RESUMO
Stress exposure has been shown to modulate innate and adaptive immune responses. Indeed, stress favors myelopoiesis and monocyte generation and contributes to cardiovascular disease development. As sex hormones regulate innate and adaptive immune responses, we decided to investigate whether stress exposure leads to a different immune response in female and male mice. Our data demonstrated that psychosocial stressinduced neutrophilia in male, but not female mice. Importantly, we identified that B-cell numbers were reduced in female, but not male mice upon exposure to stress. Thus, our study revealed that the stress-induced immune alterations are sex-dependent, and this is an important feature to consider for future investigations.
Assuntos
Hematopoese , Estresse Psicológico , Animais , Feminino , Estresse Psicológico/imunologia , Masculino , Camundongos , Hematopoese/imunologia , Linfócitos B/imunologia , Neutrófilos/imunologia , Leucócitos/imunologia , Camundongos Endogâmicos C57BL , Fatores Sexuais , Caracteres SexuaisRESUMO
Along with respiratory tract disease per se, viral respiratory infections can also cause extrapulmonary complications with a potentially critical impact on health. In the present study, we used an experimental model of influenza A virus (IAV) infection to investigate the nature and outcome of the associated gut disorders. In IAV-infected mice, the signs of intestinal injury and inflammation, altered gene expression, and compromised intestinal barrier functions peaked on day 7 postinfection. As a likely result of bacterial component translocation, gene expression of inflammatory markers was upregulated in the liver. These changes occurred concomitantly with an alteration of the composition of the gut microbiota and with a decreased production of the fermentative, gut microbiota-derived products short-chain fatty acids (SCFAs). Gut inflammation and barrier dysfunction during influenza were not attributed to reduced food consumption, which caused in part gut dysbiosis. Treatment of IAV-infected mice with SCFAs was associated with an enhancement of intestinal barrier properties, as assessed by a reduction in the translocation of dextran and a decrease in inflammatory gene expression in the liver. Lastly, SCFA supplementation during influenza tended to reduce the translocation of the enteric pathogen Salmonella enterica serovar Typhimurium and to enhance the survival of doubly infected animals. Collectively, influenza virus infection can remotely impair the gut's barrier properties and trigger secondary enteric infections. The latter phenomenon can be partially countered by SCFA supplementation.
Assuntos
Infecções por Enterobacteriaceae/etiologia , Ácidos Graxos Voláteis/biossíntese , Interações Hospedeiro-Patógeno , Vírus da Influenza A/fisiologia , Influenza Humana/complicações , Influenza Humana/virologia , Mucosa Intestinal/metabolismo , Interações Microbianas , Suscetibilidade a Doenças , Disbiose , Infecções por Enterobacteriaceae/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Humanos , Influenza Humana/metabolismo , Mucosa Intestinal/imunologiaRESUMO
Macrophages play a central role during infection, inflammation and tissue homeostasis maintenance. Macrophages have been identified in all organs and their core transcriptomic signature and functions differ from one tissue to another. Interestingly, macrophages have also been identified in the peritoneal cavity and these cells have been extensively used as a model for phagocytosis, efferocytosis and polarization. Peritoneal macrophages are involved in B-cell IgA production, control of inflammation and wound healing following thermal-induced liver surface injury. These cells presumably require and interact with the omentum, where milky spot stromal cells have been proposed to secrete CSF1 (colony stimulating factor 1). Peritoneal macrophages depend on CSF1 for their generation and survival, but the identity of CSF1 producing cells inside the large peritoneal cavity remains unknown. Here we investigated peritoneal macrophage localization and their interaction with mesothelial cells, the major cell type predicted to secrete CSF1. Our data revealed that mesothelial cells produce membrane bound and secreted CSF1 that both sustain peritoneal macrophage growth.
Assuntos
Células Epiteliais/metabolismo , Epitélio/metabolismo , Fator Estimulador de Colônias de Macrófagos/genética , Macrófagos Peritoneais/metabolismo , Células Estromais/metabolismo , Animais , Comunicação Celular/genética , Comunicação Celular/imunologia , Membrana Celular/imunologia , Membrana Celular/metabolismo , Sobrevivência Celular , Técnicas de Cocultura , Células Epiteliais/citologia , Células Epiteliais/imunologia , Epitélio/imunologia , Espaço Extracelular/imunologia , Espaço Extracelular/metabolismo , Expressão Gênica , Fator Estimulador de Colônias de Macrófagos/imunologia , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/imunologia , Camundongos , Camundongos Transgênicos , Cavidade Peritoneal/citologia , Transdução de Sinais , Células Estromais/citologia , Células Estromais/imunologiaRESUMO
RATIONALE: Macrophages face a substantial amount of cholesterol after the ingestion of apoptotic cells, and the LIPA (lysosomal acid lipase) has a major role in hydrolyzing cholesteryl esters in the endocytic compartment. OBJECTIVE: Here, we directly investigated the role of LIPA-mediated clearance of apoptotic cells both in vitro and in vivo. METHODS AND RESULTS: We show that LIPA inhibition causes a defective efferocytic response because of impaired generation of 25-hydroxycholesterol and 27-hydroxycholesterol. Reduced synthesis of 25-hydroxycholesterol after LIPA inhibition contributed to defective mitochondria-associated membrane leading to mitochondrial oxidative stress-induced NLRP3 (NOD-like receptor family, pyrin domain containing) inflammasome activation and caspase-1-dependent Rac1 (Ras-related C3 botulinum toxin substrate 1) degradation. A secondary event consisting of failure to appropriately activate liver X receptor-mediated pathways led to mitigation of cholesterol efflux and apoptotic cell clearance. In mice, LIPA inhibition caused defective clearance of apoptotic lymphocytes and stressed erythrocytes by hepatic and splenic macrophages, culminating in splenomegaly and splenic iron accumulation under hypercholesterolemia. CONCLUSIONS: Our findings position lysosomal cholesterol hydrolysis as a critical process that prevents metabolic inflammation by enabling efficient macrophage apoptotic cell clearance.
Assuntos
Colesterol/metabolismo , Inflamação/metabolismo , Lisossomos/metabolismo , Macrófagos/metabolismo , Oxisteróis/metabolismo , Esterol Esterase/metabolismo , Animais , Apoptose , Transporte Biológico , Ésteres do Colesterol/metabolismo , Eritrócitos/metabolismo , Hidrólise , Hipercolesterolemia/metabolismo , Inflamassomos/metabolismo , Receptores X do Fígado/metabolismo , Linfócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neuropeptídeos/metabolismo , Receptores de LDL/metabolismo , Esplenomegalia/metabolismo , Esterol Esterase/antagonistas & inibidores , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
RATIONALE: Inflamed atherosclerotic plaques can be visualized by noninvasive positron emission and computed tomographic imaging with (18)F-fluorodeoxyglucose, a glucose analog, but the underlying mechanisms are poorly understood. OBJECTIVE: Here, we directly investigated the role of Glut1-mediated glucose uptake in apolipoprotein E-deficient (ApoE(-/-)) mouse model of atherosclerosis. METHODS AND RESULTS: We first showed that the enhanced glycolytic flux in atheromatous plaques of ApoE(-/-) mice was associated with the enhanced metabolic activity of hematopoietic stem and multipotential progenitor cells and higher Glut1 expression in these cells. Mechanistically, the regulation of Glut1 in ApoE(-/-) hematopoietic stem and multipotential progenitor cells was not because of alterations in hypoxia-inducible factor 1α signaling or the oxygenation status of the bone marrow but was the consequence of the activation of the common ß subunit of the granulocyte-macrophage colony-stimulating factor/interleukin-3 receptor driving glycolytic substrate utilization by mitochondria. By transplanting bone marrow from WT, Glut1(+/-), ApoE(-/-), and ApoE(-/-)Glut1(+/-) mice into hypercholesterolemic ApoE-deficient mice, we found that Glut1 deficiency reversed ApoE(-/-) hematopoietic stem and multipotential progenitor cell proliferation and expansion, which prevented the myelopoiesis and accelerated atherosclerosis of ApoE(-/-) mice transplanted with ApoE(-/-) bone marrow and resulted in reduced glucose uptake in the spleen and aortic arch of these mice. CONCLUSIONS: We identified that Glut1 connects the enhanced glucose uptake in atheromatous plaques of ApoE(-/-) mice with their myelopoiesis through regulation of hematopoietic stem and multipotential progenitor cell maintenance and myelomonocytic fate and suggests Glut1 as potential drug target for atherosclerosis.
Assuntos
Transportador de Glucose Tipo 1/fisiologia , Glucose/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Hipercolesterolemia/metabolismo , Mielopoese/fisiologia , Placa Aterosclerótica/metabolismo , Animais , Aorta Torácica/metabolismo , Apolipoproteínas E/deficiência , Transplante de Medula Óssea , Divisão Celular , Subunidade beta Comum dos Receptores de Citocinas/fisiologia , Progressão da Doença , Metabolismo Energético , Regulação da Expressão Gênica , Transportador de Glucose Tipo 1/deficiência , Glicólise , Hipercolesterolemia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/deficiência , Subunidade alfa do Fator 1 Induzível por Hipóxia/fisiologia , Metformina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Multipotentes/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Receptores de Interleucina-3/antagonistas & inibidores , Receptores de Interleucina-3/fisiologia , Baço/metabolismo , Tirfostinas/farmacologiaRESUMO
Monocyte and macrophage diversity is evidenced by the modulation of cell surface markers and differential production of soluble mediators. These immune cells play key roles in controlling tissue homeostasis, infections, and excessive inflammation. Macrophages remove dead cells in a process named efferocytosis, contributing to the healthy tissue maintenance. Recently, it became clear that the main macrophage functions are under metabolic control. Modulation of glucose, fatty acid, and amino acid metabolism is associated with various macrophage activations in response to external stimuli. Deciphering these metabolic pathways provided critical information about macrophage functions.
Assuntos
Ativação de Macrófagos/fisiologia , Macrófagos/metabolismo , Aminoácidos/metabolismo , Animais , Ácidos Graxos/metabolismo , Glucose/metabolismo , Humanos , Fagocitose/fisiologiaRESUMO
Despite the ubiquitous function of macrophages across the body, the diversity, origin, and function of adrenal gland macrophages remain largely unknown. We define the heterogeneity of adrenal gland immune cells using single-cell RNA sequencing and use genetic models to explore the developmental mechanisms yielding macrophage diversity. We define populations of monocyte-derived and embryonically seeded adrenal gland macrophages and identify a female-specific subset with low major histocompatibility complex (MHC) class II expression. In adulthood, monocyte recruitment dominates adrenal gland macrophage maintenance in female mice. Adrenal gland macrophage sub-tissular distribution follows a sex-dimorphic pattern, with MHC class IIlow macrophages located at the cortico-medullary junction. Macrophage sex dimorphism depends on the presence of the cortical X-zone. Adrenal gland macrophage depletion results in altered tissue homeostasis, modulated lipid metabolism, and decreased local aldosterone production during stress exposure. Overall, these data reveal the heterogeneity of adrenal gland macrophages and point toward sex-restricted distribution and functions of these cells.
Assuntos
Glândulas Suprarrenais , Macrófagos , Monócitos , Caracteres Sexuais , Glândulas Suprarrenais/metabolismo , Animais , Feminino , Antígenos de Histocompatibilidade Classe II/genética , Contagem de Leucócitos , Macrófagos/metabolismo , Masculino , CamundongosRESUMO
Metabolism plays a key role in controlling immune cell functions. In this review, we will discuss the diversity of plaque resident myeloid cells and will focus on their metabolic demands that could reflect on their particular intraplaque localization. Defining the metabolic configuration of plaque resident myeloid cells according to their topologic distribution could provide answers to key questions regarding their functions and contribution to disease development.
Assuntos
Aterosclerose , Placa Aterosclerótica , Humanos , MacrófagosRESUMO
Monocytes are part of the mononuclear phagocytic system. Monocytes play a central role during inflammatory conditions and a better understanding of their dynamics might open therapeutic opportunities. In the present study, we focused on the characterization and impact of monocytes on brown adipose tissue (BAT) functions during tissue remodeling. Single-cell RNA sequencing analysis of BAT immune cells uncovered a large diversity in monocyte and macrophage populations. Fate-mapping experiments demonstrated that the BAT macrophage pool requires constant replenishment from monocytes. Using a genetic model of BAT expansion, we found that brown fat monocyte numbers were selectively increased in this scenario. This observation was confirmed using a CCR2-binding radiotracer and positron emission tomography. Importantly, in line with their tissue recruitment, blood monocyte counts were decreased while bone marrow hematopoiesis was not affected. Monocyte depletion prevented brown adipose tissue expansion and altered its architecture. Podoplanin engagement is strictly required for BAT expansion. Together, these data redefine the diversity of immune cells in the BAT and emphasize the role of monocyte recruitment for tissue remodeling.
Assuntos
Tecido Adiposo Marrom/citologia , Monócitos/fisiologia , Adiponectina/genética , Tecido Adiposo Marrom/fisiologia , Animais , Diferenciação Celular/genética , Contagem de Leucócitos , Macrófagos/citologia , Macrófagos/fisiologia , Glicoproteínas de Membrana/metabolismo , Camundongos Transgênicos , Monócitos/citologia , Tomografia por Emissão de Pósitrons , Receptores CCR2/genética , Receptores CCR2/metabolismoRESUMO
Inflammasomes are signalling platforms that are assembled in response to infection or sterile inflammation by cytosolic pattern recognition receptors. The consequent inflammasome-triggered caspase-1 activation is critical for the host defence against pathogens. During infection, NLRP3, which is a pattern recognition receptor that is also known as cryopyrin, triggers the assembly of the inflammasome-activating caspase-1 through the recruitment of ASC and Nek7. The activation of the NLRP3 inflammasome is tightly controlled both transcriptionally and post-translationally. Despite the importance of the NLRP3 inflammasome regulation in autoinflammatory and infectious diseases, little is known about the mechanism controlling the activation of NLRP3 and the upstream signalling that regulates the NLRP3 inflammasome assembly. We have previously shown that the Rho-GTPase-activating toxin from Escherichia coli cytotoxic necrotizing factor-1 (CNF1) activates caspase-1, but the upstream mechanism is unclear. Here, we provide evidence of the role of the NLRP3 inflammasome in sensing the activity of bacterial toxins and virulence factors that activate host Rho GTPases. We demonstrate that this activation relies on the monitoring of the toxin's activity on the Rho GTPase Rac2. We also show that the NLRP3 inflammasome is activated by a signalling cascade that involves the p21-activated kinases 1 and 2 (Pak1/2) and the Pak1-mediated phosphorylation of Thr 659 of NLRP3, which is necessary for the NLRP3-Nek7 interaction, inflammasome activation and IL-1ß cytokine maturation. Furthermore, inhibition of the Pak-NLRP3 axis decreases the bacterial clearance of CNF1-expressing UTI89 E. coli during bacteraemia in mice. Taken together, our results establish that Pak1 and Pak2 are critical regulators of the NLRP3 inflammasome and reveal the role of the Pak-NLRP3 signalling axis in vivo during bacteraemia in mice.
Assuntos
Bacteriemia/metabolismo , Toxinas Bacterianas/metabolismo , Infecções por Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo , Animais , Bacteriemia/imunologia , Bacteriemia/microbiologia , Carga Bacteriana , Toxinas Bacterianas/genética , Escherichia coli/genética , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Imunidade Inata , Camundongos , Fosforilação , Transdução de Sinais , Quinases Ativadas por p21/metabolismo , Proteínas rac de Ligação ao GTP/genética , Proteína RAC2 de Ligação ao GTPRESUMO
Macrophages rely on tightly integrated metabolic rewiring to clear dying neighboring cells by efferocytosis during homeostasis and disease. Here we reveal that glutaminase-1-mediated glutaminolysis is critical to promote apoptotic cell clearance by macrophages during homeostasis in mice. In addition, impaired macrophage glutaminolysis exacerbates atherosclerosis, a condition during which, efficient apoptotic cell debris clearance is critical to limit disease progression. Glutaminase-1 expression strongly correlates with atherosclerotic plaque necrosis in patients with cardiovascular diseases. High-throughput transcriptional and metabolic profiling reveals that macrophage efferocytic capacity relies on a non-canonical transaminase pathway, independent from the traditional requirement of glutamate dehydrogenase to fuel É-ketoglutarate-dependent immunometabolism. This pathway is necessary to meet the unique requirements of efferocytosis for cellular detoxification and high-energy cytoskeletal rearrangements. Thus, we uncover a role for non-canonical glutamine metabolism for efficient clearance of dying cells and maintenance of tissue homeostasis during health and disease in mouse and humans.
Assuntos
Aminação , Glutamina/metabolismo , Fosforilação Oxidativa , Animais , Camundongos , FagocitoseRESUMO
The marginal zone of the spleen is a precisely ordered region that contains specialized subsets of B lymphocytes and macrophages. Disruption of the negative signaling inositol phosphatase, SH2-containing inositol-5-phosphatase 1 (SHIP), results in the loss of marginal zone B cells (MZBs) with reorganization of marginal zone macrophages (MZMOs) to the red pulp of the spleen. This primary macrophage defect, as revealed by selectively depleting SHIP in myeloid cells shows that MZMOs are specifically required for the retention of MZBs. The MZMO phenotype was reverted in SHIP/Bruton's tyrosine kinase (Btk) double knockout mice, thus identifying the Btk activating pathway as an essential component being regulated by SHIP. Furthermore, we identified a direct interaction between the MARCO scavenger receptor on MZMOs and MZBs. Activation or disruption of this interaction results in MZB migration to the follicle. The migration of the MZMOs was further studied after the response to Staphylococcus aureus, which induced MZMOs to move into the red pulp while MZBs migrated into the follicular zone. The marginal zone is therefore a dynamic structure in which retention and trafficking of B cells requires specific macrophage-B cell interactions.
Assuntos
Linfócitos B/imunologia , Macrófagos/imunologia , Baço/imunologia , Animais , Subpopulações de Linfócitos B/imunologia , Linfócitos B/citologia , Citometria de Fluxo , Macrófagos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Monoéster Fosfórico Hidrolases/deficiência , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/imunologia , Baço/citologiaRESUMO
Defective cholesterol efflux pathways in mice promote the expansion of hematopoietic stem and progenitor cells and a bias toward the myeloid lineage, as observed in chronic myelomonocytic leukemia (CMML). Here, we identify 5 somatic missense mutations in ABCA1 in 26 patients with CMML. These mutations confer a proliferative advantage to monocytic leukemia cell lines in vitro. In vivo inactivation of ABCA1 or expression of ABCA1 mutants in hematopoietic cells in the setting of Tet2 loss demonstrates a myelosuppressive function of ABCA1. Mechanistically, ABCA1 mutations impair the tumor-suppressor functions of WT ABCA1 in myeloproliferative neoplasms by increasing the IL-3Rß signaling via MAPK and JAK2 and subsequent metabolic reprogramming. Overexpression of a human apolipoprotein A-1 transgene dampens myeloproliferation. These findings identify somatic mutations in ABCA1 that subvert its anti-proliferative and cholesterol efflux functions and permit the progression of myeloid neoplasms. Therapeutic increases in HDL bypass these defects and restore normal hematopoiesis.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/metabolismo , Transtornos Mieloproliferativos/metabolismo , Transportador 1 de Cassete de Ligação de ATP/deficiência , Transportador 1 de Cassete de Ligação de ATP/genética , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/patologia , Colesterol/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dioxigenases , Células-Tronco Hematopoéticas/metabolismo , Humanos , Interleucina-3/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Lipoproteínas HDL/metabolismo , Mutação com Perda de Função/genética , Camundongos , Camundongos Endogâmicos C57BL , Mielopoese , Transtornos Mieloproliferativos/patologia , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , Esplenomegalia/patologiaRESUMO
Inflammation represents the driving feature of many diseases, including atherosclerosis, cancer, autoimmunity and infections. It is now established that metabolic processes shape a proper immune response and within this context the alteration in cellular cholesterol homeostasis has emerged as a culprit of many metabolic abnormalities observed in chronic inflammatory diseases. Cholesterol accumulation supports the inflammatory response of myeloid cells (i.e. augmentation of toll-like receptor signalling, inflammasome activation, and production of monocytes and neutrophils) which is beneficial in the response to infections, but worsens diseases associated with chronic metabolic inflammation including atherosclerosis. In addition to the innate immune system, cells of adaptive immunity, upon activation, have also been shown to undergo a reprogramming of cellular cholesterol metabolism, which results in the amplification of inflammatory responses. Aim of this review is to discuss (i) the molecular mechanisms linking cellular cholesterol metabolism to specific immune functions; (ii) how cellular cholesterol accumulation sustains chronic inflammatory diseases such as atherosclerosis; (iii) the immunometabolic profile of patients with defects of genes affecting cholesterol metabolism including familial hypercholesterolaemia, cholesteryl ester storage disease, Niemann-Pick type C, and immunoglobulin D syndrome/mevalonate kinase deficiency. Available data indicate that cholesterol immunometabolism plays a key role in directing immune cells function and set the stage for investigating the repurposing of existing 'metabolic' drugs to modulate the immune response.
Assuntos
Doenças Cardiovasculares/imunologia , Sistema Cardiovascular/imunologia , Colesterol/imunologia , Metabolismo Energético/imunologia , Sistema Imunitário/imunologia , Imunomodulação , Mediadores da Inflamação/imunologia , Inflamação/imunologia , Animais , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/fisiopatologia , Sistema Cardiovascular/metabolismo , Sistema Cardiovascular/fisiopatologia , Colesterol/metabolismo , Humanos , Sistema Imunitário/metabolismo , Sistema Imunitário/fisiopatologia , Inflamação/metabolismo , Inflamação/fisiopatologia , Mediadores da Inflamação/metabolismo , Transdução de SinaisRESUMO
NTAL (non-T-cell activation linker, also called LAB) and LAT (linker for activation of T cells) are evolutionarily related transmembrane adaptor proteins that are phosphorylated upon immunoreceptor engagement. Using quantitative reverse transcription-PCR, both NTAL and LAT were found to be expressed in B cells. However, LAT expression was limited to early B cells, whereas NTAL expression typified mature B cells. To delineate their roles in B-cell development and function, Ntal-deficient mice were generated and crossed with Lat-deficient mice. B cells developed in Lat(-/-) Ntal(-/-) double-deficient mice and in mice lacking either of the two adaptors with the same efficiency as in wild-type mice. Upon B-cell antigen receptor cross-linking, Ntal(-/-) B cells exhibited slightly increased Ca(2+) mobilization and proliferation. In addition, Ntal-deficient mice had increased levels of natural antibodies and slightly increased humoral response to a T-dependent antigen. Normal titers of serum-specific immunoglobulins were produced in response to a T-cell-independent antigen. Although NTAL is also expressed in plasma cells, its absence did not affect the hypergammaglobulinemia E and G1 that developed in mice with a mutation in tyrosine 136 of LAT. Therefore, NTAL does not play a role in B cells symmetric to the role played by LAT in T cells.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Proteínas Adaptadoras de Transporte Vesicular/fisiologia , Linfócitos B/imunologia , Proteínas de Membrana/fisiologia , Fosfoproteínas/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transporte Vesicular/deficiência , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Formação de Anticorpos , Antígenos T-Independentes/imunologia , Linfócitos B/efeitos dos fármacos , Cálcio/farmacologia , Diferenciação Celular , Proliferação de Células , Deleção de Genes , Expressão Gênica , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Camundongos , Camundongos Mutantes , Mutação , Fosfoproteínas/deficiência , Fosfoproteínas/genética , Plasmócitos/imunologia , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Linfócitos T/imunologia , Tirosina/genéticaRESUMO
The increasing incidence of obesity and its socio-economical impact is a global health issue due to its associated co-morbidities, namely diabetes and cardiovascular disease [1-5]. Obesity is characterized by an increase in adipose tissue, which promotes the recruitment of immune cells resulting in low-grade inflammation and dysfunctional metabolism. Macrophages are the most abundant immune cells in the adipose tissue of mice and humans. The adipose tissue also contains other myeloid cells (dendritic cells (DC) and neutrophils) and to a lesser extent lymphocyte populations, including T cells, B cells, Natural Killer (NK) and Natural Killer T (NKT) cells. While the majority of studies have linked adipose tissue macrophages (ATM) to the development of low-grade inflammation and co-morbidities associated with obesity, emerging evidence suggests for a role of other immune cells within the adipose tissue that may act in part by supporting macrophage homeostasis. In this review, we summarize the current knowledge of the functions ATMs, DCs and B cells possess during steady-state and obesity.
Assuntos
Tecido Adiposo/imunologia , Linfócitos B/imunologia , Células Dendríticas/imunologia , Macrófagos/imunologia , Obesidade/imunologia , Adipocinas/metabolismo , Tecido Adiposo/metabolismo , Tecido Adiposo/fisiopatologia , Adiposidade , Animais , Linfócitos B/metabolismo , Comunicação Celular , Citocinas/metabolismo , Células Dendríticas/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Macrófagos/metabolismo , Obesidade/metabolismo , Obesidade/fisiopatologia , Fenótipo , Transdução de SinaisRESUMO
A rare mRNA variant of the human lymphocyte-specific protein tyrosine kinase LCK gene that retains intron B and excludes exon 7 (B+7-) due to alternative splicing of the canonical LCK transcripts was identified and characterized. LCK B+7- mRNA is detected in all tested peripheral blood T lymphocytes total RNA samples but is apparently sequestered in the nucleus. The presence of intron B sequence does not disrupt the reading frame and results in the insertion of 58 aminoacids, containing a proline-rich region just upstream of p56lck SH3 domain. This putative isoform encodes an unstable 516 aminoacids protein (LckB+7-) which can be expressed in transfected COS-7 cells. Furthermore in Jurkat T cell extracts, a recombinant intron B plus SH3 p56lck domain fails to interact with some TCR-induced tyrosine phosphorylated polypeptides and known p56lck partners such as Sam68 and c-Cbl. The biological function of this rare messenger remains to be elucidated.
Assuntos
Processamento Alternativo , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/genética , RNA Mensageiro/genética , Domínios de Homologia de src/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Western Blotting , Células COS , Células Cultivadas , Chlorocebus aethiops , Clonagem Molecular , DNA Complementar/química , DNA Complementar/genética , Humanos , Íntrons/genética , Isoenzimas/genética , Isoenzimas/metabolismo , Células Jurkat , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Dados de Sequência Molecular , Mutagênese Insercional , Ligação Proteica , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Linfócitos T/citologia , Linfócitos T/enzimologia , Linfócitos T/metabolismo , Transcrição Gênica/genéticaRESUMO
Enhanced glucose utilization can be visualized in atherosclerotic lesions and may reflect a high glycolytic rate in lesional macrophages, but its causative role in plaque progression remains unclear. We observe that the activity of the carbohydrate-responsive element binding protein ChREBP is rapidly downregulated upon TLR4 activation in macrophages. ChREBP inactivation refocuses cellular metabolism to a high redox state favoring enhanced inflammatory responses after TLR4 activation and increased cell death after TLR4 activation or oxidized LDL loading. Targeted deletion of ChREBP in bone marrow cells resulted in accelerated atherosclerosis progression in Ldlr(-/-) mice with increased monocytosis, lesional macrophage accumulation, and plaque necrosis. Thus, ChREBP-dependent macrophage metabolic reprogramming hinders plaque progression and establishes a causative role for leukocyte glucose metabolism in atherosclerosis.
Assuntos
Aterosclerose/imunologia , Macrófagos/imunologia , Proteínas Nucleares/imunologia , Placa Aterosclerótica/imunologia , Receptores de LDL/imunologia , Fatores de Transcrição/imunologia , Animais , Apoptose/efeitos dos fármacos , Aterosclerose/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Células da Medula Óssea/patologia , Feminino , Regulação da Expressão Gênica , Glucose/metabolismo , Glicólise/genética , Humanos , Inflamação , Lipoproteínas LDL/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Oxirredução , Placa Aterosclerótica/genética , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patologia , Cultura Primária de Células , Receptores de LDL/deficiência , Receptores de LDL/genética , Transdução de Sinais , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologia , Receptor 4 Toll-Like/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
We compared gene expression signatures of aggressive amelanotic (Amela) melanomas with those of slowly growing pigmented melanomas (Mela), identifying pathways potentially responsible for the aggressive Amela phenotype. Both tumors develop in mice upon conditional deletion in melanocytes of Ink4a/Arf tumor suppressor genes with concomitant expression of oncogene H-Ras(G12V) and a known tumor antigen. We previously showed that only the aggressive Amela tumors were highly infiltrated by leukocytes concomitant with local and systemic inflammation. We report that Amela tumors present a pattern of de-differentiation with reduced expression of genes involved in pigmentation. This correlates with reduced and enhanced expression, respectively, of microphthalmia-associated (Mitf) and Pou3f2/Brn-2 transcription factors. The reduced expression of Mitf-controlled melanocyte differentiation antigens also observed in some human cutaneous melanoma has important implications for immunotherapy protocols that generally target such antigens. Induced Amela tumors also express Epithelial-Mesenchymal-Transition (EMT)-like and TGFß-pathway signatures. These are correlated with constitutive Smad3 signaling in Amela tumors and melanoma cell lines. Signatures of infiltrating leukocytes and some chemokines such as chemotactic cytokine ligand 2 (Ccl2) that contribute to leukocyte recruitment further characterize Amela tumors. Inhibition of the mitogen-activated protein kinase (MAPK) activation pathway in Amela tumor lines leads to reduced expression of EMT hallmark genes and inhibits both proinflammatory cytokine Ccl2 gene expression and Ccl2 production by the melanoma cells. These results indicate a link between EMT-like processes and alterations of immune functions, both being controlled by the MAPK pathway. They further suggest that targeting the MAPK pathway within tumor cells will impact tumor-intrinsic oncogenic properties as well as the nature of the tumor microenvironment.
Assuntos
Transição Epitelial-Mesenquimal , Melanoma Amelanótico/patologia , Transdução de Sinais , Neoplasias Cutâneas/patologia , Fator de Crescimento Transformador beta/metabolismo , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Quimiocina CCL2/metabolismo , Regulação para Baixo , Ativação Enzimática , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases , Melanócitos/metabolismo , Melanócitos/patologia , Melanoma Amelanótico/genética , Melanoma Amelanótico/metabolismo , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas do Tecido Nervoso/genética , Fatores do Domínio POU/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Proteína Smad3/metabolismo , Regulação para CimaRESUMO
Thymic dendritic cells (DC) and epithelial cells play a major role in central tolerance but their respective roles are still controversial. Epithelial cells have the unique ability to ectopically express peripheral tissue-restricted antigens conferring self-tolerance to tissues. Paradoxically, while negative selection seems to occur for some of these antigens, epithelial cells, contrary to DC, are poor negative selectors. Using a thymic epithelial cell line, we show the functional intercellular transfer of membrane material, including MHC molecules, occurring between epithelial cells. Using somatic and bone marrow chimeras, we show that this transfer occurs efficiently in vivo between epithelial cells and, in a polarized fashion, from epithelial to DC. This novel mode of transfer of MHC-associated, epithelial cell-derived self-antigens onto DC might participate to the process of negative selection in the thymic medulla.