RESUMO
The positive and negative selection of lymphocytes by antigen is central to adaptive immunity and self-tolerance, yet how this is determined by different antigens is not completely understood. We found that thymocyte-selection-associated family member 2 (Themis2) increased the positive selection of B1 cells and germinal center B cells by self and foreign antigens. Themis2 lowered the threshold for B-cell activation by low-avidity, but not high-avidity, antigens. Themis2 constitutively bound the adaptor protein Grb2, src-kinase Lyn and signal transducer phospholipase γ2 (PLC-γ2), and increased activation of PLC-γ2 and its downstream pathways following B cell receptor stimulation. Our findings identify a unique function for Themis2 in differential signaling and provide insight into how B cells discriminate between antigens of different quantity and quality.
Assuntos
Linfócitos B/fisiologia , Seleção Clonal Mediada por Antígeno , Centro Germinativo/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ativação Linfocitária , Imunidade Adaptativa , Animais , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Proteína Adaptadora GRB2/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Fosfolipase C gama/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Tolerância a Antígenos Próprios , Quinases da Família src/metabolismoRESUMO
CD5 is characterized as an inhibitory coreceptor with an important regulatory role during T cell development. The molecular mechanism by which CD5 operates has been puzzling and its function in mature T cells suggests promoting rather than repressing effects on immune responses. Here, we combined quantitative mass spectrometry and genetic studies to analyze the components and the activity of the CD5 signaling machinery in primary T cells. We found that T cell receptor (TCR) engagement induces the selective phosphorylation of CD5 tyrosine 429, which serves as a docking site for proteins with adaptor functions (c-Cbl, CIN85, CRKL), connecting CD5 to positive (PI3K) and negative (UBASH3A, SHIP1) regulators of TCR signaling. c-CBL acts as a coordinator in this complex enabling CD5 to synchronize positive and negative feedbacks on TCR signaling through the other components. Disruption of CD5 signalosome in mutant mice reveals that it modulates TCR signal outputs to selectively repress the transactivation of Foxp3 and limit the inopportune induction of peripherally induced regulatory T cells during immune responses against foreign antigen. Our findings bring insights into the paradigm of coreceptor signaling, suggesting that, in addition to providing dualistic enhancing or dampening inputs, coreceptors can engage concomitant stimulatory and inhibitory signaling events, which act together to promote specific functional outcomes.
Assuntos
Antígenos/imunologia , Antígenos CD5/metabolismo , Diferenciação Celular/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Reguladores/fisiologia , Animais , Antígenos CD5/genética , Diferenciação Celular/genética , Regulação da Expressão Gênica/imunologia , Ativação Linfocitária/genética , Espectrometria de Massas , Camundongos , Camundongos Transgênicos , Cultura Primária de Células , Receptores de Antígenos de Linfócitos T/antagonistas & inibidores , Transdução de Sinais/genética , Transdução de Sinais/imunologiaRESUMO
Regulatory T cells (Treg) represent a minor subpopulation of T lymphocytes that is crucial for the maintenance of immune homeostasis. Here, we present a large-scale quantitative mass spectrometry study that defines a specific proteomic "signature" of Treg. Treg and conventional T lymphocyte (Tconv) subpopulations were sorted by flow cytometry and subjected to global proteomic analysis by single-run nanoLC-MS/MS on a fast-sequencing Q-Exactive mass spectrometer. Besides "historical" proteins that characterize Treg, our study identified numerous new proteins that are up- or downregulated in Treg versus Tconv. We focused on Themis1, a protein particularly under-represented in Treg, and recently described as being involved in the pathogenesis of immune diseases. Using a transgenic mouse model overexpressing Themis1, we provided in vivo and in vitro evidence of its importance for Treg suppressive functions, in an animal model of inflammatory bowel disease and in coculture assays. We showed that this enhanced suppressive activity in vitro is associated with an accumulation of Tregs. Thus, our study highlights the usefulness of label free quantitative methods to better characterize the Treg cell lineage and demonstrates the potential role of Themis1 in the suppressive functions of these cells.
Assuntos
Tolerância Imunológica , Proteínas/metabolismo , Proteômica/métodos , Linfócitos T Reguladores/imunologia , Animais , Cromatografia Líquida , Modelos Animais de Doenças , Citometria de Fluxo , Humanos , Doenças Inflamatórias Intestinais/imunologia , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos , Camundongos Endogâmicos C57BL , Proteínas/análise , Proteínas/genética , Linfócitos T Reguladores/química , Espectrometria de Massas em TandemRESUMO
The ubiquitin-proteasome pathway (UPP) plays a critical role in the degradation of proteins implicated in cell cycle control, signal transduction, DNA damage response, apoptosis and immune response. Proteasome inhibitors can inhibit the growth of a broad spectrum of human cancer cells by altering the balance of intracellular proteins. However, the targets of these compounds in acute myeloid leukemia (AML) cells have not been fully characterized. Herein, we combined large-scale quantitative analysis by SILAC-MS and targeted quantitative proteomic analysis in order to identify proteins regulated upon proteasome inhibition in two AML cell lines displaying different stages of maturation: immature KG1a cells and mature U937 cells. In-depth data analysis enabled accurate quantification of more than 7000 proteins in these two cell lines. Several candidates were validated by selected reaction monitoring (SRM) measurements in a large number of samples. Despite the broad range of proteins known to be affected by proteasome inhibition, such as heat shock (HSP) and cell cycle proteins, our analysis identified new differentially regulated proteins, including IL-32, MORF family mortality factors and apoptosis inducing factor SIVA, a target of p53. It could explain why proteasome inhibitors induce stronger apoptotic responses in immature AML cells.
Assuntos
Biologia Computacional , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Leucócitos/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Acetilcisteína/análogos & derivados , Acetilcisteína/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Bortezomib/farmacologia , Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Perfilação da Expressão Gênica , Ontologia Genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Interleucinas/genética , Interleucinas/metabolismo , Leucócitos/metabolismo , Leucócitos/patologia , Leupeptinas/farmacologia , Anotação de Sequência Molecular , Fosforilação/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Phosphoinositides represent a major class of lipids specifically involved in the organization of signaling cascades, maintenance of the identity of organelles and regulation of multiple intracellular trafficking steps. We previously reported that phosphatidylinositol 5-monophosphate (PI5P), produced by the Shigella flexneri phosphatase IpgD, is implicated in the endosomal sorting of the epidermal growth factor receptor (EGFR). Here, we show that the adaptor protein TOM1 is a new direct binding partner of PI5P. We identify the domain of TOM1 involved in this interaction and characterize the binding motif. Finally, we demonstrate that the recruitment of TOM1 by PI5P on signaling endosomes is responsible for the delay in EGFR degradation and fluid-phase bulk endocytosis. Taken together, our data strongly suggest that PI5P enrichment in signaling endosomes prevents endosomal maturation through the recruitment of TOM1, and point to a new function of PI5P in regulating discrete maturation steps in the endosomal system.
Assuntos
Endossomos/metabolismo , Receptores ErbB/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Proteínas/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Clonagem Molecular , Cricetinae , Endocitose/genética , Endocitose/fisiologia , Fibroblastos , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Mutagênese Sítio-Dirigida , Ligação Proteica , Estrutura Terciária de Proteína , Transporte Proteico , Proteínas/genética , Interferência de RNA , RNA Interferente Pequeno , Transdução de SinaisRESUMO
The Chromosome-Centric Human Proteome Project (C-HPP) aims to identify "missing" proteins in the neXtProt knowledgebase. We present an in-depth proteomics analysis of the human sperm proteome to identify testis-enriched missing proteins. Using protein extraction procedures and LC-MS/MS analysis, we detected 235 proteins (PE2-PE4) for which no previous evidence of protein expression was annotated. Through LC-MS/MS and LC-PRM analysis, data mining, and immunohistochemistry, we confirmed the expression of 206 missing proteins (PE2-PE4) in line with current HPP guidelines (version 2.0). Parallel reaction monitoring acquisition and sythetic heavy labeled peptides targeted 36 âªone-hit wonderâ« candidates selected based on prior peptide spectrum match assessment. 24 were validated with additional predicted and specifically targeted peptides. Evidence was found for 16 more missing proteins using immunohistochemistry on human testis sections. The expression pattern for some of these proteins was specific to the testis, and they could possibly be valuable markers with fertility assessment applications. Strong evidence was also found of four "uncertain" proteins (PE5); their status should be re-examined. We show how using a range of sample preparation techniques combined with MS-based analysis, expert knowledge, and complementary antibody-based techniques can produce data of interest to the community. All MS/MS data are available via ProteomeXchange under identifier PXD003947. In addition to contributing to the C-HPP, we hope these data will stimulate continued exploration of the sperm proteome.
Assuntos
Proteoma/análise , Espermatozoides/química , Cromatografia Líquida , Mineração de Dados , Bases de Dados de Proteínas , Humanos , Imuno-Histoquímica , Masculino , Proteômica/métodos , Espectrometria de Massas em Tandem , Testículo/químicaRESUMO
α-L-arabinofuranosidases are glycoside hydrolases that specifically hydrolyze non-reducing residues from arabinose-containing polysaccharides. In the case of arabinoxylans, which are the main components of hemicellulose, they are part of microbial xylanolytic systems and are necessary for complete breakdown of arabinoxylans. Glycoside hydrolase family 62 (GH62) is currently a small family of α-L-arabinofuranosidases that contains only bacterial and fungal members. Little is known about the GH62 mechanism of action, because only a few members have been biochemically characterized and no three-dimensional structure is available. Here, we present the first crystal structures of two fungal GH62 α-L-arabinofuranosidases from the basidiomycete Ustilago maydis (UmAbf62A) and ascomycete Podospora anserina (PaAbf62A). Both enzymes are able to efficiently remove the α-L-arabinosyl substituents from arabinoxylan. The overall three-dimensional structure of UmAbf62A and PaAbf62A reveals a five-bladed ß-propeller fold that confirms their predicted classification into clan GH-F together with GH43 α-L-arabinofuranosidases. Crystallographic structures of the complexes with arabinose and cellotriose reveal the important role of subsites +1 and +2 for sugar binding. Intriguingly, we observed that PaAbf62A was inhibited by cello-oligosaccharides and displayed binding affinity to cellulose although no activity was observed on a range of cellulosic substrates. Bioinformatic analyses showed that UmAbf62A and PaAbf62A belong to two distinct subfamilies within the GH62 family. The results presented here provide a framework to better investigate the structure-function relationships within the GH62 family.
Assuntos
Proteínas Fúngicas/química , Glicosídeo Hidrolases/química , Família Multigênica , Podospora/enzimologia , Ustilago/enzimologia , Arabinose/metabolismo , Calorimetria , Domínio Catalítico , Celulose/metabolismo , Cristalografia por Raios X , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Cinética , Modelos Moleculares , FilogeniaRESUMO
Although estrogens are known to have a deleterious effect on the venous thrombosis risk and a preventive action on the development of arterial atheroma, their effect on platelet function in vivo remains unclear. Here, we demonstrate that a chronic high physiologic level of estradiol (E2) in mice leads to a marked decrease in platelet responsiveness ex vivo and in vivo compared with ovariectomized controls. E2 treatment led to increased bleeding time and a resistance to thromboembolism. Hematopoietic chimera mice harboring a selective deletion of estrogen receptors (ERs) α or ß were used to demonstrate that the effects of E2 were exclusively because of hematopoietic ERα. Within ERα the activation function-1 domain was not required for resistance to thromboembolism, as was previously shown for atheroprotection. This domain is mandatory for E2-mediated reproductive function and suggests that this role is controlled independently. Differential proteomics indicated that E2 treatment modulated the expression of platelet proteins including ß1 tubulin and a few other proteins that may impact platelet production and activation. Overall, these data demonstrate a previously unrecognized role for E2 in regulating the platelet proteome and platelet function, and point to new potential antithrombotic and vasculoprotective therapeutic strategies.
Assuntos
Plaquetas/efeitos dos fármacos , Estradiol/uso terapêutico , Receptor alfa de Estrogênio/metabolismo , Agregação Plaquetária/efeitos dos fármacos , Tromboembolia/prevenção & controle , Animais , Tempo de Sangramento , Plaquetas/citologia , Estradiol/farmacologia , Receptor alfa de Estrogênio/genética , Feminino , Deleção de Genes , Células-Tronco Hematopoéticas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ovariectomia , Proteoma/metabolismo , Tromboembolia/genética , Tromboembolia/metabolismo , Tubulina (Proteína)/metabolismoRESUMO
Introduction: Narcolepsy type 1 (NT1) is a rare, chronic and disabling neurological disease causing excessive daytime sleepiness and cataplexy. NT1 is characterized pathologically by an almost complete loss of neurons producing the orexin neuropeptides in the lateral hypothalamus. Genetic and environmental factors strongly suggest the involvement of the immune system in the loss of orexin neurons. The cerebrospinal fluid (CSF), secreted locally and surrounding the central nervous system (CNS), represents an accessible window into CNS pathological processes. Methods: To gain insight into the biological and molecular changes in NT1 patients, we performed a comparative proteomics analysis of the CSF from 21 recent-onset NT1 patients and from two control groups: group 1 with somatoform disorders, and group 2 patients with hypersomnia other than NT1, to control for any potential effect of sleep disturbances on CSF composition. To achieve an optimal proteomic coverage analysis, the twelve most abundant CSF proteins were depleted, and samples were analyzed by nano-flow liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) using the latest generation of hybrid Orbitrap mass spectrometer. Results and discussion: Our study allowed the identification and quantification of up to 1943 proteins, providing a remarkably deep analysis of the CSF proteome. Interestingly, gene set enrichment analysis indicated that the complement and coagulation systems were enriched and significantly activated in NT1 patients in both cohorts analyzed. Notably, the lectin and alternative complement pathway as well as the downstream lytic membrane attack complex were congruently increased in NT1. Our data suggest that the complement dysregulation in NT1 patients can contribute to immunopathology either by directly promoting tissue damage or as part of local inflammatory responses. We therefore reveal an altered composition of the CSF proteome in NT1 patients, which points to an ongoing inflammatory process contributed, at least in part, by the complement system.
Assuntos
Narcolepsia , Espectrometria de Massas em Tandem , Humanos , Orexinas , Proteoma , Proteômica , Proteínas do Sistema ComplementoRESUMO
Although placental small extracellular vesicles (sEVs) are extensively studied in the context of pregnancy, little is known about their role during viral congenital infection, especially at the beginning of pregnancy. In this study, we examined the consequences of human cytomegalovirus (hCMV) infection on sEVs production, composition, and function using an immortalized human cytotrophoblast cell line derived from first trimester placenta. By combining complementary approaches of biochemistry, electron microscopy, and quantitative proteomic analysis, we showed that hCMV infection increases the yield of sEVs produced by cytotrophoblasts and modifies their protein content towards a potential proviral phenotype. We further demonstrate that sEVs secreted by hCMV-infected cytotrophoblasts potentiate infection in naive recipient cells of fetal origin, including human neural stem cells. Importantly, these functional consequences are also observed with sEVs prepared from an ex vivo model of infected histocultures from early placenta. Based on these findings, we propose that placental sEVs could be important actors favoring viral dissemination to the fetal brain during hCMV congenital infection.
Assuntos
Infecções por Citomegalovirus , Vesículas Extracelulares , Citomegalovirus/genética , Vesículas Extracelulares/metabolismo , Feminino , Humanos , Placenta , Gravidez , ProteômicaRESUMO
Hundreds of cytotoxic natural or synthetic lipidic compounds contain chiral alkynylcarbinol motifs, but the mechanism of action of those potential therapeutic agents remains unknown. Using a genetic screen in haploid human cells, we discovered that the enantiospecific cytotoxicity of numerous terminal alkynylcarbinols, including the highly cytotoxic dialkynylcarbinols, involves a bioactivation by HSD17B11, a short-chain dehydrogenase/reductase (SDR) known to oxidize the C-17 carbinol center of androstan-3-alpha,17-beta-diol to the corresponding ketone. A similar oxidation of dialkynylcarbinols generates dialkynylketones, that we characterize as highly protein-reactive electrophiles. We established that, once bioactivated in cells, the dialkynylcarbinols covalently modify several proteins involved in protein-quality control mechanisms, resulting in their lipoxidation on cysteines and lysines through Michael addition. For some proteins, this triggers their association to cellular membranes and results in endoplasmic reticulum stress, unfolded protein response activation, ubiquitin-proteasome system inhibition and cell death by apoptosis. Finally, as a proof-of-concept, we show that generic lipidic alkynylcarbinols can be devised to be bioactivated by other SDRs, including human RDH11 and HPGD/15-PGDH. Given that the SDR superfamily is one of the largest and most ubiquitous, this unique cytotoxic mechanism-of-action could be widely exploited to treat diseases, in particular cancer, through the design of tailored prodrugs.
Assuntos
Antineoplásicos , Redutases-Desidrogenases de Cadeia Curta , Antineoplásicos/farmacologia , Estresse do Retículo Endoplasmático , Humanos , Lipídeos , Resposta a Proteínas não DobradasRESUMO
In eukaryotes, ribosome biogenesis is a process of major interest that requires more than 200 factors acting coordinately in time and space. Using genetic and proteomic studies, most of the components have now been identified. Based on its nucleolar localization, we characterized the protein encoded by the open reading frame YGR251W, we renamed Nop19p as playing an essential role in ribosome biogenesis. Depletion of the Nop19p in yeast impairs pre-rRNA processing at sites A0, A1 and A2, leading to a strong decrease in 18S rRNA and 40S subunit levels. Nop19p is a component of 90S preribosomes which assembly is believed to result from stepwise incorporation of UTP modules. We show that Nop19p depletion does not impair the incorporation of UTP subcomplexes on preribosomes and conversely that depletion of UTP subcomplexes does not affect Nop19p recruitment on 90S preribosomes. TAP experiments under stringent conditions revealed that Nop19p interacts preferentially with the DEAH-box RNA helicase Dhr2p and Utp25p, both required for A 0, A 1 and A 2 cleavages. Nop19p appeared essential for the incorporation of Utp25p in preribosomes. In addition, our results suggest that in absence of Nop19p, Dhr2p remains trapped within aberrant preribosomes.
Assuntos
Proteínas de Transporte/metabolismo , RNA Helicases DEAD-box/metabolismo , Proteínas Nucleares/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Transporte/genética , Nucléolo Celular/metabolismo , RNA Helicases DEAD-box/genética , Immunoblotting , Imunoprecipitação , Mutação , Proteínas Nucleares/genética , Ligação Proteica , Precursores de RNA/genética , Precursores de RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA Fúngico/genética , RNA Fúngico/metabolismo , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , RNA Ribossômico 18S/genética , RNA Ribossômico 18S/metabolismo , Subunidades Ribossômicas Menores de Eucariotos/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
To determine the respective contribution of the LAT transmembrane adaptor and CD5 and CD6 transmembrane receptors to early TCR signal propagation, diversification, and termination, we describe a CRISPR/Cas9-based platform that uses primary mouse T cells and permits establishment of the composition of their LAT, CD5, and CD6 signalosomes in only 4 mo using quantitative mass spectrometry. We confirmed that positive and negative functions can be solely assigned to the LAT and CD5 signalosomes, respectively. In contrast, the TCR-inducible CD6 signalosome comprised both positive (SLP-76, ZAP70, VAV1) and negative (UBASH3A/STS-2) regulators of T cell activation. Moreover, CD6 associated independently of TCR engagement to proteins that support its implication in inflammatory pathologies necessitating T cell transendothelial migration. The multifaceted role of CD6 unveiled here accounts for past difficulties in classifying it as a coinhibitor or costimulator. Congruent with our identification of UBASH3A within the CD6 signalosome and the view that CD6 constitutes a promising target for autoimmune disease treatment, single-nucleotide polymorphisms associated with human autoimmune diseases have been found in the Cd6 and Ubash3a genes.
Assuntos
Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Ativação Linfocitária/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Doenças Autoimunes/imunologia , Sequência de Bases , Feminino , Inflamação/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Polimorfismo de Nucleotídeo Único/imunologia , Transdução de Sinais/imunologiaRESUMO
BACKGROUND AND AIMS: Intestinal epithelial cells [IECs] from inflammatory bowel disease [IBD] patients exhibit an excessive induction of endoplasmic reticulum stress [ER stress] linked to altered intestinal barrier function and inflammation. Colonic tissues and the luminal content of IBD patients are also characterized by increased serine protease activity. The possible link between ER stress and serine protease activity in colitis-associated epithelial dysfunctions is unknown. We aimed to study the association between ER stress and serine protease activity in enterocytes and its impact on intestinal functions. METHODS: The impact of ER stress induced by Thapsigargin on serine protease secretion was studied using either human intestinal cell lines or organoids. Moreover, treating human intestinal cells with protease-activated receptor antagonists allowed us to investigate ER stress-resulting molecular mechanisms that induce proteolytic activity and alter intestinal epithelial cell biology. RESULTS: Colonic biopsies from IBD patients exhibited increased epithelial trypsin-like activity associated with elevated ER stress. Induction of ER stress in human intestinal epithelial cells displayed enhanced apical trypsin-like activity. ER stress-induced increased trypsin activity destabilized intestinal barrier function by increasing permeability and by controlling inflammatory mediators such as C-X-C chemokine ligand 8 [CXCL8]. The deleterious impact of ER stress-associated trypsin activity was specifically dependent on the activation of protease-activated receptors 2 and 4. CONCLUSIONS: Excessive ER stress in IECs caused an increased release of trypsin activity that, in turn, altered intestinal barrier function, promoting the development of inflammatory process.
Assuntos
Colite Ulcerativa/patologia , Doença de Crohn/patologia , Estresse do Retículo Endoplasmático/fisiologia , Enterócitos/fisiologia , Absorção Intestinal/fisiologia , Tripsina/metabolismo , Técnicas de Cultura de Células , Linhagem Celular , Colite Ulcerativa/etiologia , Colite Ulcerativa/metabolismo , Doença de Crohn/etiologia , Doença de Crohn/metabolismo , Humanos , Organoides , TapsigarginaRESUMO
We synthesized affinity-based chemical probes of cytosine-adenosine bisubstrate analogs and identified several potential targets by proteomic analysis. The validation of the proteomic analysis identified the chemical probe as a specific inhibitor of glucose-regulated protein 94 (GRP94), a potential drug target for several types of cancers. Therefore, as a result of the use of bisubstrate-type chemical probes and a chemical-biology methodology, this work opens the way to the development of a new family of GRP94 inhibitors that could potentially be of therapeutic interest.
Assuntos
Adenosina/análogos & derivados , Adenosina/farmacologia , Marcadores de Afinidade/farmacologia , Citosina/análogos & derivados , Citosina/farmacologia , Glicoproteínas de Membrana/antagonistas & inibidores , Adenosina/efeitos da radiação , Marcadores de Afinidade/síntese química , Marcadores de Afinidade/efeitos da radiação , Linhagem Celular Tumoral , Química Click , Citosina/efeitos da radiação , Humanos , Glicoproteínas de Membrana/química , Proteoma/química , Proteômica , Raios UltravioletaRESUMO
Chronic remodeling postmyocardial infarction consists in various maladaptive changes including interstitial fibrosis, cardiomyocyte death and mitochondrial dysfunction that lead to heart failure (HF). Reactive aldehydes such as 4-hydroxynonenal (4-HNE) are critical mediators of mitochondrial dysfunction but the sources of mitochondrial 4-HNE in cardiac diseases together with its mechanisms of action remain poorly understood. Here, we evaluated whether the mitochondrial enzyme monoamine oxidase-A (MAO-A), which generates H2O2 as a by-product of catecholamine metabolism, is a source of deleterious 4-HNE in HF. We found that MAO-A activation increased mitochondrial ROS and promoted local 4-HNE production inside the mitochondria through cardiolipin peroxidation in primary cardiomyocytes. Deleterious effects of MAO-A/4-HNE on cardiac dysfunction were prevented by activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2), the main enzyme for 4-HNE metabolism. Mechanistically, MAO-A-derived 4-HNE bound to newly identified targets VDAC and MCU to promote ER-mitochondria contact sites and MCU higher-order complex formation. The resulting mitochondrial Ca2+ accumulation participated in mitochondrial respiratory dysfunction and loss of membrane potential, as shown with the protective effects of the MCU inhibitor, RU360. Most interestingly, these findings were recapitulated in a chronic model of ischemic remodeling where pharmacological or genetic inhibition of MAO-A protected the mice from 4-HNE accumulation, MCU oligomer formation and Ca2+ overload, thus mitigating ventricular dysfunction. To our knowledge, these are the first evidences linking MAO-A activation to mitoCa2+ mishandling through local 4-HNE production, contributing to energetic failure and postischemic remodeling.
Assuntos
Aldeídos/metabolismo , Insuficiência Cardíaca/metabolismo , Mitocôndrias Cardíacas/metabolismo , Monoaminoxidase/metabolismo , Infarto do Miocárdio/metabolismo , Miócitos Cardíacos , Animais , Cálcio/metabolismo , Células Cultivadas , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Ratos , Remodelação VentricularRESUMO
Immune checkpoint inhibitors (ICIs) have dramatically modified the prognosis of several advanced cancers, however many patients still do not respond to treatment. Optimal results might be obtained by targeting cancer cell metabolism to modulate the immunosuppressive tumor microenvironment. Here, we identify sphingosine kinase-1 (SK1) as a key regulator of anti-tumor immunity. Increased expression of SK1 in tumor cells is significantly associated with shorter survival in metastatic melanoma patients treated with anti-PD-1. Targeting SK1 markedly enhances the responses to ICI in murine models of melanoma, breast and colon cancer. Mechanistically, SK1 silencing decreases the expression of various immunosuppressive factors in the tumor microenvironment to limit regulatory T cell (Treg) infiltration. Accordingly, a SK1-dependent immunosuppressive signature is also observed in human melanoma biopsies. Altogether, this study identifies SK1 as a checkpoint lipid kinase that could be targeted to enhance immunotherapy.
Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Melanoma/tratamento farmacológico , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Neoplasias Cutâneas/tratamento farmacológico , Idoso , Animais , Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Linfócitos T CD8-Positivos/patologia , Feminino , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Melanoma/imunologia , Melanoma/mortalidade , Melanoma/patologia , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/patologia , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Terapia de Alvo Molecular , Nivolumabe/uso terapêutico , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/mortalidade , Neoplasias Cutâneas/patologia , Taxa de Sobrevida , Linfócitos T Reguladores/patologia , Evasão Tumoral/efeitos dos fármacos , Evasão Tumoral/fisiologiaRESUMO
While proteases are essential in gastrointestinal physiology, accumulating evidence indicates that dysregulated proteolysis plays a pivotal role in the pathophysiology of inflammatory bowel disease (IBD). Nonetheless, the identity of overactive proteases released by human colonic mucosa remains largely unknown. Studies of protease abundance have primarily investigated expression profiles, not taking into account their enzymatic activity. Herein we have used serine protease-targeted activity-based probes (ABPs) coupled with mass spectral analysis to identify active forms of proteases secreted by the colonic mucosa of healthy controls and IBD patients. Profiling of (Pro-Lys)-ABP bound proteases revealed that most of hyperactive proteases from IBD secretome are clustered at 28-kDa. We identified seven active proteases: the serine proteases cathepsin G, plasma kallikrein, plasmin, tryptase, chymotrypsin-like elastase 3 A, and thrombin and the aminopeptidase B. Only cathepsin G and thrombin were overactive in supernatants from IBD patient tissues compared to healthy controls. Gene expression analysis highlighted the transcription of genes encoding these proteases into intestinal mucosae. The functional ABP-targeted proteomic approach that we have used to identify active proteases in human colonic samples bears directly on the understanding of the role these enzymes may play in the pathophysiology of IBD.
Assuntos
Catepsina G/genética , Doenças Inflamatórias Intestinais/metabolismo , Proteômica/métodos , Trombina/genética , Cromatografia Líquida , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Doenças Inflamatórias Intestinais/genética , Mucosa Intestinal/metabolismo , Serina Proteases/genética , Serina Proteases/metabolismo , Espectrometria de Massas em Tandem , Regulação para CimaRESUMO
The T cell signaling protein Themis1 is essential for the positive and negative selection of thymocytes in the thymus. Although the developmental defect that results from the loss of Themis1 suggests that it enhances T cell receptor (TCR) signaling, Themis1 also recruits Src homology 2 domain-containing phosphatase-1 (SHP-1) to the vicinity of TCR signaling complexes, suggesting that it has an inhibitory role in TCR signaling. We used TCR signaling reporter mice and quantitative proteomics to explore the role of Themis1 in developing T cells. We found that Themis1 acted mostly as a positive regulator of TCR signaling in vivo when receptors were activated by positively selecting ligands. Proteomic analysis of the Themis1 interactome identified SHP-1, the TCR-associated adaptor protein Grb2, and the guanine nucleotide exchange factor Vav1 as the principal interacting partners of Themis1 in isolated mouse thymocytes. Analysis of TCR signaling in Themis1-deficient and Themis1-overexpressing mouse thymocytes demonstrated that Themis1 promoted Vav1 activity both in vitro and in vivo. The reduced activity of Vav1 and the impaired T cell development in Themis1(-/-) mice were due in part to increased degradation of Grb2, which suggests that Themis1 is required to maintain the steady-state abundance of Grb2 in thymocytes. Together, these data suggest that Themis1 acts as a positive regulator of TCR signaling in developing T cells, and identify a mechanism by which Themis1 regulates thymic selection.
Assuntos
Proteína Adaptadora GRB2/metabolismo , Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Timócitos/citologia , Animais , Diferenciação Celular , Peptídeos e Proteínas de Sinalização Intercelular , Ativação Linfocitária , Camundongos , Camundongos Transgênicos , Neuropeptídeos/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Proteômica/métodos , Transdução de Sinais , Transgenes , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
This data article describes a controlled, spiked proteomic dataset for which the "ground truth" of variant proteins is known. It is based on the LC-MS analysis of samples composed of a fixed background of yeast lysate and different spiked amounts of the UPS1 mixture of 48 recombinant proteins. It can be used to objectively evaluate bioinformatic pipelines for label-free quantitative analysis, and their ability to detect variant proteins with good sensitivity and low false discovery rate in large-scale proteomic studies. More specifically, it can be useful for tuning software tools parameters, but also testing new algorithms for label-free quantitative analysis, or for evaluation of downstream statistical methods. The raw MS files can be downloaded from ProteomeXchange with identifier PXD001819. Starting from some raw files of this dataset, we also provide here some processed data obtained through various bioinformatics tools (including MaxQuant, Skyline, MFPaQ, IRMa-hEIDI and Scaffold) in different workflows, to exemplify the use of such data in the context of software benchmarking, as discussed in details in the accompanying manuscript [1]. The experimental design used here for data processing takes advantage of the different spike levels introduced in the samples composing the dataset, and processed data are merged in a single file to facilitate the evaluation and illustration of software tools results for the detection of variant proteins with different absolute expression levels and fold change values.