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Complement factor H (CFH) negatively regulates consumption of complement component 3 (C3), thereby restricting complement activation. Genetic variants in CFH predispose to chronic inflammatory disease. Here, we examined the impact of CFH on atherosclerosis development. In a mouse model of atherosclerosis, CFH deficiency limited plaque necrosis in a C3-dependent manner. Deletion of CFH in monocyte-derived inflammatory macrophages propagated uncontrolled cell-autonomous C3 consumption without downstream C5 activation and heightened efferocytotic capacity. Among leukocytes, Cfh expression was restricted to monocytes and macrophages, increased during inflammation, and coincided with the accumulation of intracellular C3. Macrophage-derived CFH was sufficient to dampen resolution of inflammation, and hematopoietic deletion of CFH in atherosclerosis-prone mice promoted lesional efferocytosis and reduced plaque size. Furthermore, we identified monocyte-derived inflammatory macrophages expressing C3 and CFH in human atherosclerotic plaques. Our findings reveal a regulatory axis wherein CFH controls intracellular C3 levels of macrophages in a cell-autonomous manner, evidencing the importance of on-site complement regulation in the pathogenesis of inflammatory diseases.
Assuntos
Aterosclerose , Complemento C3 , Animais , Humanos , Camundongos , Aterosclerose/metabolismo , Complemento C3/genética , Complemento C3/metabolismo , Fator H do Complemento/genética , Fator H do Complemento/metabolismo , Inflamação , Macrófagos/metabolismoRESUMO
Mature B cells express immunoglobulin M (IgM)- and IgD-isotype B cell antigen receptors, but the importance of IgD for B cell function has been unclear. By using a cellular in vitro system and corresponding mouse models, we found that antigens with low valence activated IgM receptors but failed to trigger IgD signaling, whereas polyvalent antigens activated both receptor types. Investigations of the molecular mechanism showed that deletion of the IgD-specific hinge region rendered IgD responsive to monovalent antigen, whereas transferring the hinge to IgM resulted in responsiveness only to polyvalent antigen. Our data suggest that the increased IgD/IgM ratio on conventional B-2 cells is important for preferential immune responses to antigens in immune complexes, and that the increased IgM expression on B-1 cells is essential for B-1 cell homeostasis and function.
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Linfócitos B/imunologia , Imunoglobulina D/imunologia , Imunoglobulina M/imunologia , Animais , Complexo Antígeno-Anticorpo/imunologia , Antígenos/imunologia , Sítios de Ligação de Anticorpos/imunologia , Sinalização do Cálcio/genética , Diferenciação Celular , Linhagem Celular , Éxons Codificadores da Região de Dobradiça/genética , Homeostase/genética , Imunidade Humoral/genética , Imunoglobulina D/genética , Imunoglobulina M/genética , Camundongos , Camundongos Knockout , Engenharia de Proteínas , Deleção de Sequência/genéticaRESUMO
Atherosclerotic cardiovascular disease causes heart attacks and strokes, which are the leading causes of mortality worldwide1. The formation of atherosclerotic plaques is initiated when low-density lipoproteins bind to heparan-sulfate proteoglycans (HSPGs)2 and become trapped in the subendothelial space of large and medium size arteries, which leads to chronic inflammation and remodelling of the artery wall2. A proliferation-inducing ligand (APRIL) is a cytokine that binds to HSPGs3, but the physiology of this interaction is largely unknown. Here we show that genetic ablation or antibody-mediated depletion of APRIL aggravates atherosclerosis in mice. Mechanistically, we demonstrate that APRIL confers atheroprotection by binding to heparan sulfate chains of heparan-sulfate proteoglycan 2 (HSPG2), which limits the retention of low-density lipoproteins, accumulation of macrophages and formation of necrotic cores. Indeed, antibody-mediated depletion of APRIL in mice expressing heparan sulfate-deficient HSPG2 had no effect on the development of atherosclerosis. Treatment with a specific anti-APRIL antibody that promotes the binding of APRIL to HSPGs reduced experimental atherosclerosis. Furthermore, the serum levels of a form of human APRIL protein that binds to HSPGs, which we termed non-canonical APRIL (nc-APRIL), are associated independently of traditional risk factors with long-term cardiovascular mortality in patients with atherosclerosis. Our data reveal properties of APRIL that have broad pathophysiological implications for vascular homeostasis.
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Aterosclerose/metabolismo , Aterosclerose/prevenção & controle , Proteoglicanas de Heparan Sulfato/metabolismo , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismo , Animais , Antígeno de Maturação de Linfócitos B/metabolismo , Sítios de Ligação , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/mortalidade , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Proteína Transmembrana Ativadora e Interagente do CAML/metabolismo , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/sangue , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/deficiênciaRESUMO
Atherosclerosis is a lipid-driven chronic inflammatory disease that is modulated by innate and adaptive immunity including humoral immunity. Importantly, antibody alterations achieved by genetic means or active and passive immunization strategies in preclinical studies can improve or aggravate atherosclerosis. Additionally, a wide range of epidemiological data demonstrate not only an association between the total levels of different antibody isotypes but also antibody levels targeting specific antigens with atherosclerotic cardiovascular disease. Here, we discuss the potential role of atherogenic dyslipidemia on the antibody repertoire and review potential antibody-mediated effector mechanisms involved in atherosclerosis development highlighting the major atherosclerosis-associated antigens that trigger antibody responses.
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Sleep is integral to life1. Although insufficient or disrupted sleep increases the risk of multiple pathological conditions, including cardiovascular disease2, we know little about the cellular and molecular mechanisms by which sleep maintains cardiovascular health. Here we report that sleep regulates haematopoiesis and protects against atherosclerosis in mice. We show that mice subjected to sleep fragmentation produce more Ly-6Chigh monocytes, develop larger atherosclerotic lesions and produce less hypocretin-a stimulatory and wake-promoting neuropeptide-in the lateral hypothalamus. Hypocretin controls myelopoiesis by restricting the production of CSF1 by hypocretin-receptor-expressing pre-neutrophils in the bone marrow. Whereas hypocretin-null and haematopoietic hypocretin-receptor-null mice develop monocytosis and accelerated atherosclerosis, sleep-fragmented mice with either haematopoietic CSF1 deficiency or hypocretin supplementation have reduced numbers of circulating monocytes and smaller atherosclerotic lesions. Together, these results identify a neuro-immune axis that links sleep to haematopoiesis and atherosclerosis.
Assuntos
Aterosclerose/prevenção & controle , Hematopoese/fisiologia , Sono/fisiologia , Animais , Antígenos Ly/metabolismo , Aterosclerose/metabolismo , Aterosclerose/patologia , Células da Medula Óssea/metabolismo , Feminino , Hematopoese/efeitos dos fármacos , Região Hipotalâmica Lateral/metabolismo , Fator Estimulador de Colônias de Macrófagos/biossíntese , Fator Estimulador de Colônias de Macrófagos/deficiência , Fator Estimulador de Colônias de Macrófagos/metabolismo , Masculino , Camundongos , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Mielopoese/efeitos dos fármacos , Neutrófilos/metabolismo , Receptores de Orexina/deficiência , Receptores de Orexina/metabolismo , Orexinas/biossíntese , Orexinas/deficiência , Orexinas/metabolismo , Orexinas/farmacologia , Sono/efeitos dos fármacos , Privação do Sono/metabolismo , Privação do Sono/fisiopatologia , Privação do Sono/prevenção & controleRESUMO
Changes in Ca2+ influx during proinflammatory stimulation modulates cellular responses, including the subsequent activation of inflammation. Whereas the involvement of Ca2+ has been widely acknowledged, little is known about the role of Na+. Ranolazine, a piperazine derivative and established antianginal drug, is known to reduce intracellular Na+ as well as Ca2+ levels. In stable coronary artery disease patients (n = 51) we observed reduced levels of high-sensitive C-reactive protein (CRP) 3 mo after the start of ranolazine treatment (n = 25) as compared to the control group. Furthermore, we found that in 3,808 acute coronary syndrome patients of the MERLIN-TIMI 36 trial, individuals treated with ranolazine (1,934 patients) showed reduced CRP values compared to placebo-treated patients. The antiinflammatory effects of sodium modulation were further confirmed in an atherosclerotic mouse model. LDL-/- mice on a high-fat diet were treated with ranolazine, resulting in a reduced atherosclerotic plaque burden, increased plaque stability, and reduced activation of the immune system. Pharmacological Na+ inhibition by ranolazine led to reduced express of adhesion molecules and proinflammatory cytokines and reduced adhesion of leukocytes to activated endothelium both in vitro and in vivo. We demonstrate that functional Na+ shuttling is required for a full cellular response to inflammation and that inhibition of Na+ influx results in an attenuated inflammatory reaction. In conclusion, we demonstrate that inhibition of Na+-Ca2+ exchange during inflammation reduces the inflammatory response in human endothelial cells in vitro, in a mouse atherosclerotic disease model, and in human patients.
Assuntos
Síndrome Coronariana Aguda , Proteína C-Reativa , Fármacos Cardiovasculares , Doença da Artéria Coronariana , Ranolazina , Bloqueadores dos Canais de Sódio , Sódio , Síndrome Coronariana Aguda/tratamento farmacológico , Animais , Proteína C-Reativa/análise , Proteína C-Reativa/metabolismo , Fármacos Cardiovasculares/farmacologia , Fármacos Cardiovasculares/uso terapêutico , Doença da Artéria Coronariana/tratamento farmacológico , Células Endoteliais/metabolismo , Humanos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Camundongos , Ranolazina/farmacologia , Ranolazina/uso terapêutico , Sódio/metabolismo , Bloqueadores dos Canais de Sódio/farmacologia , Bloqueadores dos Canais de Sódio/uso terapêuticoRESUMO
In this Letter, affiliation number 1 was originally missing from the HTML; the affiliations were missing for author Ming-Yow Hung in the HTML; and the Fig. 4 legend erroneously referred to panels a-h, instead of a-g. These errors have been corrected online.
RESUMO
Oxidized phospholipids (OxPL) are ubiquitous, are formed in many inflammatory tissues, including atherosclerotic lesions, and frequently mediate proinflammatory changes 1 . Because OxPL are mostly the products of non-enzymatic lipid peroxidation, mechanisms to specifically neutralize them are unavailable and their roles in vivo are largely unknown. We previously cloned the IgM natural antibody E06, which binds to the phosphocholine headgroup of OxPL, and blocks the uptake of oxidized low-density lipoprotein (OxLDL) by macrophages and inhibits the proinflammatory properties of OxPL2-4. Here, to determine the role of OxPL in vivo in the context of atherogenesis, we generated transgenic mice in the Ldlr-/- background that expressed a single-chain variable fragment of E06 (E06-scFv) using the Apoe promoter. E06-scFv was secreted into the plasma from the liver and macrophages, and achieved sufficient plasma levels to inhibit in vivo macrophage uptake of OxLDL and to prevent OxPL-induced inflammatory signalling. Compared to Ldlr-/- mice, Ldlr -/- E06-scFv mice had 57-28% less atherosclerosis after 4, 7 and even 12 months of 1% high-cholesterol diet. Echocardiographic and histologic evaluation of the aortic valves demonstrated that E06-scFv ameliorated the development of aortic valve gradients and decreased aortic valve calcification. Both cholesterol accumulation and in vivo uptake of OxLDL were decreased in peritoneal macrophages, and both peritoneal and aortic macrophages had a decreased inflammatory phenotype. Serum amyloid A was decreased by 32%, indicating decreased systemic inflammation, and hepatic steatosis and inflammation were also decreased. Finally, the E06-scFv prolonged life as measured over 15 months. Because the E06-scFv lacks the functional effects of an intact antibody other than the ability to bind OxPL and inhibit OxLDL uptake in macrophages, these data support a major proatherogenic role of OxLDL and demonstrate that OxPL are proinflammatory and proatherogenic, which E06 counteracts in vivo. These studies suggest that therapies inactivating OxPL may be beneficial for reducing generalized inflammation, including the progression of atherosclerosis, aortic stenosis and hepatic steatosis.
Assuntos
Aterosclerose/tratamento farmacológico , Aterosclerose/metabolismo , Hipercolesterolemia/metabolismo , Inflamação/metabolismo , Fosfolipídeos/antagonistas & inibidores , Fosfolipídeos/metabolismo , Animais , Estenose da Valva Aórtica/tratamento farmacológico , Estenose da Valva Aórtica/metabolismo , Estenose da Valva Aórtica/patologia , Apoptose , Aterosclerose/induzido quimicamente , Aterosclerose/genética , Colesterol/administração & dosagem , Colesterol/farmacologia , Progressão da Doença , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Feminino , Hipercolesterolemia/patologia , Imunoglobulina M/genética , Imunoglobulina M/imunologia , Imunoglobulina M/uso terapêutico , Inflamação/tratamento farmacológico , Inflamação/patologia , Lipoproteínas LDL/metabolismo , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oxirredução , Fosfolipídeos/química , Fosfolipídeos/imunologia , Fosforilcolina/imunologia , Receptores de LDL/deficiência , Receptores de LDL/genética , Anticorpos de Cadeia Única/genética , Anticorpos de Cadeia Única/imunologia , Anticorpos de Cadeia Única/uso terapêuticoRESUMO
Immunoglobulin M (IgM) autoantibodies to oxidation-specific epitopes (OSEs) can be present at birth and protect against atherosclerosis in experimental models. This study sought to determine whether high titers of IgM titers to OSE (IgM OSE) are associated with a lower risk of acute myocardial infarction (AMI) in humans. IgM to malondialdehyde (MDA)-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and a peptide mimotope of MDA were measured within 24 h of first AMI in 4,559 patients and 4,617 age- and sex-matched controls in the Pakistan Risk of Myocardial Infarction Study. Multivariate-adjusted logistic regression was used to estimate odds ratio (OR) and 95% confidence interval for AMI. All four IgM OSEs were lower in AMI versus controls (P < 0.001 for all). Males, smokers and individuals with hypertension and diabetes had lower levels of all four IgM OSE than unaffected individuals (P < 0.001 for all). Compared to the lowest quintile, the highest quintiles of IgM MDA-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and MDA mimotope P1 had a lower OR of AMI: OR (95% confidence interval) of 0.67 (0.58-0.77), 0.64 (0.56-0.73), 0.70 (0.61-0.80) and 0.72 (0.62-0.82) (P < 0.001 for all), respectively. Upon the addition of IgM OSE to conventional risk factors, the C-statistic improved by 0.0062 (0.0028-0.0095) and net reclassification by 15.5% (11.4-19.6). These findings demonstrate that IgM OSE provides clinically meaningful information and supports the hypothesis that higher levels of IgM OSE may be protective against AMI.
Assuntos
Complexo Antígeno-Anticorpo , Infarto do Miocárdio , Masculino , Recém-Nascido , Humanos , Epitopos , Fosforilcolina , Autoanticorpos , Imunoglobulina M , Apolipoproteínas , Lipoproteínas LDLRESUMO
OBJECTIVE: To evaluate the impact of a parenteral lipid emulsion containing fish oil compared with a soybean oil based-lipid emulsion on the cognitive outcome and behavior of preschool children with extremely low birth weight. STUDY DESIGN: This was a retrospective secondary outcome analysis of a randomized controlled trial performed between June 2012 and June 2015. Infants with extremely low birth weight received either a mixed (soybean oil, medium chain triglycerides, olive oil, fish oil) or a soybean oil-based lipid emulsion for parenteral nutrition. Data from the Kaufman Assessment Battery for Children II, the Child Behavior Checklist 1.5-5, and anthropometry were collected from medical charts at 5.6 years of age. RESULTS: At discharge, 206 of the 230 study participants were eligible. At 5 years 6 months of age, data of 153 of 206 infants (74%) were available for analysis. There were no significant differences in Kaufman Assessment Battery for Children II scores for Sequential/Gsm, Simultaneous/Gv, Learning/Glr, and Mental Processing Index (mixed lipid: median, 97.5 [IQR, 23.5]; soybean oil: median, 96 [IQR, 19.5]; P = .43) or Child Behavior Checklist 1.5-5 scores for internalizing problems, externalizing problems, or total problems (mixed lipid: median, 37 [IQR, 12.3]; soybean oil: median, 37 [IQR, 13.5]; P = .54). CONCLUSIONS: A RandomForest machine learning regression analysis did not show an effect of type of lipid emulsion on cognitive and behavioral outcome. Parenteral nutrition using a mixed lipid emulsion containing fish oil did not affect neurodevelopment and had no impact on child behavior of infants with extremely low birth weights at preschool age. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01585935.
Assuntos
Óleos de Peixe , Óleo de Soja , Humanos , Peso ao Nascer , Emulsões , Estudos Retrospectivos , Triglicerídeos , Cognição , Emulsões Gordurosas IntravenosasRESUMO
Thrombosis and its associated complications are a major cause of morbidity and mortality worldwide. Microvesicles (MVs), a class of extracellular vesicles, are increasingly recognized as mediators of coagulation and biomarkers of thrombotic risk. Thus, identifying factors targeting MV-driven coagulation may help in the development of novel antithrombotic treatments. We have previously identified a subset of circulating MVs that is characterized by the presence of oxidation-specific epitopes and bound by natural immunoglobulin M (IgM) antibodies targeting these structures. This study investigated whether natural IgM antibodies, which are known to have important anti-inflammatory housekeeping functions, inhibit the procoagulatory properties of MVs. We found that the extent of plasma coagulation is inversely associated with the levels of both free and MV-bound endogenous IgM. Moreover, the oxidation epitope-specific natural IgM antibody LR04, which recognizes malondialdehyde adducts, reduced MV-dependent plasmatic coagulation and whole blood clotting without affecting thrombocyte aggregation. Intravenous injection of LR04 protected mice from MV-induced pulmonary thrombosis. Of note, LR04 competed the binding of coagulation factor X/Xa to MVs, providing a mechanistic explanation for its anticoagulatory effect. Thus, our data identify natural IgM antibodies as hitherto unknown modulators of MV-induced coagulation in vitro and in vivo and their prognostic and therapeutic potential in the management of thrombosis.
Assuntos
Coagulação Sanguínea , Micropartículas Derivadas de Células/metabolismo , Imunoglobulina M/metabolismo , Trombose/metabolismo , Animais , Plaquetas/citologia , Plaquetas/metabolismo , Humanos , Imunoglobulina M/análise , Camundongos Endogâmicos C57BL , Trombose/sangueRESUMO
OBJECTIVES: Anti-nucleocapsid (NC) antibodies are produced in response to SARS-CoV-2 infection. Therefore, they are well suited for the detection of a previous infection. Especially in the case of seroprevalence studies or during the evaluation of a novel in-vitro diagnostic test, samples have been stored at <-70 °C (short- and long-term) or 2-10 °C (short-term) before analysis. This study aimed to assess the impact of different storage conditions relevant to routine biobanking on anti-NC antibodies. METHODS: The preanalytical impact of short-term storage (84 [58-98] days) on <-70 °C and for 14 days at 2-10 °C was evaluated using samples from 111 donors of the MedUni Vienna Biobank. Long-term effects (443 [409-468] days) were assessed using 208 samples from Biobank Graz and 49 samples from Biobank Vienna. Anti-Nucleocapsid antibodies were measured employing electrochemiluminescence assays (Roche Anti-SARS-CoV-2). RESULTS: After short-term storage, the observed changes did not exceed the extent that could be explained by analytical variability. In contrast, results after long-term storage were approximately 20% higher and seemed to increase with storage duration. This effect was independent of the biobank from which the samples were obtained. Accordingly, the sensitivity increased from 92.6 to 95.3% (p=0.008). However, comparisons with data from Anti-Spike protein assays, where these deviations were not apparent, suggest that this deviation could also be explained by the analytical variability of the qualitative Anti-NC assay. CONCLUSIONS: Results from anti-NC antibodies are stable during short-term storage at <-70 °C and 2-10 °C. After long-term storage, a slight increase in sensitivity could not be ruled out.
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COVID-19 , SARS-CoV-2 , Humanos , Glicoproteína da Espícula de Coronavírus , COVID-19/diagnóstico , Estudos Soroepidemiológicos , Bancos de Espécimes Biológicos , Anticorpos Antivirais , Sensibilidade e EspecificidadeRESUMO
Multiple lung pathogens such as chemical agents, H5N1 avian flu, or SARS cause high lethality due to acute respiratory distress syndrome. Here we report that Toll-like receptor 4 (TLR4) mutant mice display natural resistance to acid-induced acute lung injury (ALI). We show that TLR4-TRIF-TRAF6 signaling is a key disease pathway that controls the severity of ALI. The oxidized phospholipid (OxPL) OxPAPC was identified to induce lung injury and cytokine production by lung macrophages via TLR4-TRIF. We observed OxPL production in the lungs of humans and animals infected with SARS, Anthrax, or H5N1. Pulmonary challenge with an inactivated H5N1 avian influenza virus rapidly induces ALI and OxPL formation in mice. Loss of TLR4 or TRIF expression protects mice from H5N1-induced ALI. Moreover, deletion of ncf1, which controls ROS production, improves the severity of H5N1-mediated ALI. Our data identify oxidative stress and innate immunity as key lung injury pathways that control the severity of ALI.
Assuntos
Estresse Oxidativo , Síndrome do Desconforto Respiratório/metabolismo , Receptor 4 Toll-Like/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Animais , Humanos , Influenza Humana/metabolismo , Interleucina-6/metabolismo , Pulmão , Camundongos , Camundongos Endogâmicos C57BL , NADPH Oxidases/metabolismo , NF-kappa B/metabolismo , Infecções por Orthomyxoviridae/metabolismo , Fosfolipídeos/metabolismo , Síndrome Respiratória Aguda Grave/metabolismo , Transdução de SinaisRESUMO
Genetic variants within complement factor H (CFH), a major alternative complement pathway regulator, are associated with the development of age-related macular degeneration (AMD) and other complementopathies. This is explained with the reduced binding of CFH or its splice variant factor H-like protein 1 (FHL-1) to self-ligands or altered self-ligands (e.g., malondialdehyde [MDA]-modified molecules) involved in homeostasis, thereby causing impaired complement regulation. Considering the critical role of CFH in inhibiting alternative pathway activation on MDA-modified surfaces, we performed an unbiased genome-wide search for genetic variants that modify the ability of plasma CFH to bind MDA in 1,830 individuals and characterized the mechanistic basis and the functional consequences of this. In a cohort of healthy individuals, we identified rs1061170 in CFH and the deletion of CFHR3 and CFHR1 as dominant genetic variants that modify CFH/FHL-1 binding to MDA. We further demonstrated that FHR1 and FHR3 compete with CFH for binding to MDA-epitopes and that FHR1 displays the highest affinity toward MDA-epitopes compared to CFH and FHR3. Moreover, FHR1 bound to MDA-rich areas on necrotic cells and prevented CFH from mediating its cofactor activity on MDA-modified surfaces, resulting in enhanced complement activation. These findings provide a mechanistic explanation as to why the deletion of CFHR3 and CFHR1 is protective in AMD and highlight the importance of genetic variants within the CFH/CFHR3/CFHR1 locus in the recognition of altered-self in tissue homeostasis.
Assuntos
Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Degeneração Macular/genética , Idoso , Fator H do Complemento/genética , Epitopos/genética , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Degeneração Macular/patologia , Masculino , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Ligação ProteicaRESUMO
BACKGROUND & AIMS: Previous single-cell RNA-sequencing analyses have shown that Trem2-expressing macrophages are present in the liver during obesity, non-alcoholic steatohepatitis (NASH) and cirrhosis. Herein, we aimed to functionally characterize the role of bone marrow-derived TREM2-expressing macrophage populations in NASH. METHODS: We used bulk RNA sequencing to assess the hepatic molecular response to lipid-dependent dietary intervention in mice. Spatial mapping, bone marrow transplantation in two complementary murine models and single-cell sequencing were applied to functionally characterize the role of TREM2+ macrophage populations in NASH. RESULTS: We found that the hepatic transcriptomic profile during steatohepatitis mirrors the dynamics of recruited bone marrow-derived monocytes that already acquire increased expression of Trem2 in the circulation. Increased Trem2 expression was reflected by elevated levels of systemic soluble TREM2 in mice and humans with NASH. In addition, soluble TREM2 levels were superior to traditionally used laboratory parameters for distinguishing between different fatty liver disease stages in two separate clinical cohorts. Spatial transcriptomics revealed that TREM2+ macrophages localize to sites of hepatocellular damage, inflammation and fibrosis in the steatotic liver. Finally, using multiple murine models and in vitro experiments, we demonstrate that hematopoietic Trem2 deficiency causes defective lipid handling and extracellular matrix remodeling, resulting in exacerbated steatohepatitis, cell death and fibrosis. CONCLUSIONS: Our study highlights the functional properties of bone marrow-derived TREM2+ macrophages and implies the clinical relevance of systemic soluble TREM2 levels in the context of NASH. LAY SUMMARY: Our study defines the origin and function of macrophages (a type of immune cell) that are present in the liver and express a specific protein called TREM2. We find that these cells have an important role in protecting against non-alcoholic steatohepatitis (a progressive form of fatty liver disease). We also show that the levels of soluble TREM2 in the blood could serve as a circulating marker of non-alcoholic fatty liver disease.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Modelos Animais de Doenças , Humanos , Lipídeos , Fígado/patologia , Cirrose Hepática/complicações , Macrófagos/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/metabolismo , RNA/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismoRESUMO
The diverse leukocyte infiltrate in atherosclerotic mouse aortas was recently analyzed in 9 single-cell RNA sequencing and 2 mass cytometry studies. In a comprehensive meta-analysis, we confirm 4 known macrophage subsets-resident, inflammatory, interferon-inducible cell, and Trem2 (triggering receptor expressed on myeloid cells-2) foamy macrophages-and identify a new macrophage subset resembling cavity macrophages. We also find that monocytes, neutrophils, dendritic cells, natural killer cells, innate lymphoid cells-2, and CD (cluster of differentiation)-8 T cells form prominent and separate immune cell populations in atherosclerotic aortas. Many CD4 T cells express IL (interleukin)-17 and the chemokine receptor CXCR (C-X-C chemokine receptor)-6. A small number of regulatory T cells and T helper 1 cells is also identified. Immature and naive T cells are present in both healthy and atherosclerotic aortas. Our meta-analysis overcomes limitations of individual studies that, because of their experimental approach, over- or underrepresent certain cell populations. Mass cytometry studies demonstrate that cell surface phenotype provides valuable information beyond the cell transcriptomes. The present analysis helps resolve some long-standing controversies in the field. First, Trem2+ foamy macrophages are not proinflammatory but interferon-inducible cell and inflammatory macrophages are. Second, about half of all foam cells are smooth muscle cell-derived, retaining smooth muscle cell transcripts rather than transdifferentiating to macrophages. Third, Pf4, which had been considered specific for platelets and megakaryocytes, is also prominently expressed in the main population of resident vascular macrophages. Fourth, a new type of resident macrophage shares transcripts with cavity macrophages. Finally, the discovery of a prominent innate lymphoid cell-2 cluster links the single-cell RNA sequencing work to recent flow cytometry data suggesting a strong atheroprotective role of innate lymphoid cells-2. This resolves apparent discrepancies regarding the role of T helper 2 cells in atherosclerosis based on studies that predated the discovery of innate lymphoid cells-2 cells.
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Aorta/imunologia , Doenças da Aorta/imunologia , Aterosclerose/imunologia , Leucócitos/imunologia , Animais , Aorta/metabolismo , Aorta/patologia , Doenças da Aorta/metabolismo , Doenças da Aorta/patologia , Aterosclerose/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Biomarcadores/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Leucócitos/metabolismo , Leucócitos/patologia , Fenótipo , Placa Aterosclerótica , RNA-Seq , Análise de Célula Única , TranscriptomaRESUMO
Hypercholesterolemia is a major risk factor in atherosclerosis development and lipid-lowering drugs (i.e., statins) remain the treatment of choice. Despite effective reduction of LDL cholesterol in patients, a residual cardiovascular risk persists in some individuals, highlighting the need for further therapeutic intervention. Recently, the CANTOS trial paved the way toward the development of specific therapies targeting inflammation, a key feature in atherosclerosis progression. The pre-existence of multiple drugs modulating both innate and adaptive immune responses has significantly accelerated the number of translational studies applying these drugs to atherosclerosis. Additional preclinical research has led to the discovery of new therapeutic targets, offering promising perspectives for the treatment and prevention of atherosclerosis. Currently, both drugs with selective targeting and broad unspecific anti-inflammatory effects have been tested. In this chapter, we aim to give an overview of current advances in immunomodulatory treatment approaches for atherosclerotic cardiovascular diseases.
Assuntos
Aterosclerose , Hipercolesterolemia , Anti-Inflamatórios/uso terapêutico , Aterosclerose/tratamento farmacológico , Aterosclerose/prevenção & controle , Ensaios Clínicos como Assunto , Humanos , Imunomodulação , Inflamação/tratamento farmacológicoRESUMO
BACKGROUND: There is preliminary evidence that individuals with previous SARS-CoV-2 infections exhibit a more pronounced antibody response. However, these assumptions have not yet been supported by data obtained through various CE-marked tests. This study aimed to close this gap. METHODS: Sixty-nine seronegatives and 12 individuals post-SARS-CoV-2 infection (tested by CE-labelled Roche NC immunoassay or PCR-confirmed assay) were included 21 ± 1 days after receiving the first dose of the Pfizer/BioNTech BNT162b2 vaccine. Antibody response to viral spike protein (S) was assessed by CE-labelled Roche S and DiaSorin S1/S2 assays and by a surrogate virus neutralization test (sVNT). RESULTS: After a single dose of BNT162b2, individuals after natural SARS-CoV-2 infection presented with markedly higher anti-S levels than naïve individuals (Roche S: 9078.5 BAU/mL [5267.0-24 298.5] vs 79.6 [24.7-142.3]; and DiaSorin S1/S2: 1465.0 AU/mL [631.0-5365.0] vs 63.7 [47.8-87.5]) and showed all the maximum observed inhibition activity in the sVNT (98%), without overlaps between groups. There was a trend for higher responses in those with a more distant infection, although not statistically significant. The relative antibody increase after dose 2 was significantly higher among naïve individuals (25-fold), but antibody levels remained below that of seropositives. CONCLUSIONS: Compared with naïve individuals, seropositives after natural SARS-CoV-2 infection presented with a substantially higher antibody response already after dose 1 of BNT162b2, as measured by two CE-marked in vitro diagnostic tests and a sVNT. These results should stimulate discussion and research on whether individuals after previous SARS-CoV-2 infection would benefit from a two-part vaccination schedule or whether these currently much-needed second doses could be saved.
Assuntos
Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Vacinas contra COVID-19/uso terapêutico , COVID-19/prevenção & controle , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Fatores Etários , Vacina BNT162 , COVID-19/imunologia , Teste Sorológico para COVID-19 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/imunologia , SARS-CoV-2RESUMO
RATIONALE: Atherosclerosis is a chronic inflammatory disease. Recent studies have shown that dysfunctional autophagy in endothelial cells, smooth muscle cells, and macrophages, plays a detrimental role during atherogenesis, leading to the suggestion that autophagy-stimulating approaches may provide benefit. OBJECTIVE: Dendritic cells (DCs) are at the crossroad of innate and adaptive immune responses and profoundly modulate the development of atherosclerosis. Intriguingly, the role of autophagy in DC function during atherosclerosis and how the autophagy process would impact disease development has not been addressed. METHODS AND RESULTS: Here, we show that the autophagic flux in atherosclerosis-susceptible Ldlr-/- (low-density lipoprotein receptor-deficient) mice is substantially higher in splenic and aortic DCs compared with macrophages and is further activated under hypercholesterolemic conditions. RNA sequencing and functional studies on selective cell populations reveal that disruption of autophagy through deletion of Atg16l1 differentially affects the biology and functions of DC subsets in Ldlr-/- mice under high-fat diet. Atg16l1 deficient CD11b+ DCs develop a TGF (transforming growth factor)-ß-dependent tolerogenic phenotype and promote the expansion of regulatory T cells, whereas no such effects are seen with Atg16l1 deficient CD8α+ DCs. Atg16l1 deletion in DCs (all CD11c-expressing cells) expands aortic regulatory T cells in vivo, limits the accumulation of T helper cells type 1, and reduces the development of atherosclerosis in Ldlr-/- mice. In contrast, no such effects are seen when Atg16l1 is deleted selectively in conventional CD8α+ DCs and CD103+ DCs. Total T-cell or selective regulatory T-cell depletion abrogates the atheroprotective effect of Atg16l1 deficient DCs. CONCLUSIONS: In contrast to its proatherogenic role in macrophages, autophagy disruption in DCs induces a counter-regulatory response that maintains immune homeostasis in Ldlr-/- mice under high-fat diet and limits atherogenesis. Selective modulation of autophagy in DCs could constitute an interesting therapeutic target in atherosclerosis.