RESUMEN
Ferroptosis is an iron-dependent form of necrotic cell death marked by oxidative damage to phospholipids1,2. To date, ferroptosis has been thought to be controlled only by the phospholipid hydroperoxide-reducing enzyme glutathione peroxidase 4 (GPX4)3,4 and radical-trapping antioxidants5,6. However, elucidation of the factors that underlie the sensitivity of a given cell type to ferroptosis7 is crucial to understand the pathophysiological role of ferroptosis and how it may be exploited for the treatment of cancer. Although metabolic constraints8 and phospholipid composition9,10 contribute to ferroptosis sensitivity, no cell-autonomous mechanisms have been identified that account for the resistance of cells to ferroptosis. Here we used an expression cloning approach to identify genes in human cancer cells that are able to complement the loss of GPX4. We found that the flavoprotein apoptosis-inducing factor mitochondria-associated 2 (AIFM2) is a previously unrecognized anti-ferroptotic gene. AIFM2, which we renamed ferroptosis suppressor protein 1 (FSP1) and which was initially described as a pro-apoptotic gene11, confers protection against ferroptosis elicited by GPX4 deletion. We further demonstrate that the suppression of ferroptosis by FSP1 is mediated by ubiquinone (also known as coenzyme Q10, CoQ10): the reduced form, ubiquinol, traps lipid peroxyl radicals that mediate lipid peroxidation, whereas FSP1 catalyses the regeneration of CoQ10 using NAD(P)H. Pharmacological targeting of FSP1 strongly synergizes with GPX4 inhibitors to trigger ferroptosis in a number of cancer entities. In conclusion, the FSP1-CoQ10-NAD(P)H pathway exists as a stand-alone parallel system, which co-operates with GPX4 and glutathione to suppress phospholipid peroxidation and ferroptosis.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Ferroptosis/genética , Glutatión/metabolismo , Proteínas Mitocondriales/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Técnicas de Inactivación de Genes , Humanos , Peroxidación de Lípido/genética , Ratones , Proteínas Mitocondriales/genética , Ubiquinona/análogos & derivados , Ubiquinona/metabolismoRESUMEN
BACKGROUND: Individuals with developmental and/or intellectual disabilities (I/DD) are at a greater risk for atrial fibrillation (AF), the most common type of cardiac arrhythmia. AF is associated with heart failure, stroke, poor mental health, and reduced quality of life. Management and treatment decisions are based on the ability to detect AF; however, noninvasive, remote cardiac monitoring may not be tolerated by individuals with I/DD. OBJECTIVE: To examine adherence to the placement of an ambulatory cardiac rhythm monitoring patch device by adult patients with I/DD. METHODS: Investigators extracted chart data from a consecutive series of adult patients (18 years+) who received the patch device as part of standard treatment at an adult health center between November 1, 2015 and October 31, 2019. RESULTS: A total of 95 patients were included in data analysis. Average age of subjects was 53.8 ± 13.9 years (range: 20.2-88.5); 66.7% were male. All subjects had intellectual disabilities as follows: mild, 37.9%; moderate, 29.5%; severe, 21.0%; and, profound, 11.6%. With a prescribed duration of 14 days, subjects wore the device a median (interquartile range [IQR]) of 12.2 days (4.1-14.0); total analysis time was a median of 9.5 days (3.4-13.5). A total of 29 subjects (30.5%) received cardiac diagnoses not previously identified (median = 1 new diagnosis; range: 1-5). CONCLUSIONS: This pilot study suggests the possible utility of an ambulatory monitoring patch device in an adult population with I/DD. Investigators recommend larger studies to confirm such preliminary findings to ultimately improve clinical management and patient quality of life.
Asunto(s)
Electrocardiografía Ambulatoria , Cooperación del Paciente , Humanos , Masculino , Femenino , Persona de Mediana Edad , Adulto , Anciano , Anciano de 80 o más Años , Fibrilación Atrial , Adhesivos , Personas con Discapacidad , Discapacidad Intelectual/complicacionesRESUMEN
OBJECTIVE: To demonstrate and validate the improvement of current risk stratification for bronchopulmonary dysplasia (BPD) early after birth by plasma protein markers (sialic acid-binding Ig-like lectin 14 (SIGLEC-14), basal cell adhesion molecule (BCAM), angiopoietin-like 3 protein (ANGPTL-3)) in extremely premature infants. METHODS AND RESULTS: Proteome screening in first-week-of-life plasma samples of n = 52 preterm infants <32 weeks gestational age (GA) on two proteomic platforms (SomaLogic®, Olink-Proteomics®) confirmed three biomarkers with significant predictive power: BCAM, SIGLEC-14, and ANGPTL-3. We demonstrate high sensitivity (0.92) and specificity (0.86) under consideration of GA, show the proteins' critical contribution to the predictive power of known clinical risk factors, e.g., birth weight and GA, and predicted the duration of mechanical ventilation, oxygen supplementation, as well as neonatal intensive care stay. We confirmed significant predictive power for BPD cases when switching to a clinically applicable method (enzyme-linked immunosorbent assay) in an independent sample set (n = 25, p < 0.001) and demonstrated disease specificity in different cohorts of neonatal and adult lung disease. CONCLUSION: While successfully addressing typical challenges of clinical biomarker studies, we demonstrated the potential of BCAM, SIGLEC-14, and ANGPTL-3 to inform future clinical decision making in the preterm infant at risk for BPD. TRIAL REGISTRATION: Deutsches Register Klinische Studien (DRKS) No. 00004600; https://www.drks.de . IMPACT: The urgent need for biomarkers that enable early decision making and personalized monitoring strategies in preterm infants with BPD is challenged by targeted marker analyses, cohort size, and disease heterogeneity. We demonstrate the potential of the plasma proteins BCAM, SIGLEC-14, and ANGPTL-3 to identify infants with BPD early after birth while improving the predictive power of clinical variables, confirming the robustness toward proteome assays and proving disease specificity. Our comprehensive analysis enables a phase-III clinical trial that allows full implementation of the biomarkers into clinical routine to enable early risk stratification in preterms with BPD.
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Displasia Broncopulmonar , Lactante , Recién Nacido , Humanos , Displasia Broncopulmonar/prevención & control , Proteoma , Proteómica , Edad Gestacional , Recien Nacido Extremadamente Prematuro , BiomarcadoresRESUMEN
Human macrophage migration inhibitory factor (MIF) is an atypical chemokine implicated in intercellular signaling and innate immunity. MIF orthologs (MIF/D-DT-like proteins, MDLs) are present throughout the plant kingdom, but remain experimentally unexplored in these organisms. Here, we provide an in planta characterization and functional analysis of the three-member gene/protein MDL family in Arabidopsis thaliana. Subcellular localization experiments indicated a nucleo-cytoplasmic distribution of MDL1 and MDL2, while MDL3 is localized to peroxisomes. Protein-protein interaction assays revealed the in vivo formation of MDL1, MDL2, and MDL3 homo-oligomers, as well as the formation of MDL1-MDL2 hetero-oligomers. Functionally, Arabidopsismdl mutants exhibited a delayed transition from vegetative to reproductive growth (flowering) under long-day conditions, but not in a short-day environment. In addition, mdl mutants were more resistant to colonization by the bacterial pathogen Pseudomonas syringae pv. maculicola. The latter phenotype was compromised by the additional mutation of SALICYLIC ACID INDUCTION DEFICIENT 2 (SID2), a gene implicated in the defense-induced biosynthesis of the key signaling molecule salicylic acid. However, the enhanced antibacterial immunity was not associated with any constitutive or pathogen-induced alterations in the levels of characteristic phytohormones or defense-associated metabolites. Interestingly, bacterial infection triggered relocalization and accumulation of MDL1 and MDL2 at the peripheral lobes of leaf epidermal cells. Collectively, our data indicate redundant functionality and a complex interplay between the three chemokine-like Arabidopsis MDL proteins in the regulation of both developmental and immune-related processes. These insights expand the comparative cross-kingdom analysis of MIF/MDL signaling in human and plant systems.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/inmunología , Quimiocinas/metabolismo , Flores/inmunología , Inmunidad Innata/inmunología , Enfermedades de las Plantas/inmunología , Pseudomonas syringae/fisiología , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Arabidopsis/microbiología , Proteínas de Arabidopsis/genética , Flores/crecimiento & desarrollo , Flores/metabolismo , Flores/microbiología , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas/microbiologíaRESUMEN
Chemical modifications are found on almost all RNAs and affect their coding and noncoding functions. The identification of m6A on mRNA and its important role in gene regulation stimulated the field to investigate whether additional modifications are present on mRNAs. Indeed, modifications including m1A, m5C, m7G, 2'-OMe, and Ψ were detected. However, since their abundances are low and tools used for their corroboration are often not well characterized, their physiological relevance remains largely elusive. Antibodies targeting modified nucleotides are often used but have limitations such as low affinity or specificity. Moreover, they are not always well characterized and due to the low abundance of the modification, particularly on mRNAs, generated data sets might resemble noise rather than specific modification patterns. Therefore, it is critical that the affinity and specificity is rigorously tested using complementary approaches. Here, we provide an experimental toolbox that allows for testing antibody performance prior to their use.
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Anticuerpos/genética , Ribonucleótidos/genética , Nucleótidos/genética , ARN/genética , ARN Mensajero/genéticaRESUMEN
During interphase centromeres often coalesce into a small number of chromocenters, which can be visualized as distinct, DAPI dense nuclear domains. Intact chromocenters play a major role in maintaining genome stability as they stabilize the transcriptionally silent state of repetitive DNA while ensuring centromere function. Despite its biological importance, relatively little is known about the molecular composition of the chromocenter or the processes that mediate chromocenter formation and maintenance. To provide a deeper molecular insight into the composition of the chromocenter and to demonstrate the usefulness of proximity-based biotinylation as a tool to investigate those questions, we performed super resolution microscopy and proximity-based biotinylation experiments of three distinct proteins associated with the chromocenter in Drosophila. Our work revealed an intricate internal architecture of the chromocenter suggesting a complex multilayered structure of this intranuclear domain.
Asunto(s)
Proteína A Centromérica/metabolismo , Centrómero/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Proteínas de Drosophila/metabolismo , Interfase/genética , Adenosina Trifosfatasas/metabolismo , Animales , Biotinilación , Proteínas de Ciclo Celular/análisis , Línea Celular , Núcleo Celular/metabolismo , Proteína A Centromérica/genética , Cromatina/metabolismo , Secuenciación de Inmunoprecipitación de Cromatina , Homólogo de la Proteína Chromobox 5 , Proteínas Cromosómicas no Histona/análisis , Proteínas Cromosómicas no Histona/genética , Proteínas de Unión al ADN/metabolismo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Complejos Multiproteicos/metabolismo , Proteómica , Proteínas Recombinantes de Fusión/análisis , CohesinasRESUMEN
Chitinase-like proteins (CLP) are chitin-binding proteins that lack chitin hydrolyzing activity, but possess cytokine-like and growth factor-like properties, and play crucial role in intercellular crosstalk. Both human and mice express two members of CLP family: YKL-40 and stabilin-1 interacting chitinase-like protein (SI-CLP). Despite numerous reports indicating the role of YKL-40 in the support of angiogenesis, tumor cell proliferation, invasion and metastasis, the role of its structurally related protein SI-CLP in cancer was not reported. Using gain-of-function approach, we demonstrate in the current study that the expression of recombinant SI-CLP in mouse TS/A mammary adenocarcinoma cells results in significant and persistent inhibition of in vivo tumor growth. Using quantitative immunohistochemistry, we show that on the cellular level this phenomenon is associated with reduced infiltration of tumor-associated macrophages (TAMs), CD4+ and FoxP3+ cells in SI-CLP expressing tumors. Gene expression analysis in TAM isolated from SI-CLP-expressing and control tumors demonstrated that SI-CLP does not affect macrophage phenotype. However, SI-CLP significantly inhibited migration of murine bone-marrow derived macrophages and human primary monocytes toward monocyte-recruiting chemokine CCL2 produced in the tumor microenvironment (TME). Mechanistically, SI-CLP did not affect CCL2/CCR2 interaction, but suppressed cytoskeletal rearrangements in response to CCL2. Altogether, our data indicate that SI-CLP functions as a tumor growth inhibitor in mouse breast cancer by altering cellular composition of TME and blocking cytokine-induced TAM recruitment. Taking into consideration weak to absent expression of SI-CLP in human breast cancer, it can be considered as a therapeutic protein to block TAM-mediated support of breast tumor growth.
Asunto(s)
Proteínas de Unión al Calcio/inmunología , Proteínas Portadoras/inmunología , Macrófagos/inmunología , Neoplasias Mamarias Experimentales/inmunología , Animales , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/patología , Procesos de Crecimiento Celular/inmunología , Movimiento Celular/inmunología , Femenino , Células HEK293 , Humanos , Activación de Macrófagos , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Endogámicos BALB C , Persona de Mediana EdadRESUMEN
N6-methyladenine (m6A) is found on many eukaryotic RNAs including mRNAs. m6A modification has been implicated in mRNA stability and turnover, localization, or translation efficiency. A heterodimeric enzyme complex composed of METTL3 and METTL14 generates m6A on mRNAs. METTL3/14 is found in the nucleus where it is localized to nuclear speckles and the splicing regulator WTAP is required for this distinct nuclear localization pattern. Although recent crystal structures revealed how the catalytic MT-A70 domains of METTL3 and METTL14 interact with each other, a more global architecture including WTAP and RNA interactions has not been reported so far. Here, we used recombinant proteins and mapped binding surfaces within the METTL3/14-WTAP complex. Furthermore, we identify nuclear localization signals and identify phosphorylation sites on the endogenous proteins. Using an in vitro methylation assay, we confirm that monomeric METTL3 is soluble and inactive while the catalytic center of METTL14 is degenerated and thus also inactive. In addition, we show that the C-terminal RGG repeats of METTL14 are required for METTL3/14 activity by contributing to RNA substrate binding. Our biochemical work identifies characteristic features of METTL3/14-WTAP and reveals novel insight into the overall architecture of this important enzyme complex.
Asunto(s)
Adenosina/análogos & derivados , Metiltransferasas/metabolismo , Proteínas Nucleares/metabolismo , ARN Mensajero/química , Adenosina/química , Secuencia de Aminoácidos , Dominio Catalítico/fisiología , Proteínas de Ciclo Celular , Línea Celular Tumoral , Células HEK293 , Células HeLa , Humanos , Metiltransferasas/genética , Complejos Multiproteicos/metabolismo , Proteínas Nucleares/genética , Fosforilación , Mapeo de Interacción de Proteínas , Procesamiento Postranscripcional del ARN , Factores de Empalme de ARN , Proteínas de Unión al ARN/metabolismo , Proteínas Recombinantes/genéticaRESUMEN
The Epstein-Barr virus is a human herpes virus with oncogenic potential. The virus-encoded nuclear antigen 2 (EBNA2) is a key mediator of viral tumorigenesis. EBNA2 features an arginine-glycine (RG) repeat at amino acids (aa)339-354 that is essential for the transformation of lymphocytes and contains symmetrically (SDMA) and asymmetrically (ADMA) di-methylated arginine residues. The SDMA-modified EBNA2 binds the survival motor neuron protein (SMN), thus mimicking SMD3, a cellular SDMA-containing protein that interacts with SMN. Accordingly, a monoclonal antibody (mAb) specific for the SDMA-modified RG repeat of EBNA2 also binds to SMD3. With the novel mAb 19D4 we now show that EBNA2 contains mono-methylated arginine (MMA) residues within the RG repeat. Using 19D4, we immune-precipitated and analysed by mass spectrometry cellular proteins in EBV-transformed B-cells that feature MMA motifs that are similar to the one in EBNA2. Among the cellular proteins identified, we confirmed by immunoprecipitation and/or Western blot analyses Aly/REF, Coilin, DDX5, FXR1, HNRNPK, LSM4, MRE11, NRIP, nucleolin, PRPF8, RBM26, SMD1 (SNRDP1) and THRAP3 proteins that are either known to contain MMA residues or feature RG repeat sequences that probably serve as methylation substrates. The identified proteins are involved in splicing, tumorigenesis, transcriptional activation, DNA stability and RNA processing or export. Furthermore, we found that several proteins involved in energy metabolism are associated with MMA-modified proteins. Interestingly, the viral EBNA1 protein that features methylated RG repeat motifs also reacted with the antibodies. Our results indicate that the region between aa 34-52 of EBNA1 contains ADMA or SDMA residues, while the region between aa 328-377 mainly contains MMA residues.
Asunto(s)
Transformación Celular Viral , Antígenos Nucleares del Virus de Epstein-Barr/metabolismo , Herpesvirus Humano 4/patogenicidad , Interacciones Huésped-Patógeno , Proteínas Virales/metabolismo , Anticuerpos Monoclonales/metabolismo , Anticuerpos Antivirales/metabolismo , Western Blotting , Reacciones Cruzadas , Humanos , Inmunoprecipitación , Espectrometría de MasasRESUMEN
Eukaryotic RNA polymerase II (Pol II) has evolved an array of heptad repeats with the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7 at the carboxy-terminal domain (CTD) of the large subunit (Rpb1). Differential phosphorylation of Ser2, Ser5, and Ser7 in the 5' and 3' regions of genes coordinates the binding of transcription and RNA processing factors to the initiating and elongating polymerase complexes. Here, we report phosphorylation of Thr4 by Polo-like kinase 3 in mammalian cells. ChIPseq analyses indicate an increase of Thr4-P levels in the 3' region of genes occurring subsequently to an increase of Ser2-P levels. A Thr4/Ala mutant of Pol II displays a lethal phenotype. This mutant reveals a global defect in RNA elongation, while initiation is largely unaffected. Since Thr4 replacement mutants are viable in yeast we conclude that this amino acid has evolved an essential function(s) in the CTD of Pol II for gene transcription in mammalian cells.
Asunto(s)
Regulación de la Expresión Génica , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Polimerasa II/metabolismo , Treonina/metabolismo , Transcripción Genética , Sustitución de Aminoácidos , Animales , Línea Celular , Inmunoprecipitación de Cromatina , Perfilación de la Expresión Génica , Genes Esenciales , Humanos , Mutagénesis Sitio-Dirigida , Fosforilación , ARN Polimerasa II/genética , Proteínas Supresoras de TumorRESUMEN
Little is known on the control of lymphomas by NK cells. Here, we study the role of the NK group 2D (NKG2D) receptor for the immunosurveillance of lymphoma. By using transplantable tumors as well as a λ-myc-transgenic model of endogenously arising lymphoma and NKG2D-deficient mice, we show that NK cells eliminate tumor cells in vivo after receiving two signals. One step involved the activation of NK cells giving rise to IFN-γ expression, which was effected by MHCI(low) tumor cells or DCs. However, this was necessary but not sufficient to mediate cytotoxicity. Triggering cytotoxicity additionally required a second step, which could be mediated by engagement of the NKG2D receptor. Thus, NKG2D-deficient NK cells could become activated in vivo, but they were not able to reject transplanted lymphomas or to degranulate in animals bearing autochthonous lymphomas. Tumor growth in NKG2D-deficient λ-myc-transgenic mice was significantly accelerated compared to NKG2D-competent animals. Whereas the latter developed tumors that lost expression of NKG2D ligands (NKG2D-L) in late disease stages, this did not occur in NKG2D-deficient mice. This indicates that NK cells and the NKG2D receptor play a role for control of lymphomas and that selection for NKG2D-L loss mutants provides a mechanism of tumor escape.
Asunto(s)
Proteínas Portadoras/inmunología , Regulación Neoplásica de la Expresión Génica , Antígenos de Histocompatibilidad Clase I/inmunología , Células Asesinas Naturales/inmunología , Linfoma de Células B/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Escape del Tumor/genética , Animales , Proteínas Portadoras/genética , Línea Celular Tumoral , Citotoxicidad Inmunológica , Antígenos de Histocompatibilidad Clase I/genética , Interferón gamma/genética , Interferón gamma/inmunología , Células Asesinas Naturales/patología , Activación de Linfocitos , Linfoma de Células B/genética , Linfoma de Células B/patología , Proteínas de la Membrana , Ratones , Ratones Transgénicos , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Trasplante de Neoplasias , Transducción de SeñalRESUMEN
Methanobactin, a small modified polypeptide synthesized by methanotrophs for copper uptake, has been found to be chromosomally encoded. The gene encoding the polypeptide precursor of methanobactin, mbnA, is part of a gene cluster that also includes several genes encoding proteins of unknown function (but speculated to be involved in methanobactin formation) as well as mbnT, which encodes a TonB-dependent transporter hypothesized to be responsible for methanobactin uptake. To determine if mbnT is truly responsible for methanobactin uptake, a knockout was constructed in Methylosinus trichosporium OB3b using marker exchange mutagenesis. The resulting M. trichosporium mbnT::Gm(r) mutant was found to be able to produce methanobactin but was unable to internalize it. Further, if this mutant was grown in the presence of copper and exogenous methanobactin, copper uptake was significantly reduced. Expression of mmoX and pmoA, encoding polypeptides of the soluble methane monooxygenase (sMMO) and particulate methane monooxygenase (pMMO), respectively, also changed significantly when methanobactin was added, which indicates that the mutant was unable to collect copper under these conditions. Copper uptake and gene expression, however, were not affected in wild-type M. trichosporium OB3b, indicating that the TonB-dependent transporter encoded by mbnT is responsible for methanobactin uptake and that methanobactin is a key mechanism used by methanotrophs for copper uptake. When the mbnT::Gm(r) mutant was grown under a range of copper concentrations in the absence of methanobactin, however, the phenotype of the mutant was indistinguishable from that of wild-type M. trichosporium OB3b, indicating that this methanotroph has multiple mechanisms for copper uptake.
Asunto(s)
Proteínas Bacterianas/metabolismo , Imidazoles/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Methylosinus trichosporium/metabolismo , Oligopéptidos/metabolismo , Cobre/metabolismo , Técnicas de Inactivación de Genes , Proteínas de Transporte de Membrana/genética , Methylosinus trichosporium/genéticaRESUMEN
It is well established that an interplay between natural killer (NK) cells and dendritic cells (DCs) gives rise to their reciprocal activation and provides a Th1-biased cytokine milieu that fosters antitumor T-cell responses. Ex vivo-differentiated DCs transferred into mice strongly stimulate endogenous NK cells to produce interferon (IFN)-γ and initiate a cascade that eventually leads to cytotoxic T-lymphocyte responses. We show that the ability of exogenous DCs to trigger this pathway obviates CD40 signaling and CD4(+) T-cell help and depends on a preceding maturation step. Importantly, this mechanism was also effective in endogenously arising tumors where IFN-γ production is compromised in contrast to transplantable tumors. In c-myc-transgenic mice developing spontaneous lymphomas, injection of unpulsed DCs caused NK-cell activation and induced CD8(+) T cells capable of recognizing the lymphoma cells. Animals treated with unpulsed DCs showed a survival benefit compared to untreated myc mice. Hence, tumor immunity induced by DC-based vaccines not only depends on specific antigens loaded on the DCs. Rather, DC vaccines generate broader immune responses, because endogenous DCs presenting tumor antigens may also become stimulated by NK cells that were activated by exogenous DCs. Thus, the DC/NK-cell/cytotoxic T lymphocyte axis may commonly have relevance for DC-based vaccination protocols in clinical settings.
Asunto(s)
Vacunas contra el Cáncer/inmunología , Células Dendríticas/inmunología , Células Asesinas Naturales/inmunología , Linfoma de Células B/inmunología , Linfoma de Células B/terapia , Linfocitos T Citotóxicos/inmunología , Animales , Antígenos CD40/metabolismo , Línea Celular Tumoral , Citocinas/metabolismo , Femenino , Genes myc , Interferón gamma/metabolismo , Células Asesinas Naturales/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Trasplante de NeoplasiasRESUMEN
Adoptive transfer (AT) of T cells forced to express tumor-reactive T-cell receptor (TCR) genes is an attractive strategy to direct autologous T-cell immunity against tumor-associated antigens. However, clinical effectiveness has been hampered by limited in vivo persistence. We investigated whether the use of major histocompatibility complex-mismatched T cells would prolong the in vivo persistence of tumor-reactive TCR gene expressing T cells by continuous antigen-driven proliferation via the endogenous potentially alloreactive receptor. Donor-derived CD8(+) T cells engineered to express a TCR against a leukemia-associated antigen mediated strong graft-versus-leukemia (GVL) effects with reduced graft-versus-host disease (GVHD) severity when given early after transplantation. AT later after transplantation resulted in a complete loss of GVL. Loss of function was associated with reduced expansion of TCR-transduced T cells as assessed by CDR3 spectratyping analysis and PD-1 up-regulation on T cells in leukemia-bearing recipients. PD-L1 blockade in allogeneic transplant recipients largely restored the GVL efficacy without triggering GVHD, whereas no significant antileukemia effects of PD-L1 blockade were observed in syngeneic controls. These data suggest a clinical approach in which the AT of gene-modified allogeneic T cells early after transplantation can provide a potent GVL effect without GVHD, whereas later AT is effective only with concurrent PD-L1 blockade.
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Antígeno B7-1/inmunología , Linfocitos T CD8-positivos/inmunología , Efecto Injerto vs Leucemia/inmunología , Glicoproteínas de Membrana/inmunología , Péptidos/inmunología , Traslado Adoptivo/métodos , Secuencia de Aminoácidos , Animales , Antígeno B7-1/metabolismo , Antígeno B7-H1 , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/trasplante , Línea Celular Tumoral , Citometría de Flujo , Supervivencia de Injerto/inmunología , Enfermedad Injerto contra Huésped/inmunología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Leucemia Experimental/inmunología , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Péptidos/metabolismo , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Factores de Tiempo , Transfección , Trasplante Homólogo , Trasplante IsogénicoRESUMEN
Neuritin represents a neurotrophic factor that is not only important in neuronal development and plasticity but also impacts endothelial angiogenesis, cell migration, tumor growth and the production of antibodies by B cells. We established monoclonal mouse anti-mouse neuritin antibodies by immunizing knock-out mice with two different neuritin-derived peptides. Because neuritin is well conserved between species, these new monoclonal antibodies recognize the neuritin of a wide variety of species, including human. Moreover, they not only recognize specifically surface-bound neuritin expressed by murine follicular regulatory T cells but also the block binding of recombinant neuritin to germinal center B cells. This suggests that these newly generated tools will be of great use in studying neuritin expression and function.
RESUMEN
Mammalian macrophage migration inhibitory factor (MIF) and its paralog, D-dopachrome tautomerase, are multifunctional inflammatory cytokines. Plants have orthologous MIF and D-dopachrome tautomerase-like (MDL) proteins that mimic some of the effects of MIF on immune cells in vitro. We explored the structural and functional similarities between the three Arabidopsis thaliana MDLs and MIF. X-ray crystallography of the MDLs revealed high structural similarity between MDL and MIF homotrimers and suggested a potential explanation for the lack of tautomerase activity in the MDLs. MDL1 and MDL2 interacted with each other and with MIF in vitro, in yeast, and in plant leaves and formed hetero-oligomeric complexes with MIF in vitro. The MDLs stimulated signaling through the MIF receptors CXCR2 or CXCR4 and enhanced the responses to MIF in a yeast reporter system, in human neutrophils, and in human lung epithelial cells. Pharmacological inhibitors that disrupted MIF activity or prevented the formation of MIF-MDL hetero-oligomers blocked the observed synergism. These findings demonstrate that MDLs can enhance cellular responses to MIF, which may have functional implications in tissues exposed to MDLs from the diet or environment.
Asunto(s)
Factores Inhibidores de la Migración de Macrófagos , Animales , Humanos , Factores Inhibidores de la Migración de Macrófagos/genética , Factores Inhibidores de la Migración de Macrófagos/química , Proteínas de Plantas , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Saccharomyces cerevisiae/metabolismo , Neutrófilos/metabolismo , Mamíferos/metabolismo , Oxidorreductasas Intramoleculares/genéticaRESUMEN
Cytoplasmic aggregation and concomitant nuclear clearance of the RNA-binding protein TDP-43 are found in ~ 90% of cases of amyotrophic lateral sclerosis and ~ 45% of patients living with frontotemporal lobar degeneration, but no disease-modifying therapy is available. Antibody therapy targeting other aggregating proteins associated with neurodegenerative disorders has shown beneficial effects in animal models and clinical trials. The most effective epitopes for safe antibody therapy targeting TDP-43 are unknown. Here, we identified safe and effective epitopes in TDP-43 for active and potential future passive immunotherapy. We prescreened 15 peptide antigens covering all regions of TDP-43 to identify the most immunogenic epitopes and to raise novel monoclonal antibodies in wild-type mice. Most peptides induced a considerable antibody response and no antigen triggered obvious side effects. Thus, we immunized mice with rapidly progressing TDP-43 proteinopathy ("rNLS8" model) with the nine most immunogenic peptides in five pools prior to TDP-43ΔNLS transgene induction. Strikingly, combined administration of two N-terminal peptides induced genetic background-specific sudden lethality in several mice and was therefore discontinued. Despite a strong antibody response, no TDP-43 peptide prevented the rapid body weight loss or reduced phospho-TDP-43 levels as well as the profound astrogliosis and microgliosis in rNLS8 mice. However, immunization with a C-terminal peptide containing the disease-associated phospho-serines 409/410 significantly lowered serum neurofilament light chain levels, indicative of reduced neuroaxonal damage. Transcriptomic profiling showed a pronounced neuroinflammatory signature (IL-1ß, TNF-α, NfκB) in rNLS8 mice and suggested modest benefits of immunization targeting the glycine-rich region. Several novel monoclonal antibodies targeting the glycine-rich domain potently reduced phase separation and aggregation of TDP-43 in vitro and prevented cellular uptake of preformed aggregates. Our unbiased screen suggests that targeting the RRM2 domain and the C-terminal region of TDP-43 by active or passive immunization may be beneficial in TDP-43 proteinopathies by inhibiting cardinal processes of disease progression.
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Anticuerpos Monoclonales , Filamentos Intermedios , Animales , Ratones , Epítopos , Inmunización , FN-kappa BRESUMEN
Procalcitonin (PCT)-a diagnostic serum parameter for bacterial infection and sepsis-is of great interest in the field of biosensors for point-of-care testing. Its detection needs specific biological recognition elements, such as antibodies. Herein, we describe the development and characterization of rat monoclonal antibodies (mAbs) for PCT, and their application in enzyme-linked immunosorbent assays (ELISAs) for the determination of PCT in patient serum samples. From about 50 mAbs, two mAbs, CALCA 2F3 and CALCA 4A6, were selected as a pair with high affinity for PCT in sandwich immunoassays. Both mAbs could be used either as capture or as detection mAb. They were Protein G-purified and biotinylated when used as detection mAb. The setup of two sandwich ELISAs with standards of human recombinant (hr) PCT, using either CALCA 2F3 (assay A) or CALCA 4A6 (assay B) as capture mAbs and the biotinylated mAbs CALCA 4A6 or CALCA 2F3, respectively, as detection mAbs, led to highly specific determinations of PCT without cross-reactivity to calcitonin and katacalcin. Test midpoints (IC(50)) of both assays were determined for hrPCT standards in 4% (w/v) human serum albumin and found with 2.5 (assay A) and 2.7 µg L(-1) (assay B). With both sandwich ELISAs a collection of eight patient serum samples have been determined in comparison to the determination by the Elecsys BRAHMS PCT assay. Good correlations between our prototype ELISAs and the BRAHMS assay could be demonstrated (R (2): assay A, 0.996 and assay B, 0.990). The use of these newly developed anti-PCT mAbs should find broad applications in immunosensors for point-of-care diagnostics of sepsis and systemic inflammation processes.
Asunto(s)
Anticuerpos Monoclonales/análisis , Anticuerpos Monoclonales/inmunología , Calcitonina/sangre , Calcitonina/inmunología , Precursores de Proteínas/sangre , Precursores de Proteínas/inmunología , Animales , Anticuerpos Monoclonales/aislamiento & purificación , Reacciones Antígeno-Anticuerpo , Análisis Químico de la Sangre , Péptido Relacionado con Gen de Calcitonina , Ensayo de Inmunoadsorción Enzimática , Humanos , Ratas , Proteínas Recombinantes/sangre , Proteínas Recombinantes/inmunología , Sensibilidad y EspecificidadRESUMEN
The COVID-19 disease has been linked to multiple physical and mental health consequences which may be partially attributed to multi-system modulation by inflammatory cytokines. Post-acute sequelae (PASC) of SARS-CoV-2 infection, colloquially known as "Long Covid", has become an established entity. However, screening guidelines and interventions for COVID-19 survivors remain elusive. The neuropsychiatric sequelae of COVID-19 seem to originate from a cumulation of biopsychosocial factors which may predispose individuals to acute psychiatric decompensation irrespective of a previously diagnosed mental illness. We present a case report which illustrates how cognitive issues and medical complaints may negatively interact resulting in significant depression and a severe suicide attempt.
RESUMEN
Aerobic methanotrophy is strongly controlled by copper, and methanotrophs are known to use different mechanisms for copper uptake. Some methanotrophs secrete a modified polypeptide-methanobactin-while others utilize a surface-bound protein (MopE) and a secreted form of it (MopE*) for copper collection. As different methanotrophs have different means of sequestering copper, competition for copper significantly impacts methanotrophic activity. Herein, we show that Methylomicrobium album BG8, Methylocystis sp. strain Rockwell, and Methylococcus capsulatus Bath, all lacking genes for methanobactin biosynthesis, are not limited for copper by multiple forms of methanobactin. Interestingly, Mm. album BG8 and Methylocystis sp. strain Rockwell were found to have genes similar to mbnT that encodes for a TonB-dependent transporter required for methanobactin uptake. Data indicate that these methanotrophs "steal" methanobactin and such "theft" enhances the ability of these strains to degrade methylmercury, a potent neurotoxin. Further, when mbnT was deleted in Mm. album BG8, methylmercury degradation in the presence of methanobactin was indistinguishable from when MB was not added. Mc. capsulatus Bath lacks anything similar to mbnT and was unable to degrade methylmercury either in the presence or absence of methanobactin. Rather, Mc. capsulatus Bath appears to rely on MopE/MopE* for copper collection. Finally, not only does Mm. album BG8 steal methanobactin, it synthesizes a novel chalkophore, suggesting that some methanotrophs utilize both competition and cheating strategies for copper collection. Through a better understanding of these strategies, methanotrophic communities may be more effectively manipulated to reduce methane emissions and also enhance mercury detoxification in situ.