RESUMO
Genotoxic agents, that are used in cancer therapy, elicit the reprogramming of the transcriptome of cancer cells. These changes reflect the cellular response to stress and underlie some of the mechanisms leading to drug resistance. Here, we profiled genome-wide changes in pre-mRNA splicing induced by cisplatin in breast cancer cells. Among the set of cisplatin-induced alternative splicing events we focused on COASY, a gene encoding a mitochondrial enzyme involved in coenzyme A biosynthesis. Treatment with cisplatin induces the production of a short isoform of COASY lacking exons 4 and 5, whose depletion impedes mitochondrial function and decreases sensitivity to cisplatin. We identified RBM39 as a major effector of the cisplatin-induced effect on COASY splicing. RBM39 also controls a genome-wide set of alternative splicing events partially overlapping with the cisplatin-mediated ones. Unexpectedly, inactivation of RBM39 in response to cisplatin involves its interaction with the AP-1 family transcription factor c-Jun that prevents RBM39 binding to pre-mRNA. Our findings therefore uncover a novel cisplatin-induced interaction between a splicing regulator and a transcription factor that has a global impact on alternative splicing and contributes to drug resistance.
Assuntos
Processamento Alternativo , Cisplatino , Resistencia a Medicamentos Antineoplásicos , Proteínas de Ligação a RNA , Fatores de Transcrição , Processamento Alternativo/genética , Cisplatino/farmacologia , Cisplatino/metabolismo , Dano ao DNA , Proteínas Nucleares/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/metabolismo , Linhagem Celular Tumoral , Humanos , AnimaisRESUMO
ANISEED (www.aniseed.cnrs.fr) is the main model organism database for tunicates, the sister-group of vertebrates. This release gives access to annotated genomes, gene expression patterns, and anatomical descriptions for nine ascidian species. It provides increased integration with external molecular and taxonomy databases, better support for epigenomics datasets, in particular RNA-seq, ChIP-seq and SELEX-seq, and features novel interactive interfaces for existing and novel datatypes. In particular, the cross-species navigation and comparison is enhanced through a novel taxonomy section describing each represented species and through the implementation of interactive phylogenetic gene trees for 60% of tunicate genes. The gene expression section displays the results of RNA-seq experiments for the three major model species of solitary ascidians. Gene expression is controlled by the binding of transcription factors to cis-regulatory sequences. A high-resolution description of the DNA-binding specificity for 131 Ciona robusta (formerly C. intestinalis type A) transcription factors by SELEX-seq is provided and used to map candidate binding sites across the Ciona robusta and Phallusia mammillata genomes. Finally, use of a WashU Epigenome browser enhances genome navigation, while a Genomicus server was set up to explore microsynteny relationships within tunicates and with vertebrates, Amphioxus, echinoderms and hemichordates.
Assuntos
Bases de Dados Genéticas , Conjuntos de Dados como Assunto , Genoma , Urocordados/genética , Animais , Evolução Biológica , Ciona intestinalis/genética , DNA/metabolismo , Mineração de Dados , Evolução Molecular , Expressão Gênica , Ontologia Genética , Internet , Anotação de Sequência Molecular , Filogenia , Ligação Proteica , Especificidade da Espécie , Fatores de Transcrição/metabolismo , Transcrição Gênica , Vertebrados/genética , NavegadorRESUMO
BACKGROUND: Tunicates are the closest relatives of vertebrates and are widely used as models to study the evolutionary developmental biology of chordates. Their phylogeny, however, remains poorly understood, and to date, only the 18S rRNA nuclear gene and mitogenomes have been used to delineate the major groups of tunicates. To resolve their evolutionary relationships and provide a first estimate of their divergence times, we used a transcriptomic approach to build a phylogenomic dataset including all major tunicate lineages, consisting of 258 evolutionarily conserved orthologous genes from representative species. RESULTS: Phylogenetic analyses using site-heterogeneous CAT mixture models of amino acid sequence evolution resulted in a strongly supported tree topology resolving the relationships among four major tunicate clades: (1) Appendicularia, (2) Thaliacea + Phlebobranchia + Aplousobranchia, (3) Molgulidae, and (4) Styelidae + Pyuridae. Notably, the morphologically derived Thaliacea are confirmed as the sister group of the clade uniting Phlebobranchia + Aplousobranchia within which the precise position of the model ascidian genus Ciona remains uncertain. Relaxed molecular clock analyses accommodating the accelerated evolutionary rate of tunicates reveal ancient diversification (~ 450-350 million years ago) among the major groups and allow one to compare their evolutionary age with respect to the major vertebrate model lineages. CONCLUSIONS: Our study represents the most comprehensive phylogenomic dataset for the main tunicate lineages. It offers a reference phylogenetic framework and first tentative timescale for tunicates, allowing a direct comparison with vertebrate model species in comparative genomics and evolutionary developmental biology studies.
Assuntos
Evolução Molecular , Genômica/métodos , Filogenia , Transcriptoma/genética , Urocordados/genética , Animais , RNA Ribossômico 18S/genética , Urocordados/classificaçãoRESUMO
Glioblastomas are the deadliest type of brain cancer and are frequently associated with poor prognosis and a high degree of recurrence despite removal by surgical resection and treatment by chemo- and radio-therapy. Photodynamic therapy (PDT) is a treatment well known to induce mainly necrotic and apoptotic cell death in solid tumors. 5-Aminolevulinic acid (5-ALA)-based PDT was recently shown to sensitize human glioblastoma cells (LN-18) to a RIP3 (Receptor Interacting Protein 3)-dependent cell death which is counter-acted by activation of autophagy. These promising results led us to investigate the pathways involved in cell death and survival mechanisms occurring in glioblastoma following PDT. In the present study, we describe a new TSC2 (Tuberous Sclerosis 2)-dependent survival pathway implicating MK2 (MAPKAPK2) kinase and 14-3-3 proteins which conducts to the activation of a pro-survival autophagy. Moreover, we characterized a new RIP3/TSC2 complex where RIP3 is suggested to promote cell death by targeting TSC2-dependent survival pathway. These results highlight (i) a new role of TSC2 to protect glioblastoma against PDT-induced cell death and (ii) TSC2 and 14-3-3 as new RIP3 partners.
Assuntos
Proteínas 14-3-3/genética , Ácido Aminolevulínico/farmacologia , Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Neuroglia/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Supressoras de Tumor/genética , Proteínas 14-3-3/antagonistas & inibidores , Proteínas 14-3-3/metabolismo , Ácido Aminolevulínico/metabolismo , Animais , Autofagia/efeitos dos fármacos , Autofagia/genética , Proteína 7 Relacionada à Autofagia/antagonistas & inibidores , Proteína 7 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Inativação Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Luz , Neuroglia/metabolismo , Neuroglia/patologia , Fotoquimioterapia , Fármacos Fotossensibilizantes/metabolismo , Ligação Proteica , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Proteína Serina-Treonina Quinases de Interação com Receptores/antagonistas & inibidores , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Transdução de Sinais , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/antagonistas & inibidores , Proteínas Supressoras de Tumor/metabolismoRESUMO
Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. The procedure involves administration of a photosensitizing agent followed by irradiation at a wavelength corresponding to an absorbance band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature, and induction of a local inflammatory reaction. Clinical studies revealed that PDT can be curative, particularly in early stage tumors. It can prolong survival in patients with inoperable cancers and significantly improve quality of life. Minimal normal tissue toxicity, negligible systemic effects, greatly reduced long-term morbidity, lack of intrinsic or acquired resistance mechanisms, and excellent cosmetic as well as organ function-sparing effects of this treatment make it a valuable therapeutic option for combination treatments. With a number of recent technological improvements, PDT has the potential to become integrated into the mainstream of cancer treatment.
Assuntos
Neoplasias/tratamento farmacológico , Fotoquimioterapia , Humanos , Fotoquimioterapia/instrumentação , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêuticoRESUMO
Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr.
Assuntos
Ciona intestinalis/embriologia , Ciona intestinalis/genética , Bases de Dados Genéticas , Urocordados/embriologia , Urocordados/genética , Animais , Desenvolvimento Embrionário/genética , Genômica , Urocordados/anatomia & histologiaRESUMO
Melanoma antigen D2 (MAGE-D2) is recognized as a cancer diagnostic marker; however, it has poorly characterized functions. Here, we established its intracellular localization and shuttling during cell cycle progression and in response to cellular stress. In normal conditions, MAGE-D2 is present in the cytoplasm, nucleoplasm, and nucleoli. Within the latter, MAGE-D2 is mostly found in the granular and the dense fibrillar components, and it interacts with nucleolin. Transfection of MAGE-D2 deletion mutants demonstrated that Δ203-254 leads to confinement of MAGE-D2 to the cytoplasm, while Δ248-254 prevents its accumulation in nucleoli but still allows its presence in the nucleoplasm. Consequently, this short sequence belongs to a nucleolar localization signal. MAGE-D2 deletion does not alter the nucleolar organization or rRNA levels. However, its intracellular localization varies with the cell cycle in a different kinetic than nucleolin. After genotoxic and nucleolar stresses, MAGE-D2 is excluded from nucleoli and concentrates in the nucleoplasm. We demonstrated that its camptothecin-related delocalization results from two distinct events: a rapid nucleolar release and a slower phospho-ERK-dependent cytoplasm to nucleoplasm translocation, which results from an increased flux from the cytoplasm to nucleoplasm. In conclusion, MAGE-D2 is a dynamic protein whose shuttling properties could suggest a role in cell cycle regulation.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Antígenos de Neoplasias/metabolismo , Ciclo Celular/fisiologia , Estresse Fisiológico/fisiologia , Nucléolo Celular/metabolismo , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Células HCT116 , Células HEK293 , Células HT29 , Humanos , Células MCF-7 , Transporte Proteico , Células Tumorais CultivadasRESUMO
The protein encoded by ORF9 is essential for varicella-zoster virus (VZV) replication. Previous studies documented its presence in the trans-Golgi network and its involvement in secondary envelopment. In this work, we deleted the ORF9p acidic cluster, destroying its interaction with ORF47p, and this resulted in a nuclear accumulation of both proteins. This phenotype results in an accumulation of primary enveloped capsids in the perinuclear space, reflecting a capsid de-envelopment defect.
Assuntos
Capsídeo/metabolismo , Herpesvirus Humano 3/fisiologia , Deleção de Sequência , Proteínas Virais/genética , Liberação de Vírus , Replicação Viral , Núcleo Celular/virologia , Herpesvirus Humano 3/genéticaRESUMO
Exposure to hepatitis C virus (HCV) typically results in chronic infection that leads to progressive liver disease ranging from mild inflammation to severe fibrosis and cirrhosis as well as primary liver cancer. HCV triggers innate immune signaling within the infected hepatocyte, a first step in mounting of the adaptive response against HCV infection. Persistent inflammation is strongly associated with liver tumorigenesis. The goal of our work was to investigate the initiation of the inflammatory processes triggered by HCV viral proteins in their host cell and their possible link with HCV-related liver cancer. We report a dramatic upregulation of the lymphotoxin signaling pathway and more specifically of lymphotoxin-ß in tumors of the FL-N/35 HCV-transgenic mice. Lymphotoxin expression is accompanied by activation of NF-κB, neosynthesis of chemokines and intra-tumoral recruitment of mononuclear cells. Spectacularly, IKKß inactivation in FL-N/35 mice drastically reduces tumor incidence. Activation of lymphotoxin-ß pathway can be reproduced in several cellular models, including the full length replicon and HCV-infected primary human hepatocytes. We have identified NS5B, the HCV RNA dependent RNA polymerase, as the viral protein responsible for this phenotype and shown that pharmacological inhibition of its activity alleviates activation of the pro-inflammatory pathway. These results open new perspectives in understanding the inflammatory mechanisms linked to HCV infection and tumorigenesis.
Assuntos
Hepacivirus/enzimologia , Neoplasias Hepáticas/metabolismo , Linfócitos/imunologia , Linfotoxina-beta/metabolismo , RNA Polimerase Dependente de RNA/metabolismo , Animais , Linhagem Celular , Quimiocinas/metabolismo , Quimiotaxia de Leucócito , Hepacivirus/patogenicidade , Hepatócitos/metabolismo , Hepatócitos/patologia , Hepatócitos/virologia , Interações Hospedeiro-Patógeno , Humanos , Quinase I-kappa B/metabolismo , Imunidade Inata , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/virologia , Fígado/metabolismo , Fígado/patologia , Fígado/virologia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Ativação Linfocitária , Linfócitos/virologia , Masculino , Camundongos , Camundongos Transgênicos , NF-kappa B , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Transdução de Sinais , Regulação para Cima , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismoRESUMO
BACKGROUND: Modification of splicing by chemotherapeutic drugs has usually been evaluated on a limited number of pre-mRNAs selected for their recognized or potential importance in cell proliferation or apoptosis. However, the pathways linking splicing alterations to the efficiency of cancer therapy remain unclear. METHODS: Next-generation sequencing was used to analyse the transcriptome of breast carcinoma cells treated by cisplatin. Pharmacological inhibitors, RNA interference, cells deficient in specific signalling pathways, RT-PCR and FACS analysis were used to investigate how the anti-cancer drug cisplatin affected alternative splicing and the cell death pathway. RESULTS: We identified 717 splicing events affected by cisplatin, including 245 events involving cassette exons. Gene ontology analysis indicates that cell cycle, mRNA processing and pre-mRNA splicing were the main pathways affected. Importantly, the cisplatin-induced splicing alterations required class I PI3Ks P110ß but not components such as ATM, ATR and p53 that are involved in the DNA damage response. The siRNA-mediated depletion of the splicing regulator SRSF4, but not SRSF6, expression abrogated many of the splicing alterations as well as cell death induced by cisplatin. CONCLUSION: Many of the splicing alterations induced by cisplatin are caused by SRSF4 and they contribute to apoptosis in a process requires class I PI3K.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Cisplatino/farmacologia , Precursores de RNA/genética , Splicing de RNA/efeitos dos fármacos , Proteínas de Ligação a RNA/metabolismo , Linhagem Celular Tumoral , Biologia Computacional , Dano ao DNA , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Processamento Pós-Transcricional do RNA/efeitos dos fármacos , Fatores de Processamento de Serina-Arginina , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
The response of tumors to photodynamic therapy (PDT) largely varies depending upon the intensity of the stress created in the cancer cells and also in the local environment. Singlet oxygen has been demonstrated, in many instances, to be the primary reactive oxygen species generated by PDT and responsible for most of the cellular effects. Cancer cells have developed various sensors which activate signalling pathways in response to PDT, and the nature of the activated pathway varies with the PDT stress intensity. At low doses of PDT, signalling pathways allow cancer cells to both proliferate and switch on pro-survival responses such as autophagy. Above a certain level of PDT stress intensity, cancer cells cannot cope with the heavy damage, and signalling pathways leading to cell death are activated. Two types of regulated cell death have been shown to be induced by PDT: apoptosis and necrosis. Signalling pathways activating NF-κB transcription factors have the peculiar characteristic of being activated both at low and high doses of PDT. These pathways coordinate the cross-talk between the immune system via the release of cytokines and chemokines and an anti-cell death response via the control of apoptosis and necrosis. Therefore, NF-κB induced by PDT appears to play a positive role in educating the immune system to fight tumors but also a negative role in helping cancer cells to survive the stress generated by singlet oxygen. This is why NF-κB cannot easily be considered as a pharmacological target whose inhibition will favor tumor cell eradication by PDT.
Assuntos
NF-kappa B/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Fotoquimioterapia , Animais , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Humanos , Fotoquimioterapia/métodos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiaçãoRESUMO
The role of the tegument during the herpesvirus lytic cycle is still not clearly established, particularly at the late phase of infection, when the newly produced viral particles need to be fully assembled before being released from the infected cell. The varicella-zoster virus (VZV) protein coded by open reading frame (ORF) 9 (ORF9p) is an essential tegument protein, and, even though its mRNA is the most expressed during the productive infection, little is known about its functions. Using a GalK positive/negative selection technique, we modified a bacterial artificial chromosome (BAC) containing the complete VZV genome to create viruses expressing mutant versions of ORF9p. We showed that ORF9p is hyperphosphorylated during the infection, especially through its interaction with the viral Ser/Thr kinase ORF47p; we identified a consensus site within ORF9p recognized by ORF47p and demonstrated its importance for ORF9p phosphorylation. Strikingly, an ultrastructural analysis revealed that the mutation of this consensus site (glutamate 85 to arginine) strongly affects viral assembly and release, reproducing the ORF47 kinase-dead VZV phenotype. It also slightly diminishes the infectivity toward immature dendritic cells. Taken together, our results identify ORF9p as a new viral substrate of ORF47p and suggest a determinant role of this phosphorylation for viral infectivity, especially during the process of viral particle formation and egress.
Assuntos
Herpesvirus Humano 3/metabolismo , Proteínas Virais/metabolismo , Liberação de Vírus , Linhagem Celular Tumoral , Cromossomos Artificiais Bacterianos , Células Dendríticas/imunologia , Células HEK293 , Herpesvirus Humano 3/fisiologia , Herpesvirus Humano 3/ultraestrutura , Humanos , Mutação , Fases de Leitura Aberta , Fosforilação , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteínas Virais/genética , Proteínas Estruturais Virais/genética , Proteínas Estruturais Virais/metabolismo , Vírion/fisiologia , Vírion/ultraestrutura , Montagem de Vírus , Replicação ViralRESUMO
Obesity and related diseases have reached epidemic proportions and continue to rise. Beyond creating an economical burden, obesity and its co-morbidities are associated with shortened human life expectancy. Despite major advances, the underlying mechanisms of obesity remain not fully elucidated. Recently, several studies have highlighted that various immune cells are metabolically reprogrammed in obesity, thereby profoundly affecting the immune system. This sheds light on a new field of interest: the impact of obesity-related systemic metabolic changes affecting immune system that could lead to immunosurveillance loss. Among immune cells altered by obesity, invariant Natural Killer T (iNKT) cells have recently garnered intense focus due to their ability to recognize lipid antigen. While iNKT cells are well-described to be affected by obesity, how and to what extent immunometabolic factors (e.g., lipids, glucose, cytokines, adipokines, insulin and free fatty acids) can drive iNKT cells alterations remains unclear, but represent an emerging field of research. Here, we review the current knowledge on iNKT cells in obesity and discuss the immunometabolic factors that could modulate their phenotype and activity.
Assuntos
Células T Matadoras Naturais , Obesidade , Humanos , Obesidade/metabolismo , Obesidade/imunologia , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/metabolismo , Animais , Citocinas/metabolismo , Citocinas/imunologia , Adipocinas/metabolismo , Adipocinas/imunologiaRESUMO
Plasma growth differentiation factor-15 (GDF-15) levels increase with obesity and metabolic dysfunction-associated steatotic liver disease (MASLD) but the underlying mechanism remains poorly defined. Using male mouse models of obesity and MASLD, and biopsies from carefully-characterized patients regarding obesity, type 2 diabetes (T2D) and MASLD status, we identify adipose tissue (AT) as the key source of GDF-15 at onset of obesity and T2D, followed by liver during the progression towards metabolic dysfunction-associated steatohepatitis (MASH). Obesity and T2D increase GDF15 expression in AT through the accumulation of macrophages, which are the main immune cells expressing GDF15. Inactivation of Gdf15 in macrophages reduces plasma GDF-15 concentrations and exacerbates obesity in mice. During MASH development, Gdf15 expression additionally increases in hepatocytes through stress-induced TFEB and DDIT3 signaling. Together, these results demonstrate a dual contribution of AT and liver to GDF-15 production in metabolic diseases and identify potential therapeutic targets to raise endogenous GDF-15 levels.
Assuntos
Tecido Adiposo , Diabetes Mellitus Tipo 2 , Fígado Gorduroso , Fator 15 de Diferenciação de Crescimento , Hepatócitos , Macrófagos , Obesidade , Fator 15 de Diferenciação de Crescimento/metabolismo , Fator 15 de Diferenciação de Crescimento/genética , Animais , Obesidade/metabolismo , Obesidade/patologia , Hepatócitos/metabolismo , Masculino , Macrófagos/metabolismo , Camundongos , Humanos , Tecido Adiposo/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Camundongos Endogâmicos C57BL , Fígado/metabolismo , Fígado/patologia , Modelos Animais de Doenças , Transdução de SinaisRESUMO
The NLRP3 inflammasome is involved in many obesity-associated diseases, such as type 2 diabetes, atherosclerosis, and gouty arthritis, through its ability to induce interleukin (IL)-1ß release. The molecular link between obesity and inflammasome activation is still unclear, but free fatty acids have been proposed as one triggering event. Here we reported opposite effects of saturated fatty acids (SFAs) compared with unsaturated fatty acids (UFAs) on NLRP3 inflammasome in human monocytes/macrophages. Palmitate and stearate, both SFAs, triggered IL-1ß secretion in a caspase-1/ASC/NLRP3-dependent pathway. Unlike SFAs, the UFAs oleate and linoleate did not lead to IL-1ß secretion. In addition, they totally prevented the IL-1ß release induced by SFAs and, with less efficiency, by a broad range of NLRP3 inducers, including nigericin, alum, and monosodium urate. UFAs did not affect the transcriptional effect of SFAs, suggesting a specific effect on the NLRP3 activation. These results provide a new anti-inflammatory mechanism of UFAs by preventing the activation of the NLRP3 inflammasome and, therefore, IL-1ß processing. By this way, UFAs might play a protective role in NLRP3-associated diseases.
Assuntos
Proteínas de Transporte/metabolismo , Ácidos Graxos Insaturados/farmacologia , Inflamassomos/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Linhagem Celular , Humanos , Interleucina-1beta/metabolismo , Macrófagos/citologia , Monócitos/citologia , Proteína 3 que Contém Domínio de Pirina da Família NLR , Palmitatos/farmacologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Estearatos/farmacologiaRESUMO
AIMS/HYPOTHESIS: Obesity is a heterogeneous condition comprising both individuals who remain metabolically healthy (MHO) and those who develop metabolic disorders (metabolically unhealthy, MUO). Adipose tissue is also heterogeneous in that its visceral component is more frequently associated with metabolic dysfunction than its subcutaneous component. The development of metabolic disorders is partly mediated by the NLR family pyrin domain containing-3 (NLRP3) inflammasome, which increases the secretion of inflammatory cytokines via activation of caspase-1. We compared the immunological profile and NLRP3 activity in adipose tissue between MUO and MHO individuals. METHODS: MHO and MUO phenotypes were defined, respectively, as the absence and the presence of the metabolic syndrome. Cellular composition and intrinsic inflammasome activity were investigated by flow cytometry, quantitative RT-PCR and tissue culture studies in subcutaneous and visceral adipose tissue from 23 MUO, 21 MHO and nine lean individuals. RESULTS: We found significant differences between the three study groups, including an increased secretion of IL-1ß, increased expression of IL1B and NLRP3, increased number of adipose tissue macrophages and decreased number of regulatory T cells in the visceral adipose tissue of MUO patients compared with MHO and lean participants. In macrophages derived from visceral adipose tissue, both caspase-1 activity and IL-1ß levels were higher in MUO patients than in MHO patients. Furthermore, caspase-1 activity was higher in CD11c(+)CD206(+) adipose tissue macrophages than in CD11c(-)CD206(+) cells. CONCLUSIONS/INTERPRETATION: The MUO phenotype seems to be associated with an increased activation of the NLPR3 inflammasome in macrophages infiltrating visceral adipose tissue, and a less favourable inflammatory profile compared with the MHO phenotype.
Assuntos
Proteínas de Transporte/metabolismo , Inflamassomos/metabolismo , Gordura Intra-Abdominal/imunologia , Gordura Intra-Abdominal/metabolismo , Obesidade/metabolismo , Adulto , Proteínas de Transporte/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Masculino , Pessoa de Meia-Idade , Proteína 3 que Contém Domínio de Pirina da Família NLR , Obesidade/imunologia , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
NOD2 is one of the best characterized members of the cytosolic NOD-like receptor family. NOD2 is able to sense muramyl dipeptide, a specific bacterial cell wall component, and to subsequently induce various signaling pathways leading to NF-κB activation and autophagy, both events contributing to an efficient innate and adaptive immune response. Interestingly, loss-of-function NOD2 variants were associated with a higher susceptibility for Crohn disease, which highlights the physiological importance of proper regulation of NOD2 activity. We performed a biochemical screen to search for new NOD2 regulators. We identified a new NOD2 partner, c-Jun N-terminal kinase-binding protein 1 (JNKBP1), a scaffold protein characterized by an N-terminal WD-40 domain. JNKBP1, through its WD-40 domain, binds to NOD2 following muramyl dipeptide activation. This interaction attenuates NOD2-mediated NF-κB activation and IL-8 secretion as well as NOD2 antibacterial activity. JNKBP1 exerts its repressor effect by disturbing NOD2 oligomerization and RIP2 tyrosine phosphorylation, both steps required for downstream NOD2 signaling. We furthermore showed that JNKBP1 and NOD2 are co-expressed in the human intestinal epithelium and in immune cells recruited in the lamina propria, which suggests that JNKBP1 contributes to maintain NOD2-mediated intestinal immune homeostasis.
Assuntos
Mucosa Intestinal/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Adaptadora de Sinalização NOD2/metabolismo , Multimerização Proteica/fisiologia , Transdução de Sinais/fisiologia , Células HEK293 , Humanos , Interleucina-8/imunologia , Interleucina-8/metabolismo , Mucosa Intestinal/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Células Jurkat , NF-kappa B/genética , NF-kappa B/imunologia , NF-kappa B/metabolismo , Proteína Adaptadora de Sinalização NOD2/genética , Proteína Adaptadora de Sinalização NOD2/imunologia , Fosforilação/fisiologia , Estrutura Terciária de Proteína , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/genética , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/imunologia , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Células U937RESUMO
The IkappaB kinases (IKKs) IKK-alpha and IKK-beta, and the IKK-related kinases TBK1 and IKK-epsilon, have essential roles in innate immunity through signal-induced activation of NF-kappaB, IRF3 and IRF7, respectively. Although the signaling events within these pathways have been extensively studied, the mechanisms of IKK and IKK-related complex assembly and activation remain poorly defined. Recent data provide insight into the requirement for scaffold proteins in complex assembly; NF-kappaB essential modulator coordinates some IKK complexes, whereas TANK, NF-kappaB-activating kinase-associated protein 1 (NAP1) or similar to NAP1 TBK1 adaptor (SINTBAD) assemble TBK1 and IKK-epsilon complexes. The different scaffold proteins undergo similar post-translational modifications, including phosphorylation and non-degradative polyubiquitylation. Moreover, increasing evidence indicates that distinct scaffold proteins assemble IKK, and potentially TBK1 and IKK-epsilon subcomplexes, in a stimulus-specific manner, which might be a mechanism to achieve specificity.
Assuntos
Regulação Enzimológica da Expressão Gênica , Quinase I-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Humanos , Quinase I-kappa B/fisiologia , Modelos Biológicos , Modelos Genéticos , NF-kappa B/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Serina-Treonina Quinases/fisiologia , Transdução de Sinais , Ubiquitina/metabolismoRESUMO
In obesity, adipose tissue infiltrating macrophages acquire a unique pro-inflammatory polarization, thereby playing a key role in the development of chronic inflammation and Type 2 diabetes. Increased saturated fatty acids (SFAs) levels have been proposed to drive this specific polarization. Accordingly, we investigated the immunometabolic reprogramming in SFA-treated human macrophages. As expected, RNA sequencing highlighted a pro-inflammatory profile but also metabolic signatures including glycolysis and hypoxia as well as a strong unfolded protein response. Glycolysis upregulation was confirmed in SFA-treated macrophages by measuring glycolytic gene expression, glucose uptake, lactate production and extracellular acidification rate. Like in LPS-stimulated macrophages, glycolysis activation in SFA-treated macrophages was dependent on HIF-1α activation and fueled the production of pro-inflammatory cytokines. SFAs and LPS both induced IRE1α endoribonuclease activity, as demonstrated by XBP1 mRNA splicing, but with different kinetics matching HIF-1α activation and the glycolytic gene expression. Interestingly, the knockdown of IRE1α and/or the pharmacological inhibition of its RNase activity prevented HIF-1α activation and significantly decreased glycolysis upregulation. Surprisingly, XBP1s appeared to be dispensable, as demonstrated by the lack of inhibiting effect of XBP1s knockdown on glycolytic genes expression, glucose uptake, lactate production and HIF-1α activation. These experiments demonstrate for the first time a key role of IRE1α in HIF-1α-mediated glycolysis upregulation in macrophages stimulated with pro-inflammatory triggers like LPS or SFAs through XBP1s-independent mechanism. IRE1 could mediate this novel function by targeting other transcripts (mRNA or pre-miRNA) through a mechanism called regulated IRE1-dependent decay or RIDD. Deciphering the underlying mechanisms of this novel IRE1 function might lead to novel therapeutic targets to curtail sterile obesity- or infection-linked inflammation.
Assuntos
Diabetes Mellitus Tipo 2 , Endorribonucleases , Humanos , Glucose , Glicólise , Lipopolissacarídeos/farmacologia , Proteínas Serina-Treonina Quinases , Ribonuclease Pancreático , Ribonucleases , Regulação para Cima , Proteína 1 de Ligação a X-Box/genéticaRESUMO
Cellular senescence is, essentially, a permanent proliferation arrest induced by various cellular stresses or inappropriate stimuli. This arrest, which is associated with dramatic changes in cell morphology, metabolism and gene expression, involves a complex signalling network aiming at stable inactivation of CDKs, major cell cycle regulators. Notably, several tumour suppressors, such as p53, pRb or p16(Ink4a), play key roles both in the initiation of the senescence program and in its maintenance, which often involves epigenetic changes. While having widely recognized roles in tumour suppression and wound healing, senescence, like the roman god Janus, recently revealed another darker face. Mostly due to altered secretion phenotype favouring inflammation, senescent cells strongly influence surrounding tissue contributing to the development of age-related pathologies, including cancer.