Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.513
Filtrar
1.
J Agric Food Chem ; 72(12): 6414-6423, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38501560

RESUMO

Previous research has demonstrated that in pregnant mice deficient in l-methionine (Met), the mixture of the dipeptide l-methionyl-l-methionine (Met-Met) with Met was more effective than Met alone in promoting mammogenesis and lactogenesis. This study aimed to investigate the role of a novel long noncoding RNA (lncRNA), named mammary gland proliferation-associated lncRNA (MGPNCR), in these processes. Transcriptomic analysis of mammary tissues from Met-deficient mice, supplemented either with a Met-Met/Met mixture or with Met alone, revealed significantly higher MGPNCR expression in the Met group compared to the mixture group, a finding recapitulated in a mammary epithelial cell model. Our findings suggested that MGPNCR hindered mammogenesis and milk protein synthesis by binding to eukaryotic initiation factor 4B (eIF4B). This interaction promoted the dephosphorylation of eIF4B at serine-422 by enhancing its association with protein phosphatase 2A (PP2A). Our study sheds light on the regulatory mechanisms of lncRNA-mediated dipeptide effects on mammary cell proliferation and milk protein synthesis. These insights underscore the potential benefits of utilizing dipeptides to improve milk protein in animals and potentially in humans.


Assuntos
Fatores de Iniciação em Eucariotos , Metionina , RNA Longo não Codificante , Gravidez , Humanos , Feminino , Animais , Camundongos , Metionina/metabolismo , RNA Longo não Codificante/metabolismo , Dipeptídeos/metabolismo , Racemetionina/metabolismo , Proteínas do Leite/metabolismo , Células Epiteliais/metabolismo , Glândulas Mamárias Animais/metabolismo
2.
Wiley Interdiscip Rev RNA ; 15(2): e1833, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38433101

RESUMO

Selection of the correct start codon is critical for high-fidelity protein synthesis. In eukaryotes, this is typically governed by a multitude of initiation factors (eIFs), including eIF2·GTP that directly delivers the initiator tRNA (Met-tRNAi Met ) to the P site of the ribosome. However, numerous reports, some dating back to the early 1970s, have described other initiation factors having high affinity for the initiator tRNA and the ability of delivering it to the ribosome, which has provided a foundation for further work demonstrating non-canonical initiation mechanisms using alternative initiation factors. Here we provide a critical analysis of current understanding of eIF2A, eIF2D, and the MCT-1·DENR dimer, the evidence surrounding their ability to initiate translation, their implications in human disease, and lay out important key questions for the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Mechanisms Translation > Regulation.


Assuntos
Fatores de Iniciação em Eucariotos , RNA de Transferência de Metionina , Ribossomos , Humanos , Eucariotos , Fatores de Iniciação de Peptídeos , Ribossomos/genética , RNA , Fator de Iniciação 2 em Eucariotos
3.
J Mol Neurosci ; 74(1): 6, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38189881

RESUMO

The objective of this study is to investigate the potential biomarkers and therapeutic target genes for Parkinson's disease (PD). We analyzed four datasets (GSE8397, GSE20292, GSE20163, GSE20164) from the Gene Expression Omnibus database. We employed weighted gene co-expression network analysis and differential expression analysis to select genes and perform functional analysis. We applied three algorithms, namely, random forest, support vector machine recursive feature elimination, and least absolute shrinkage and selection operator, to identify hub genes, perform functional analysis, and assess their clinical diagnostic potential using receiver operating characteristic (ROC) curve analysis. We employed the xCell website to evaluate differences in the composition patterns of immune cells in the GEO datasets. We also collected serum samples from PD patients and established PD cell model to validate the expression of hub genes using enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction. Our findings identified SV2C and DENR as two hub genes for PD and decreased in PD brain tissue compared with controls. ROC analysis showed effectively value of SV2C and DENR to diagnose PD, and they were downregulated in the serum of PD patients and cell model. Functional analysis revealed that dopamine vesicle transport and synaptic vesicle recycling are crucial pathways in PD. Besides, the differences in the composition of immune cells, especially basophils and T cells, were discovered between PD and controls. In summary, our study identifies SV2C and DENR as potential biomarkers for diagnosing PD and provides a new perspective for exploring the molecular mechanisms of PD.


Assuntos
Doença de Parkinson , Humanos , Doença de Parkinson/diagnóstico , Doença de Parkinson/genética , Biologia Computacional , Aprendizado de Máquina , Algoritmos , Biomarcadores , Fatores de Iniciação em Eucariotos , Glicoproteínas de Membrana , Proteínas do Tecido Nervoso
4.
Diabetes ; 73(3): 461-473, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055903

RESUMO

As professional secretory cells, ß-cells require adaptable mRNA translation to facilitate a rapid synthesis of proteins, including insulin, in response to changing metabolic cues. Specialized mRNA translation programs are essential drivers of cellular development and differentiation. However, in the pancreatic ß-cell, the majority of factors identified to promote growth and development function primarily at the level of transcription. Therefore, despite its importance, the regulatory role of mRNA translation in the formation and maintenance of functional ß-cells is not well defined. In this study, we have identified a translational regulatory mechanism mediated by the specialized mRNA translation factor eukaryotic initiation factor 5A (eIF5A), which facilitates the maintenance of ß-cell identity and function. The mRNA translation function of eIF5A is only active when it is posttranslationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS). We have discovered that the absence of ß-cell DHPS in mice reduces the synthesis of proteins critical to ß-cell identity and function at the stage of ß-cell maturation, leading to a rapid and reproducible onset of diabetes. Therefore, our work has revealed a gatekeeper of specialized mRNA translation that permits the ß-cell, a metabolically responsive secretory cell, to maintain the integrity of protein synthesis necessary during times of induced or increased demand.


Assuntos
Células Secretoras de Insulina , Fatores de Iniciação de Peptídeos , Animais , Camundongos , Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo , Processamento de Proteína Pós-Traducional , Células Secretoras de Insulina/metabolismo , Biossíntese de Proteínas , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo
5.
Cell Rep ; 42(10): 113283, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37862172

RESUMO

Cells activate stress response pathways to survive adverse conditions. Such responses involve the inhibition of global cap-dependent translation. This inhibition is a block that essential transcripts must escape via alternative methods of translation initiation, e.g., an internal ribosome entry site (IRES). IRESs have distinct structures and generally require a limited repertoire of translation factors. Cellular IRESs have been identified in many critical cellular stress response transcripts. We previously identified cellular IRESs in the murine insulin receptor (Insr) and insulin-like growth factor 1 receptor (Igf1r) transcripts and demonstrated their resistance to eukaryotic initiation factor 4F (eIF4F) inhibition. Here, we find that eIF5B preferentially promotes Insr, Igf1r, and hepatitis C virus IRES activity through a non-canonical mechanism that requires its highly charged and disordered N terminus. We find that the N-terminal region of eIF5B can drive cytoplasmic granule formation. This eIF5B granule is triggered by cellular stress and is sufficient to specifically promote IRES activity.


Assuntos
Hepatite C , Sítios Internos de Entrada Ribossomal , Animais , Camundongos , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Fator de Iniciação 4F em Eucariotos/metabolismo , Biossíntese de Proteínas
6.
J Mol Biol ; 435(21): 168274, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37714299

RESUMO

During translation, a stop codon on the mRNA signals the ribosomes to terminate the process. In certain mRNAs, the termination fails due to the recoding of the canonical stop codon, and ribosomes continue translation to generate C-terminally extended protein. This process, termed stop codon readthrough (SCR), regulates several cellular functions. SCR is driven by elements/factors that act immediately downstream of the stop codon. Here, we have analysed the process of SCR using a simple mathematical model to investigate how the kinetics of translating ribosomes influences the efficiency of SCR. Surprisingly, the analysis revealed that the rate of translation inversely regulates the efficiency of SCR. We tested this prediction experimentally in mammalian AGO1 and MTCH2 mRNAs. Reduction in translation either globally by harringtonine or locally by rare codons caused an increase in the efficiency of SCR. Thus, our study has revealed a hitherto unknown mode of regulation of SCR.


Assuntos
Códon de Terminação , Biossíntese de Proteínas , RNA Mensageiro , Ribossomos , Códon de Terminação/genética , Códon de Terminação/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Humanos , Células HEK293 , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo
7.
Sci Rep ; 13(1): 15247, 2023 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-37709842

RESUMO

Members of the eukaryotic translation initiation complex are co-opted in viral infection, leading to susceptibility in many crop species, including stone fruit trees (Prunus spp.). Therefore, modification of one of those eukaryotic translation initiation factors or changes in their gene expression may result in resistance. We searched the crop and wild Prunus germplasm from the Armeniaca and Amygdalus taxonomic sections for allelic variants in the eIF4E and eIFiso4E genes, to identify alleles potentially linked to resistance to Plum pox virus (PPV). Over one thousand stone fruit accessions (1397) were screened for variation in eIF4E and eIFiso4E transcript sequences which are in single copy within the diploid Prunus genome. We identified new alleles for both genes differing from haplotypes associated with PPV susceptible accessions. Overall, analyses showed that eIFiso4E is genetically more constrained since it displayed less polymorphism than eIF4E. We also demonstrated more variations at both loci in the related wild species than in crop species. As the eIFiso4E translation initiation factor was identified as indispensable for PPV infection, a selection of ten different eIFiso4E haplotypes along 13 accessions were tested by infection with PPV and eight of them displayed a range of reduced susceptibility to resistance, indicating new potential sources of resistance to sharka.


Assuntos
Fator de Iniciação 4E em Eucariotos , Prunus , Alelos , Fator de Iniciação 4E em Eucariotos/genética , Fatores de Iniciação em Eucariotos/genética , Citoplasma , Prunus/genética
8.
Biomol NMR Assign ; 17(2): 199-203, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37368134

RESUMO

Translation initiation in eukaryotes is an early step in protein synthesis, requiring multiple factors to recruit the ribosomal small subunit to the mRNA 5' untranslated region. One such protein factor is the eukaryotic translation initiation factor 4B (eIF4B), which increases the activity of the eIF4A RNA helicase, and is linked to cell survival and proliferation. We report here the protein backbone chemical shift assignments corresponding to the C-terminal 279 residues of human eIF4B. Analysis of the chemical shift values identifies one main helical region in the area previously linked to RNA binding, and confirms that the overall C-terminal region is intrinsically disordered.


Assuntos
Fatores de Iniciação em Eucariotos , Fatores de Iniciação de Peptídeos , Humanos , Ressonância Magnética Nuclear Biomolecular , Fatores de Iniciação em Eucariotos/química , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Fatores de Iniciação de Peptídeos/química , Fatores de Iniciação de Peptídeos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
9.
Int J Mol Sci ; 24(9)2023 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-37175950

RESUMO

Transient cerebral ischemia induces neuronal degeneration, followed in time by secondary delayed neuronal death that is strongly correlated with a permanent inhibition of protein synthesis in vulnerable brain regions, while protein translational rates are recovered in resistant areas. In the translation-regulation initiation step, the eukaryotic initiation factor (eIF) 4E is a key player regulated by its association with eIF4E-binding proteins (4E-BPs), mostly 4E-BP2 in brain tissue. In a previous work, we identified dihydropyrimidinase-related protein 2 (DRP2) as a 4E-BP2-interacting protein. Here, using a proteomic approach in a model of transient cerebral ischemia, a detailed study of DRP2 was performed in order to address the challenge of translation restoration in vulnerable regions. In this report, several DRP2 isoforms that have a specific interaction with both 4E-BP2 and eIF4E were identified, showing significant and opposite differences in this association, and being differentially detected in resistant and vulnerable regions in response to ischemia reperfusion. Our results provide the first evidence of DRP2 isoforms as potential regulators of the 4E-BP2-eIF4E association that would have consequences in the delayed neuronal death under ischemic-reperfusion stress. The new knowledge reported here identifies DRP2 as a new target to promote neuronal survival after cerebral ischemia.


Assuntos
Isquemia Encefálica , Ataque Isquêmico Transitório , Isquemia Encefálica/metabolismo , Infarto Cerebral , Fator de Iniciação 4E em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Ligação Proteica , Biossíntese de Proteínas , Isoformas de Proteínas/metabolismo , Proteômica , Animais , Ratos
10.
Int J Mol Sci ; 24(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37047039

RESUMO

The human eukaryotic translation initiation factor 5A (EIF5A) family consists of three members, namely EIF5A1, EIF5A2, and EIF5AL1. Recent studies have shown that the expression of EIF5As is related to many human diseases, such as diabetes, viral infection, central nervous system injury, and cancer. Among them, EIF5A1 plays different functions in various cancers, possibly as a tumor-suppressor or oncogene, while EIF5A2 promotes the occurrence and development of cancer. Yet, the biological function of EIF5AL1 is not being studied so far. Interestingly, although there are only three amino acid (at residues 36, 45, and 109) differences between EIF5A1 and EIF5AL1, we demonstrate that only EIF5A1 can be hypusinated while EIF5AL1 cannot, and EIF5AL1 has a tumor-suppressor-like function by inhibiting cell proliferation and migration. We also show that EIF5AL1 protein turnover is mediated through the proteasomal pathway, and EIF5AL1 protein turnover is much faster than that of EIF5A1, which may explain their differential protein expression level in cells. By engineering single and double mutations on these three amino acids, we pinpoint which of these amino acids are critical for hypusination and protein stability. The data of this work should fill in the gaps in EIF5As research and pave the way for future studies on EIF5AL1.


Assuntos
Lisina , Neoplasias , Humanos , Aminoácidos , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Lisina/metabolismo , Neoplasias/metabolismo , Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo , Estabilidade Proteica
11.
Biol Pharm Bull ; 46(2): 158-162, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36724943

RESUMO

Translation initiation is the rate-limiting step of protein synthesis and is the main target of translation regulation. RNA-binding proteins (RBPs) are key mediators of the spatiotemporal control of translation and are critical for cell proliferation, development, and differentiation. We have previously shown that HuD, one of the neuronal RBPs, enhances cap-dependent translation through the direct interaction with eukaryotic initiation factor 4A (eIF4A) and poly(A) tail using a HeLa-derived in vitro translation system. We have also found that translation stimulation of HuD is essential for HuD-induced neurite outgrowth in PC12 cells. However, it remains unclear how HuD is involved in the regulation of translation initiation. Here, we report that HuD binds to eukaryotic initiation factor 3 (eIF3) via the eIF3b subunit, which belongs to the functional core of mammalian eIF3. eIF3 plays an essential role in recruiting the 40S ribosomal subunit onto mRNA in translation initiation. We hypothesize that the interaction between HuD and eIF3 stabilizes the translation initiation complex and increases translation efficiency. We also showed that the linker region of HuD is required for the interaction with eIF3b. Moreover, we found that eIF3b-binding region of HuD is conserved in all Hu proteins (HuB, HuC, HuD, and HuR). These data might also help to explain how Hu proteins stimulate translation in a cap- and poly(A)-dependent way.


Assuntos
Fator de Iniciação 3 em Eucariotos , Fatores de Iniciação em Eucariotos , Animais , Humanos , Ratos , Fator de Iniciação 3 em Eucariotos/genética , Fator de Iniciação 3 em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Neurônios/metabolismo , Fator de Iniciação 3 em Procariotos/genética , Fator de Iniciação 3 em Procariotos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Células HeLa
12.
EMBO J ; 42(7): e110496, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36843541

RESUMO

Aberrant splicing is typically attributed to splice-factor (SF) mutation and contributes to malignancies including acute myeloid leukemia (AML). Here, we discovered a mutation-independent means to extensively reprogram alternative splicing (AS). We showed that the dysregulated expression of eukaryotic translation initiation factor eIF4E elevated selective splice-factor production, thereby impacting multiple spliceosome complexes, including factors mutated in AML such as SF3B1 and U2AF1. These changes generated a splicing landscape that predominantly supported altered splice-site selection for ~800 transcripts in cell lines and ~4,600 transcripts in specimens from high-eIF4E AML patients otherwise harboring no known SF mutations. Nuclear RNA immunoprecipitations, export assays, polysome analyses, and mutational studies together revealed that eIF4E primarily increased SF production via its nuclear RNA export activity. By contrast, eIF4E dysregulation did not induce known SF mutations or alter spliceosome number. eIF4E interacted with the spliceosome and some pre-mRNAs, suggesting its direct involvement in specific splicing events. eIF4E induced simultaneous effects on numerous SF proteins, resulting in a much larger range of splicing alterations than in the case of mutation or dysregulation of individual SFs and providing a novel paradigm for splicing control and dysregulation.


Assuntos
Processamento Alternativo , Leucemia Mieloide Aguda , Humanos , Fatores de Processamento de RNA/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Splicing de RNA , Fatores de Iniciação em Eucariotos/genética , Leucemia Mieloide Aguda/genética , Mutação
13.
Nucleic Acids Res ; 51(4): 1803-1822, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36651285

RESUMO

Assembly of ribosomal subunits into active ribosomal complexes is integral to protein synthesis. Release of eIF6 from the 60S ribosomal subunit primes 60S to associate with the 40S subunit and engage in translation. The dynamics of eIF6 interaction with the uL14 (RPL23) interface of 60S and its perturbation by somatic mutations acquired in Shwachman-Diamond Syndrome (SDS) is yet to be clearly understood. Here, by using a modified strategy to obtain high yields of recombinant human eIF6 we have uncovered the critical interface entailing eight key residues in the C-tail of uL14 that is essential for physical interactions between 60S and eIF6. Disruption of the complementary binding interface by conformational changes in eIF6 disease variants provide a mechanism for weakened interactions of variants with the 60S. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) analyses uncovered dynamic configurational rearrangements in eIF6 induced by binding to uL14 and exposed an allosteric interface regulated by the C-tail of eIF6. Disrupting key residues in the eIF6-60S binding interface markedly limits proliferation of cancer cells, which highlights the significance of therapeutically targeting this interface. Establishing these key interfaces thus provide a therapeutic framework for targeting eIF6 in cancers and SDS.


Assuntos
Fatores de Iniciação em Eucariotos , Humanos , Proteínas Ribossômicas/metabolismo , Subunidades Ribossômicas Maiores de Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/antagonistas & inibidores , Fatores de Iniciação em Eucariotos/química , Fatores de Iniciação em Eucariotos/metabolismo , Síndrome de Shwachman-Diamond/terapia
14.
Br J Radiol ; 96(1144): 20220948, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36715145

RESUMO

OBJECTIVE: To evaluate a series of vascular parameters derived from abdominal dual-phase contrast-enhanced CT as predictors of 14-day mortality and AKI within 7 days in septic shock. METHODS: 144 patients with septic shock and 60 negative cases were included. The vascular parameters from CT were measured and calculated, including aortic density in arterial (Dena-A) and venous phase (Dena-V), renal vein density in arterial (Denrv-A) and venous phase (Denrv-V), and renal vein-to-aortic density ratio in arterial (DenRrv/a-A) and venous phase (DenRrv/a-V). The parameters were compared between patients and controls, and between patients with different clinical outcomes, and assessed for predictive value of 14-day mortality and AKI within 7 days. RESULTS: Patients with septic shock presented significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.002) levels than the controls. In the septic shock group, patients who died had significantly lower Denrv-A (p = 0.001) and lower DenRrv/a-A (p < 0.001) than those who survived. Patients who developed AKI had significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.011) than those who did not. Multivariate analysis suggested DenRrv/a-A as an independent predictor of 14-day mortality (OR 0.012; 95% confidence interval [CI]:0.002,0.086; p < 0.001) and Denrv-A as an independent predictor of AKI (OR 0.989;95% CI:0.982,0.997; p = 0.006). CONCLUSION: In septic shock, significant decreases in Denrv-A and DenRrv/a-A were associated with the onset of AKI and predicted higher 14-day mortality. ADVANCES IN KNOWLEDGE: The renal vein density and renal vein-aortic density ratio in arterial phase of dual-phase contrast-enhanced CT may serve as good predictors of AKI and mortality in septic shock.


Assuntos
Injúria Renal Aguda , Choque Séptico , Humanos , Choque Séptico/diagnóstico por imagem , Choque Séptico/complicações , Veias Renais/diagnóstico por imagem , Prognóstico , Injúria Renal Aguda/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Estudos Retrospectivos , Fatores de Iniciação em Eucariotos
15.
Nat Commun ; 13(1): 6318, 2022 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-36274088

RESUMO

Ferroptosis is a type of lipid peroxidation-dependent cell death that is emerging as a therapeutic target for cancer. However, the mechanisms of ferroptosis during the generation and detoxification of lipid peroxidation products remain rather poorly defined. Here, we report an unexpected role for the eukaryotic translation initiation factor EIF4E as a determinant of ferroptotic sensitivity by controlling lipid peroxidation. A drug screening identified 4EGI-1 and 4E1RCat (previously known as EIF4E-EIF4G1 interaction inhibitors) as powerful inhibitors of ferroptosis. Genetic and functional studies showed that EIF4E (but not EIF4G1) promotes ferroptosis in a translation-independent manner. Using mass spectrometry and subsequent protein-protein interaction analysis, we identified EIF4E as an endogenous repressor of ALDH1B1 in mitochondria. ALDH1B1 belongs to the family of aldehyde dehydrogenases and may metabolize the aldehyde substrate 4-hydroxynonenal (4HNE) at high concentrations. Supraphysiological levels of 4HNE triggered ferroptosis, while low concentrations of 4HNE increased the cell susceptibility to classical ferroptosis inducers by activating the NOX1 pathway. Accordingly, EIF4E-dependent ALDH1B1 inhibition enhanced the anticancer activity of ferroptosis inducers in vitro and in vivo. Our results support a key function of EIF4E in orchestrating lipid peroxidation to ignite ferroptosis.


Assuntos
Fator de Iniciação 4E em Eucariotos , Ferroptose , Fator de Iniciação 4E em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Aldeídos , Oxirredutases/metabolismo , Peroxidação de Lipídeos
16.
Sheng Wu Gong Cheng Xue Bao ; 38(9): 3489-3500, 2022 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-36151816

RESUMO

Eukaryotic translation initiation factor 4B (eIF4B) plays an important role in mRNA translation initiation, cell survival and proliferation in vitro, but the in vivo function is poorly understood. In this study, via various experimental techniques such as hematoxylin-eosin (HE) staining, flow cytometry, Western blotting, and immunohistochemistry, we investigated the role of eIF4B in mouse embryo development using an eIF4B knockout (KO) mouse model and explored the mechanism. We found that the livers, but not lungs, brain, stomach, or pancreas, derived from eIF4B KO mouse embryos displayed severe pathological changes characterized by enhanced apoptosis and necrosis. Accordingly, high expression of cleaved-caspase 3, and excessive activation of mTOR signaling as evidenced by increased expression and phosphorylation of p70S6K and enhanced phosphorylation of 4EBP1, were observed in mouse embryonic fibroblasts and fetal livers from eIF4B KO mice. These results uncover a critical role of eIF4B in mouse embryo development and provide important insights into the biological functions of eIF4B in vivo.


Assuntos
Fibroblastos , Proteínas Quinases S6 Ribossômicas 70-kDa , Animais , Apoptose/genética , Caspase 3 , Amarelo de Eosina-(YS) , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Hematoxilina , Fígado/metabolismo , Camundongos , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Serina-Treonina Quinases TOR
17.
Int J Mol Sci ; 23(18)2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36142498

RESUMO

Argonaute (AGO) proteins, through their key role in the regulation of gene expression, participate in many biological processes, including cell differentiation, proliferation, death and DNA repair. Accurate regulation of gene expression appears to be important for the proper development of complex neural circuits. Loss of AGO proteins is known to lead to early embryonic mortality in mice with various malformations, including anomalies of the central nervous system. Single-nucleotide polymorphisms (SNPs) of AGO genes can lead to deregulation of the processes in which AGO proteins are involved. The contribution of different SNPs in depression has been extensively studied. However, there are hardly any studies on the contribution of AGO genes. The aim of our research was to assess the relationship between the occurrence of depression and the presence of SNPs in genes AGO1 (rs636882) and AGO2 (rs4961280; rs2292779; rs2977490) in a Polish population. One hundred and one subjects in the study group were diagnosed with recurrent depressive disorder by a psychiatrist. The control group comprised 117 healthy subjects. Study participants performed the HDRS (Hamilton Depression Scale) test to confirm or exclude depression and assess severity. The frequency of polymorphic variants of genes AGO1 (rs636882) and AGO2 (rs4961280; rs2292779; rs2977490) was determined using TaqMan SNP genotyping assays and the TaqMan universal PCR master mix, no AmpErase UNG. The rs4961280/AGO2 polymorphism was associated with a decrease in depression occurrence in the codominant (OR = 0.51, p = 0.034), dominant (OR = 0.49, p = 0.01), and overdominant (OR = 0.58, p = 0.049) models. Based on the obtained results, we found that the studied patients demonstrated a lower risk of depression with the presence of the polymorphic variant of the rs4961280/AGO2 gene-genotype C/A and C/A-A/A.


Assuntos
Proteínas Argonautas/genética , Depressão , Fatores de Iniciação em Eucariotos/genética , Alelos , Animais , Estudos de Casos e Controles , Depressão/genética , Humanos , Camundongos , Polônia , Polimorfismo de Nucleotídeo Único
18.
BMC Med Genomics ; 15(1): 180, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35971121

RESUMO

BACKGROUND: Serine and arginine-rich splicing factor 9 (SRSF9) has been linked to the occurrence and progression of various cancers; however, its effects and mechanism of action hepatocellular carcinoma (HCC) have not been reported. In this study, we used a bioinformatics approach and in vitro assays to evaluate the expression of SRSF9 in HCC, its prognostic value, and its underlying regulatory mechanisms, including analyses of related pathways and the role of methylation. METHODS: Transcriptomic and DNA methylation data for 357 HCC cases and 50 paratumor tissues in The Cancer Genome Atlas database were obtained. Additionally, protein expression data for cell lines and tissue samples were obtained from the Human Protein Atlas. The CMap databased was used to predict candidate drugs targeting SRSF9. Various cell lines were used for in vitro validation. RESULTS: SRSF9 expression was significantly elevated in HCC and was negatively regulated by its methylation site cg06116271. The low expression of SRSF9 and hypermethylation of cg06116271 were both associated with a longer overall survival time. A correlation analysis revealed ten genes that were co-expressed with SRSF9; levels of CDK4, RAN, DENR, RNF34, and ANAPC5 were positively correlated and levels of RBP4, APOC1, MASP2, HP, and HPX were negatively correlated with SRSF9 expression. The knockdown of SRSF9 in vitro inhibited the proliferation and migration of HCC cells and significantly reduced the expression of proteins in the Wnt signaling pathway (DVL2 and ß-catenin) and cell cycle pathway (Cyclin D and Cyclin E). A CMap analysis identified two drugs, camptothecin and apigenin, able to target and inhibit the expression of SRSF9. CONCLUSIONS: This study expands our understanding of the molecular biological functions of SRSF9 and cg06116271 and provides candidate diagnostic and therapeutic targets for HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Fatores de Processamento de Serina-Arginina , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/patologia , Proteínas de Transporte , Linhagem Celular Tumoral , Proliferação de Células , Metilação de DNA , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Fator IX/genética , Fator IX/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , Serina Proteases Associadas a Proteína de Ligação a Manose/genética , Serina Proteases Associadas a Proteína de Ligação a Manose/metabolismo , Prognóstico , Fatores de Processamento de RNA/genética , Proteínas Plasmáticas de Ligação ao Retinol , Serina/genética , Serina/metabolismo , Fatores de Processamento de Serina-Arginina/genética
19.
Proc Natl Acad Sci U S A ; 119(30): e2120339119, 2022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35857873

RESUMO

During translation initiation, eIF4G1 dynamically interacts with eIF4E and eIF1. While the role of eIF4E-eIF4G1 is well established, the regulatory functions of eIF4G1-eIF1 are poorly understood. Here, we report the identification of the eIF4G1-eIF1 inhibitors i14G1-10 and i14G1-12. i14G1s directly bind eIF4G1 and inhibit translation in vitro and in the cell, and their effects on translation are dependent on eIF4G1 levels. Translatome analyses revealed that i14G1s mimic eIF1 and eIF4G1 perturbations on the stringency of start codon selection and the opposing roles of eIF1-eIF4G1 in scanning-dependent and scanning-independent short 5' untranslated region (UTR) translation. Remarkably, i14G1s activate ER/unfolded protein response (UPR) stress-response genes via enhanced ribosome loading, elevated 5'UTR translation at near-cognate AUGs, and unexpected concomitant up-regulation of coding-region translation. These effects are, at least in part, independent of eIF2α-phosphorylation. Interestingly, eIF4G1-eIF1 interaction itself is negatively regulated by ER stress and mTOR inhibition. Thus, i14G1s uncover an unknown mechanism of ER/UPR translational stress response and are valuable research tools and potential drugs against diseases exhibiting dysregulated translation.


Assuntos
Estresse do Retículo Endoplasmático , Fator de Iniciação 2 em Eucariotos , Fator de Iniciação 4G em Eucariotos , Fatores de Iniciação em Eucariotos , Proteínas de Neoplasias , Proteínas do Tecido Nervoso , Resposta a Proteínas não Dobradas , Animais , Códon de Iniciação , Estresse do Retículo Endoplasmático/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Fator de Iniciação 4G em Eucariotos/antagonistas & inibidores , Fator de Iniciação 4G em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/antagonistas & inibidores , Fatores de Iniciação em Eucariotos/metabolismo , Humanos , Camundongos , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Fosforilação , Biossíntese de Proteínas , Resposta a Proteínas não Dobradas/genética
20.
Int J Mol Sci ; 23(14)2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35887068

RESUMO

Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of lipids in the liver. Given the high prevalence of NAFLD, its evolution to nonalcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) is of global concern. Therapies for managing NASH-driven HCC can benefit from targeting factors that play a continuous role in NAFLD evolution to HCC. Recent work has shown that postprandial liver translation exacerbates lipid accumulation through the activity of a translation factor, eukaryotic initiation factor 6 (eIF6). Here, we test the effect of eIF6 inhibition on the progression of HCC. Mice heterozygous for eIF6 express half the level of eIF6 compared to wt mice and are resistant to the formation of HCC nodules upon exposure to a high fat/high sugar diet combined with liver damage. Histology showed that nodules in eIF6 het mice were smaller with reduced proliferation compared to wt nodules. By using an in vitro model of human HCC, we confirm that eIF6 depletion reduces the growth of HCC spheroids. We also tested three pharmacological inhibitors of eIF6 activity-eIFsixty-1, eIFsixty-4, and eIFsixty-6-and all three reduced eIF6 binding to 60S ribosomes and limited the growth of HCC spheroids. Thus, inhibition of eIF6 activity is feasible and limits HCC formation.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Animais , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Fatores de Iniciação em Eucariotos/antagonistas & inibidores , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Camundongos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fatores de Iniciação de Peptídeos/antagonistas & inibidores , Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...