio/metabolismo , Endotélio/virologia , Células HEK293 , Infecções por HIV/metabolismo , Humanos , Células Jurkat , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/virologia , Pulmão/metabolismo , Pulmão/virologia , Macrófagos/metabolismo , Macrófagos/virologia , Camundongos , Proteínas de Neoplasias/metabolismo , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/virologia , Proteínas de Ligação a RNA/metabolismo , Linfócitos T/metabolismo , Linfócitos T/virologiaRESUMO
Diabetic retinopathy (DR) is the leading cause of vision loss among working-age adults. The interplay between hyperglycemia and endothelial activation in inducing endoplasmic reticulum (ER) stress pathways and visual deficits in DR is not fully understood. To address this, we used a mouse model of chronic vascular activation using endothelial-specific tumor necrosis factor-α (TNF-α)-expressing (tie2-TNF) mice to induce diabetes with streptozotocin. At 4 weeks post streptozotocin, a significant 2-fold to 10-fold increase in retinal neurovascular inflammatory gene transcript response in tie2-TNF mice was further increased in diabetic tie2-TNF mice. A decrease in visual acuity and scotopic b-wave amplitude in tie2-TNF mice was further accentuated in diabetic tie2-TNF mice and these changes correlated with a multi-fold increase in retinal ER stress markers and a reduction in adherens junctions. Cultured retinal endothelial cells showed a significant decrease in trans-endothelial resistance as well as VE-cadherin expression under TNF-α and high glucose stress. These changes were partly rescued by tauroursodeoxycholic acid, a potent ER stress inhibitor. Taken together, constant endothelial activation induced by TNF-α further exacerbated by hyperglycemia results in activation of ER stress and chronic proinflammation in a feed forward loop ultimately resulting in endothelial junction protein alterations leading to visual deficits in the retina. Inhibition of ER stress and endothelial activation may prove to be a novel therapeutic target in DR.
Assuntos
Retinopatia Diabética/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Retículo Endoplasmático/metabolismo , Células Endoteliais/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Análise de Variância , Animais , Linhagem Celular , Diabetes Mellitus Experimental/induzido quimicamente , Modelos Animais de Doenças , Eletrorretinografia , Expressão Gênica , Humanos , Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptor TIE-2/genética , Retina/patologia , Estreptozocina , Acuidade Visual/fisiologiaRESUMO
Influenza A virus (IAV) remains a major worldwide health threat, especially to high-risk populations, including the young and elderly. There is an unmet clinical need for therapy that will protect the lungs from damage caused by lower respiratory infection. Here, we analyzed the role of EMAPII, a stress- and virus-induced pro-inflammatory and pro-apoptotic factor, in IAV-induced lung injury. First, we demonstrated that IAV induces EMAPII surface translocation, release, and apoptosis in cultured endothelial and epithelial cells. Next, we showed that IAV induces EMAPII surface translocation and release to bronchoalveolar lavage fluid (BALF) in mouse lungs, concomitant with increases in caspase 3 activity. Injection of monoclonal antibody (mAb) against EMAPII attenuated IAV-induced EMAPII levels, weight loss, reduction of blood oxygenation, lung edema, and increase of the pro-inflammatory cytokine TNF alpha. In accordance with the pro-apoptotic properties of EMAPII, levels of caspase 3 activity in BALF were also decreased by mAb treatment. Moreover, we detected EMAPII mAb-induced increase in lung levels of M2-like macrophage markers YM1 and CD206. All together, these data strongly suggest that EMAPII mAb ameliorates IAV-induced lung injury by limiting lung cell apoptosis and shifting the host inflammatory setting toward resolution of inflammation.
Assuntos
Anticorpos Monoclonais/administração & dosagem , Influenza Humana/tratamento farmacológico , Lesão Pulmonar/virologia , Proteínas Associadas aos Microtúbulos/metabolismo , Animais , Anticorpos Monoclonais/farmacologia , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/virologia , Caspase 3 , Linhagem Celular , Modelos Animais de Doenças , Humanos , Vírus da Influenza A/efeitos dos fármacos , Influenza Humana/metabolismo , Injeções , Lesão Pulmonar/tratamento farmacológico , Lesão Pulmonar/metabolismo , Camundongos , Transporte Proteico/efeitos dos fármacos , Resultado do Tratamento , Redução de Peso/efeitos dos fármacosRESUMO
In chronic obstructive pulmonary disease (COPD), acute exacerbations and emphysema development are characteristics for disease pathology. COPD is complicated by infectious exacerbations with acute worsening of respiratory symptoms with Moraxella catarrhalis as one of the most frequent pathogens. Although cigarette smoke (CS) is the primary risk factor, additional molecular mechanisms for emphysema development induced by bacterial infections are incompletely understood. We investigated the impact of M. catarrhalis on emphysema development in CS exposed mice and asked whether an additional infection would induce a solubilization of pro-apoptotic and pro-inflammatory endothelial monocyte-activating-protein-2 (EMAPII) to exert its activities in the pulmonary microvas-culature and other parts of the lungs not exposed directly to CS. Mice were exposed to smoke (6 or 9 months) and/or infected with M. catarrhalis. Lungs, bronchoalveolar lavage fluid (BALF), and plasma were analyzed. CS exposure reduced ciliated area, caused rarefaction of the lungs, and induced apoptosis. EMAPII was increased independent of prior smoke exposure in BALF of infected mice. Importantly, acute M. catarrhalis infection increased release of matrixmetalloproteases-9 and -12, which are involved in emphysema development and comprise a mechanism of EMAPII release. Our data suggest that acute M. catarrhalis infection represents an independent risk factor for emphysema development in smoke-exposed mice.
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Tumour necrosis factor alpha converting enzyme (TACE/ADAM17) is a member of the A disintegrin and metalloproteinase (ADAM) family of ectodomain shedding proteinases. It regulates many inflammatory processes by cleaving several transmembrane proteins, including tumour necrosis factor alpha (TNFα) and its receptors tumour necrosis factor alpha receptor 1 and tumour necrosis factor alpha receptor 2. There is evidence that TACE is involved in several inflammatory diseases, such as ischaemia, heart failure, arthritis, atherosclerosis, diabetes and cancer as well as neurological and immune diseases. This review summarizes the latest discoveries regarding the mechanism of action and regulation of TACE. It also focuses on the role of TACE in atherosclerosis and coronary artery disease (CAD), highlighting clinical studies that have investigated its expression and protein activity. The multitude of substrates cleaved by TACE make this enzyme an attractive target for therapy and a candidate for biomarker research and development in CAD.
Assuntos
Proteína ADAM17/metabolismo , Sistema Cardiovascular/enzimologia , Doença da Artéria Coronariana/enzimologia , Proteína ADAM17/química , Animais , Biomarcadores/metabolismo , Sistema Cardiovascular/fisiopatologia , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/fisiopatologia , Ativação Enzimática , Humanos , Prognóstico , Conformação Proteica , Transdução de Sinais , Relação Estrutura-Atividade , Especificidade por SubstratoAssuntos
Acetilcisteína/uso terapêutico , Antivirais/uso terapêutico , Endotélio Vascular/efeitos dos fármacos , F2-Isoprostanos/sangue , Sequestradores de Radicais Livres/uso terapêutico , Infecções por HIV/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Acetilcisteína/administração & dosagem , Idoso , Antivirais/administração & dosagem , Método Duplo-Cego , Esquema de Medicação , Endotélio Vascular/fisiologia , Sequestradores de Radicais Livres/administração & dosagem , Infecções por HIV/metabolismo , Humanos , Malondialdeído/sangue , Pessoa de Meia-Idade , Projetos Piloto , Estudos ProspectivosRESUMO
RATIONALE: Transmembrane tumor necrosis factor-α (tmTNF-α) is the prime ligand for TNF receptor 2, which has been shown to mediate angiogenic and blood vessel repair activities in mice. We have previously reported that the angiogenic potential of highly proliferative endothelial colony-forming cells (ECFCs) can be explained by the absence of senescent cells, which in mature endothelial cells occupy >30% of the population, and that exposure to a chronic inflammatory environment induced premature, telomere-independent senescence in ECFCs. OBJECTIVE: The goal of this study was to determine the role of tmTNF-α in the proliferation of ECFCs. METHODS AND RESULTS: Here, we show that tmTNF-α expression on ECFCs selects for higher proliferative potential and when removed from the cell surface promotes ECFC senescence. Moreover, the induction of premature senescence by chronic inflammatory conditions is blocked by inhibition of tmTNF-α cleavage. Indeed, the mechanism of chronic inflammation-induced premature senescence involves an abrogation of tmTNF/TNF receptor 2 signaling. This process is mediated by activation of the tmTNF cleavage metalloprotease TNF-α-converting enzyme via p38 MAP kinase activation and its concurrent export to the cell surface by means of increased iRhom2 expression. CONCLUSIONS: Thus, we conclude that tmTNF-α on the surface of highly proliferative ECFCs plays an important role in the regulation of their proliferative capacity.
Assuntos
Proliferação de Células , Senescência Celular , Células Progenitoras Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Idoso , Artérias/citologia , Células Cultivadas , Células Progenitoras Endoteliais/citologia , Endotélio Vascular/citologia , Humanos , Masculino , Metaloproteases/metabolismo , Pessoa de Meia-Idade , Proteólise , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Chronic lung diseases, such as pulmonary emphysema, are increasingly recognized complications of infection with the human immunodeficiency virus (HIV). Emphysema in HIV may occur independent of cigarette smoking, via mechanisms that are poorly understood but may involve lung endothelial cell apoptosis induced by the HIV envelope protein gp120. Recently, we have demonstrated that lung endothelial apoptosis is an important contributor to the development of experimental emphysema, via upregulation of the proinflammatory cytokine endothelial monocyte-activating polypeptide II (EMAP II) in the lung. Here we investigated the role of EMAP II and its receptor, CXCR3, in gp120-induced lung endothelial cell apoptosis. We could demonstrate that gp120 induces a rapid and robust increase in cell surface expression of EMAP II and its receptor CXCR3. This surface expression occurred via a mechanism involving gp120 signaling through its CXCR4 receptor and p38 MAPK activation. Both EMAP II and CXCR3 were essentially required for gp120-induced apoptosis and exposures to low gp120 concentrations enhanced the susceptibility of endothelial cells to undergo apoptosis when exposed to soluble cigarette smoke extract. These data indicate a novel mechanism by which HIV infection causes endothelial cell loss involved in lung emphysema formation, independent but potentially synergistic with smoking, and suggest therapeutic targets for emphysema prevention and/or treatment.
Assuntos
Apoptose , Citocinas/metabolismo , Células Endoteliais/fisiologia , Proteína gp120 do Envelope de HIV/fisiologia , Proteínas de Neoplasias/metabolismo , Proteínas de Ligação a RNA/metabolismo , Receptores CXCR3/metabolismo , Animais , Células CHO , Cricetinae , Cricetulus , Células Endoteliais/virologia , Infecções por HIV/complicações , Infecções por HIV/metabolismo , Infecções por HIV/patologia , Humanos , Pulmão/irrigação sanguínea , Microvasos/patologia , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/patologia , Enfisema Pulmonar/virologia , Receptores CXCR4/metabolismo , Transdução de Sinais , Fumar/efeitos adversos , Regulação para Cima , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
BACKGROUND: Untreated HIV may increase the risk of cardiovascular events. Our preliminary in vitro and in vivo research suggests that pentoxifylline (PTX) reduces vascular inflammation and improves endothelial function in HIV-infected persons not requiring antiretroviral therapy. METHODS: We performed a randomized, placebo-controlled trial of PTX 400 mg orally thrice daily for 8 weeks in 26 participants. The primary endpoint was change in flow-mediated dilation (FMD) of the brachial artery after 8 weeks. Nitroglycerin-mediated dilation (NTGMD) and circulating markers of inflammation, cellular immune activation, coagulation, and metabolism were also assessed. RESULTS: The difference in mean absolute change (SD) in FMD after 8 weeks between the placebo [-1.06 (1.45)%] and PTX [-1.93 (3.03)%] groups was not significant (Pâ=â0.44). No differences in NTGMD were observed. The only significant between-group difference in the changes in biomarkers from baseline to week 8 was in soluble tumor necrosis factor receptor-1 (sTNFRI) [-83.2 pg/mL in the placebo group vs. +65.9 pg/mL in the PTX group; Pâ=â0.03]. PTX was generally well-tolerated. CONCLUSIONS: PTX did not improve endothelial function and unexpectedly increased the inflammatory biomarker sTNFRI in HIV-infected participants not requiring antiretroviral therapy. Additional interventional research is needed to reduce inflammation and cardiovascular risk in this population. TRIAL REGISTRATION: ClinicalTrials.gov NCT00796822.
Assuntos
Endotélio Vascular/metabolismo , Infecções por HIV/complicações , Pentoxifilina/uso terapêutico , Vasculite/tratamento farmacológico , Vasculite/etiologia , Adulto , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Biomarcadores , Endotélio Vascular/efeitos dos fármacos , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Pentoxifilina/efeitos adversos , Pentoxifilina/farmacologia , Fatores Sexuais , Resultado do Tratamento , Adulto JovemRESUMO
Endothelial monocyte-activating polypeptide II (EMAP II) and interferon-inducible protein (IP)-10 are proinflammatory mediators, which in addition to their chemokine activities, selectively induce apoptosis in endothelial cells and are up-regulated in the lungs of cigarette smoke-exposed humans. Previously, we showed that EMAP II is an essential mediator of cigarette smoke-induced lung emphysema in mice linking endothelial cell apoptosis with inflammation. Here we addressed the role of the CXCR3 receptor in EMAP II-induced and IP-10-induced apoptosis in endothelial cells and its regulation by cigarette smoke. We found that both neutralizing antibodies and small inhibitory RNA to CXCR3 abrogated EMAP II-induced and IP-10-induced endothelial caspase-3 activation and DNA fragmentation. CXCR3 receptor surface expression in human lung microvascular endothelial cells and in lung tissue endothelium was up-regulated by exposure to cigarette smoke. In tissue culture conditions, EMAP II-induced and IP-10-induced apoptosis was enhanced by preincubation with cigarette smoke extract. Interestingly, serum starvation also induced CXCR3 up-regulation and enhanced EMAP II-induced endothelial apoptosis. Signal transduction via p38 mitogen-activated protein kinase activation was essential for CXCR3-induced cell death, but not for CXCR3 receptor up-regulation by cigarette smoke. In turn, protein nitration was required for CXCR3 receptor up-regulation by cigarette smoke and consequently for subsequent CXCR3-induced cell death. In conclusion, the concerted up-regulation of proinflammatory EMAP II, IP-10, and CXCR3 by cigarette smoke could sustain a cascade of cell death that may promote the alveolar tissue loss noted in human emphysema.
Assuntos
Apoptose , Células Endoteliais/metabolismo , Nicotiana/química , Extratos Vegetais/farmacologia , Receptores CXCR3/metabolismo , Fumaça , Regulação para Cima/efeitos dos fármacos , Animais , Células Cultivadas , Quimiocina CXCL10/farmacologia , Meios de Cultura Livres de Soro , Citocinas/farmacologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/fisiologia , Endotélio Vascular/citologia , Feminino , Humanos , Pulmão/citologia , Pulmão/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos C57BL , Microvasos/citologia , Proteínas de Neoplasias/farmacologia , Proteínas de Ligação a RNA/farmacologia , Receptores CXCR3/genética , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Untreated HIV infection is associated with endothelial dysfunction and subsequent cardiovascular disease, likely due to both direct effects of the virus and to indirect effects of systemic inflammation on the vasculature. We have recently shown that treatment with the antiinflammatory agent pentoxifylline (PTX) improved in vivo endothelial function and reduced circulating levels of the inflammatory markers vascular cell adhesion molecule-1 (VCAM-1) and interferon-gamma-induced protein (IP-10) in HIV-infected patients. To delineate the mechanisms underlying this therapeutic effect, we tested whether clinically relevant concentrations of PTX suppress VCAM-1 or IP-10 release in cultivated human lung microvascular endothelial cells. Indeed, we found that tumor necrosis factor (TNF)-α-induced VCAM-1 was reduced with concentrations of PTX in the low nanomolar range, comparable to plasma levels in PTX-treated groups. We also investigated the effect of HIV proteins and found that HIV transactivator of transcription (HIV-Tat) and HIV-envelope-derived recombinant gp120 enhanced TNF-α-induced VCAM-1 gene expression in lung microvascular and coronary macrovascular endothelial cells, respectively. In addition, PTX and a NF-κB-specific inhibitor reduced this enhanced VCAM-1 gene induction in microvascular and macrovascular endothelial cells. These results provide novel insights in how the antiinflammatory agent PTX can directly reduce HIV-associated proinflammatory endothelial activation, which may underlie vascular dysfunction and coronary vascular diseases.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Anti-Inflamatórios/farmacologia , Quimiocina CXCL10/imunologia , HIV-1/imunologia , Pentoxifilina/farmacologia , Fator de Necrose Tumoral alfa/imunologia , Molécula 1 de Adesão de Célula Vascular/imunologia , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Células Cultivadas , Quimiocina CXCL10/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , HIV-1/efeitos dos fármacos , Humanos , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Ativação Transcricional/efeitos dos fármacos , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Molécula 1 de Adesão de Célula Vascular/efeitos dos fármacos , Vasodilatadores/farmacologia , Replicação Viral/efeitos dos fármacosRESUMO
Chronic kidney disease pathogenesis involves both tubular and vascular injuries. Despite abundant investigations to identify the risk factors, the involvement of chronic endothelial dysfunction in developing nephropathies is insufficiently explored. Previously, soluble thrombomodulin (sTM), a cofactor in the activation of protein C, has been shown to protect endothelial function in models of acute kidney injury. In this study, the role for sTM in treating chronic kidney disease was explored by employing a mouse model of chronic vascular activation using endothelial-specific TNF-α-expressing (tie2-TNF) mice. Analysis of kidneys from these mice after 3 mo showed no apparent phenotype, whereas 6-mo-old mice demonstrated infiltration of CD45-positive leukocytes accompanied by upregulated gene expression of inflammatory chemokines, markers of kidney injury, and albuminuria. Intervention with murine sTM with biweekly subcutaneous injections during this window of disease development between months 3 and 6 prevented the development of kidney pathology. To better understand the mechanisms of these findings, we determined whether sTM could also prevent chronic endothelial cell activation in vitro. Indeed, treatment with sTM normalized increased chemokines, adhesion molecule expression, and reduced transmigration of monocytes in continuously activated TNF-expressing endothelial cells. Our results suggest that vascular inflammation associated with vulnerable endothelium can contribute to loss in renal function as suggested by the tie2-TNF mice, a unique model for studying the role of vascular activation and inflammation in chronic kidney disease. Furthermore, the ability to restore the endothelial balance by exogenous administration of sTM via downregulation of specific adhesion molecules and chemokines suggests a potential for therapeutic intervention in kidney disease associated with chronic inflammation.
Assuntos
Albuminúria/prevenção & controle , Inflamação/tratamento farmacológico , Falência Renal Crônica/metabolismo , Trombomodulina/uso terapêutico , Albuminúria/tratamento farmacológico , Albuminúria/genética , Albuminúria/metabolismo , Animais , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Regulação da Expressão Gênica/fisiologia , Inflamação/genética , Inflamação/metabolismo , Falência Renal Crônica/genética , Camundongos , Camundongos Transgênicos , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Receptor TIE-2 , Técnicas de Cultura de Tecidos , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: The use of abacavir and didanosine in HAART has been associated with an increased risk of myocardial infarction in HIV-infected patients. The aim of this study was to address the development of endothelial dysfunction in cultivated coronary artery endothelial cells (HCAECs) in response to abacavir, didanosine and tenofovir. We examined the impact of these drugs on the expression levels of the proinflammatory, oxidative stress and apoptosis regulating genes in HCAECs. METHODS: We tested gene and protein expression changes in HCAECs in response to abacavir, didanosine and tenofovir using quantitative real-time reverse transciptase PCR, FACS and ELISA. The assessed genes/proteins included the proinflammatory molecules VCAM-1, ICAM-1, MCP-1, RANTES and IL-6. In addition, we assessed the gene expression of the intracellular reactive oxygen producing NADPH oxidase subunit gp91(PHOX) and the apoptosis regulating molecules Bcl-2 and BAD. RESULTS: Exposure of HCAECs to abacavir, didanosine and tenofovir resulted in no statistically significant changes in any of the tested genes/proteins at any time point or at any concentration. CONCLUSIONS: We found no evidence that abacavir, didanosine or tenofovir had direct in vitro effects on coronary endothelial cell gene transcription and protein expression of the selected mediators. If abacavir or didanosine increase cardiovascular risk, it is likely not through the direct endothelial activation pathways tested in these experiments. However, further studies are needed to completely exclude the toxicity of abacavir or didanosine on endothelial cells.