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1.
Immunity ; 54(1): 53-67.e7, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33058782

RESUMO

Several classes of antibiotics have long been known to have beneficial effects that cannot be explained strictly on the basis of their capacity to control the infectious agent. Here, we report that tetracycline antibiotics, which target the mitoribosome, protected against sepsis without affecting the pathogen load. Mechanistically, we found that mitochondrial inhibition of protein synthesis perturbed the electron transport chain (ETC) decreasing tissue damage in the lung and increasing fatty acid oxidation and glucocorticoid sensitivity in the liver. Using a liver-specific partial and acute deletion of Crif1, a critical mitoribosomal component for protein synthesis, we found that mice were protected against sepsis, an observation that was phenocopied by the transient inhibition of complex I of the ETC by phenformin. Together, we demonstrate that mitoribosome-targeting antibiotics are beneficial beyond their antibacterial activity and that mitochondrial protein synthesis inhibition leading to ETC perturbation is a mechanism for the induction of disease tolerance.


Assuntos
Antibacterianos/uso terapêutico , Doxiciclina/uso terapêutico , Fígado/imunologia , Pulmão/imunologia , Mitocôndrias/metabolismo , Sepse/tratamento farmacológico , Tetraciclina/uso terapêutico , Animais , Proteínas de Ciclo Celular/genética , Modelos Animais de Doenças , Transporte de Elétrons , Células Hep G2 , Humanos , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
2.
Immunity ; 54(1): 68-83.e6, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33238133

RESUMO

While antibiotics are intended to specifically target bacteria, most are known to affect host cell physiology. In addition, some antibiotic classes are reported as immunosuppressive for reasons that remain unclear. Here, we show that Linezolid, a ribosomal-targeting antibiotic (RAbo), effectively blocked the course of a T cell-mediated autoimmune disease. Linezolid and other RAbos were strong inhibitors of T helper-17 cell effector function in vitro, showing that this effect was independent of their antibiotic activity. Perturbing mitochondrial translation in differentiating T cells, either with RAbos or through the inhibition of mitochondrial elongation factor G1 (mEF-G1) progressively compromised the integrity of the electron transport chain. Ultimately, this led to deficient oxidative phosphorylation, diminishing nicotinamide adenine dinucleotide concentrations and impairing cytokine production in differentiating T cells. In accordance, mice lacking mEF-G1 in T cells were protected from experimental autoimmune encephalomyelitis, demonstrating that this pathway is crucial in maintaining T cell function and pathogenicity.


Assuntos
Antibacterianos/uso terapêutico , Encefalomielite Autoimune Experimental/tratamento farmacológico , Linezolida/uso terapêutico , Mitocôndrias/metabolismo , Peptídeos Cíclicos/uso terapêutico , Ribossomos/metabolismo , Células Th17/fisiologia , Animais , Autoimunidade/efeitos dos fármacos , Diferenciação Celular , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Terapia de Alvo Molecular , Esclerose Múltipla/tratamento farmacológico , NAD/metabolismo , Fosforilação Oxidativa , Fator G para Elongação de Peptídeos/genética , Fator G para Elongação de Peptídeos/metabolismo
3.
Cell ; 147(6): 1355-68, 2011 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-22153078

RESUMO

Antigen (Ag) crosspresentation by dendritic cells (DCs) involves the presentation of internalized Ags on MHC class I molecules to initiate CD8+ T cell-mediated immunity in response to certain pathogens and tumor cells. Here, we identify the SNARE Sec22b as a specific regulator of Ag crosspresentation. Sec22b localizes to the ER-Golgi intermediate compartment (ERGIC) and pairs to the plasma membrane SNARE syntaxin 4, which is present in phagosomes (Phgs). Depletion of Sec22b inhibits the recruitment of ER-resident proteins to Phgs and to the vacuole containing the Toxoplasma gondii parasite. In Sec22b-deficient DCs, crosspresentation is compromised after Ag phagocytosis or endocytosis and after invasion by T. gondii. Sec22b silencing inhibited Ag export to the cytosol and increased phagosomal degradation by accelerating lysosomal recruitment. Our findings provide insight into an intracellular traffic pathway required for crosspresentation and show that Sec22b-dependent recruitment of ER proteins to Phgs critically influences phagosomal functions in DCs.


Assuntos
Apresentação de Antígeno , Células Dendríticas/imunologia , Infecções por Escherichia coli/imunologia , Escherichia coli , Fagossomos/imunologia , Proteínas R-SNARE/metabolismo , Toxoplasma , Toxoplasmose/imunologia , Animais , Reações Cruzadas , Células Dendríticas/citologia , Camundongos , Camundongos Endogâmicos C57BL
4.
Cephalalgia ; 44(4): 3331024241247845, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38676534

RESUMO

BACKGROUND: Cluster headache is a primary headache disorder characterized by bouts with circadian and circannual patterns. The CLOCK gene has a central role in regulating circadian rhythms. Here, we investigate the circannual CLOCK expression in a population of cluster headache patients in comparison to matched controls. METHODS: Patients with cluster headache were sampled two to four times over at least one year, both in or outside bouts, one week after each solstice and equinox. The expression of CLOCK was measured by quantitative real-time polymerase chain reaction (RT-PCR) in the peripheral blood. RESULTS: This study included 50 patients and 58 matched controls. Among the patient population, composed of 42/50 males (84%) with an average age of 44.6 years, 45/50 (90%) suffered from episodic cluster headache. Two to four samples were collected from each patient adding up to 161 samples, 36 (22.3%) of which were collected within a bout. CLOCK expression for cluster headache patients was considerably different from that of the control population in winter (p-value mean = 0.006283), spring (p-value mean = 0.000006) and summer (p-value mean = 0.000064), but not in autumn (p-value mean = 0.262272). For each season transition, the variations in CLOCK expression were more pronounced in the control group than in the cluster headache population. No statistically significant differences were found between bout and non-bout samples. No individual factors (age, sex, circadian chronotype, smoking and coffee habits or history of migraine) were related to CLOCK expression. CONCLUSIONS: We observed that CLOCK expression in cluster headache patients fluctuates less throughout the year than in the control population. Bout activity and lifestyle factors do not seem to influence CLOCK expression.


Assuntos
Proteínas CLOCK , Cefaleia Histamínica , Humanos , Cefaleia Histamínica/genética , Masculino , Feminino , Adulto , Proteínas CLOCK/genética , Proteínas CLOCK/biossíntese , Pessoa de Meia-Idade , Ritmo Circadiano , Estações do Ano
5.
Proc Natl Acad Sci U S A ; 118(27)2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34187898

RESUMO

An acute increase in the circulating concentration of glucocorticoid hormones is essential for the survival of severe somatic stresses. Circulating concentrations of GDF15, a hormone that acts in the brain to reduce food intake, are frequently elevated in stressful states. We now report that GDF15 potently activates the hypothalamic-pituitary-adrenal (HPA) axis in mice and rats. A blocking antibody to the GDNF-family receptor α-like receptor completely prevented the corticosterone response to GDF15 administration. In wild-type mice exposed to a range of stressful stimuli, circulating levels of both corticosterone and GDF15 rose acutely. In the case of Escherichia coli or lipopolysaccharide injections, the vigorous proinflammatory cytokine response elicited was sufficient to produce a near-maximal HPA response, regardless of the presence or absence of GDF15. In contrast, the activation of the HPA axis seen in wild-type mice in response to the administration of genotoxic or endoplasmic reticulum toxins, which do not provoke a marked rise in cytokines, was absent in Gdf15-/- mice. In conclusion, consistent with its proposed role as a sentinel hormone, endogenous GDF15 is required for the activation of the protective HPA response to toxins that do not induce a substantial cytokine response. In the context of efforts to develop GDF15 as an antiobesity therapeutic, these findings identify a biomarker of target engagement and a previously unrecognized pharmacodynamic effect, which will require monitoring in human studies.


Assuntos
Fator 15 de Diferenciação de Crescimento/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipófise-Suprarrenal/metabolismo , Animais , Cisplatino/administração & dosagem , Cisplatino/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Glucocorticoides/metabolismo , Fator 15 de Diferenciação de Crescimento/administração & dosagem , Humanos , Lipopolissacarídeos , Camundongos , Ratos , Tunicamicina/farmacologia
6.
Cell Mol Life Sci ; 79(3): 164, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35229202

RESUMO

Alternative polyadenylation in the 3' UTR (3' UTR-APA) is a mode of gene expression regulation, fundamental for mRNA stability, translation and localization. In the immune system, it was shown that upon T cell activation, there is an increase in the relative expression of mRNA isoforms with short 3' UTRs resulting from 3' UTR-APA. However, the functional significance of 3' UTR-APA remains largely unknown. Here, we studied the physiological function of 3' UTR-APA in the regulation of Myeloid Cell Leukemia 1 (MCL1), an anti-apoptotic member of the Bcl-2 family essential for T cell survival. We found that T cells produce two MCL1 mRNA isoforms (pA1 and pA2) by 3' UTR-APA. We show that upon T cell activation, there is an increase in both the shorter pA1 mRNA isoform and MCL1 protein levels. Moreover, the less efficiently translated pA2 isoform is downregulated by miR-17, which is also more expressed upon T cell activation. Therefore, by increasing the expression of the more efficiently translated pA1 mRNA isoform, which escapes regulation by miR-17, 3' UTR-APA fine tunes MCL1 protein levels, critical for activated T cells' survival. Furthermore, using CRISPR/Cas9-edited cells, we show that depletion of either pA1 or pA2 mRNA isoforms causes severe defects in mitochondria morphology, increases apoptosis and impacts cell proliferation. Collectively, our results show that MCL1 alternative polyadenylation has a key role in the regulation of MCL1 protein levels upon T cell activation and reveal an essential function for MCL1 3' UTR-APA in cell viability and mitochondria dynamics.


Assuntos
Ativação Linfocitária , MicroRNAs/metabolismo , Mitocôndrias/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Poliadenilação , Linfócitos T/metabolismo , Sobrevivência Celular , Humanos , Células Jurkat , Isoformas de RNA , Linfócitos T/fisiologia
7.
Proc Natl Acad Sci U S A ; 117(22): 12281-12287, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32424099

RESUMO

Sepsis is a life-threatening organ dysfunction condition caused by a dysregulated host response to an infection. Here we report that the circulating levels of growth and differentiation factor-15 (GDF15) are strongly increased in septic shock patients and correlate with mortality. In mice, we find that peptidoglycan is a potent ligand that signals through the TLR2-Myd88 axis for the secretion of GDF15, and that Gdf15-deficient mice are protected against abdominal sepsis due to increased chemokine CXC ligand 5 (CXCL5)-mediated recruitment of neutrophils into the peritoneum, leading to better local bacterial control. Our results identify GDF15 as a potential target to improve sepsis treatment. Its inhibition should increase neutrophil recruitment to the site of infection and consequently lead to better pathogen control and clearance.


Assuntos
Bacteriemia/imunologia , Quimiocina CXCL5/imunologia , Fator 15 de Diferenciação de Crescimento/imunologia , Neutrófilos/imunologia , Animais , Bacteriemia/genética , Bacteriemia/microbiologia , Bacteriemia/prevenção & controle , Quimiocina CXCL5/genética , Feminino , Fator 15 de Diferenciação de Crescimento/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infiltração de Neutrófilos , Cavidade Peritoneal/microbiologia
8.
Nat Immunol ; 11(6): 495-502, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20473299

RESUMO

Chemokines and other chemoattractants direct leukocyte migration and are essential for the development and delivery of immune and inflammatory responses. To probe the molecular mechanisms that underlie chemoattractant-guided migration, we did an RNA-mediated interference screen that identified several members of the synaptotagmin family of calcium-sensing vesicle-fusion proteins as mediators of cell migration: SYT7 and SYTL5 were positive regulators of chemotaxis, whereas SYT2 was a negative regulator of chemotaxis. SYT7-deficient leukocytes showed less migration in vitro and in a gout model in vivo. Chemoattractant-induced calcium-dependent lysosomal fusion was impaired in SYT7-deficient neutrophils. In a chemokine gradient, SYT7-deficient lymphocytes accumulated lysosomes in their uropods and had impaired uropod release. Our data identify a molecular pathway required for chemotaxis that links chemoattractant-induced calcium flux to exocytosis and uropod release.


Assuntos
Movimento Celular/fisiologia , Sinaptotagminas/metabolismo , Animais , Quimiocina CXCL12/metabolismo , Quimiotaxia , Immunoblotting , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase , Receptores CXCR4/metabolismo , Sinaptotagmina II/metabolismo , Sinaptotagminas/genética , Linfócitos T/imunologia
9.
Immunity ; 39(5): 874-84, 2013 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-24184056

RESUMO

Severe sepsis remains a poorly understood systemic inflammatory condition with high mortality rates and limited therapeutic options in addition to organ support measures. Here we show that the clinically approved group of anthracyclines acts therapeutically at a low dose regimen to confer robust protection against severe sepsis in mice. This salutary effect is strictly dependent on the activation of DNA damage response and autophagy pathways in the lung, as demonstrated by deletion of the ataxia telangiectasia mutated (Atm) or the autophagy-related protein 7 (Atg7) specifically in this organ. The protective effect of anthracyclines occurs irrespectively of pathogen burden, conferring disease tolerance to severe sepsis. These findings demonstrate that DNA damage responses, including the ATM and Fanconi Anemia pathways, are important modulators of immune responses and might be exploited to confer protection to inflammation-driven conditions, including severe sepsis.


Assuntos
Antraciclinas/farmacologia , Antibacterianos/farmacologia , Reparo do DNA/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Peritonite/tratamento farmacológico , Sepse/prevenção & controle , Infecções por Adenoviridae/imunologia , Animais , Antraciclinas/uso terapêutico , Antibacterianos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Proteínas Mutadas de Ataxia Telangiectasia/fisiologia , Proteína 7 Relacionada à Autofagia , Ceco/lesões , Dano ao DNA , Epirubicina/administração & dosagem , Epirubicina/farmacologia , Epirubicina/uso terapêutico , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/fisiologia , Inflamação , Mediadores da Inflamação/análise , Injeções Intraperitoneais , Pulmão/metabolismo , Meropeném , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/deficiência , Proteínas Associadas aos Microtúbulos/fisiologia , Especificidade de Órgãos , Peritonite/etiologia , Peritonite/genética , Peritonite/imunologia , Peritonite/fisiopatologia , Infecções Respiratórias/imunologia , Choque Séptico/prevenção & controle , Tienamicinas/uso terapêutico , Irradiação Corporal Total
10.
Nature ; 514(7523): 498-502, 2014 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-25341788

RESUMO

After immunogenic challenge, infiltrating and dividing lymphocytes markedly increase lymph node cellularity, leading to organ expansion. Here we report that the physical elasticity of lymph nodes is maintained in part by podoplanin (PDPN) signalling in stromal fibroblastic reticular cells (FRCs) and its modulation by CLEC-2 expressed on dendritic cells. We show in mouse cells that PDPN induces actomyosin contractility in FRCs via activation of RhoA/C and downstream Rho-associated protein kinase (ROCK). Engagement by CLEC-2 causes PDPN clustering and rapidly uncouples PDPN from RhoA/C activation, relaxing the actomyosin cytoskeleton and permitting FRC stretching. Notably, administration of CLEC-2 protein to immunized mice augments lymph node expansion. In contrast, lymph node expansion is significantly constrained in mice selectively lacking CLEC-2 expression in dendritic cells. Thus, the same dendritic cells that initiate immunity by presenting antigens to T lymphocytes also initiate remodelling of lymph nodes by delivering CLEC-2 to FRCs. CLEC-2 modulation of PDPN signalling permits FRC network stretching and allows for the rapid lymph node expansion--driven by lymphocyte influx and proliferation--that is the critical hallmark of adaptive immunity.


Assuntos
Células Dendríticas/fisiologia , Fibroblastos/citologia , Linfonodos/citologia , Células Estromais/citologia , Actomiosina/metabolismo , Animais , Membrana Celular/metabolismo , Citoesqueleto/metabolismo , Células Dendríticas/imunologia , Feminino , Fibroblastos/fisiologia , Inflamação/imunologia , Lectinas Tipo C/metabolismo , Linfonodos/imunologia , Linfonodos/metabolismo , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Células Estromais/fisiologia , Proteínas ras/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP , Proteína de Ligação a GTP rhoC
11.
Mediators Inflamm ; 2019: 8146257, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31772507

RESUMO

Acute appendicitis is the most frequent surgical abdominal emergency, but its etiology remains poorly understood. Histological examination of the appendix, following its removal due to acute appendicitis, consistently shows features in common with bronchial asthma, suggesting an allergic reaction as a candidate etiologic factor. Here, we propose the concept of appendicular lavage and use it to study the levels of the Th2 cytokines IL-4, IL-5, and IL-9 in patients with a clinical diagnosis of acute appendicitis. The study group included 20 patients with a histological diagnosis of phlegmonous appendicitis, 13 patients with gangrenous appendicitis, and a control group of 8 patients with a clinical diagnosis of appendicitis but with normal histology. Cytokine levels were higher in acute appendicitis. The difference was more pronounced when comparing phlegmonous appendicitis with nonpathological appendicitis (p = 0.01) for IL-4 (48.3 vs. 21.3 pg/mL), IL-5 (29.2 vs. 8.0 pg/mL), and IL-9 (34.1 vs. 16.6 pg/mL). This Th2 cytokine profile is compatible with the hypothesis of allergy as an etiologic factor for acute appendicitis and may have important implications for the diagnosis, prevention, and treatment of this condition.


Assuntos
Apendicite/etiologia , Apendicite/metabolismo , Citocinas/metabolismo , Hipersensibilidade/complicações , Hipersensibilidade/metabolismo , Células Th2/metabolismo , Doença Aguda , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
J Biol Chem ; 292(2): 732-747, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-27913625

RESUMO

Podocyte injury is an early event in diabetic kidney disease and is a hallmark of glomerulopathy. MicroRNA-146a (miR-146a) is highly expressed in many cell types under homeostatic conditions, and plays an important anti-inflammatory role in myeloid cells. However, its role in podocytes is unclear. Here, we show that miR-146a expression levels decrease in the glomeruli of patients with type 2 diabetes (T2D), which correlates with increased albuminuria and glomerular damage. miR-146a levels are also significantly reduced in the glomeruli of albuminuric BTBR ob/ob mice, indicating its significant role in maintaining podocyte health. miR-146a-deficient mice (miR-146a-/-) showed accelerated development of glomerulopathy and albuminuria upon streptozotocin (STZ)-induced hyperglycemia. The miR-146a targets, Notch-1 and ErbB4, were also significantly up-regulated in the glomeruli of diabetic patients and mice, suggesting induction of the downstream TGFß signaling. Treatment with a pan-ErbB kinase inhibitor erlotinib with nanomolar activity against ErbB4 significantly suppressed diabetic glomerular injury and albuminuria in both WT and miR-146a-/- animals. Treatment of podocytes in vitro with TGF-ß1 resulted in increased expression of Notch-1, ErbB4, pErbB4, and pEGFR, the heterodimerization partner of ErbB4, suggesting increased ErbB4/EGFR signaling. TGF-ß1 also increased levels of inflammatory cytokine monocyte chemoattractant protein-1 (MCP-1) and MCP-1 induced protein-1 (MCPIP1), a suppressor of miR-146a, suggesting an autocrine loop. Inhibition of ErbB4/EGFR with erlotinib co-treatment of podocytes suppressed this signaling. Our findings suggest a novel role for miR-146a in protecting against diabetic glomerulopathy and podocyte injury. They also point to ErbB4/EGFR as a novel, druggable target for therapeutic intervention, especially because several pan-ErbB inhibitors are clinically available.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/metabolismo , MicroRNAs/metabolismo , Podócitos/metabolismo , Receptor ErbB-4/biossíntese , Receptor Notch1/biossíntese , Regulação para Cima , Animais , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Cloridrato de Erlotinib/farmacologia , Camundongos , Camundongos Knockout , MicroRNAs/genética , Podócitos/patologia , Receptor ErbB-4/genética , Receptor Notch1/genética , Ribonucleases/genética , Ribonucleases/metabolismo , Fatores de Risco , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo
13.
PLoS Pathog ; 12(3): e1005524, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27031111

RESUMO

Mucosal-Associated Invariant T (MAIT) cells, present in high frequency in airway and other mucosal tissues, have Th1 effector capacity positioning them to play a critical role in the early immune response to intracellular pathogens, including Mycobacterium tuberculosis (Mtb). MR1 is a highly conserved Class I-like molecule that presents vitamin B metabolites to MAIT cells. The mechanisms for loading these ubiquitous small molecules are likely to be tightly regulated to prevent inappropriate MAIT cell activation. To define the intracellular localization of MR1, we analyzed the distribution of an MR1-GFP fusion protein in antigen presenting cells. We found that MR1 localized to endosomes and was translocated to the cell surface upon addition of 6-formyl pterin (6-FP). To understand the mechanisms by which MR1 antigens are presented, we used a lentiviral shRNA screen to identify trafficking molecules that are required for the presentation of Mtb antigen to HLA-diverse T cells. We identified Stx18, VAMP4, and Rab6 as trafficking molecules regulating MR1-dependent MAIT cell recognition of Mtb-infected cells. Stx18 but not VAMP4 or Rab6 knockdown also resulted in decreased 6-FP-dependent surface translocation of MR1 suggesting distinct pathways for loading of exogenous ligands and intracellular mycobacterially-derived ligands. We postulate that endosome-mediated trafficking of MR1 allows for selective sampling of the intracellular environment.


Assuntos
Apresentação de Antígeno/imunologia , Endossomos/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Ativação Linfocitária/imunologia , Mycobacterium tuberculosis/imunologia , Transporte Proteico/fisiologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Antígenos de Histocompatibilidade Menor , Mucosa/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Subpopulações de Linfócitos T/imunologia
14.
Immunity ; 30(4): 544-55, 2009 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-19328020

RESUMO

A unique subpopulation of spleen dendritic cells (DCs) that express the CD8 surface marker efficiently present phagocytosed antigens to CD8(+) T lymphocytes in a process called "crosspresentation," which initiates cytotoxic immune responses. We now show that the small GTPase Rac2 plays a critical role in antigen crosspresentation selectively in this DC subpopulation. In CD8(+) DCs, Rac2 determines the subcellular assembly of the NADPH oxidase complex (NOX2) to phagosomes, whereas in CD8(-) DCs, Rac1 mediates the assembly of NOX2 at the plasma membrane. In the absence of Rac2, the production of reactive oxygen species (ROS) in DC-phagosomes was abolished, the phagosomal pH dropped, and the efficiency of antigen crosspresentation was reduced. We conclude that the activity of Rac1 and 2 control crosspresentation in DC subpopulations through the regulation of phagosomal oxidation and pH.


Assuntos
Antígenos CD8 , Células Dendríticas/imunologia , Fagossomos/imunologia , Proteínas rac de Ligação ao GTP/metabolismo , Animais , Células Cultivadas , Apresentação Cruzada , Imunofluorescência , Concentração de Íons de Hidrogênio , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , NADPH Oxidase 2 , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína RAC2 de Ligação ao GTP
15.
EMBO J ; 32(18): 2454-62, 2013 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-23872947

RESUMO

SAMHD1 is a host restriction factor for human immunodeficiency virus 1 (HIV-1) in cultured human cells. SAMHD1 mutations cause autoimmune Aicardi-Goutières syndrome and are found in cancers including chronic lymphocytic leukaemia. SAMHD1 is a triphosphohydrolase that depletes the cellular pool of deoxynucleoside triphosphates, thereby preventing reverse transcription of retroviral genomes. However, in vivo evidence for SAMHD1's antiviral activity has been lacking. We generated Samhd1 null mice that do not develop autoimmune disease despite displaying a type I interferon signature in spleen, macrophages and fibroblasts. Samhd1(-/-) cells have elevated deoxynucleoside triphosphate (dNTP) levels but, surprisingly, SAMHD1 deficiency did not lead to increased infection with VSV-G-pseudotyped HIV-1 vectors. The lack of restriction is likely attributable to the fact that dNTP concentrations in SAMHD1-sufficient mouse cells are higher than the KM of HIV-1 reverse transcriptase (RT). Consistent with this notion, an HIV-1 vector mutant bearing an RT with lower affinity for dNTPs was sensitive to SAMHD1-dependent restriction in cultured cells and in mice. This shows that SAMHD1 can restrict lentiviruses in vivo and that nucleotide starvation is an evolutionarily conserved antiviral mechanism.


Assuntos
Doenças Autoimunes do Sistema Nervoso/metabolismo , Infecções por HIV/fisiopatologia , HIV-1/fisiologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Malformações do Sistema Nervoso/metabolismo , Transcrição Reversa/fisiologia , Animais , Doenças Autoimunes do Sistema Nervoso/genética , Linhagem Celular , Vetores Genéticos/genética , Infecções por HIV/genética , Transcriptase Reversa do HIV/metabolismo , HIV-1/enzimologia , Interferon Tipo I/metabolismo , Camundongos , Camundongos Knockout , Proteínas Monoméricas de Ligação ao GTP/genética , Malformações do Sistema Nervoso/genética , Nucleotídeos/metabolismo , Transcrição Reversa/genética , Proteína 1 com Domínio SAM e Domínio HD
16.
J Cell Sci ; 126(Pt 24): 5553-65, 2013 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-24105262

RESUMO

Exosomes are extracellular vesicles (EVs) secreted upon fusion of endosomal multivesicular bodies (MVBs) with the plasma membrane. The mechanisms involved in their biogenesis have not yet been fully identified although they could be used to modulate exosome formation and therefore are a promising tool in understanding exosome functions. We have performed an RNA interference screen targeting 23 components of the endosomal sorting complex required for transport (ESCRT) machinery and associated proteins in MHC class II (MHC II)-expressing HeLa-CIITA cells. Silencing of HRS, STAM1 or TSG101 reduced the secretion of EV-associated CD63 and MHC II but each gene altered differently the size and/or protein composition of secreted EVs, as quantified by immuno-electron microscopy. By contrast, depletion of VPS4B augmented this secretion while not altering the features of EVs. For several other ESCRT subunits, it was not possible to draw any conclusions about their involvement in exosome biogenesis from the screen. Interestingly, silencing of ALIX increased MHC II exosomal secretion, as a result of an overall increase in intracellular MHC II protein and mRNA levels. In human dendritic cells (DCs), ALIX depletion also increased MHC II in the cells, but not in the released CD63-positive EVs. Such differences could be attributed to a greater heterogeneity in size, and higher MHC II and lower CD63 levels in vesicles recovered from DCs as compared with HeLa-CIITA. The results reveal a role for selected ESCRT components and accessory proteins in exosome secretion and composition by HeLa-CIITA. They also highlight biogenetic differences in vesicles secreted by a tumour cell line and primary DCs.


Assuntos
Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Exossomos/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Dendríticas/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Técnicas de Silenciamento de Genes , Células HeLa , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Microscopia Imunoeletrônica , Corpos Multivesiculares/metabolismo , RNA Interferente Pequeno/genética , Tetraspanina 30/metabolismo
18.
Trends Endocrinol Metab ; 35(3): 177-179, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38302400

RESUMO

Pseudomonas aeruginosa is an opportunistic pathogen of great medical relevance, although the mechanisms involved in chronic P. aeruginosa infection are unclear. Tomlinson et al. have now shown that systemic and local pathogen-induced ketone bodies (KBs) select strains that preserve respiratory integrity by failing to substantially increase glycolysis, which drives immunopathology resulting from resistance mechanisms.


Assuntos
Fosforilação Oxidativa , Infecções por Pseudomonas , Humanos , Corpos Cetônicos
19.
Cell Metab ; 36(5): 927-946, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38513649

RESUMO

Effective responses against severe systemic infection require coordination between two complementary defense strategies that minimize the negative impact of infection on the host: resistance, aimed at pathogen elimination, and disease tolerance, which limits tissue damage and preserves organ function. Resistance and disease tolerance mostly rely on divergent metabolic programs that may not operate simultaneously in time and space. Due to evolutionary reasons, the host initially prioritizes the elimination of the pathogen, leading to dominant resistance mechanisms at the potential expense of disease tolerance, which can contribute to organ failure. Here, we summarize our current understanding of the role of physiological perturbations resulting from infection in immune response dynamics and the metabolic program requirements associated with resistance and disease tolerance mechanisms. We then discuss how insight into the interplay of these mechanisms could inform future research aimed at improving sepsis outcomes and the potential for therapeutic interventions.


Assuntos
Sepse , Sepse/metabolismo , Humanos , Animais , Infecções/metabolismo , Reprogramação Metabólica
20.
Cells ; 13(11)2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38891095

RESUMO

Basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) are high-incidence, non-melanoma skin cancers (NMSCs). The success of immune-targeted therapies in advanced NMSCs led us to anticipate that NMSCs harbored significant populations of tumor-infiltrating lymphocytes with potential anti-tumor activity. The main aim of this study was to characterize T cells infiltrating NMSCs. Flow cytometry and immunohistochemistry were used to assess, respectively, the proportions and densities of T cell subpopulations in BCCs (n = 118), SCCs (n = 33), and normal skin (NS, n = 30). CD8+ T cells, CD4+ T cell subsets, namely, Th1, Th2, Th17, Th9, and regulatory T cells (Tregs), CD8+ and CD4+ memory T cells, and γδ T cells were compared between NMSCs and NS samples. Remarkably, both BCCs and SCCs featured a significantly higher Th1/Th2 ratio (~four-fold) and an enrichment for Th17 cells. NMSCs also showed a significant enrichment for IFN-γ-producing CD8+T cells, and a depletion of γδ T cells. Using immunohistochemistry, NMSCs featured denser T cell infiltrates (CD4+, CD8+, and Tregs) than NS. Overall, these data favor a Th1-predominant response in BCCs and SCCs, providing support for immune-based treatments in NMSCs. Th17-mediated inflammation may play a role in the progression of NMSCs and thus become a potential therapeutic target in NMSCs.


Assuntos
Carcinoma Basocelular , Carcinoma de Células Escamosas , Linfócitos do Interstício Tumoral , Neoplasias Cutâneas , Células Th1 , Células Th17 , Humanos , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/patologia , Células Th17/imunologia , Linfócitos do Interstício Tumoral/imunologia , Células Th1/imunologia , Carcinoma Basocelular/imunologia , Carcinoma Basocelular/patologia , Feminino , Masculino , Idoso , Estudos Transversais , Pessoa de Meia-Idade , Linfócitos T CD8-Positivos/imunologia , Idoso de 80 Anos ou mais , Adulto
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