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1.
Cell ; 185(24): 4526-4540.e18, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36347253

RESUMO

Low-molecular-weight (LMW) thiols are small-molecule antioxidants required for the maintenance of intracellular redox homeostasis. However, many host-associated microbes, including the gastric pathogen Helicobacter pylori, unexpectedly lack LMW-thiol biosynthetic pathways. Using reactivity-guided metabolomics, we identified the unusual LMW thiol ergothioneine (EGT) in H. pylori. Dietary EGT accumulates to millimolar levels in human tissues and has been broadly implicated in mitigating disease risk. Although certain microorganisms synthesize EGT, we discovered that H. pylori acquires this LMW thiol from the host environment using a highly selective ATP-binding cassette transporter-EgtUV. EgtUV confers a competitive colonization advantage in vivo and is widely conserved in gastrointestinal microbes. Furthermore, we found that human fecal bacteria metabolize EGT, which may contribute to production of the disease-associated metabolite trimethylamine N-oxide. Collectively, our findings illustrate a previously unappreciated mechanism of microbial redox regulation in the gut and suggest that inter-kingdom competition for dietary EGT may broadly impact human health.


Assuntos
Ergotioneína , Humanos , Ergotioneína/metabolismo , Antioxidantes/metabolismo , Oxirredução , Compostos de Sulfidrila , Peso Molecular
2.
Cell ; 166(6): 1512-1525.e12, 2016 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-27610573

RESUMO

Acute infections are associated with a set of stereotypic behavioral responses, including anorexia, lethargy, and social withdrawal. Although these so-called sickness behaviors are the most common and familiar symptoms of infections, their roles in host defense are largely unknown. Here, we investigated the role of anorexia in models of bacterial and viral infections. We found that anorexia was protective while nutritional supplementation was detrimental in bacterial sepsis. Furthermore, glucose was necessary and sufficient for these effects. In contrast, nutritional supplementation protected against mortality from influenza infection and viral sepsis, whereas blocking glucose utilization was lethal. In both bacterial and viral models, these effects were largely independent of pathogen load and magnitude of inflammation. Instead, we identify opposing metabolic requirements tied to cellular stress adaptations critical for tolerance of differential inflammatory states. VIDEO ABSTRACT.


Assuntos
Gerenciamento Clínico , Jejum , Glucose/metabolismo , Comportamento de Doença/fisiologia , Influenza Humana/metabolismo , Listeriose/metabolismo , Apoio Nutricional/efeitos adversos , Animais , Antimetabólitos/uso terapêutico , Células Cultivadas , Desoxiglucose/uso terapêutico , Glucose/administração & dosagem , Humanos , Inflamação , Influenza Humana/fisiopatologia , Influenza Humana/terapia , Lipopolissacarídeos , Listeriose/mortalidade , Listeriose/fisiopatologia , Listeriose/terapia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Poli I-C , Sepse/induzido quimicamente , Sepse/prevenção & controle , Fator de Transcrição CHOP/metabolismo
3.
Nature ; 598(7882): 682-687, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34671158

RESUMO

Tumours use various strategies to evade immune surveillance1,2. Immunotherapies targeting tumour immune evasion such as immune checkpoint blockade have shown considerable efficacy on multiple cancers3,4 but are ineffective for most patients due to primary or acquired resistance5-7. Recent studies showed that some epigenetic regulators suppress anti-tumour immunity2,8-12, suggesting that epigenetic therapies could boost anti-tumour immune responses and overcome resistance to current immunotherapies. Here we show that, in mouse melanoma models, depletion of KDM5B-an H3K4 demethylase that is critical for melanoma maintenance and drug resistance13-15-induces robust adaptive immune responses and enhances responses to immune checkpoint blockade. Mechanistically, KDM5B recruits the H3K9 methyltransferase SETDB1 to repress endogenous retroelements such as MMVL30 in a demethylase-independent manner. Derepression of these retroelements activates cytosolic RNA-sensing and DNA-sensing pathways and the subsequent type-I interferon response, leading to tumour rejection and induction of immune memory. Our results demonstrate that KDM5B suppresses anti-tumour immunity by epigenetic silencing of retroelements. We therefore reveal roles of KDM5B in heterochromatin regulation and immune evasion in melanoma, opening new paths for the development of KDM5B-targeting and SETDB1-targeting therapies to enhance tumour immunogenicity and overcome immunotherapy resistance.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Inativação Gênica , Histona-Lisina N-Metiltransferase/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Melanoma/imunologia , Retroelementos , Evasão Tumoral , Animais , Linhagem Celular Tumoral , Epigênese Genética , Heterocromatina , Humanos , Interferon Tipo I/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares , Proteínas Repressoras
4.
PLoS Biol ; 21(10): e3002331, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37862360

RESUMO

Arthropod-borne pathogens cause some of the most important human and animal infectious diseases. Many vectors acquire or transmit pathogens through the process of blood feeding. Here, we report adiponectin, the most abundant adipocyte-derived hormone circulating in human blood, directly or indirectly inhibits acquisition of the Lyme disease agent, Borrelia burgdorferi, by Ixodes scapularis ticks. Rather than altering tick feeding or spirochete viability, adiponectin or its associated factors induces host histamine release when the tick feeds, which leads to vascular leakage, infiltration of neutrophils and macrophages, and inflammation at the bite site. Consistent with this, adiponectin-deficient mice have diminished pro-inflammatory responses, including interleukin (IL)-12 and IL-1ß, following a tick bite, compared with wild-type animals. All these factors mediated by adiponectin or associated factors influence B. burgdorferi survival at the tick bite site. These results suggest a host adipocyte-derived hormone modulates pathogen acquisition by a blood-feeding arthropod.


Assuntos
Grupo Borrelia Burgdorferi , Ixodes , Doença de Lyme , Picadas de Carrapatos , Animais , Camundongos , Humanos , Adiponectina , Grupo Borrelia Burgdorferi/fisiologia , Ixodes/fisiologia , Mamíferos
5.
Cell ; 145(5): 745-57, 2011 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-21565393

RESUMO

Inflammasomes are multiprotein complexes that function as sensors of endogenous or exogenous damage-associated molecular patterns. Here, we show that deficiency of NLRP6 in mouse colonic epithelial cells results in reduced IL-18 levels and altered fecal microbiota characterized by expanded representation of the bacterial phyla Bacteroidetes (Prevotellaceae) and TM7. NLRP6 inflammasome-deficient mice were characterized by spontaneous intestinal hyperplasia, inflammatory cell recruitment, and exacerbation of chemical colitis induced by exposure to dextran sodium sulfate (DSS). Cross-fostering and cohousing experiments revealed that the colitogenic activity of this microbiota is transferable to neonatal or adult wild-type mice, leading to exacerbation of DSS colitis via induction of the cytokine, CCL5. Antibiotic treatment and electron microscopy studies further supported the role of Prevotellaceae as a key representative of this microbiota-associated phenotype. Altogether, perturbations in this inflammasome pathway, including NLRP6, ASC, caspase-1, and IL-18, may constitute a predisposing or initiating event in some cases of human IBD.


Assuntos
Colite/imunologia , Colite/microbiologia , Colo/microbiologia , Inflamassomos/imunologia , Receptores de Superfície Celular/metabolismo , Animais , Bactérias/classificação , Bacteroidetes , Quimiocina CCL5/metabolismo , Colite/induzido quimicamente , Colite/fisiopatologia , Colo/imunologia , Sulfato de Dextrana , Suscetibilidade a Doenças , Interleucina-18/imunologia , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Receptores de Superfície Celular/genética
6.
PLoS Pathog ; 16(11): e1009030, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33175909

RESUMO

Lyme disease, the most common vector-borne illness in North America, is caused by the spirochete Borrelia burgdorferi. Infection begins in the skin following a tick bite and can spread to the hearts, joints, nervous system, and other organs. Diverse host responses influence the level of B. burgdorferi infection in mice and humans. Using a systems biology approach, we examined potential molecular interactions between human extracellular and secreted proteins and B. burgdorferi. A yeast display library expressing 1031 human extracellular proteins was probed against 36 isolates of B. burgdorferi sensu lato. We found that human Peptidoglycan Recognition Protein 1 (PGLYRP1) interacted with the vast majority of B. burgdorferi isolates. In subsequent experiments, we demonstrated that recombinant PGLYRP1 interacts with purified B. burgdorferi peptidoglycan and exhibits borreliacidal activity, suggesting that vertebrate hosts may use PGLYRP1 to identify B. burgdorferi. We examined B. burgdorferi infection in mice lacking PGLYRP1 and observed an increased spirochete burden in the heart and joints, along with splenomegaly. Mice lacking PGLYRP1 also showed signs of immune dysregulation, including lower serum IgG levels and higher levels of IFNγ, CXCL9, and CXCL10.Taken together, our findings suggest that PGLYRP1 plays a role in the host's response to B. burgdorferi and further demonstrate the utility of expansive yeast display screening in capturing biologically relevant interactions between spirochetes and their hosts.


Assuntos
Borrelia burgdorferi/fisiologia , Citocinas/metabolismo , Doença de Lyme/microbiologia , Animais , Citocinas/genética , Biblioteca Gênica , Humanos , Camundongos , Camundongos Endogâmicos BALB C
7.
Proc Natl Acad Sci U S A ; 116(6): 2200-2209, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30674681

RESUMO

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a highly mortal complication associated with sepsis. In adults, it is often seen in the setting of infections, especially viral infections, but the mechanisms that underlie pathogenesis are unknown. sHLH is characterized by a hyperinflammatory state and the presence hemophagocytosis. We found that sequential challenging of mice with a nonlethal dose of viral toll-like receptor (TLR) agonist followed by a nonlethal dose of TLR4 agonist, but not other permutations, produced a highly lethal state that recapitulates many aspects of human HLH. We found that this hyperinflammatory response could be recapitulated in vitro in bone marrow-derived macrophages. RNA sequencing analyses revealed dramatic up-regulation of the red-pulp macrophage lineage-defining transcription factor SpiC and its associated transcriptional program, which was also present in bone marrow macrophages sorted from patients with sHLH. Transcriptional profiling also revealed a unique metabolic transcriptional profile in these macrophages, and immunometabolic phenotyping revealed impaired mitochondrial function and oxidative metabolism and a reliance on glycolytic metabolism. Subsequently, we show that therapeutic administration of the glycolysis inhibitor 2-deoxyglucose was sufficient to rescue animals from HLH. Together, these data identify a potential mechanism for the pathogenesis of sHLH and a potentially useful therapeutic strategy for its treatment.


Assuntos
Doenças Transmissíveis/complicações , Linfo-Histiocitose Hemofagocítica/etiologia , Animais , Biomarcadores , Contagem de Células Sanguíneas , Linhagem Celular , Doenças Transmissíveis/microbiologia , Doenças Transmissíveis/virologia , Citocinas/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Lipopolissacarídeos/efeitos adversos , Lipopolissacarídeos/imunologia , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Metabolômica/métodos , Camundongos , Camundongos Knockout , Receptores Toll-Like/antagonistas & inibidores , Receptores Toll-Like/metabolismo
8.
Proc Natl Acad Sci U S A ; 116(27): 13498-13507, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31209025

RESUMO

Lyme disease is a multisystem disorder caused by the spirochete Borrelia burgdorferi A common late-stage complication of this disease is oligoarticular arthritis, often involving the knee. In ∼10% of cases, arthritis persists after appropriate antibiotic treatment, leading to a proliferative synovitis typical of chronic inflammatory arthritides. Here, we provide evidence that peptidoglycan (PG), a major component of the B. burgdorferi cell envelope, may contribute to the development and persistence of Lyme arthritis (LA). We show that B. burgdorferi has a chemically atypical PG (PGBb) that is not recycled during cell-wall turnover. Instead, this pathogen sheds PGBb fragments into its environment during growth. Patients with LA mount a specific immunoglobulin G response against PGBb, which is significantly higher in the synovial fluid than in the serum of the same patient. We also detect PGBb in 94% of synovial fluid samples (32 of 34) from patients with LA, many of whom had undergone oral and intravenous antibiotic treatment. These same synovial fluid samples contain proinflammatory cytokines, similar to those produced by human peripheral blood mononuclear cells stimulated with PGBb In addition, systemic administration of PGBb in BALB/c mice elicits acute arthritis. Altogether, our study identifies PGBb as a likely contributor to inflammatory responses in LA. Persistence of this antigen in the joint may contribute to synovitis after antibiotics eradicate the pathogen. Furthermore, our finding that B. burgdorferi sheds immunogenic PGBb fragments during growth suggests a potential role for PGBb in the immunopathogenesis of other Lyme disease manifestations.


Assuntos
Antígenos de Bactérias/imunologia , Borrelia burgdorferi/imunologia , Doença de Lyme/imunologia , Peptidoglicano/imunologia , Imunidade Adaptativa/imunologia , Animais , Citocinas/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Peptidoglicano/análise , Peptidoglicano/química , Líquido Sinovial/química , Líquido Sinovial/imunologia
9.
Nat Immunol ; 10(6): 603-9, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19448631

RESUMO

Interleukin 23 (IL-23) and IL-17 have been linked to the pathogenesis of several chronic inflammatory disorders, including inflammatory bowel disease. Yet as an important function for IL-23 is emerging, the function of IL-17 in inflammatory bowel disease remains unclear. Here we demonstrate IL-17A-mediated protection in the CD45RBhi transfer model of colitis. An accelerated wasting disease elicited by T cells deficient in IL-17A correlated with higher expression of genes encoding T helper type 1-type cytokines in colon tissue. IL-17A also modulated T helper type 1 polarization in vitro. Furthermore, T cells deficient in the IL-17 receptor elicited an accelerated, aggressive wasting disease relative to that elicited by wild-type T cells in recipient mice. Our data demonstrate a protective function for IL-17 and identify T cells as not only the source but also a target of IL-17 in vivo.


Assuntos
Colite/imunologia , Interleucina-17/imunologia , Células Th1/imunologia , Síndrome de Emaciação/imunologia , Transferência Adotiva , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Interferon gama , Interleucina-17/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Receptores de Interleucina-17/imunologia , Proteínas com Domínio T/metabolismo
10.
Proc Natl Acad Sci U S A ; 115(43): 11042-11047, 2018 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-30291189

RESUMO

Sickness behaviors are a conserved set of stereotypic responses to inflammatory diseases. We recently demonstrated that interfering with inflammation-induced anorexia led to metabolic changes that had profound effects on survival of acute inflammatory conditions. We found that different inflammatory states needed to be coordinated with corresponding metabolic programs to actuate tissue-protective mechanisms. Survival of viral inflammation required intact glucose utilization pathways, whereas survival of bacterial inflammation required alternative fuel substrates and ketogenic programs. We thus hypothesized that organismal metabolism would be important in other classes of infectious inflammation and sought to understand its role in the prototypic parasitic disease malaria. Utilizing the cerebral malaria model, Plasmodium berghei ANKA (PbA) infection in C57BL/6J male mice, we unexpectedly found that inhibition of glycolysis using 2-deoxy glucose (2DG) conferred protection from cerebral malaria. Unlike vehicle-treated animals, 2DG-treated animals did not develop cerebral malaria and survived until ultimately succumbing to fatal anemia. We did not find any differences in parasitemia or pathogen load in affected tissues. There were no differences in the kinetics of anemia. We also did not detect differences in immune infiltration in the brain or in blood-brain barrier permeability. Rather, on pathological analyses performed on the entire brain, we found that 2DG prevented the formation of thrombi and thrombotic complications. Using thromboelastography (TEG), we found that 2DG-treated animals formed clots that were significantly less strong and stable. Together, these data suggest that glucose metabolism is involved in inflammation-induced hemostasis and provide a potential therapeutic target in treatment of cerebral malaria.


Assuntos
Encéfalo/imunologia , Encéfalo/parasitologia , Glucose/imunologia , Glucose/metabolismo , Tolerância Imunológica/imunologia , Malária Cerebral/imunologia , Malária Cerebral/metabolismo , Animais , Barreira Hematoencefálica/imunologia , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/parasitologia , Modelos Animais de Doenças , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/parasitologia , Malária Cerebral/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Parasitemia/imunologia , Plasmodium berghei/imunologia
11.
J Neurosci ; 39(24): 4829-4841, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-30971439

RESUMO

Absence epilepsy is a heritable human neurological disorder characterized by brief nonconvulsive seizures with behavioral arrest, moderate-to-severe loss of consciousness (absence), and distinct spike-wave discharges (SWDs) in the EEG and electrocorticogram (ECoG). Genetic models of this disorder have been created by selectively inbreeding rats for absence seizure-like events with similar electrical and behavioral characteristics. However, these events are also common in outbred laboratory rats, raising concerns about whether SWD/immobility accurately reflects absence epilepsy as opposed to "normal" rodent behavior. We hypothesized that, if SWD/immobility models absence seizures, it would not exist in wild-caught rats due to the pressures of natural selection. To test this hypothesis, we compared chronic video/electrocorticogram recordings from male and female wild-caught (Brown-Norway [BN]) rats to recordings from laboratory outbred BN, outbred Long-Evans, and inbred WAG/Rij rats (i.e., a model of absence epilepsy). Wild-caught BN rats displayed absence-like SWD/immobility events that were highly similar to outbred BN rats in terms of spike-wave morphology, frequency, diurnal rhythmicity, associated immobility, and sensitivity to the anti-absence drug, ethosuximide; however, SWD bursts were less frequent and of shorter duration in wild-caught and outbred BN rats than the outbred Long-Evans and inbred WAG/Rij strains. We conclude that SWD/immobility in rats does not represent absence seizures, although they appear to have many similarities. In wild rats, SWD/immobility appears to represent normal brain activity that does not reduce survival in natural environments, a conclusion that logically extends to outbred laboratory rats and possibly to those that have been inbred to model absence epilepsy.SIGNIFICANCE STATEMENT Spike-wave discharges (SWDs), behavioral arrest, and diminished consciousness are cardinal signs of seizures in human absence epilepsy and are used to model this disorder in inbred rats. These characteristics, however, are routinely found in outbred laboratory rats, leading to debate on whether SWD/immobility is a valid model of absence seizures. The SWD/immobility events in wild-caught rats appear equivalent to those found in outbred and inbred rat strains, except for lower incidence and shorter durations. Our results indicate that the electrophysiological and behavioral characteristics of events underlying hypothetical absence epilepsy in rodent models are found in wild rats captured in their natural environment. Other criteria beyond observation of SWDs and associated immobility are required to objectively establish absence epilepsy in rat models.


Assuntos
Convulsões/psicologia , Animais , Animais Selvagens , Anticonvulsivantes/farmacologia , Ritmo Circadiano , Eletrocorticografia , Eletroencefalografia , Etossuximida/farmacologia , Feminino , Masculino , Atividade Motora/efeitos dos fármacos , Movimento , Ratos , Ratos Long-Evans , Convulsões/prevenção & controle
12.
Infect Immun ; 88(12)2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-32928964

RESUMO

Borrelia burgdorferi causes Lyme disease, the most common tick-transmitted illness in North America. When Ixodes scapularis feed on an infected vertebrate host, spirochetes enter the tick gut along with the bloodmeal and colonize the vector. Here, we show that a secreted tick protein, I. scapularisprotein disulfide isomerase A3 (IsPDIA3), enhances B. burgdorferi colonization of the tick gut. I. scapularis ticks in which ispdiA3 has been knocked down using RNA interference have decreased spirochete colonization of the tick gut after engorging on B. burgdorferi-infected mice. Moreover, administration of IsPDIA3 antiserum to B. burgdorferi-infected mice reduced the ability of spirochetes to colonize the tick when feeding on these animals. We show that IsPDIA3 modulates inflammatory responses at the tick bite site, potentially facilitating spirochete survival at the vector-host interface as it exits the vertebrate host to enter the tick gut. These data provide functional insights into the complex interactions between B. burgdorferi and its arthropod vector and suggest additional targets to interfere with the spirochete life cycle.


Assuntos
Borrelia burgdorferi/fisiologia , Ixodes/metabolismo , Doença de Lyme/transmissão , Isomerases de Dissulfetos de Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Vetores Aracnídeos/microbiologia , Linhagem Celular , Técnicas de Silenciamento de Genes , Humanos , Imunidade Humoral , Inflamação/enzimologia , Inflamação/genética , Inflamação/metabolismo , Ixodes/enzimologia , Ixodes/genética , Proteínas de Membrana/metabolismo , Camundongos , Filogenia , Isomerases de Dissulfetos de Proteínas/genética , Isomerases de Dissulfetos de Proteínas/imunologia , Interferência de RNA , Proteínas Recombinantes , Alinhamento de Sequência , Spirochaetales/fisiologia
13.
Immunity ; 34(4): 554-65, 2011 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-21511184

RESUMO

T helper 17 (Th17) cells are important for host defense against extracellular microorganisms. However, they are also implicated in autoimmune and chronic inflammatory diseases, and as such need to be tightly regulated. The mechanisms that directly control committed pathogenic Th17 cells in vivo remain unclear. We showed here that IL-17A-producing CD4+ T cells expressed interleukin-10 receptor α (IL-10Rα) in vivo. Importantly, T cell-specific blockade of IL-10 signaling led to a selective increase of IL-17A+IFN-γ⁻ (Th17) and IL-17A+IFN-γ+ (Th17+Th1) CD4+ T cells during intestinal inflammation in the small intestine. CD4+Foxp3⁻ IL-10-producing (Tr1) cells and CD4+Foxp3+ regulatory (Treg) cells were able to control Th17 and Th17+Th1 cells in an IL-10-dependent manner in vivo. Lastly, IL-10 treatment of mice with established colitis decreased Th17 and Th17+Th1 cell frequencies via direct signaling in T cells. Thus, IL-10 signaling directly suppresses Th17 and Th17+Th1 cells.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Subunidade alfa de Receptor de Interleucina-10/imunologia , Interleucina-10/imunologia , Células Th17/imunologia , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Proliferação de Células , Colite/imunologia , Colite/patologia , Progressão da Doença , Fatores de Transcrição Forkhead/imunologia , Interferon gama/imunologia , Interleucina-10/metabolismo , Subunidade alfa de Receptor de Interleucina-10/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fragmentos de Peptídeos/imunologia , Transdução de Sinais , Células Th17/citologia , Células Th17/metabolismo
14.
J Neurosci ; 37(24): 5861-5869, 2017 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-28522734

RESUMO

Genetically inherited absence epilepsy in humans is typically characterized by brief (seconds) spontaneous seizures, which involve spike-wave discharges (SWDs) in the EEG and interruption of consciousness and ongoing behavior. Genetic (inbred) models of this disorder in rats have been used to examine mechanisms, comorbidities, and antiabsence drugs. SWDs have also been proposed as models of complex partial seizures (CPSs) following traumatic brain injury (post-traumatic epilepsy). However, the ictal characteristics of these rat models, including SWDs and associated immobility, are also prevalent in healthy outbred laboratory rats. We therefore hypothesized that SWDs are not always associated with classically defined absence seizures or CPSs. To test this hypothesis, we used operant conditioning in male rats to determine whether outbred strains, Sprague Dawley and Long-Evans, and/or the inbred WAG/Rij strain (a rat model of heritable human absence epilepsy) could exercise voluntary control over these epileptiform events. We discovered that both inbred and outbred rats could shorten the duration of SWDs to obtain a reward. These results indicate that SWD and associated immobility in rats may not reflect the obvious cognitive/behavioral interruption classically associated with absence seizures or CPSs in humans. One interpretation of these results is that human absence seizures and perhaps CPSs could permit a far greater degree of cognitive capacity than often assumed and might be brought under voluntary control in some cases. However, these results also suggest that SWDs and associated immobility may be nonepileptic in healthy outbred rats and reflect instead voluntary rodent behavior unrelated to genetic manipulation or to brain trauma.SIGNIFICANCE STATEMENT Our evidence that inbred and outbred rats learn to control the duration of spike-wave discharges (SWDs) suggests a voluntary behavior with maintenance of consciousness. If SWDs model mild absence seizures and/or complex partial seizures in humans, then an opportunity may exist for operant control complementing or in some cases replacing medication. Their equal occurrence in outbred rats also implies a major potential confound for behavioral neuroscience experiments, at least in adult rats where SWDs are prevalent. Alternatively, the presence and voluntary control of SWDs in healthy outbred rats could indicate that these phenomena do not always model heritable absence epilepsy or post-traumatic epilepsy in humans, and may instead reflect typical rodent behavior.


Assuntos
Potenciais de Ação , Biorretroalimentação Psicológica/métodos , Ondas Encefálicas , Encéfalo/fisiopatologia , Epilepsia/fisiopatologia , Volição , Animais , Masculino , Ratos , Ratos Long-Evans , Ratos Sprague-Dawley , Vigília
15.
Blood ; 127(1): 102-12, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26385350

RESUMO

Somatic hypermutation and class-switch recombination of the immunoglobulin (Ig) genes occur in germinal center (GC) B cells and are initiated through deamination of cytidine to uracil by activation-induced cytidine deaminase (AID). Resulting uracil-guanine mismatches are processed by uracil DNA glycosylase (UNG)-mediated base-excision repair and MSH2-mediated mismatch repair (MMR) to yield mutations and DNA strand lesions. Although off-target AID activity also contributes to oncogenic point mutations and chromosome translocations associated with GC and post-GC B-cell lymphomas, the role of downstream AID-associated DNA repair pathways in the pathogenesis of lymphoma is unknown. Here, we show that simultaneous deficiency of UNG and MSH2 or MSH2 alone causes genomic instability and a shorter latency to the development of BCL6-driven diffuse large B-cell lymphoma (DLBCL) in a murine model. The additional development of several BCL6-independent malignancies in these mice underscores the critical role of MMR in maintaining general genomic stability. In contrast, absence of UNG alone is highly protective and prevents the development of BCL6-driven DLBCL. We further demonstrate that clonal and nonclonal mutations arise within non-Ig AID target genes in the combined absence of UNG and MSH2 and that DNA strand lesions arise in an UNG-dependent manner but are offset by MSH2. These findings lend insight into a complex interplay whereby potentially deleterious UNG activity and general genomic instability are opposed by the protective influence of MSH2, producing a net protective effect that promotes immune diversification while simultaneously attenuating malignant transformation of GC B cells.


Assuntos
Transformação Celular Neoplásica/patologia , Citidina Desaminase/metabolismo , Reparo do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Proteína 2 Homóloga a MutS/fisiologia , Uracila-DNA Glicosidase/fisiologia , Animais , Linfócitos B/metabolismo , Linfócitos B/patologia , Transformação Celular Neoplásica/genética , Proteínas de Ligação a DNA/genética , Feminino , Citometria de Fluxo , Perfilação da Expressão Gênica , Centro Germinativo , Técnicas Imunoenzimáticas , Switching de Imunoglobulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Proteínas Proto-Oncogênicas c-bcl-6 , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Hipermutação Somática de Imunoglobulina/genética , Cariotipagem Espectral , Células Tumorais Cultivadas
16.
Nature ; 491(7423): 259-63, 2012 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-23075849

RESUMO

Chronic mucosal inflammation and tissue damage predisposes patients to the development of colorectal cancer. This association could be explained by the hypothesis that the same factors and pathways important for wound healing also promote tumorigenesis. A sensor of tissue damage should induce these factors to promote tissue repair and regulate their action to prevent development of cancer. Interleukin 22 (IL-22), a cytokine of the IL-10 superfamily, has an important role in colonic epithelial cell repair, and its levels are increased in the blood and intestine of inflammatory bowel disease patients. This cytokine can be neutralized by the soluble IL-22 receptor, known as the IL-22 binding protein (IL-22BP, also known as IL22RA2); however, the significance of endogenous IL-22BP in vivo and the pathways that regulate this receptor are unknown. Here we describe that IL-22BP has a crucial role in controlling tumorigenesis and epithelial cell proliferation in the colon. IL-22BP is highly expressed by dendritic cells in the colon in steady-state conditions. Sensing of intestinal tissue damage via the NLRP3 or NLRP6 inflammasomes led to an IL-18-dependent downregulation of IL-22BP, thereby increasing the ratio of IL-22/IL-22BP. IL-22, which is induced during intestinal tissue damage, exerted protective properties during the peak of damage, but promoted tumour development if uncontrolled during the recovery phase. Thus, the IL-22-IL-22BP axis critically regulates intestinal tissue repair and tumorigenesis in the colon.


Assuntos
Transformação Celular Neoplásica , Inflamassomos/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/patologia , Receptores de Interleucina/metabolismo , Animais , Colite/complicações , Colite/metabolismo , Colite/patologia , Colo/metabolismo , Colo/patologia , Neoplasias do Colo/complicações , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Modelos Animais de Doenças , Regulação para Baixo , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Genes APC , Interleucina-18/metabolismo , Interleucinas/deficiência , Interleucinas/genética , Interleucinas/metabolismo , Camundongos , Camundongos Knockout , Receptores de Interleucina/deficiência , Receptores de Interleucina/genética , Fatores de Tempo , Redução de Peso , Interleucina 22
17.
Br J Haematol ; 178(4): 616-628, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28466468

RESUMO

In a dominant mouse ethylnitrosurea mutagenesis screen for genes regulating erythropoiesis, we identified a pedigree with a novel microcytic hypochromia caused by a V235G missense mutation in Dynamin 2 (Dnm2). Mutations in Dnm2, a GTPase, are highly disease-specific and have been implicated in four forms of human diseases: centronuclear myopathy, Charcot-Marie Tooth neuropathy and, more recently, T-cell leukaemia and Hereditary Spastic Paraplegia, but red cell abnormalities have not been reported to date. The V235G mutation lies within a crucial GTP nucleotide-binding pocket of Dnm2, and resulted in defective GTPase activity and incompatibility with life in the homozygous state. Dnm2 is an essential mediator of clathrin-mediated endocytosis, which is required for the uptake of transferrin (Tf) into red cells for incorporation of haem. Accordingly, we observed significantly reduced Tf uptake by Dnm2+/V235G cells, which led to impaired endosome formation. Despite these deficiencies, surprisingly all iron studies were unchanged, suggesting an unexplained alternative mechanism underlies microcytic anaemia in Dnm2+/V235G mice. This study provides the first in vivo evidence for the requirements of Dnm2 in normal erythropoiesis.


Assuntos
Anemia Hipocrômica/genética , Dinamina II/genética , Mutação de Sentido Incorreto , Anemia Hipocrômica/sangue , Animais , Mapeamento Cromossômico/métodos , Modelos Animais de Doenças , Dinamina II/deficiência , Dinamina II/fisiologia , Endocitose/genética , Endocitose/fisiologia , Eritrócitos/metabolismo , Eritrócitos/patologia , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Camundongos Knockout , Transferrina/metabolismo
18.
Circ Res ; 116(10): 1670-9, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-25801896

RESUMO

RATIONALE: Early graft inflammation enhances both acute and chronic rejection of heart transplants, but it is unclear how this inflammation is initiated. OBJECTIVE: To identify specific inflammatory modulators and determine their underlying molecular mechanisms after cardiac transplantation. METHODS AND RESULTS: We used a murine heterotopic cardiac transplant model to identify inflammatory modulators of early graft inflammation. Unbiased mass spectrometric analysis of cardiac tissue before and ≤72 hours after transplantation revealed that 22 proteins including haptoglobin, a known antioxidant, are significantly upregulated in our grafts. Through the use of haptoglobin-deficient mice, we show that 80% of haptoglobin-deficient recipients treated with perioperative administration of the costimulatory blocking agent CTLA4 immunoglobulin exhibited >100-day survival of full major histocompatibility complex mismatched allografts, whereas all similarly treated wild-type recipients rejected their transplants by 21 days after transplantation. We found that haptoglobin modifies the intra-allograft inflammatory milieu by enhancing levels of the inflammatory cytokine interleukin-6 and the chemokine MIP-2 (macrophage inflammatory protein 2) but impair levels of the immunosuppressive cytokine interleukin-10. Haptoglobin also enhances dendritic cell graft recruitment and augments antidonor T-cell responses. Moreover, we confirmed that the protein is present in human cardiac allograft specimens undergoing acute graft rejection. CONCLUSIONS: Our findings provide new insights into the mechanisms of inflammation after cardiac transplantation and suggest that, in contrast to its prior reported antioxidant function in vascular inflammation, haptoglobin is an enhancer of inflammation after cardiac transplantation. Haptoglobin may also be a key component in other sterile inflammatory conditions.


Assuntos
Rejeição de Enxerto/imunologia , Haptoglobinas/imunologia , Transplante de Coração/efeitos adversos , Mediadores da Inflamação/imunologia , Inflamação/imunologia , Miocárdio/imunologia , Abatacepte , Animais , Proliferação de Células , Células Cultivadas , Quimiocina CXCL2/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Feminino , Rejeição de Enxerto/sangue , Rejeição de Enxerto/genética , Rejeição de Enxerto/patologia , Rejeição de Enxerto/prevenção & controle , Haptoglobinas/metabolismo , Humanos , Imunoconjugados/farmacologia , Imunossupressores/farmacologia , Inflamação/sangue , Inflamação/patologia , Mediadores da Inflamação/sangue , Interferon gama/metabolismo , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Ativação Linfocitária , Masculino , Espectrometria de Massas , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/genética , Miocárdio/metabolismo , Miocárdio/patologia , Proteômica/métodos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Fatores de Tempo
19.
Proc Natl Acad Sci U S A ; 110(32): 13091-6, 2013 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-23878224

RESUMO

The receptor tyrosine kinases Axl and Mer, belonging to the Tyro3, Axl and Mer (TAM) receptor family, are expressed in a number of tumor cells and have well-characterized oncogenic roles. The therapeutic targeting of these kinases is considered an anticancer strategy, and various inhibitors are currently under development. At the same time, Axl and Mer are expressed in dendritic cells and macrophages and have an essential function in limiting inflammation. Inflammation is an enabling characteristic of multiple cancer hallmarks. These contrasting oncogenic and anti-inflammatory functions of Axl and Mer posit a potential paradox in terms of anticancer therapy. Here we demonstrate that azoxymethane (AOM) and dextran sulfate sodium (DSS)-induced inflammation-associated cancer is exacerbated in mice lacking Axl and Mer. Ablation of Axl and Mer signaling is associated with increased production of proinflammatory cytokines and failure to clear apoptotic neutrophils in the intestinal lamina propria, thereby favoring a tumor-promoting environment. Interestingly, loss of these genes in the hematopoietic compartment is not associated with increased colitis. Axl and Mer are expressed in radioresistant intestinal macrophages, and the loss of these genes is associated with an increased inflammatory signature in this compartment. Our results raise the possibility of potential adverse effects of systemic anticancer therapies with Axl and Mer inhibitors, and underscore the importance of understanding their tissue and cell type-specific functions in cancer.


Assuntos
Colite/imunologia , Neoplasias do Colo/imunologia , Proteínas Proto-Oncogênicas/imunologia , Receptores Proteína Tirosina Quinases/imunologia , Animais , Apoptose/genética , Apoptose/imunologia , Azoximetano , Colite/induzido quimicamente , Colite/genética , Colo/imunologia , Colo/metabolismo , Colo/patologia , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/genética , Citocinas/genética , Citocinas/imunologia , Sulfato de Dextrana , Feminino , Citometria de Fluxo , Expressão Gênica/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Mucosa/imunologia , Mucosa/metabolismo , Mucosa/patologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Fagocitose/genética , Fagocitose/imunologia , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Transdução de Sinais/imunologia , c-Mer Tirosina Quinase , Receptor Tirosina Quinase Axl
20.
Proc Natl Acad Sci U S A ; 109(26): E1695-704, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22685206

RESUMO

MicroRNA-155 (miR-155) is an oncogenic microRNA that regulates several pathways involved in cell division and immunoregulation. It is overexpressed in numerous cancers, is often correlated with poor prognosis, and is thus a key target for future therapies. In this work we show that overexpression of miR-155 in lymphoid tissues results in disseminated lymphoma characterized by a clonal, transplantable pre-B-cell population of neoplastic lymphocytes. Withdrawal of miR-155 in mice with established disease results in rapid regression of lymphadenopathy, in part because of apoptosis of the malignant lymphocytes, demonstrating that these tumors are dependent on miR-155 expression. We show that systemic delivery of antisense peptide nucleic acids encapsulated in unique polymer nanoparticles inhibits miR-155 and slows the growth of these "addicted" pre-B-cell tumors in vivo, suggesting a promising therapeutic option for lymphoma/leukemia.


Assuntos
Modelos Animais de Doenças , Linfoma/terapia , MicroRNAs/antagonistas & inibidores , Nanopartículas , Animais , Apoptose , Sequência de Bases , Western Blotting , Primers do DNA , Doxiciclina/farmacologia , Citometria de Fluxo , Tecido Linfoide/metabolismo , Linfoma/genética , Linfoma/patologia , Camundongos , MicroRNAs/biossíntese , Reação em Cadeia da Polimerase
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