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1.
J Immunol ; 206(8): 1932-1942, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33789981

RESUMO

The cell has several mechanisms to sense and neutralize stress. Stress-related stimuli activate pathways that counteract danger, support cell survival, and activate the inflammatory response. We use human cells to show that these processes are modulated by EGOT, a long noncoding RNA highly induced by viral infection, whose inhibition results in increased levels of antiviral IFN-stimulated genes (ISGs) and decreased viral replication. We now show that EGOT is induced in response to cell stress, viral replication, or the presence of pathogen-associated molecular patterns via the PI3K/AKT, MAPKs, and NF-κB pathways, which lead to cell survival and inflammation. Transcriptome analysis and validation experiments show that EGOT modulates PI3K/AKT and NF-κB responses. On the one hand, EGOT inhibition decreases expression of PI3K/AKT-induced cellular receptors and cell proliferation. In fact, EGOT levels are increased in several tumors. On the other hand, EGOT inhibition results in decreased levels of key NF-κB target genes, including those required for inflammation and ISGs in those cells that build an antiviral response. Mechanistically, EGOT depletion decreases the levels of the key coactivator TBLR1, essential for transcription by NF-κB. In summary, EGOT is induced in response to stress and may function as a switch that represses ISG transcription until a proper antiviral or stress response is initiated. EGOT then helps PI3K/AKT, MAPKs, and NF-κB pathways to activate the antiviral response, cell inflammation, and growth. We believe that modulation of EGOT levels could be used as a therapy for the treatment of certain viral infections, immune diseases, and cancer.


Assuntos
Hepacivirus/fisiologia , Hepatite C/imunologia , Inflamação/genética , RNA Longo não Codificante/genética , Estresse Fisiológico/imunologia , Processos de Crescimento Celular , Linhagem Celular , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais
2.
Int J Mol Sci ; 21(17)2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32899429

RESUMO

The proper functioning of the immune system requires a robust control over a delicate equilibrium between an ineffective response and immune overactivation. Poor responses to viral insults may lead to chronic or overwhelming infection, whereas unrestrained activation can cause autoimmune diseases and cancer. Control over the magnitude and duration of the antiviral immune response is exerted by a finely tuned positive or negative regulation at the DNA, RNA, and protein level of members of the type I interferon (IFN) signaling pathways and on the expression and activity of antiviral and proinflammatory factors. As summarized in this review, committed research during the last decade has shown that several of these processes are exquisitely regulated by long non-coding RNAs (lncRNAs), transcripts with poor coding capacity, but highly versatile functions. After infection, viruses, and the antiviral response they trigger, deregulate the expression of a subset of specific lncRNAs that function to promote or repress viral replication by inactivating or potentiating the antiviral response, respectively. These IFN-related lncRNAs are also highly tissue- and cell-type-specific, rendering them as promising biomarkers or therapeutic candidates to modulate specific stages of the antiviral immune response with fewer adverse effects.


Assuntos
Antivirais/farmacologia , Interferon Tipo I/farmacologia , RNA Longo não Codificante/genética , Viroses/imunologia , Vírus/imunologia , Animais , Humanos , Viroses/tratamento farmacológico , Viroses/genética , Viroses/virologia , Replicação Viral , Vírus/efeitos dos fármacos , Vírus/genética
3.
EMBO Rep ; 17(7): 1013-28, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27283940

RESUMO

The role of long noncoding RNAs (lncRNAs) in viral infection is poorly studied. We have identified hepatitis C virus (HCV)-Stimulated lncRNAs (CSRs) by transcriptome analysis. Interestingly, two of these CSRs (PVT1 and UCA1) play relevant roles in tumorigenesis, providing a novel link between HCV infection and development of liver tumors. Expression of some CSRs seems induced directly by HCV, while others are upregulated by the antiviral response against the virus. In fact, activation of pathogen sensors induces the expression of CSR32/EGOT RIG-I and the RNA-activated kinase PKR sense HCV RNA, activate NF-κB and upregulate EGOT EGOT is increased in the liver of patients infected with HCV and after infection with influenza or Semliki Forest virus (SFV). Genome-wide guilt-by-association studies predict that EGOT may function as a negative regulator of the antiviral pathway. Accordingly, EGOT depletion increases the expression of several interferon-stimulated genes and leads to decreased replication of HCV and SFV Our results suggest that EGOT is a lncRNA induced after infection that increases viral replication by antagonizing the antiviral response.


Assuntos
Resistência à Doença/genética , Hepacivirus/fisiologia , Interações Hospedeiro-Patógeno/genética , RNA Longo não Codificante/genética , Replicação Viral , Linhagem Celular Tumoral , Análise por Conglomerados , Proteína DEAD-box 58/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Hepatite C/genética , Hepatite C/virologia , Humanos , Interferon gama/metabolismo , Espaço Intracelular , Fases de Leitura Aberta , Transporte de RNA , Receptores Toll-Like/metabolismo , Transcriptoma , eIF-2 Quinase/metabolismo
4.
Nucleic Acids Res ; 42(16): 10668-80, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25122750

RESUMO

Long non-coding RNAs (lncRNAs) play critical roles in diverse cellular processes; however, their involvement in many critical aspects of the immune response including the interferon (IFN) response remains poorly understood. To address this gap, we compared the global gene expression pattern of primary human hepatocytes before and at three time points after treatment with IFN-α. Among ∼ 200 IFN-induced lncRNAs, one transcript showed ∼ 100-fold induction. This RNA, which we named lncRNA-CMPK2, was a spliced, polyadenylated nuclear transcript that was induced by IFN in diverse cell types from human and mouse. Similar to protein-coding IFN-stimulated genes (ISGs), its induction was dependent on JAK-STAT signaling. Intriguingly, knockdown of lncRNA-CMPK2 resulted in a marked reduction in HCV replication in IFN-stimulated hepatocytes, suggesting that it could affect the antiviral role of IFN. We could show that lncRNA-CMPK2 knockdown resulted in upregulation of several protein-coding antiviral ISGs. The observed upregulation was caused by an increase in both basal and IFN-stimulated transcription, consistent with loss of transcriptional inhibition in knockdown cells. These results indicate that the IFN response involves a lncRNA-mediated negative regulatory mechanism. lncRNA-CMPK2 was strongly upregulated in a subset of HCV-infected human livers, suggesting a role in modulation of the IFN response in vivo.


Assuntos
Interferon-alfa/farmacologia , RNA Longo não Codificante/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Regulação da Expressão Gênica , Hepatite C/genética , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Interferon gama/farmacologia , Janus Quinases/metabolismo , Fígado/metabolismo , Camundongos , RNA Longo não Codificante/biossíntese , RNA Longo não Codificante/genética , Fatores de Transcrição STAT/metabolismo , Regulação para Cima
6.
Liver Int ; 35(4): 1274-89, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24754307

RESUMO

BACKGROUND & AIMS: Adenoviral (Ad) vectors are currently one of the most efficient tools for in vivo gene transfer to the liver. However, anti-Ad immune responses limit the safety and efficacy of these vectors. The initial inflammatory reaction is a concern in terms of toxicity, and it favours the development of cellular and humoral responses leading to short transgene persistence and inefficient vector re-administrations. Therefore, safe and simple ways to interfere with these processes are needed. Study ways to deplete specific immune cell populations and their impact on liver-directed gene transfer. METHODS: First-generation Ad vectors encoding reporter genes (luciferase or ß-galactosidase) were injected intravenously into Balb/c mice. Kupffer cells and splenic macrophages were depleted by intravenous administration of clodronate liposomes. B lymphocytes, CD4(+) , CD8(+) T lymphocytes or NK cells were depleted by intraperitoneal injection of anti-M plus anti-D, anti-CD4, anti-CD8 or anti-asialo-GM1 antibodies respectively. Long-term evolution of luciferase expression in the liver was monitored by bioluminescence imaging. RESULTS: The anti-CD4 monoclonal antibody impaired cellular and humoral immune responses, leading to efficient vector re-administration. Clodronate liposomes had no impact on humoral responses but caused a 100-1000 fold increase in liver transduction, stabilized transgene expression, reduced the concentration of inflammatory cytokines, and inhibited lymphocyte activation. CONCLUSIONS: Transient CD4(+) T-cell depletion using antibodies is a clinically feasible procedure that allows efficient Ad redosing. Systemic administration of clodronate liposomes may further increase the safety and efficacy of vectors.


Assuntos
Adenoviridae/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Vetores Genéticos , Imunossupressores/farmacologia , Fígado/efeitos dos fármacos , Depleção Linfocítica/métodos , Transdução Genética , Transgenes , Adenoviridae/genética , Adenoviridae/metabolismo , Animais , Anticorpos/farmacologia , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Ácido Clodrônico/farmacologia , Feminino , Regulação da Expressão Gênica , Genes Reporter , Imunidade Humoral/efeitos dos fármacos , Fígado/imunologia , Fígado/metabolismo , Luciferases/biossíntese , Luciferases/genética , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Tempo , beta-Galactosidase/biossíntese , beta-Galactosidase/genética
7.
Adv Exp Med Biol ; 848: 51-69, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25757615

RESUMO

U1 snRNP (U1 small nuclear ribonucleoprotein) is an essential component of the splicing machinery. U1 snRNP also plays an additional role in 3'-end mRNA processing when it binds close to polyadenylation sites (PAS). Cotranscriptionally, U1 snRNP binding close to putative PAS prevents premature cleavage and polyadenylation and consequently safeguards pre-mRNA transcripts and defines promoter directionality. At the 3'-end of mRNAs, U1 snRNP binding to putative PAS may regulate mRNA length or inhibit polyadenylation and, therefore, gene expression. U1 interference (U1i) is a technique to inhibit gene expression based on the property of U1 snRNP to inhibit polyadenylation. It requires the expression of a modified U1 snRNP, which interacts with a target gene upstream of its PAS and inhibits target gene expression. U1i has been used to inhibit the expression of reporter or endogenous genes both in tissue culture and in animal models. In addition, U1i combination with RNA interference (RNAi), another RNA-based gene silencing technology, results in a synergistic increased inhibition. This is of special interest for antiviral therapy, where strong inhibitions may be required to decrease the expression of replicative viral RNAs and impact the replication cycle. Furthermore, the combination of U1i and RNAi-based inhibitors should prevent the appearance of viral variants resistant to the treatment and allows the dose of inhibitors to be decreased and a functional inhibition to be obtained with fewer off target effects. In fact, U1i has been used to inhibit the expression of HIV-1 and HBV, whose viral genomes express mRNAs that must be polyadenylated by the nuclear polyadenylation machinery. In the case of HBV, antiviral U1i has been combined with RNAi to demonstrate a strong inhibition of expression from HBV sequences in vivo. This shows that, although several aspects of U1i technology remain to be addressed, U1i and U1i combined with RNAi have great potential as antivirals.


Assuntos
Antivirais/uso terapêutico , Terapia de Alvo Molecular/métodos , Interferência de RNA , Ribonucleoproteína Nuclear Pequena U1/genética , Viroses/terapia , Animais , Humanos , Conformação Molecular , Interferência de RNA/fisiologia , Ribonucleoproteína Nuclear Pequena U1/antagonistas & inibidores , Ribonucleoproteína Nuclear Pequena U1/química , Ribonucleoproteína Nuclear Pequena U1/fisiologia , Relação Estrutura-Atividade
8.
Nucleic Acids Res ; 40(1): e8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22086952

RESUMO

Inhibition of gene expression can be achieved with RNA interference (RNAi) or U1 small nuclear RNA-snRNA-interference (U1i). U1i is based on U1 inhibitors (U1in), U1 snRNA molecules modified to inhibit polyadenylation of a target pre-mRNA. In culture, we have shown that the combination of RNAi and U1i results in stronger inhibition of reporter or endogenous genes than that obtained using either of the techniques alone. We have now used these techniques to inhibit gene expression in mice. We show that U1ins can induce strong inhibition of the expression of target genes in vivo. Furthermore, combining U1i and RNAi results in synergistic inhibitions also in mice. This is shown for the inhibition of hepatitis B virus (HBV) sequences or endogenous Notch1. Surprisingly, inhibition obtained by combining a U1in and a RNAi mediator is higher than that obtained by combining two U1ins or two RNAi mediators. Our results suggest that RNAi and U1i cooperate by unknown mechanisms to result in synergistic inhibitions. Analysis of toxicity and specificity indicates that expression of U1i inhibitors is safe. Therefore, we believe that the combination of RNAi and U1i will be a good option to block damaging endogenous genes, HBV and other infectious agents in vivo.


Assuntos
Interferência de RNA , RNA Nuclear Pequeno/antagonistas & inibidores , Animais , Linhagem Celular , Vírus da Hepatite B/genética , Vírus da Hepatite B/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptor Notch1/genética , Receptor Notch1/metabolismo
9.
Hum Vaccin Immunother ; 20(1): 2303799, 2024 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38346926

RESUMO

Efficacy of cancer immunotherapies relies on correct recognition of tumor antigens by lymphocytes, eliciting thus functional responses capable of eliminating tumor cells. Therefore, important efforts have been carried out in antigen identification, with the aim of understanding mechanisms of response to immunotherapy and to design safer and more efficient strategies. In addition to classical tumor-associated antigens identified during the last decades, implementation of next-generation sequencing methodologies is enabling the identification of neoantigens (neoAgs) arising from mutations, leading to the development of new neoAg-directed therapies. Moreover, there are numerous non-classical tumor antigens originated from other sources and identified by new methodologies. Here, we review the relevance of neoAgs in different immunotherapies and the results obtained by applying neoAg-based strategies. In addition, the different types of non-classical tumor antigens and the best approaches for their identification are described. This will help to increase the spectrum of targetable molecules useful in cancer immunotherapies.


Assuntos
Vacinas Anticâncer , Neoplasias , Humanos , Antígenos de Neoplasias/genética , Imunoterapia , Neoplasias/genética , Neoplasias/terapia , Mutação
10.
Biochim Biophys Acta Mol Basis Dis ; 1870(2): 166926, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-37956602

RESUMO

BACKGROUND: In intrahepatic cholestasis of pregnancy (ICP), there are elevated maternal serum levels of total bile acids, progesterone, and some sulfated metabolites, such as allopregnanolone sulfate, which inhibits canalicular function. AIM: To investigate the relationship between cholestasis and the expression of crucial enzymes involved in progesterone metabolism in the liver and placenta. METHODS: Obstructive cholestasis was induced by bile duct ligation (BDL). RT-qPCR (mRNA) and western blot (protein) were used to determine expression levels. Srd5a1 and Akr1c2 enzymatic activities were assayed by substrate disappearance (progesterone and 5α-dihydroprogesterone, respectively), measured by HPLC-MS/MS. RESULTS: BDL induced decreased Srd5a1 and Akr1c2 expression and activity in rat liver, whereas both enzymes were up-regulated in rat placenta. Regarding sulfotransferases, Sult2b1 was also moderately up-regulated in the liver. In placenta from ICP patients, SRD5A1 and AKR1C2 expression was elevated, whereas both genes were down-regulated in liver biopsies collected from patients with several liver diseases accompanied by cholestasis. SRD5A1 and AKR1C2 expression was not affected by incubating human hepatoma HepG2 cells with FXR agonists (chenodeoxycholic acid and GW4064). Knocking-out Fxr in mice did not reduce Srd5a1 and Akr1c14 expression, which was similarly down-regulated by BDL. CONCLUSION: SRD5A1 and AKR1C2 expression was markedly altered by cholestasis. This was enhanced in the placenta but decreased in the liver, which is not mediated by FXR. These results suggest that the excess of progesterone metabolites in the serum of ICP patients can involve both enhanced placental production and decreased hepatic clearance. The latter may also occur in other cholestatic conditions.


Assuntos
Colestase , Placenta , Gravidez , Humanos , Feminino , Camundongos , Ratos , Animais , Placenta/metabolismo , Progesterona/metabolismo , Espectrometria de Massas em Tandem , Fígado/metabolismo , Colestase/metabolismo
11.
Hum Mutat ; 34(10): 1387-95, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23864287

RESUMO

Limb-girdle muscular dystrophy type 2A (LGMD2A) is the most frequent autosomal recessive muscular dystrophy. It is caused by mutations in the calpain-3 (CAPN3) gene. The majority of the mutations described to date are located in the coding sequence of the gene. However, it is estimated that 25% of the mutations are present at exon-intron boundaries and modify the pre-mRNA splicing of the CAPN3 transcript. We have previously described the first deep intronic mutation in the CAPN3 gene: c.1782+1072G>C mutation. This mutation causes the pseudoexonization of an intronic sequence of the CAPN3 gene in the mature mRNA. In the present work, we show that the point mutation generates the inclusion of the pseudoexon in the mRNA using a minigene assay. In search of a treatment that restores normal splicing, splicing modulation was induced by RNA-based strategies, which included antisense oligonucleotides and modified small-nuclear RNAs. The best effect was observed with antisense sequences, which induced pseudoexon skipping in both HeLa cells cotransfected with mutant minigene and in fibroblasts from patients. Finally, transfection of antisense sequences and siRNA downregulation of serine/arginine-rich splicing factor 1 (SRSF1) indicate that binding of this factor to splicing enhancer sequences is involved in pseudoexon activation.


Assuntos
Éxons , Íntrons , Distrofia Muscular do Cíngulo dos Membros/genética , Mutação , Oligonucleotídeos Antissenso/genética , RNA Nuclear Pequeno/genética , Processamento Alternativo , Calpaína/genética , Linhagem Celular , Feminino , Fibroblastos/metabolismo , Expressão Gênica , Regulação da Expressão Gênica , Ordem dos Genes , Humanos , Pessoa de Meia-Idade , Proteínas Musculares/genética , Proteínas Nucleares/metabolismo , Oligonucleotídeos Antissenso/metabolismo , Proteínas de Ligação a RNA/metabolismo , Sequências Reguladoras de Ácido Nucleico , Fatores de Processamento de Serina-Arginina
12.
J Neurochem ; 127(1): 124-38, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23638794

RESUMO

The prion protein (PrP) plays a key role in prion disease pathogenesis. Although the misfolded and pathologic variant of this protein (PrP(SC)) has been studied in depth, the physiological role of PrP(C) remains elusive and controversial. PrP(C) is a cell-surface glycoprotein involved in multiple cellular functions at the plasma membrane, where it interacts with a myriad of partners and regulates several intracellular signal transduction cascades. However, little is known about the gene expression changes modulated by PrP(C) in animals and in cellular models. In this article, we present PrP(C)-dependent gene expression signature in N2a cells and its implication in the most overrepresented functions: cell cycle, cell growth and proliferation, and maintenance of cell shape. PrP(C) over-expression enhances cell proliferation and cell cycle re-entrance after serum stimulation, while PrP(C) silencing slows down cell cycle progression. In addition, MAP kinase and protein kinase B (AKT) pathway activation are under the regulation of PrP(C) in asynchronous cells and following mitogenic stimulation. These effects are due in part to the modulation of epidermal growth factor receptor (EGFR) by PrP(C) in the plasma membrane, where the two proteins interact in a multimeric complex. We also describe how PrP(C) over-expression modulates filopodia formation by Rho GTPase regulation mainly in an AKT-Cdc42-N-WASP-dependent pathway.


Assuntos
Receptores ErbB/fisiologia , Neurônios/ultraestrutura , Proteínas PrPC/fisiologia , Western Blotting , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células , Forma Celular/fisiologia , Citometria de Fluxo , Imunofluorescência , Expressão Gênica , Inativação Gênica/efeitos dos fármacos , Humanos , Imunoprecipitação , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/fisiologia , Microdomínios da Membrana/fisiologia , Análise em Microsséries , Mitógenos/farmacologia , Neuritos/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Proteína Oncogênica v-akt/fisiologia , Proteínas PrPC/antagonistas & inibidores , Proteínas PrPC/genética , RNA Interferente Pequeno/farmacologia , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
13.
Int J Mol Sci ; 14(8): 15386-422, 2013 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-23887658

RESUMO

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides in length. LncRNAs are as diverse as mRNAs and they normally share the same biosynthetic machinery based on RNA polymerase II, splicing and polyadenylation. However, lncRNAs have low coding potential. Compared to mRNAs, lncRNAs are preferentially nuclear, more tissue specific and expressed at lower levels. Most of the lncRNAs described to date modulate the expression of specific genes by guiding chromatin remodelling factors; inducing chromosomal loopings; affecting transcription, splicing, translation or mRNA stability; or serving as scaffolds for the organization of cellular structures. They can function in cis, cotranscriptionally, or in trans, acting as decoys, scaffolds or guides. These functions seem essential to allow cell differentiation and growth. In fact, many lncRNAs have been shown to exert oncogenic or tumor suppressor properties in several cancers including haematological malignancies. In this review, we summarize what is known about lncRNAs, the mechanisms for their regulation in cancer and their role in leukemogenesis, lymphomagenesis and hematopoiesis. Furthermore, we discuss the potential of lncRNAs in diagnosis, prognosis and therapy in cancer, with special attention to haematological malignancies.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Hematológicas/genética , RNA Longo não Codificante/genética , Diferenciação Celular/genética , Genes Supressores de Tumor , Neoplasias Hematológicas/diagnóstico , Neoplasias Hematológicas/terapia , Hematopoese/genética , Humanos , RNA Longo não Codificante/biossíntese
14.
ACS Nano ; 17(23): 23331-23346, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37971502

RESUMO

Synthetic riboswitches are promising regulatory devices due to their small size, lack of immunogenicity, and ability to fine-tune gene expression in the absence of exogenous trans-acting factors. Based on a gene inhibitory system developed at our lab, termed U1snRNP interference (U1i), we developed tetracycline (TC)-inducible riboswitches that modulate mRNA polyadenylation through selective U1 snRNP recruitment. First, we engineered different TC-U1i riboswitches, which repress gene expression unless TC is added, leading to inductions of gene expression of 3-to-4-fold. Second, we developed a technique called Systematic Evolution of Riboswitches by Exponential Enrichment (SEREX), to isolate riboswitches with enhanced U1 snRNP binding capacity and activity, achieving inducibilities of up to 8-fold. Interestingly, by multiplexing riboswitches we increased inductions up to 37-fold. Finally, we demonstrated that U1i-based riboswitches are dose-dependent and reversible and can regulate the expression of reporter and endogenous genes in culture cells and mouse models, resulting in attractive systems for gene therapy applications. Our work probes SEREX as a much-needed technology for the in vitro identification of riboswitches capable of regulating gene expression in vivo.


Assuntos
Riboswitch , Animais , Camundongos , Riboswitch/genética , Ribonucleoproteína Nuclear Pequena U1/genética , Tetraciclina/farmacologia , Antibacterianos , Mamíferos/genética , Expressão Gênica
15.
Cell Rep ; 42(1): 111917, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36640344

RESUMO

The synapsis of DNA ends is a critical step for the repair of double-strand breaks by non-homologous end joining (NHEJ). This is performed by a multicomponent protein complex assembled around Ku70-Ku80 heterodimers and regulated by accessory factors, including long non-coding RNAs, through poorly understood mechanisms. Here, we use magnetic tweezers to investigate the contributions of core NHEJ proteins and APLF and lncRNA NIHCOLE to DNA synapsis. APLF stabilizes DNA end bridging and, together with Ku70-Ku80, establishes a minimal complex that supports DNA synapsis for several minutes under piconewton forces. We find the C-terminal acidic region of APLF to be critical for bridging. NIHCOLE increases the dwell time of the synapses by Ku70-Ku80 and APLF. This effect is further enhanced by a small and structured RNA domain within NIHCOLE. We propose a model where Ku70-Ku80 can simultaneously bind DNA, APLF, and structured RNAs to promote the stable joining of DNA ends.


Assuntos
RNA Longo não Codificante , RNA Longo não Codificante/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Autoantígeno Ku/genética , Autoantígeno Ku/metabolismo , Reparo do DNA por Junção de Extremidades , DNA/metabolismo , Reparo do DNA
16.
Biochim Biophys Acta ; 1809(11-12): 660-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21621026

RESUMO

Adenovirus infection has a tremendous impact on the cellular silencing machinery. Adenoviruses express high amounts of non-coding virus associated (VA) RNAs able to saturate key factors of the RNA interference (RNAi) processing pathway, such as Exportin 5 and Dicer. Furthermore, a proportion of VA RNAs is cleaved by Dicer into viral microRNAs (mivaRNAs) that can saturate Argonaute, an essential protein for miRNA function. Thus, processing and function of cellular miRNAs is blocked in adenoviral-infected cells. However, viral miRNAs actively target the expression of cellular genes involved in relevant functions such as cell proliferation, DNA repair or RNA regulation. Interestingly, the cellular silencing machinery is active at early times post-infection and can be used to control the adenovirus cell cycle. This is relevant for therapeutic purposes against adenoviral infections or when recombinant adenoviruses are used as vectors for gene therapy. Manipulation of the viral genome allows the use of adenoviral vectors to express therapeutic miRNAs or to be silenced by the RNAi machinery leading to safer vectors with a specific tropism. This article is part of a "Special Issue entitled:MicroRNAs in viral gene regulation".


Assuntos
Adenoviridae/genética , MicroRNAs/metabolismo , Adenoviridae/metabolismo , Animais , Reparo do DNA , Inativação Gênica , Genoma Viral , Humanos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , RNA Viral/metabolismo
17.
J Exp Med ; 203(13): 2809-15, 2006 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-17178916

RESUMO

Ischemia-reperfusion (I/R) liver injury occurs when blood flow is restored after prolonged ischemia. A short interruption of blood flow (ischemic preconditioning [IP]) induces tolerance to subsequent prolonged ischemia through ill-defined mechanisms. Cardiotrophin (CT)-1, a cytokine of the interleukin-6 family, exerts hepatoprotective effects and activates key survival pathways like JAK/STAT3. Here we show that administration of CT-1 to rats or mice protects against I/R liver injury and that CT-1-deficient mice are exceedingly sensitive to this type of damage. IP markedly reduced transaminase levels and abrogated caspase-3 and c-Jun-NH2-terminal kinase activation after I/R in normal mice but not in CT-1-null mice. Moreover, the protective effect afforded by IP was reduced by previous administration of neutralizing anti-CT-1 antibody. Prominent STAT3 phosphorylation in liver tissue was observed after IP plus I/R in normal mice but not in CT-1-null mice. Oxidative stress, a process involved in IP-induced hepatoprotection, was found to stimulate CT-1 release from isolated hepatocytes. Interestingly, brief ischemia followed by short reperfusion caused mild serum transaminase elevation and strong STAT3 activation in normal and IL-6-deficient mice, but failed to activate STAT3 and provoked marked hypertransaminasemia in CT-1-null animals. In conclusion, CT-1 is an essential endogenous defense of the liver against I/R and is a key mediator of the protective effect induced by IP.


Assuntos
Citocinas/fisiologia , Precondicionamento Isquêmico , Traumatismo por Reperfusão/metabolismo , Alanina Transaminase/sangue , Animais , Anticorpos/farmacologia , Aspartato Aminotransferases/sangue , Western Blotting , Caspase 3/metabolismo , Citocinas/genética , Citocinas/farmacologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/fisiologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Wistar , Proteínas Recombinantes/farmacologia , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologia , Fator de Transcrição STAT3/metabolismo , terc-Butil Hidroperóxido/farmacologia
18.
Stem Cells ; 29(11): 1661-71, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21948564

RESUMO

Many antitumor therapies affect rapidly dividing cells. However, tumor proliferation may be driven by cancer stem cells (CSCs), which divide slowly and are relatively resistant to cytotoxic drugs. Thus, many tumors may progress because CSCs are not sensitive to the treatment. In this work, we searched for target genes whose expression is involved in proliferation and chemoresistance of CSCs. Both of these processes could be controlled simultaneously by cell regulators such as microRNAs (miRNAs). Therefore, colonospheres with properties of CSCs were obtained from different colon carcinoma cells, and miRNA profiling was performed. The results showed that miR-451 was downregulated in colonspheres versus parental cells. Surprisingly, expression of miR-451 caused a decrease in self-renewal, tumorigenicity, and chemoresistance to irinotecan of colonspheres. We identified cyclooxygenase-2 (COX-2) as an indirect miR-451 target gene involved in sphere growth. Our results indicate that miR-451 downregulation allows the expression of the direct target gene macrophage migration inhibitory factor, involved in the expression of COX-2. In turn, COX-2 allows Wnt activation, which is essential for CSC growth. Furthermore, miR-451 restoration decreases expression of the ATP-binding cassette drug transporter ABCB1 and results in irinotecan sensitization. These findings correlate well with the lower expression of miR-451 observed in patients who did not respond to irinotecan-based first-line therapy compared with patients who did. Our data suggest that miR-451 is a novel candidate to circumvent recurrence and drug resistance in colorectal cancer and could be used as a marker to predict response to irinotecan in patients with colon carcinoma.


Assuntos
MicroRNAs/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Antineoplásicos/farmacologia , Western Blotting , Camptotecina/análogos & derivados , Camptotecina/farmacologia , Linhagem Celular , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Irinotecano , MicroRNAs/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
19.
Nucleic Acids Res ; 38(3): 750-63, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19933264

RESUMO

Adenovirus virus-associated (VA) RNAs are processed to functional viral miRNAs or mivaRNAs. mivaRNAs are important for virus production, suggesting that they may target cellular or viral genes that affect the virus cell cycle. To look for cellular targets of mivaRNAs, we first identified genes downregulated in the presence of VA RNAs by microarray analysis. These genes were then screened for mivaRNA target sites using several bioinformatic tools. The combination of microarray analysis and bioinformatics allowed us to select the splicing and translation regulator TIA-1 as a putative mivaRNA target. We show that TIA-1 is downregulated at mRNA and protein levels in infected cells expressing functional mivaRNAs and in transfected cells that express mivaRNAI-138, one of the most abundant adenoviral miRNAs. Also, reporter assays show that TIA-1 is downregulated directly by mivaRNAI-138. To determine whether mivaRNAs could target other cellular genes we analyzed 50 additional putative targets. Thirty of them were downregulated in infected or transfected cells expressing mivaRNAs. Some of these genes are important for cell growth, transcription, RNA metabolism and DNA repair. We believe that a mivaRNA-mediated fine tune of the expression of some of these genes could be important in adenovirus cell cycle.


Assuntos
MicroRNAs/metabolismo , Interferência de RNA , RNA Viral/metabolismo , Processos de Crescimento Celular , Linhagem Celular , Reparo do DNA , Regulação para Baixo , Expressão Gênica , Ensaios de Triagem em Larga Escala , Humanos , Proteínas de Ligação a Poli(A)/genética , Proteínas de Ligação a Poli(A)/metabolismo , RNA Mensageiro/metabolismo , Antígeno-1 Intracelular de Células T
20.
Front Immunol ; 13: 829335, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35860270

RESUMO

The study of the interferon (IFN) α-induced cell transcriptome has shown altered expression of several long non-coding RNAs (lncRNAs). ISR8/IRF1-AS1 (IFN stimulated RNA 8), located close to IFN regulatory factor 1 (IRF1) coding gene, transcribes a lncRNA induced at early times after IFNα treatment or IRF1 or NF-κB activation. Depletion or overexpression of ISR8 RNA does not lead to detected deregulation of the IFN response. Surprisingly, disruption of ISR8 locus with CRISPR-Cas9 genome editing results in cells that fail to induce several key ISGs and pro-inflammatory cytokines after a trigger with IFNα or overexpression of IRF1 or the NF-κB subunit RELA. This suggests that the ISR8 locus may play a relevant role in IFNα and NF-κB pathways. Interestingly, IFNα, IRFs and NF-κB-responding luciferase reporters are normally induced in ISR8-disrupted cells when expressed from a plasmid but not when integrated into the genome. Therefore, IFNα and NF-κB pathways are functional to induce the expression of exogenous episomic transcripts but fail to activate transcription from genomic promoters. Transcription from these promoters is not restored with silencing inhibitors, by decreasing the levels of several negative regulators or by overexpression of inducers. Transcriptome analyses indicate that ISR8-disrupted cells have a drastic increase in the levels of negative regulators such as XIST and Zinc finger proteins. Our results agree with ISR8 loci being an enhancer region that is fundamental for proper antiviral and proinflammatory responses. These results are relevant because several SNPs located in the ISR8 region are associated with chronic inflammatory and autoimmune diseases including Crohn's disease, inflammatory bowel disease, ulcerative colitis or asthma.


Assuntos
Interferon-alfa , NF-kappa B , Antivirais/farmacologia , Fator Regulador 1 de Interferon/genética , Fator Regulador 1 de Interferon/metabolismo , Interferon-alfa/metabolismo , NF-kappa B/metabolismo , RNA , Transdução de Sinais
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