Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 992
Filtrar
1.
J Cell Biol ; 223(3)2024 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-38319288

RESUMO

TNFα and IFNγ (TNF/IFNγ) synergistically induce caspase-8 activation and cancer cell death. However, the mechanism of IFNγ in promoting TNF-initiated caspase-8 activation in cancer cells is poorly understood. Here, we found that in addition to CASP8, CYLD is transcriptionally upregulated by IFNγ-induced transcription factor IRF1. IRF1-mediated CASP8 and CYLD upregulation additively mediates TNF/IFNγ-induced cancer cell death. Clinically, the expression levels of TNF, IFNγ, CYLD, and CASP8 in melanoma tumors are increased in patients responsive to immune checkpoint blockade (ICB) therapy after anti-PD-1 treatment. Accordingly, our genetic screen revealed that ELAVL1 (HuR) is required for TNF/IFNγ-induced caspase-8 activation. Mechanistically, ELAVL1 binds CASP8 mRNA and extends its stability to sustain caspase-8 expression both in IFNγ-stimulated and in basal conditions. Consequently, ELAVL1 determines death receptors-initiated caspase-8-dependent cell death triggered from stimuli including TNF and TRAIL by regulating basal/stimulated caspase-8 levels. As caspase-8 is a master regulator in cell death and inflammation, these results provide valuable clues for tumor immunotherapy and inflammatory diseases.


Assuntos
Imunoterapia , Fator Regulador 1 de Interferon , Interferon gama , Melanoma , Humanos , Caspase 8/genética , Morte Celular , Proteína Semelhante a ELAV 1/genética , Inflamação , Fator Regulador 1 de Interferon/genética , Melanoma/genética , Interferon gama/genética , Fator de Necrose Tumoral alfa/genética , Enzima Desubiquitinante CYLD/genética , Animais , Camundongos
2.
Cell Signal ; 117: 111112, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38387687

RESUMO

Breast cancer (BC) is the most prevalent malignant tumor in women worldwide with high morbidity and mortality. NSUN2, a crucial RNA methyltransferase, plays a pivotal role in regulating the proliferation and metastasis of tumor cells. Our study demonstrated that NSUN2 is upregulated in BC tissues and cell lines, and its high expression is associated with a poor prognosis in BC patients. Knockout of NSUN2 exerted inhibitory effects on the proliferation and migration of BC cells in vitro and in vivo. Mechanistic investigations revealed that the RNA-binding protein ELAVL1 can bind to NSUN2 mRNA and increase its stability. Additionally, we identified HOST2, a long non-coding RNA, as a key player in blocking the ubiquitin-dependent proteasomal degradation of ELAVL1, thereby influencing the stability of NSUN2 mRNA. In conclusion, this study revealed for the first time that HOST2 maintains NSUN2 mRNA stability by blocking ubiquitin-dependent degradation of ELAVL1, which in turn affects BC progression. HOST2/ELAVL1/NSUN2 oncogenic cascade has the potential to be a novel therapeutic target for BC.


Assuntos
Neoplasias da Mama , Proteína Semelhante a ELAV 1 , Metiltransferases , RNA Longo não Codificante , Feminino , Humanos , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Regulação Neoplásica da Expressão Gênica , Metiltransferases/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , RNA Mensageiro/genética , Ubiquitinas/metabolismo
3.
PLoS Pathog ; 20(2): e1011999, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38306394

RESUMO

Hepatitis B virus (HBV) chronically infects 296 million people worldwide, posing a major global health threat. Export of HBV RNAs from the nucleus to the cytoplasm is indispensable for viral protein translation and genome replication, however the mechanisms regulating this critical process remain largely elusive. Here, we identify a key host factor embryonic lethal, abnormal vision, Drosophila-like 1 (ELAVL1) that binds HBV RNAs and controls their nuclear export. Using an unbiased quantitative proteomics screen, we demonstrate direct binding of ELAVL1 to the HBV pregenomic RNA (pgRNA). ELAVL1 knockdown inhibits HBV RNAs posttranscriptional regulation and suppresses viral replication. Further mechanistic studies reveal ELAVL1 recruits the nuclear export receptor CRM1 through ANP32A and ANP32B to transport HBV RNAs to the cytoplasm via specific AU-rich elements, which can be targeted by a compound CMLD-2. Moreover, ELAVL1 protects HBV RNAs from DIS3+RRP6+ RNA exosome mediated nuclear RNA degradation. Notably, we find HBV core protein is dispensable for HBV RNA-CRM1 interaction and nuclear export. Our results unveil ELAVL1 as a crucial host factor that regulates HBV RNAs stability and trafficking. By orchestrating viral RNA nuclear export, ELAVL1 is indispensable for the HBV life cycle. Our study highlights a virus-host interaction that may be exploited as a new therapeutic target against chronic hepatitis B.


Assuntos
Vírus da Hepatite B , RNA Viral , Animais , Humanos , Vírus da Hepatite B/metabolismo , Transporte Ativo do Núcleo Celular , RNA Viral/genética , RNA Viral/metabolismo , Drosophila/genética , Replicação Viral/genética , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo
4.
Biochem Biophys Res Commun ; 695: 149484, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38211530

RESUMO

Ubiquitination factor E4B (UBE4B) has a tumor-promoting effect, demonstrated by its aberrant expression in various types of cancers, and in vitro studies have shown that the retardation of cancer cell proliferation can be induced by targeting UBE4B. However, the molecular pathways through which UBE4B exerts its oncogenic activities have not yet been clearly identified and existing knowledge is limited to p53 and its subsequent downstream targets. In this study, we demonstrated that UBE4B regulates p27 expression in A549 cells via the cap-independent translation pathway following treatment with rapamycin and cycloheximide (CHX). Subsequently, we identified that UBE4B regulates p27 translation by regulating the interaction between human antigen R (HuR) and the p27 internal ribosomal entry site (IRES). First, UBE4B interacts with HuR, which inhibits p27 translation through the IRES. Secondly, the interaction between HuR and the p27 IRES was diminished by UBE4B depletion and enhanced by UBE4B overexpression. Finally, HuR depletion-induced growth retardation, accompanied by p27 accumulation, was restored by UBE4B overexpression. Collectively, these results suggest that the oncogenic properties of UBE4B in A549 cells are mediated by HuR, suggesting the potential of targeting the UBE4B-HuR-p27 axis as a therapeutic strategy for lung cancer.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Inibidor de Quinase Dependente de Ciclina p27 , Neoplasias Pulmonares , Ubiquitina-Proteína Ligases , Humanos , Regiões 5' não Traduzidas , Células A549 , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteína Semelhante a ELAV 1/metabolismo
5.
Int J Mol Sci ; 25(2)2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38256026

RESUMO

HuR regulates cytoplasmic mRNA stability and translatability, with its expression correlating with adverse outcomes in various cancers. This study aimed to assess the prognostic value and pro-oncogenic properties of HuR and its post-translational isoforms methyl-HuR and phospho-HuR in endometrial adenocarcinoma. Examining 89 endometrioid adenocarcinomas, we analyzed the relationship between HuR nuclear or cytoplasmic immunostaining, tumor-cell proliferation, and patient survival. HuR cytoplasmic expression was significantly increased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001), correlating with worse overall survival (OS) (p = 0.02). Methyl-HuR cytoplasmic expression significantly decreased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001) and correlated with better OS (p = 0.002). Phospho-HuR nuclear expression significantly decreased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001) and non-significantly correlated with increased OS (p = 0.06). Cytoplasmic HuR expression strongly correlated with proliferation markers MCM6 (rho = 0.59 and p < 0.001) and Ki67 (rho = 0.49 and p < 0.001). Conversely, these latter inversely correlated with cytoplasmic methyl-HuR and nuclear phospho-HuR. Cytoplasmic HuR expression is a poor prognosis marker in endometrioid endometrial adenocarcinoma, while cytoplasmic methyl-HuR and nuclear phosphoHuR expressions are markers of better prognosis. This study highlights HuR as a promising potential therapeutic target, especially in treatment-resistant tumors, though further research is needed to understand the mechanisms regulating HuR subcellular localization and post-translational modifications.


Assuntos
Carcinoma Endometrioide , Proteína Semelhante a ELAV 1 , Neoplasias do Endométrio , Feminino , Humanos , Carcinoma Endometrioide/genética , Carcinoma Endometrioide/metabolismo , Proliferação de Células , Citoplasma , Citosol , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo
6.
Ecotoxicol Environ Saf ; 271: 115954, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38232523

RESUMO

BACKGROUND: Nickel is a confirmed human lung carcinogen. Nonetheless, the molecular mechanisms driving its carcinogenic impact on lung tissue remain poorly defined. In this study, we assessed SESN2 expression and the signaling pathways responsible for cellular transformation in human bronchial epithelial cells (HBECs) as a result of nickel exposure. METHODS: We employed the Western blotting to determine the induction of SESN2 by nickel. To clarify the signaling pathways leading to cellular transformation following nickel exposure, we applied techniques such as gene knockdown, methylation-specific PCR, and chromatin immunoprecipitation. RESULT: Exposure to nickel results in the upregulation of SESN2 and the initiation of autophagy in human bronchial epithelial cells (HBECs). This leads to degradation of HUR protein and consequently downregulation of USP28 mRNA, PP2AC protein, ß-catenin protein, and diminished VHL transcription, culminating in the accumulation of hypoxia-inducible factor-1α (HIF-1α) and the malignant transformation of these cells. Mechanistic studies revealed that the increased expression of SESN2 is attributed to the demethylation of the SESN2 promoter induced by nickel, a process facilitated by decreased DNA methyl-transferase 3 A (DNMT3a) expression, while The downregulation of VHL transcription is linked to the suppression of the PP2A-C/GSK3ß/ß-Catenin/C-Myc pathway. Additionally, we discovered that SESN2-mediated autophagy triggers the degradation of HUR protein, which subsequently reduces the stability of USP28 mRNA and inhibits the PP2A-C/GSK3ß/ß-Catenin pathway and c-Myc transcription in HBECs post nickel exposure. CONCLUSION: Our results reveal that nickel exposure leads to the downregulation of DNMT3a, resulting in the hypomethylation of the SESN2 promoter and its protein induction. This triggers autophagy-dependent suppression of the HUR/USP28/PP2A/ß-Catenin/c-Myc pathway, subsequently leading to reduced VHL transcription, accumulation of HIF-1α protein, and the malignant transformation of human bronchial epithelial cells (HBECs). Our research offers novel insights into the molecular mechanisms that underlie the lung carcinogenic effects of nickel exposure. Specifically, nickel induces aberrant DNA methylation in the SESN2 promoter region through the decrease of DNMT3a levels, which ultimately leads to HIF-1α protein accumulation and the malignant transformation of HBECs. Specifically, nickel initiates DNA-methylation of the SESN2 promoter region by decreasing DNMT3a, ultimately resulting in HIF-1α protein accumulation and malignant transformation of HBECs. This study highlights DNMT3a as a potential prognostic biomarker or therapeutic target to improve clinical outcomes in lung cancer patients.


Assuntos
Níquel , beta Catenina , Humanos , Níquel/toxicidade , Níquel/metabolismo , beta Catenina/metabolismo , Sestrinas/metabolismo , Regulação para Cima , Transferases/metabolismo , Proteína Semelhante a ELAV 1/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Células Epiteliais/metabolismo , Transformação Celular Neoplásica/genética , DNA/metabolismo , RNA Mensageiro/metabolismo , Ubiquitina Tiolesterase/metabolismo
7.
Cancer Gene Ther ; 31(2): 237-249, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38072968

RESUMO

Circular RNAs (circRNAs) are covalently closed noncoding RNA molecules that play multiple roles in tumorigenesis and metastasis. Ferroptosis is an iron-dependent, regulated form of cell death and has emerged as a promising target for cancer treatment. However, whether and how circRNAs regulate ferroptotic cell death in colorectal cancer (CRC) remains largely unknown. Three circRNA microarrays were used to screen differentially expressed circRNAs in CRC tissues. A series of functional experiments were conducted to investigate the effects of circRNA on CRC cell proliferation, migration and ferroptosis. We found that hsa_circ_0058495 (circRHBDD1), a novel circRNA, was significantly upregulated in colorectal cancer tissues and cells. The expression levels of circRHBDD1 in serum samples were strongly associated with the advancement of CRC. Silencing of circRHBDD1 remarkably suppressed the proliferation and migration of CRC cells in vitro. Moreover, the depletion of circRHBDD1 notably increased ferroptotic cell death and enhanced RSL3-induced ferroptosis in CRC cells. Mechanistically, circRHBDD1 upregulated the expression of stearoyl-CoA desaturase (SCD), a ferroptosis suppressor mediating lipid remodelling, by enhancing the ELAVL1/SCD mRNA interaction. Finally, circRHBDD1 knockdown repressed the tumorigenesis and ferroptosis of CRC cells in vivo. In conclusion, circRHBDD1 facilitates tumour progression and obstructs ferroptosis in CRC by regulating SCD expression in an ELAVL1-dependent manner.


Assuntos
Neoplasias Colorretais , Ferroptose , MicroRNAs , Humanos , RNA Circular/genética , RNA Circular/metabolismo , RNA Mensageiro/genética , Estearoil-CoA Dessaturase/metabolismo , Ferroptose/genética , Proliferação de Células/genética , Neoplasias Colorretais/patologia , Carcinogênese/genética , MicroRNAs/genética , Proteína Semelhante a ELAV 1/genética , Serina Endopeptidases/metabolismo
8.
Nat Commun ; 14(1): 7093, 2023 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-37925433

RESUMO

Human antigen R (HuR) is a ubiquitously expressed RNA-binding protein, which functions as an RNA regulator. Overexpression of HuR correlates with high grade tumours and poor patient prognosis, implicating it as an attractive therapeutic target. However, an effective small molecule antagonist to HuR for clinical use remains elusive. Here, a single domain antibody (VHH) that binds HuR with low nanomolar affinity was identified and shown to inhibit HuR binding to RNA. This VHH was used to engineer a TRIM21-based biological PROTAC (bioPROTAC) that could degrade endogenous HuR. Significantly, HuR degradation reverses the tumour-promoting properties of cancer cells in vivo by altering the HuR-regulated proteome, highlighting the benefit of HuR degradation and paving the way for the development of HuR-degrading therapeutics. These observations have broader implications for degrading intractable therapeutic targets, with bioPROTACs presenting a unique opportunity to explore targeted-protein degradation through a modular approach.


Assuntos
Proteína Semelhante a ELAV 1 , Neoplasias , Quimera de Direcionamento de Proteólise , Humanos , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , RNA , Proteínas de Ligação a RNA/metabolismo
9.
Am J Physiol Gastrointest Liver Physiol ; 325(6): G518-G527, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37788332

RESUMO

Gut barrier dysfunction occurs commonly in patients with critical disorders, leading to the translocation of luminal toxic substances and bacteria to the bloodstream. Connexin 43 (Cx43) acts as a gap junction protein and is crucial for intercellular communication and the diffusion of nutrients. The levels of cellular Cx43 are tightly regulated by multiple factors, including polyamines, but the exact mechanism underlying the control of Cx43 expression remains largely unknown. The RNA-binding protein HuR regulates the stability and translation of target mRNAs and is involved in many aspects of intestinal epithelial pathobiology. Here we show that HuR directly bound to Cx43 mRNA via its 3'-untranslated region in intestinal epithelial cells (IECs) and this interaction enhanced Cx43 expression by stabilizing Cx43 mRNA. Depletion of cellular polyamines inhibited the [HuR/Cx43 mRNA] complex and decreased the level of Cx43 protein by destabilizing its mRNA, but these changes were prevented by ectopic overexpression of HuR. Polyamine depletion caused intestinal epithelial barrier dysfunction, which was reversed by ectopic Cx43 overexpression. Moreover, overexpression of checkpoint kinase 2 in polyamine-deficient cells increased the [HuR/Cx43 mRNA] complex, elevated Cx43 levels, and promoted barrier function. These findings indicate that Cx43 mRNA is a novel target of HuR in IECs and that polyamines regulate Cx43 mRNA stability via HuR, thus playing a critical role in the maintenance of intestinal epithelial barrier function.NEW & NOTEWORTHY The current study shows that polyamines stabilize the Cx43 mRNA via HuR, thus enhancing the function of the Cx43-mediated gap junction. These findings suggest that induced Cx43 by HuR plays a critical role in the process by which polyamines regulate intestinal epithelial barrier.


Assuntos
Conexina 43 , Proteína Semelhante a ELAV 1 , Poliaminas , RNA Mensageiro , Humanos , Conexina 43/genética , Conexina 43/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Mucosa Intestinal/metabolismo , Poliaminas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estabilidade de RNA
10.
Cancer Res ; 83(21): 3507-3516, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37683260

RESUMO

The RNA-binding protein human antigen R (HuR) is a well-established regulator of gene expression at the posttranscriptional level. Its dysregulation has been implicated in various human diseases, particularly cancer. In cancer, HuR is considered "active" when it shows increased subcellular localization in the cytoplasm, in addition to its normal nuclear localization. Cytoplasmic HuR plays a crucial role in stabilizing and enhancing the translation of prosurvival mRNAs that are involved in stress responses relevant to cancer progression, such as hypoxia, radiotherapy, and chemotherapy. In general, due to HuR's abundance and function in cancer cells compared with normal cells, it is an appealing target for oncology research. Exploiting the principles underlying HuR's role in tumorigenesis and resistance to stressors, targeting HuR has the potential for synergy with existing and novel oncologic therapies. This review aims to explore HuR's role in homeostasis and cancer pathophysiology, as well as current targeting strategies, which include silencing HuR expression, preventing its translocation and dimerization from the nucleus to the cytoplasm, and inhibiting mRNA binding. Furthermore, this review will discuss recent studies investigating the potential synergy between HuR inhibition and traditional chemotherapeutics.


Assuntos
Proteína Semelhante a ELAV 1 , Neoplasias , Humanos , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas ELAV/genética
11.
Int J Mol Sci ; 24(17)2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-37685931

RESUMO

The RNA-binding protein human antigen R (HuR) regulates stability, translation, and nucleus-to-cytoplasm shuttling of its target mRNAs. This protein has been progressively recognized as a relevant therapeutic target for several pathologies, like cancer, neurodegeneration, as well as inflammation. Inhibitors of mRNA binding to HuR might thus be beneficial against a variety of diseases. Here, we present the rational identification of structurally novel HuR inhibitors. In particular, by combining chemoinformatic approaches, high-throughput virtual screening, and RNA-protein pulldown assays, we demonstrate that the 4-(2-(2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)hydrazineyl)benzoate ligand exhibits a dose-dependent HuR inhibition effect in binding experiments. Importantly, the chemical scaffold is new with respect to the currently known HuR inhibitors, opening up a new avenue for the design of pharmaceutical agents targeting this important protein.


Assuntos
Benzoatos , Bioensaio , Proteína Semelhante a ELAV 1 , Humanos , Núcleo Celular , Peso Molecular , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteína Semelhante a ELAV 1/antagonistas & inibidores
12.
Int J Mol Sci ; 24(17)2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37685961

RESUMO

The aryl hydrocarbon receptor (AHR) is a transcription factor that is commonly upregulated in pancreatic ductal adenocarcinoma (PDAC). AHR hinders the shuttling of human antigen R (ELAVL1) from the nucleus to the cytoplasm, where it stabilises its target messenger RNAs (mRNAs) and enhances protein expression. Among these target mRNAs are those induced by gemcitabine. Increased AHR expression leads to the sequestration of ELAVL1 in the nucleus, resulting in chemoresistance. This study aimed to investigate the interaction between AHR and ELAVL1 in the pathogenesis of PDAC in vitro. AHR and ELAVL1 genes were silenced by siRNA transfection. The RNA and protein were extracted for quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analysis. Direct binding between the ELAVL1 protein and AHR mRNA was examined through immunoprecipitation (IP) assay. Cell viability, clonogenicity, and migration assays were performed. Our study revealed that both AHR and ELAVL1 inter-regulate each other, while also having a role in cell proliferation, migration, and chemoresistance in PDAC cell lines. Notably, both proteins function through distinct mechanisms. The silencing of ELAVL1 disrupts the stability of its target mRNAs, resulting in the decreased expression of numerous cytoprotective proteins. In contrast, the silencing of AHR diminishes cell migration and proliferation and enhances cell sensitivity to gemcitabine through the AHR-ELAVL1-deoxycytidine kinase (DCK) molecular pathway. In conclusion, AHR and ELAVL1 interaction can form a negative feedback loop. By inhibiting AHR expression, PDAC cells become more susceptible to gemcitabine through the ELAVL1-DCK pathway.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Proteína Semelhante a ELAV 1/genética , Gencitabina , Pâncreas , Hormônios Pancreáticos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Receptores de Hidrocarboneto Arílico/genética , RNA Mensageiro/genética , Desoxicitidina Quinase/efeitos dos fármacos , Desoxicitidina Quinase/metabolismo , Neoplasias Pancreáticas
13.
J Exp Med ; 220(11)2023 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-37698554

RESUMO

Natural killer (NK) cells are lymphocytes capable of controlling tumors and virus infections through direct lysis and cytokine production. While both T and NK cells expand and accumulate in affected tissues, the role of NK cell expansion in tumor and viral control is not well understood. Here, we show that posttranscriptional regulation by the RNA-binding protein HuR is essential for NK cell expansion without negatively affecting effector functions. HuR-deficient NK cells displayed defects in the metaphase of the cell cycle, including decreased expression and alternative splicing of Ska2, a component of the spindle and kinetochore complex. HuR-dependent NK cell expansion contributed to long-term cytomegalovirus control and facilitated control of subcutaneous tumors but not tumor metastases in two independent tumor models. These results show that posttranscriptional regulation by HuR specifically affects NK cell expansion, which is required for the control of long-term virus infection and solid tumors, but not acute infection or tumor metastases, highlighting fundamental differences with antigen-specific T cell control.


Assuntos
Proteína Semelhante a ELAV 1 , Células Matadoras Naturais , Neoplasias , Viroses , Humanos , Ciclo Celular , Divisão Celular , Proliferação de Células , Proteína Semelhante a ELAV 1/metabolismo , Proteínas Cromossômicas não Histona/metabolismo
14.
Life Sci Alliance ; 6(11)2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37696579

RESUMO

Rapid self-renewal of the intestinal epithelium requires the activity of intestinal stem cells (ISCs) that are intermingled with Paneth cells (PCs) at the crypt base. PCs provide multiple secreted and surface-bound niche signals and play an important role in the regulation of ISC proliferation. Here, we show that control of PC function by RNA-binding protein HuR via mitochondria affects intestinal mucosal growth by altering ISC activity. Targeted deletion of HuR in mice disrupted PC gene expression profiles, reduced PC-derived niche factors, and impaired ISC function, leading to inhibited renewal of the intestinal epithelium. Human intestinal mucosa from patients with critical surgical disorders exhibited decreased levels of tissue HuR and PC/ISC niche dysfunction, along with disrupted mucosal growth. HuR deletion led to mitochondrial impairment by decreasing the levels of several mitochondrial-associated proteins including prohibitin 1 (PHB1) in the intestinal epithelium, whereas HuR enhanced PHB1 expression by preventing microRNA-195 binding to the Phb1 mRNA. These results indicate that HuR is essential for maintaining the integrity of the PC/ISC niche and highlight a novel role for a defective PC/ISC niche in the pathogenesis of intestinal mucosa atrophy.


Assuntos
Proteína Semelhante a ELAV 1 , MicroRNAs , Mucosa , Celulas de Paneth , Animais , Humanos , Camundongos , Transporte Biológico , Fenômenos Fisiológicos Celulares , Mucosa Intestinal , MicroRNAs/genética , Proteínas Mitocondriais , Células-Tronco , Proteína Semelhante a ELAV 1/genética
15.
Mol Cancer Res ; 21(12): 1342-1355, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37647111

RESUMO

The pathologic significance of the circular RNA DDIT4 (circDDIT4), which is formed by backsplicing at the 3'-untranslated region (UTR) with a 5' splice acceptor site in exon 2 of linear DDIT4 mRNA, has yet to be determined. Our study found that circDDIT4 is downregulated in prostate cancer and functions as a tumor suppressor during prostate cancer progression. By competitively binding to ELAV-like RNA binding protein 1 (ELAVL1/HuR) through its 3'-UTR, circDDIT4 acts as a protein sponge to decrease the expression of prostate cancer-overexpressed anoctamin 7 (ANO7). This promotes prostate cancer cell apoptosis while inhibiting cell proliferation and metastasis. Furthermore, we discovered that N6-methyladenosine (m6A) modification facilitates the biogenesis of circDDIT4. The methyltransferase complex consisting of WTAP/METTL3/METTL14 increases the level of circDDIT4, while the RNA demethylase FTO decreases it. IMPLICATIONS: These findings suggest that abnormal cotranscriptional modification of m6A promotes prostate cancer initiation and progression via a circular RNA-protein-cell signaling network.


Assuntos
Neoplasias da Próstata , RNA Circular , Masculino , Humanos , RNA Circular/genética , Metiltransferases/genética , Neoplasias da Próstata/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo
16.
PLoS Pathog ; 19(8): e1011552, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37540723

RESUMO

Host protein HuR translocation from nucleus to cytoplasm following infection is crucial for the life cycle of several RNA viruses including hepatitis C virus (HCV), a major causative agent of hepatocellular carcinoma. HuR assists the assembly of replication-complex on the viral-3'UTR, and its depletion hampers viral replication. Although cytoplasmic HuR is crucial for HCV replication, little is known about how the virus orchestrates the mobilization of HuR into the cytoplasm from the nucleus. We show that two viral proteins, NS3 and NS5A, act co-ordinately to alter the equilibrium of the nucleo-cytoplasmic movement of HuR. NS3 activates protein kinase C (PKC)-δ, which in-turn phosphorylates HuR on S318 residue, triggering its export to the cytoplasm. NS5A inactivates AMP-activated kinase (AMPK) resulting in diminished nuclear import of HuR through blockade of AMPK-mediated phosphorylation and acetylation of importin-α1. Cytoplasmic retention or entry of HuR can be reversed by an AMPK activator or a PKC-δ inhibitor. Our findings suggest that efforts should be made to develop inhibitors of PKC-δ and activators of AMPK, either separately or in combination, to inhibit HCV infection.


Assuntos
Hepacivirus , Hepatite C , Humanos , Hepacivirus/fisiologia , Proteínas Quinases Ativadas por AMP/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Citoplasma/metabolismo , Hepatite C/metabolismo , Linhagem Celular Tumoral , Replicação Viral , Proteínas não Estruturais Virais/metabolismo
17.
FASEB J ; 37(8): e23074, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37392376

RESUMO

Myosin heavy chain-embryonic encoded by the Myh3 gene is a skeletal muscle-specific contractile protein expressed during mammalian development and regeneration, essential for proper myogenic differentiation and function. It is likely that multiple trans-factors are involved in this precise temporal regulation of Myh3 expression. We identify a 4230 bp promoter-enhancer region that drives Myh3 transcription in vitro during C2C12 myogenic differentiation and in vivo during muscle regeneration, including sequences both upstream and downstream of the Myh3 TATA-box that are necessary for complete Myh3 promoter activity. Using C2C12 mouse myogenic cells, we find that Zinc-finger E-box binding homeobox 1 (Zeb1) and Transducin-like Enhancer of Split 3 (Tle3) proteins are crucial trans-factors that interact and differentially regulate Myh3 expression. Loss of Zeb1 function results in earlier expression of myogenic differentiation genes and accelerated differentiation, whereas Tle3 depletion leads to reduced expression of myogenic differentiation genes and impaired differentiation. Tle3 knockdown resulted in downregulation of Zeb1, which could be mediated by increased expression of miR-200c, a microRNA that binds to Zeb1 transcript and degrades it. Tle3 functions upstream of Zeb1 in regulating myogenic differentiation since double knockdown of Zeb1 and Tle3 resulted in effects seen upon Tle3 depletion. We identify a novel E-box in the Myh3 distal promoter-enhancer region, where Zeb1 binds to repress Myh3 expression. In addition to regulation of myogenic differentiation at the transcriptional level, we uncover post-transcriptional regulation by Tle3 to regulate MyoG expression, mediated by the mRNA stabilizing Human antigen R (HuR) protein. Thus, Tle3 and Zeb1 are essential trans-factors that differentially regulate Myh3 expression and C2C12 cell myogenic differentiation in vitro.


Assuntos
Proteínas Correpressoras , Músculo Esquelético , Cadeias Pesadas de Miosina , Fatores de Transcrição , Homeobox 1 de Ligação a E-box em Dedo de Zinco , Animais , Humanos , Camundongos , Diferenciação Celular/genética , Proteínas Correpressoras/genética , Proteínas Contráteis , Proteína Semelhante a ELAV 1 , Músculo Esquelético/embriologia , Cadeias Pesadas de Miosina/genética , Fatores de Transcrição/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética
18.
Nan Fang Yi Ke Da Xue Xue Bao ; 43(5): 807-814, 2023 May 20.
Artigo em Chinês | MEDLINE | ID: mdl-37313823

RESUMO

OBJECTIVE: To investigate the regulatory role of the long non-coding RNA LINC00926 in pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells (HUVECs) and explore the molecular mechanism. METHODS: HUVECs were transfected with a LINC00926-overexpressing plasmid (OE-LINC00926), a siRNA targeting ELAVL1, or both, followed by exposure to hypoxia (5% O2) or normoxia. The expression of LINC00926 and ELAVL1 in hypoxia-treated HUVECs was detected using real-time quantitative PCR (RT-qPCR) and Western blotting. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8), and the levels of IL-1ß in the cell cultures was determined with ELISA. The protein expression levels of pyroptosis-related proteins (caspase-1, cleaved caspase-1 and NLRP3) in the treated cells were analyzed using Western blotting, and the binding between LINC00926 and ELAVL1 was verified with RNA immunoprecipitation (RIP) assay. RESULTS: Exposure to hypoxia obviously up-regulated the mRNA expression of LINC00926 and the protein expression of ELAVL1 in HUVECs, but did not affect the mRNA expression of ELAVL1. LINC00926 overexpression in the cells significantly inhibited cell proliferation, increased IL-1ß level and enhanced the expressions of pyroptosis-related proteins (all P < 0.05). LINC00926 overexpression further up-regulated the protein expression of ELAVL1 in hypoxia-exposed HUVECs. The results of RIP assay confirmed the binding between LINC00926 and ELAVL1. ELAVL1 knockdown significantly decreased IL-1ß level and the expressions of pyroptosis-related proteins in hypoxia-exposed HUVECs (P < 0.05), while LINC00926 overexpression partially reversed the effects of ELAVL1 knockdown. CONCLUSION: LINC00926 promotes pyroptosis of hypoxia-induced HUVECs by recruiting ELAVL1.


Assuntos
Hipóxia Celular , Proteína Semelhante a ELAV 1 , Piroptose , RNA Longo não Codificante , Humanos , Caspase 1 , Células Endoteliais da Veia Umbilical Humana , RNA Mensageiro , RNA Longo não Codificante/genética
19.
Cell Mol Biol (Noisy-le-grand) ; 69(3): 69-74, 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-37300687

RESUMO

MicroRNAs (miRNAs) were reportedly demonstrated to participate in ovarian cancer (OC) progression. Here, we inquired into the role of miR-188-5punderneath OC cell proliferation and migration. In this respect, our work examined the miR-188-5p expression and demonstrated its expression level in OC by qRT-PCR analysis. Enforced miR-188-5p expression resulted in a serious downfall of cell growth and mobility, and acceleration apoptosis in OC cells. Furthermore, we identified CCND2 as a target gene of miR-188-5p. RIP assay and luciferase reporter assay verified the interaction of miR-188-5p and CCND2 and exhibited that miR-188-5p greatly hindered the expression of CCND2. Besides, HuR stabilized CCND2 mRNA and counteracted the miR-188-5p suppressive effect on CCND2 mRNA. Functionally, rescue experiments also showed that miR-188-5p-mediated suppression on OC cell proliferation and migration was reverted by CCND2 or HuR overexpression. Our study found miR-188-5p was a tumor suppressor in OC via competing for CCND2 with ELAVL1, contributing to coming up with novel clues for OC therapies.


Assuntos
MicroRNAs , Neoplasias Ovarianas , Humanos , Feminino , Linhagem Celular Tumoral , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Ovarianas/patologia , Proliferação de Células/genética , Ciclo Celular , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Ciclina D2/genética , Ciclina D2/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo
20.
Arterioscler Thromb Vasc Biol ; 43(7): 1157-1175, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37128912

RESUMO

BACKGROUND: Obesity and diabetes are associated with elevated free fatty acids like palmitic acid (PA), which promote chronic inflammation and impaired inflammation resolution associated with cardiometabolic disorders. Long noncoding RNAs (lncRNAs) are implicated in inflammatory processes; however, their roles in PA-regulated inflammation and resolution are unclear. METHODS: We performed RNA-sequencing analysis to identify PA-regulated coding genes and novel lncRNAs in CD14+ monocytes from healthy volunteers. We investigated the regulation and function of an uncharacterized PA-induced lncRNA PARAIL (PA-regulated anti-inflammatory lncRNA). We examined its role in inflammation resolution by employing knockdown and overexpression strategies in human and mouse macrophages. We also used RNA pulldown coupled with mass spectrometry to identify PARAIL interacting nuclear proteins and their mechanistic involvement in PARAIL functions in human macrophages. RESULTS: Treatment of human CD14+ monocytes with PA-induced several lncRNAs and genes associated with inflammatory phenotype. PA strongly induced lncRNA PARAIL expressed near RIPK2. PARAIL was also induced by cytokines and infectious agents in human monocytes/macrophages and was regulated by NF-κB (nuclear factor-kappa B). Time course studies showed PARAIL was induced during inflammation resolution phase in PA-treated macrophages. PARAIL knockdown with antisense oligonucleotides upregulated key inflammatory genes and vice versa with PARAIL overexpression. We found that PARAIL interacts with ELAVL1 (ELAV-like RNA-binding protein 1) protein via adenylate/uridylate-rich elements (AU-rich elements; AREs). ELAVL1 knockdown inhibited the anti-inflammatory functions of PARAIL. Moreover, PARAIL knockdown increased cytosolic localization of ELAVL1 and increased the stability of ARE-containing inflammatory genes. Mouse orthologous Parail was downregulated in macrophages from mice with diabetes and atherosclerosis. Parail overexpression attenuated proinflammatory genes in mouse macrophages. CONCLUSIONS: Upregulation of PARAIL under acute inflammatory conditions contributes to proresolution mechanisms via PARAIL-ELAVL1 interactions. Conversely, PARAIL downregulation in cardiometabolic diseases enhances ELAVL1 function and impairs inflammation resolution to further augment inflammation. Thus, inflammation-resolving lncRNAs like PARAIL represent novel targets to combat inflammatory cardiometabolic diseases.


Assuntos
Aterosclerose , RNA Longo não Codificante , Humanos , Camundongos , Animais , Monócitos/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Ácido Palmítico/toxicidade , Ácido Palmítico/metabolismo , Macrófagos/metabolismo , Inflamação/induzido quimicamente , Inflamação/genética , Inflamação/metabolismo , NF-kappa B/metabolismo , Aterosclerose/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...