RESUMEN
Nitrogen (N) deficiency responses are essential for plant survival and reproduction. Here, via an expression genome-wide association study (eGWAS), we reveal a mechanism that regulates microRNA (miRNA) dynamics necessary for N deficiency responses in Arabidopsis. Differential expression levels of three NAC transcription factor (TF) genes involved in leaf N deficiency responses among Arabidopsis accessions are most significantly associated with polymorphisms in HASTY (HST), which encodes an importin/exportin family protein responsible for the generation of mature miRNAs. HST acts as a negative regulator of N deficiency-induced leaf senescence, and the disruption and overexpression of HST differently modifies miRNA dynamics in response to N deficiency, altering levels of miRNAs targeting transcripts. Interestingly, N deficiency prevents the interaction of HST with HST-interacting proteins, DCL1 and RAN1, and some miRNAs. This suggests that HST-mediated regulation of miRNA dynamics collectively controls regulations mediated by multiple N deficiency response-associated NAC TFs, thereby being central to the N deficiency response network.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , MicroARNs , Nitrógeno , Hojas de la Planta , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/metabolismo , MicroARNs/metabolismo , MicroARNs/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Nitrógeno/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Senescencia de la Planta/genética , Estudio de Asociación del Genoma Completo , Carioferinas/metabolismo , Carioferinas/genética , Ribonucleasa III/metabolismo , Ribonucleasa III/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proteína de Unión al GTP ran/metabolismo , Proteína de Unión al GTP ran/genéticaRESUMEN
XPO1 (Exportin-1/CRM1) is a nuclear export protein that is frequently overexpressed in cancer and functions as a driver of oncogenesis. Currently small molecules that target XPO1 are being used in the clinic as anticancer agents. We identify XPO1 as a target for natural killer (NK) cells. Using immunopeptidomics, we have identified a peptide derived from XPO1 that can be recognized by the activating NK cell receptor KIR2DS2 in the context of human leukocyte antigen-C. The peptide can be endogenously processed and presented to activate NK cells specifically through this receptor. Although high XPO1 expression in cancer is commonly associated with a poor prognosis, we show that the outcome of specific cancers, such as hepatocellular carcinoma, can be substantially improved if there is concomitant evidence of NK cell infiltration. We thus identify XPO1 as a bona fide tumor antigen recognized by NK cells that offers an opportunity for a personalized approach to NK cell therapy for solid tumors.
Asunto(s)
Proteína Exportina 1 , Carioferinas , Células Asesinas Naturales , Péptidos , Receptores Citoplasmáticos y Nucleares , Humanos , Línea Celular Tumoral , Proteína Exportina 1/genética , Proteína Exportina 1/metabolismo , Carioferinas/metabolismo , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Ligandos , Neoplasias/inmunología , Neoplasias/metabolismo , Péptidos/química , Péptidos/inmunología , Receptores Citoplasmáticos y Nucleares/metabolismoRESUMEN
Nuclear export of the viral ribonucleoprotein (vRNP) is a critical step in the influenza A virus (IAV) life cycle and may be an effective target for the development of anti-IAV drugs. The host factor ras-related nuclear protein (RAN) is known to participate in the life cycle of several viruses, but its role in influenza virus replication remains unknown. In the present study, we aimed to determine the function of RAN in influenza virus replication using different cell lines and subtype strains. We found that RAN is essential for the nuclear export of vRNP, as it enhances the binding affinity of XPO1 toward the viral nuclear export protein NS2. Depletion of RAN constrained the vRNP complex in the nucleus and attenuated the replication of various subtypes of influenza virus. Using in silico compound screening, we identified that bepotastine could dissociate the RAN-XPO1-vRNP trimeric complex and exhibit potent antiviral activity against influenza virus both in vitro and in vivo. This study demonstrates the important role of RAN in IAV replication and suggests its potential use as an antiviral target.
Asunto(s)
Transporte Activo de Núcleo Celular , Antivirales , Proteína Exportina 1 , Virus de la Influenza A , Carioferinas , Replicación Viral , Proteína de Unión al GTP ran , Replicación Viral/efectos de los fármacos , Humanos , Proteína de Unión al GTP ran/metabolismo , Proteína de Unión al GTP ran/genética , Antivirales/farmacología , Animales , Virus de la Influenza A/efectos de los fármacos , Virus de la Influenza A/fisiología , Carioferinas/metabolismo , Carioferinas/antagonistas & inhibidores , Perros , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Células de Riñón Canino Madin Darby , Proteínas no Estructurales Virales/metabolismo , Proteínas no Estructurales Virales/genética , Ratones , Piperidinas/farmacología , Gripe Humana/virología , Células A549 , Nucleoproteínas/metabolismo , Nucleoproteínas/genética , Células HEK293 , Línea Celular , Núcleo Celular/metabolismo , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genéticaRESUMEN
The spatial separation of protein synthesis from the compartmental destiny of proteins led to the evolution of transport systems that are efficient and yet highly specific. Co-translational transport has emerged as a strategy to avoid cytosolic aggregation of folding intermediates and the need for energy-consuming unfolding strategies to enable transport through narrow conduits connecting compartments. While translation and compartmental translocation are at times tightly coordinated, we know very little about the temporal coordination of translation, protein folding, and nuclear import. Here, we consider the implications of co-translational engagement of nuclear import machinery. We propose that the dynamic interplay of karyopherins and intrinsically disordered nucleoporins create a favorable protein folding environment for cargo en route to the nuclear compartment while maintaining a barrier function of the nuclear pore complex. Our model is discussed in the context of neurological disorders that are tied to defects in nuclear transport and protein quality control.
Asunto(s)
Transporte Activo de Núcleo Celular , Pliegue de Proteína , Humanos , Animales , Núcleo Celular/metabolismo , Poro Nuclear/metabolismo , Poro Nuclear/química , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas de Complejo Poro Nuclear/química , Carioferinas/metabolismo , Carioferinas/químicaRESUMEN
Flaviviridae is a family of positive-stranded RNA viruses, including human pathogens, such as Japanese encephalitis virus (JEV), dengue virus (DENV), Zika virus (ZIKV), and West Nile virus (WNV). Nuclear localization of the viral core protein is conserved among Flaviviridae, and this feature may be targeted for developing broad-ranging anti-flavivirus drugs. However, the mechanism of core protein translocation to the nucleus and the importance of nuclear translocation in the viral life cycle remain unknown. We aimed to identify the molecular mechanism underlying core protein nuclear translocation. We identified importin-7 (IPO7), an importin-ß family protein, as a nuclear carrier for Flaviviridae core proteins. Nuclear import assays revealed that core protein was transported into the nucleus via IPO7, whereas IPO7 deletion by CRISPR/Cas9 impaired their nuclear translocation. To understand the importance of core protein nuclear translocation, we evaluated the production of infectious virus or single-round-infectious-particles in wild-type or IPO7-deficient cells; both processes were significantly impaired in IPO7-deficient cells, whereas intracellular infectious virus levels were equivalent in wild-type and IPO7-deficient cells. These results suggest that IPO7-mediated nuclear translocation of core proteins is involved in the release of infectious virus particles of flaviviruses.
Asunto(s)
Transporte Activo de Núcleo Celular , Núcleo Celular , Flavivirus , Humanos , Flavivirus/metabolismo , Flavivirus/fisiología , Animales , Núcleo Celular/metabolismo , Núcleo Celular/virología , Replicación Viral/fisiología , Proteínas del Núcleo Viral/metabolismo , Proteínas del Núcleo Viral/genética , Carioferinas/metabolismo , Carioferinas/genética , Infecciones por Flavivirus/metabolismo , Infecciones por Flavivirus/virología , Chlorocebus aethiops , Células HEK293RESUMEN
BACKGROUND: Exportin 1 (XPO1) is a nuclear export protein that facilitates the transportation of various substances. XPO1 promotes tumor development as a poor prognostic factor in a variety of tumors and is a therapeutic target for screening inhibitors. However, the role of XPO1 in oral squamous cell carcinoma (OSCC) has yet to be determined. METHODS: The expression patterns of XPO1 mRNA in OSCC were investigated using bioinformatics tools, and the expression levels of XPO1 protein in OSCC specimens were confirmed by immunohistochemical assays. Survival analysis was conducted to evaluate the impact of XPO1 on prognosis. GO and KEGG enrichment analyses were utilized to uncover the signaling pathways mediated by XPO1. Additionally, we examined the association between XPO1 and AKT/MAPK/TGFBR1 and immune infiltration. RESULTS: XPO1 mRNA and protein expression levels were significantly enhanced in OSCC and associated with OSCC severity. Enhanced XPO1 expression was indicative of poor survival. Functional analysis showed that XPO1 mediated pathways associated with cell cycle and DNA replication and reduced immune infiltration in OSCC. Additionally, XPO1 mRNA and protein expression levels had significant positive relationships with AKT/MAPK/TGFBR1. CONCLUSIONS: XPO1, as a marker of poor prognosis in OSCC, can promote OSCC through AKT/MAPK/TGFBR1.
Asunto(s)
Biomarcadores de Tumor , Proteína Exportina 1 , Carioferinas , Neoplasias de la Boca , Proteínas Proto-Oncogénicas c-akt , Receptores Citoplasmáticos y Nucleares , Humanos , Carioferinas/metabolismo , Carioferinas/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Pronóstico , Proteínas Proto-Oncogénicas c-akt/metabolismo , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Neoplasias de la Boca/patología , Neoplasias de la Boca/genética , Neoplasias de la Boca/metabolismo , Neoplasias de la Boca/mortalidad , Masculino , Femenino , Regulación Neoplásica de la Expresión Génica , Transducción de Señal , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/mortalidad , Persona de Mediana EdadRESUMEN
Though RNAi and RNA-splicing machineries are involved in regulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication, their precise roles in coronavirus disease 2019 (COVID-19) pathogenesis remain unclear. Herein, we show that decreased RNAi component (Dicer and XPO5) and splicing factor (SRSF3 and hnRNPA3) expression correlate with increased COVID-19 severity. SARS-CoV-2 N protein induces the autophagic degradation of Dicer, XPO5, SRSF3, and hnRNPA3, inhibiting miRNA biogenesis and RNA splicing and triggering DNA damage, proteotoxic stress, and pneumonia. Dicer, XPO5, SRSF3, and hnRNPA3 knockdown increases, while their overexpression decreases, N protein-induced pneumonia's severity. Older mice show lower expression of Dicer, XPO5, SRSF3, and hnRNPA3 in their lung tissues and exhibit more severe N protein-induced pneumonia than younger mice. PJ34, a poly(ADP-ribose) polymerase inhibitor, or anastrozole, an aromatase inhibitor, ameliorates N protein- or SARS-CoV-2-induced pneumonia by restoring Dicer, XPO5, SRSF3, and hnRNPA3 expression. These findings will aid in developing improved treatments for SARS-CoV-2-associated pneumonia.
Asunto(s)
COVID-19 , Carioferinas , Ribonucleasa III , SARS-CoV-2 , Factores de Empalme Serina-Arginina , Animales , Factores de Empalme Serina-Arginina/metabolismo , Factores de Empalme Serina-Arginina/genética , Humanos , Ribonucleasa III/metabolismo , Ribonucleasa III/genética , SARS-CoV-2/genética , COVID-19/metabolismo , COVID-19/virología , COVID-19/genética , Ratones , Carioferinas/metabolismo , Carioferinas/genética , ARN Helicasas DEAD-box/metabolismo , ARN Helicasas DEAD-box/genética , Regulación hacia Abajo , Pulmón/metabolismo , Pulmón/patología , Pulmón/virología , Masculino , Femenino , MicroARNs/genética , MicroARNs/metabolismo , Empalme del ARN , Autofagia/genética , Daño del ADN , Ribonucleoproteína Heterogénea-Nuclear Grupo A-BRESUMEN
Intron-containing RNA expressed from the HIV-1 provirus activates type 1 interferon in primary human blood cells, including CD4+ T cells, macrophages, and dendritic cells. To identify the innate immune receptor required for detection of intron-containing RNA expressed from the HIV-1 provirus, a loss-of-function screen was performed with short hairpin RNA-expressing lentivectors targeting twenty-one candidate genes in human monocyte-derived dendritic cells. Among the candidate genes tested, only knockdown of XPO1 (CRM1), IFIH1 (MDA5), or MAVS prevented activation of the interferon-stimulated gene ISG15. The importance of IFIH1 protein was demonstrated by rescue of the knockdown with nontargetable IFIH1 coding sequence. Inhibition of HIV-1-induced ISG15 by the IFIH1-specific Nipah virus V protein, and by IFIH1-transdominant 2-CARD domain-deletion or phosphomimetic point mutations, indicates that IFIH1 (MDA5) filament formation, dephosphorylation, and association with MAVS are all required for innate immune activation in response to HIV-1 transduction. Since both IFIH1 (MDA5) and DDX58 (RIG-I) signal via MAVS, the specificity of HIV-1 RNA detection by IFIH1 was demonstrated by the fact that DDX58 knockdown had no effect on activation. RNA-Seq showed that IFIH1 knockdown in dendritic cells globally disrupted the induction of IFN-stimulated genes by HIV-1. Finally, specific enrichment of unspliced HIV-1 RNA by IFIH1 (MDA5), over two orders of magnitude, was revealed by formaldehyde cross-linking immunoprecipitation (f-CLIP). These results demonstrate that IFIH1 is the innate immune receptor for intron-containing RNA from the HIV-1 provirus and that IFIH1 potentially contributes to chronic inflammation in people living with HIV-1, even in the presence of effective antiretroviral therapy.
Asunto(s)
Células Dendríticas , VIH-1 , Inmunidad Innata , Helicasa Inducida por Interferón IFIH1 , Intrones , Provirus , ARN Viral , Humanos , VIH-1/genética , VIH-1/inmunología , Helicasa Inducida por Interferón IFIH1/genética , Helicasa Inducida por Interferón IFIH1/metabolismo , Provirus/genética , Células Dendríticas/inmunología , Células Dendríticas/virología , Células Dendríticas/metabolismo , Intrones/genética , ARN Viral/genética , ARN Viral/inmunología , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/inmunología , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/genética , Carioferinas/genética , Carioferinas/metabolismoRESUMEN
Covalent drug discovery has experienced a renaissance, with numerous electrophilic small molecules recently gaining FDA approval. Many structurally diverse electrophilic small molecules target exportin-1 (XPO1/CRM1) at cysteine 528, including the selective inhibitor of nuclear export (SINE) selinexor, which was FDA-approved as an anticancer agent in 2019. Emerging evidence supports additional pharmacological classes of XPO1 modulators targeting Cys528, including the selective inhibitors of transcriptional activation (SITAs) and probes that induce rapid degradation of XPO1. Here, we analyzed structure-activity relationships across multiple structural series of XPO1 Cys528-targeting probes. We observe that the electrophilic moiety of Cys528-targeting small molecules plays a decisive role in the cellular behavior observed, with subtle changes in electrophile structure being sufficient to convert XPO1-targeting probes to different pharmacological classes. This investigation represents a unique case study in which the electrophile functionality used to target a specific cysteine determines the pharmacological effect among diverse XPO1-targeting small molecules.
Asunto(s)
Proteína Exportina 1 , Carioferinas , Receptores Citoplasmáticos y Nucleares , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores Citoplasmáticos y Nucleares/antagonistas & inhibidores , Carioferinas/antagonistas & inhibidores , Carioferinas/metabolismo , Humanos , Relación Estructura-Actividad , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Fenotipo , Cisteína/química , Cisteína/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Hidrazinas/farmacología , Hidrazinas/química , Hidrazinas/síntesis química , Triazoles/farmacología , Triazoles/química , Triazoles/síntesis química , Estructura MolecularRESUMEN
Myeloid-derived suppressor cells (MDSCs) are a main driver of immunosuppression in tumors. Understanding the mechanisms that determine the development and immunosuppressive function of these cells could provide new therapeutic targets to improve antitumor immunity. Here, using preclinical murine models, we discovered that exportin 1 (XPO1) expression is upregulated in tumor MDSCs and that this upregulation is induced by IL-6-induced STAT3 activation during MDSC differentiation. XPO1 blockade transforms MDSCs into T-cell-activating neutrophil-like cells, enhancing the antitumor immune response and restraining tumor growth. Mechanistically, XPO1 inhibition leads to the nuclear entrapment of ERK1/2, resulting in the prevention of ERK1/2 phosphorylation following the IL-6-mediated activation of the MAPK signaling pathway. Similarly, XPO1 blockade in human MDSCs induces the formation of neutrophil-like cells with immunostimulatory functions. Therefore, our findings revealed a critical role for XPO1 in MDSC differentiation and suppressive functions; exploiting these new discoveries revealed new targets for reprogramming immunosuppressive MDSCs to improve cancer therapeutic responses.
Asunto(s)
Transporte Activo de Núcleo Celular , Proteína Exportina 1 , Carioferinas , Células Supresoras de Origen Mieloide , Receptores Citoplasmáticos y Nucleares , Animales , Humanos , Ratones , Diferenciación Celular , Línea Celular Tumoral , Núcleo Celular/metabolismo , Tolerancia Inmunológica , Interleucina-6/metabolismo , Carioferinas/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones Endogámicos C57BL , Células Supresoras de Origen Mieloide/inmunología , Células Supresoras de Origen Mieloide/metabolismo , Neoplasias/inmunología , Neoplasias/patología , Receptores Citoplasmáticos y Nucleares/metabolismo , Factor de Transcripción STAT3/metabolismoRESUMEN
The model of RNA stability has undergone a transformative shift with the revelation of a cytoplasmic capping activity that means a subset of transcripts are recapped autonomously of their nuclear counterparts. The present study demonstrates nucleo-cytoplasmic shuttling of the mRNA-capping enzyme (CE, also known as RNA guanylyltransferase and 5'-phosphatase; RNGTT), traditionally acknowledged for its nuclear localization and functions, elucidating its contribution to cytoplasmic capping activities. A unique nuclear export sequence in CE mediates XPO1-dependent nuclear export of CE. Notably, during sodium arsenite-induced oxidative stress, cytoplasmic CE (cCE) congregates within stress granules (SGs). Through an integrated approach involving molecular docking and subsequent co-immunoprecipitation, we identify eIF3b, a constituent of SGs, as an interactive associate of CE, implying that it has a potential role in guiding cCE to SGs. We measured the cap status of specific mRNA transcripts from U2OS cells that were non-stressed, stressed and recovered from stress, which indicated that cCE-target transcripts lost their caps during stress but remarkably regained cap stability during the recovery phase. This comprehensive study thus uncovers a novel facet of cytoplasmic CE, which facilitates cellular recovery from stress by maintaining cap homeostasis of target mRNAs.
Asunto(s)
Citoplasma , Homeostasis , ARN Mensajero , Gránulos de Estrés , Humanos , ARN Mensajero/metabolismo , ARN Mensajero/genética , Gránulos de Estrés/metabolismo , Citoplasma/metabolismo , Caperuzas de ARN/metabolismo , Arsenitos/farmacología , Estrés Oxidativo , Transporte Activo de Núcleo Celular , ARN Nucleotidiltransferasas/metabolismo , ARN Nucleotidiltransferasas/genética , Compuestos de Sodio/farmacología , Proteína Exportina 1 , Carioferinas/metabolismo , Carioferinas/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Gránulos Citoplasmáticos/metabolismo , Estabilidad del ARN , Núcleo Celular/metabolismo , Línea Celular Tumoral , NucleotidiltransferasasRESUMEN
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer with high rates of metastasis and mortality. In vitro studies suggest that selinexor (KPT-330), an inhibitor of exportin 1, may be a targeted therapeutic option for MCC. This selective inhibitor prevents the transport of oncogenic mRNA out of the nucleus. Of note, 80% of MCC tumors are integrated with Merkel cell polyomavirus (MCPyV), and virally encoded tumor-antigens, small T (sT) and large T (LT) mRNAs may require an exportin transporter to relocate to the cytoplasm and modulate host tumor-suppressing pathways. To explore selinexor as a targeted therapy for MCC, we examine its ability to inhibit LT and sT antigen expression in vitro and its impact on the prostaglandin synthesis pathway. Protein expression was determined through immunoblotting and quantified by densitometric analysis. Statistical significance was determined with t-test. Treatment of MCPyV-infected cell lines with selinexor resulted in a significant dose-dependent downregulation of key mediators of the prostaglandin synthesis pathway. Given the role of prostaglandin synthesis pathway in MCC, our findings suggest that selinexor, alone or in combination with immunotherapy, could be a promising treatment for MCPyV-infected MCC patients who are resistant to chemotherapy and immunotherapy.
Asunto(s)
Carcinoma de Células de Merkel , Hidrazinas , Neoplasias Cutáneas , Triazoles , Hidrazinas/farmacología , Hidrazinas/uso terapéutico , Humanos , Carcinoma de Células de Merkel/virología , Carcinoma de Células de Merkel/tratamiento farmacológico , Carcinoma de Células de Merkel/patología , Triazoles/farmacología , Triazoles/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/virología , Neoplasias Cutáneas/patología , Línea Celular Tumoral , Prostaglandinas/metabolismo , Poliomavirus de Células de Merkel , Proteína Exportina 1 , Carioferinas/metabolismo , Carioferinas/antagonistas & inhibidores , Antígenos Virales de Tumores , Receptores Citoplasmáticos y Nucleares/metabolismoRESUMEN
Molecular glues can induce proximity between a target protein and ubiquitin ligases to induce target degradation, but strategies for their discovery remain limited. We screened 3,200 bioactive small molecules and identified that C646 requires neddylation-dependent protein degradation to induce cytotoxicity. Although the histone acetyltransferase p300 is the canonical target of C646, we provide extensive evidence that C646 directly targets and degrades Exportin-1 (XPO1). Multiple cellular phenotypes induced by C646 were abrogated in cells expressing the known XPO1C528S drug-resistance allele. While XPO1 catalyzes nuclear-to-cytoplasmic transport of many cargo proteins, it also directly binds chromatin. We demonstrate that p300 and XPO1 co-occupy hundreds of chromatin loci. Degrading XPO1 using C646 or the known XPO1 modulator S109 diminishes the chromatin occupancy of both XPO1 and p300, enabling direct targeting of XPO1 to phenocopy p300 inhibition. This work highlights the utility of drug-resistant alleles and further validates XPO1 as a targetable regulator of chromatin state.
Asunto(s)
Cromatina , Proteína p300 Asociada a E1A , Proteína Exportina 1 , Carioferinas , Receptores Citoplasmáticos y Nucleares , Humanos , Cromatina/metabolismo , Proteína p300 Asociada a E1A/metabolismo , Carioferinas/metabolismo , Carioferinas/antagonistas & inhibidores , Proteolisis/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/metabolismoRESUMEN
BACKGROUND: The high fatality rate of glioblastoma (GBM) is attributed to glioblastoma stem cells (GSCs), which exhibit heterogeneity and therapeutic resistance. Metabolic plasticity of mitochondria is the hallmark of GSCs. Targeting mitochondrial biogenesis of GSCs is crucial for improving clinical prognosis in GBM patients. METHODS: SMYD2-induced PGC1α methylation and followed nuclear export are confirmed by co-immunoprecipitation, cellular fractionation, and immunofluorescence. The effects of SMYD2/PGC1α/CRM1 axis on GSCs mitochondrial biogenesis are validated by oxygen consumption rate, ECAR, and intracranial glioma model. RESULTS: PGC1α methylation causes the disabled mitochondrial function to maintain the stemness, thereby enhancing the radio-resistance of GSCs. SMYD2 drives PGC1α K224 methylation (K224me), which is essential for promoting the stem-like characteristics of GSCs. PGC1α K224me is preferred binding with CRM1, accelerating PGC1α nuclear export and subsequent dysfunction. Targeting PGC1α methylation exhibits significant radiotherapeutic efficacy and prolongs patient survival. CONCLUSIONS: These findings unveil a novel regulatory pathway involving mitochondria that govern stemness in GSCs, thereby emphasizing promising therapeutic strategies targeting PGC1α and mitochondria for the treatment of GBM.
Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Células Madre Neoplásicas , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Animales , Humanos , Ratones , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/genética , Línea Celular Tumoral , Proliferación Celular , Proteína Exportina 1 , Regulación Neoplásica de la Expresión Génica , Glioblastoma/metabolismo , Glioblastoma/patología , Glioblastoma/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , N-Metiltransferasa de Histona-Lisina/genética , Carioferinas/metabolismo , Carioferinas/genética , Metilación , Ratones Desnudos , Mitocondrias/metabolismo , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Pronóstico , Receptores Citoplasmáticos y Nucleares/metabolismo , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Chronic obstructive pulmonary disease (COPD) poses a significant health threat characterized by lung inflammation primarily triggered by pulmonary monocytes. Despite the centrality of inflammation in COPD, the regulatory mechanisms governing this response remain elusive, presenting a challenge for anti-inflammatory interventions. In this study, we assessed the expression of exportins in COPD mouse models, revealing a notable upregulation of XPO6 in the mouse lung (P = 0.0011). Intriguingly, we observed a consistent upregulation of XPO6 in pulmonary monocytes from both human and mouse COPD subjects (P < 0.0001). Furthermore, in human lung tissue, XPO6 expression exhibited a positive correlation with TLR2 expression (P = 0). In vitro investigations demonstrated that XPO6 enhances TLR2 expression, activating the MyD88/NF-κB inflammatory signaling pathway. This activation, in turn, promotes the secretion of pro-inflammatory cytokines such as TNFα, IL-6, and IL-1ß in monocytes. Mechanistically, XPO6 facilitates the nuclear export of TLR2 mRNA, ensuring its stability and subsequent protein expression in monocytes. In conclusion, our findings unveil that the upregulation of XPO6 in COPD pulmonary monocytes activates the MyD88/NF-κB inflammatory signaling pathway by facilitating the nuclear export of TLR2 mRNA, thereby identifying XPO6 as a promising therapeutic target for anti-inflammatory interventions in COPD.
Asunto(s)
Carioferinas , Ratones Endogámicos C57BL , Monocitos , Factor 88 de Diferenciación Mieloide , FN-kappa B , Enfermedad Pulmonar Obstructiva Crónica , ARN Mensajero , Transducción de Señal , Receptor Toll-Like 2 , Regulación hacia Arriba , Receptor Toll-Like 2/metabolismo , Receptor Toll-Like 2/genética , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/inmunología , Animales , Humanos , Factor 88 de Diferenciación Mieloide/metabolismo , Monocitos/metabolismo , Monocitos/inmunología , Monocitos/efectos de los fármacos , FN-kappa B/metabolismo , Ratones , Masculino , Carioferinas/metabolismo , ARN Mensajero/metabolismo , ARN Mensajero/genética , Transporte Activo de Núcleo Celular , Pulmón/patología , Pulmón/inmunología , Pulmón/metabolismo , Modelos Animales de Enfermedad , FemeninoRESUMEN
A role for exportin 4 (XPO4) in the pathogenesis of liver fibrosis was recently identified. We sought to determine changes in hepatic XPO4 promoter methylation levels during liver fibrosis. The quantitative real-time RT-PCR technique was used to quantify the mRNA level of XPO4. Additionally, pyrosequencing was utilized to assess the promoter methylation status of XPO4. The methylation rate of the XPO4 promoter was significantly increased with fibrosis in human and mouse models, while XPO4 mRNA expression negatively correlated with methylation of its promoter. DNA methyltransferases (DNMTs) levels (enzymes that drive DNA methylation) were upregulated in patients with liver fibrosis compared to healthy controls and in hepatic stellate cells upon transforming growth factor beta (TGFß) stimulation. The DNA methylation inhibitor 5-Aza or specific siRNAs for these DNMTs led to restoration of XPO4 expression. The process of DNA methylation plays a crucial role in the repression of XPO4 transcription in the context of liver fibrosis development.
Asunto(s)
Metilación de ADN , Carioferinas , Cirrosis Hepática , Regiones Promotoras Genéticas , Animales , Humanos , Masculino , Ratones , Células Estrelladas Hepáticas/metabolismo , Células Estrelladas Hepáticas/patología , Carioferinas/genética , Carioferinas/metabolismo , Cirrosis Hepática/genética , Cirrosis Hepática/patología , Cirrosis Hepática/metabolismo , Ratones Endogámicos C57BL , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Factor de Crecimiento Transformador beta/genéticaRESUMEN
Stress-induced retrograde signal transmission from the plastids to the nucleus has long puzzled plant biologists. To address this, we performed a suppressor screen of the ceh1 mutant, which contains elevated 2-C-methyl-d-erythritol-2,4-cyclopyrophosphate (MEcPP) levels, and identified the gain-of-function mutant impα-9, which shows reversed dwarfism and suppressed expression of stress-response genes in the ceh1 background despite heightened MEcPP. Subsequent genetic and biochemical analyses established that the accumulation of MEcPP initiates an upsurge in Arabidopsis SKP1-like 1 (ASK1) abundance, a pivotal component in the proteasome degradation pathway. This increase in ASK1 prompts the degradation of IMPα-9. Moreover, we uncovered a protein-protein interaction between IMPα-9 and TPR2, a transcriptional co-suppressor and found that a reduction in IMPα-9 levels coincides with a decrease in TPR2 abundance. Significantly, the interaction between IMPα-9 and TPR2 was disrupted in impα-9 mutants, highlighting the critical role of a single amino acid alteration in maintaining their association. Disruption of their interaction results in the reversal of MEcPP-associated phenotypes. Chromatin immunoprecipitation coupled with sequencing analyses revealed that TPR2 binds globally to stress-response genes and suggested that IMPα-9 associates with the chromatin. They function together to suppress the expression of stress-response genes under normal conditions, but this suppression is alleviated in response to stress through the degradation of the suppressing machinery. The biological relevance of our discoveries was validated under high light stress, marked by MEcPP accumulation, elevated ASK1 levels, IMPα-9 degredation, reduced TPR2 abundance, and subsequent activation of a network of stress-response genes. In summary, our study collectively unveils fresh insights into plant adaptive mechanisms, highlighting intricate interactions among retrograde signaling, the proteasome, and nuclear transport machinery.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Transducción de Señal , Estrés Fisiológico , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Estrés Fisiológico/genética , Núcleo Celular/metabolismo , Carioferinas/metabolismo , Carioferinas/genética , Unión ProteicaRESUMEN
BACKGROUND: Exportin-1 (XPO1), a crucial protein regulating nuclear-cytoplasmic transport, is frequently overexpressed in various cancers, driving tumor progression and drug resistance. This makes XPO1 an attractive therapeutic target. Over the past few decades, the number of available nuclear export-selective inhibitors has been increasing. Only KPT-330 (selinexor) has been successfully used for treating haematological malignancies, and KPT-8602 (eltanexor) has been used for treating haematologic tumours in clinical trials. However, the use of nuclear export-selective inhibitors for the inhibition of XPO1 expression has yet to be thoroughly investigated in clinical studies and therapeutic outcomes for solid tumours. METHODS: We collected numerous literatures to explain the efficacy of XPO1 Inhibitors in preclinical and clinical studies of a wide range of solid tumours. RESULTS: In this review, we focus on the nuclear export function of XPO1 and results from clinical trials of its inhibitors in solid malignant tumours. We summarized the mechanism of action and therapeutic potential of XPO1 inhibitors, as well as adverse effects and response biomarkers. CONCLUSION: XPO1 inhibition has emerged as a promising therapeutic strategy in the fight against cancer, offering a novel approach to targeting tumorigenic processes and overcoming drug resistance. SINE compounds have demonstrated efficacy in a wide range of solid tumours, and ongoing research is focused on optimizing their use, identifying response biomarkers, and developing effective combination therapies. KEY POINTS: Exportin-1 (XPO1) plays a critical role in mediating nucleocytoplasmic transport and cell cycle. XPO1 dysfunction promotes tumourigenesis and drug resistance within solid tumours. The therapeutic potential and ongoing researches on XPO1 inhibitors in the treatment of solid tumours. Additional researches are essential to address safety concerns and identify biomarkers for predicting patient response to XPO1 inhibitors.
Asunto(s)
Proteína Exportina 1 , Carioferinas , Neoplasias , Receptores Citoplasmáticos y Nucleares , Humanos , Receptores Citoplasmáticos y Nucleares/antagonistas & inhibidores , Receptores Citoplasmáticos y Nucleares/metabolismo , Carioferinas/antagonistas & inhibidores , Carioferinas/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Transporte Activo de Núcleo Celular/efectos de los fármacos , Ensayos Clínicos como Asunto , Antineoplásicos/uso terapéutico , Antineoplásicos/farmacologíaRESUMEN
Genome-wide association studies have identified many single nucleotide polymorphisms (SNPs) associated with erythrocyte traits. However, the functional variants and their working mechanisms remain largely unknown. Here, we reported that the SNP of rs80207740, which was associated with red blood cell (RBC) volume and hemoglobin content across populations, conferred enhancer activity to XPO7 gene via allele-differentially binding to Ikaros family zinc finger 1 (IKZF1). We showed that the region around rs80207740 was an erythroid-specific enhancer using reporter assays, and that the G-allele further enhanced activity. 3D genome evidence showed that the enhancer interacted with the XPO7 promoter, and eQTL analysis suggested that the G-allele upregulated expression of XPO7. We further showed that the rs80207740-G allele facilitated the binding of transcription factor IKZF1 in EMSA and ChIP analyses. Knockdown of IKZF1 and GATA1 resulted in decreased expression of Xpo7 in both human and mouse erythroid cells. Finally, we constructed Xpo7 knockout mouse by CRISPR/Cas9 and observed anemic phenotype with reduced volume and hemoglobin content of RBC, consistent to the effect of rs80207740 on erythrocyte traits. Overall, our study demonstrated that rs80207740 modulated erythroid indices by regulating IKZF1 binding and Xpo7 expression.
Asunto(s)
Alelos , Eritrocitos , Estudio de Asociación del Genoma Completo , Factor de Transcripción Ikaros , Polimorfismo de Nucleótido Simple , Factor de Transcripción Ikaros/genética , Factor de Transcripción Ikaros/metabolismo , Humanos , Animales , Ratones , Eritrocitos/metabolismo , Carioferinas/genética , Carioferinas/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Regiones Promotoras GenéticasRESUMEN
BACKGROUND: Primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (cHL) are distinct hematological malignancies of B-cell origin that share many biological, molecular, and clinical characteristics. In particular, the JAK/STAT signaling pathway is a driver of tumor development due to multiple recurrent mutations, particularly in STAT6. Furthermore, the XPO1 gene that encodes exportin 1 (XPO1) shows a frequent point mutation (E571K) resulting in an altered export of hundreds of cargo proteins, which may impact the success of future therapies in PMBL and cHL. Therefore, targeted therapies have been envisioned for these signaling pathways and mutations. METHODS: To identify novel molecular targets that could overcome the treatment resistance that occurs in PMBL and cHL patients, we have explored the efficacy of a first-in-class HSP110 inhibitor (iHSP110-33) alone and in combination with selinexor, a XPO1 specific inhibitor, both in vitro and in vivo. RESULTS: We show that iHSP110-33 decreased the survival of several PMBL and cHL cell lines and the size of tumor xenografts. We demonstrate that HSP110 is a cargo of XPO1wt as well as of XPO1E571K. Using immunoprecipitation, proximity ligation, thermophoresis and kinase assays, we showed that HSP110 directly interacts with STAT6 and favors its phosphorylation. The combination of iHSP110-33 and selinexor induces a synergistic reduction of STAT6 phosphorylation and of lymphoma cell growth in vitro and in vivo. In biopsies from PMBL patients, we show a correlation between HSP110 and STAT6 phosphorylation levels. CONCLUSIONS: These findings suggest that HSP110 could be proposed as a novel target in PMBL and cHL therapy.