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1.
J Virol ; 98(1): e0135023, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38169284

RESUMO

Epitranscriptomic RNA modifications can regulate the stability of mRNA and affect cellular and viral RNA functions. The N4-acetylcytidine (ac4C) modification in the RNA viral genome was recently found to promote viral replication; however, the mechanism by which RNA acetylation in the host mRNA regulates viral replication remains unclear. To help elucidate this mechanism, the roles of N-acetyltransferase 10 (NAT10) and ac4C during the infection and replication processes of the alphavirus, Sindbis virus (SINV), were investigated. Cellular NAT10 was upregulated, and ac4C modifications were promoted after alphavirus infection, while the loss of NAT10 or inhibition of its N-acetyltransferase activity reduced alphavirus replication. The NAT10 enhanced alphavirus replication as it helped to maintain the stability of lymphocyte antigen six family member E mRNA, which is a multifunctional interferon-stimulated gene that promotes alphavirus replication. The ac4C modification was thus found to have a non-conventional role in the virus life cycle through regulating host mRNA stability instead of viral mRNA, and its inhibition could be a potential target in the development of new alphavirus antivirals.IMPORTANCEThe role of N4-acetylcytidine (ac4C) modification in host mRNA and virus replication is not yet fully understood. In this study, the role of ac4C in the regulation of Sindbis virus (SINV), a prototype alphavirus infection, was investigated. SINV infection results in increased levels of N-acetyltransferase 10 (NAT10) and increases the ac4C modification level of cellular RNA. The NAT10 was found to positively regulate SINV infection in an N-acetyltransferase activity-dependent manner. Mechanistically, the NAT10 modifies lymphocyte antigen six family member E (LY6E) mRNA-the ac4C modification site within the 3'-untranslated region (UTR) of LY6E mRNA, which is essential for its translation and stability. The findings of this study demonstrate that NAT10 regulated mRNA stability and translation efficiency not only through the 5'-UTR or coding sequence but also via the 3'-UTR region. The ac4C modification of host mRNA stability instead of viral mRNA impacting the viral life cycle was thus identified, indicating that the inhibition of ac4C could be a potential target when developing alphavirus antivirals.


Assuntos
Infecções por Alphavirus , Antígenos de Superfície , Proteínas Ligadas por GPI , Acetiltransferases N-Terminal , Sindbis virus , Replicação Viral , Humanos , Infecções por Alphavirus/genética , Antígenos de Superfície/genética , Citidina/análogos & derivados , Proteínas Ligadas por GPI/genética , RNA Mensageiro/genética , Sindbis virus/fisiologia , Linhagem Celular , Acetiltransferases N-Terminal/genética , Estabilidade de RNA
2.
Virol J ; 21(1): 23, 2024 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243270

RESUMO

N6-methyladenosine (m6A) is present in diverse viral RNA and plays important regulatory roles in virus replication and host antiviral innate immunity. However, the role of m6A in regulating JEV replication has not been investigated. Here, we show that the JEV genome contains m6A modification upon infection of mouse neuroblast cells (neuro2a). JEV infection results in a decrease in the expression of m6A writer METTL3 in mouse brain tissue. METTL3 knockdown by siRNA leads to a substantial decrease in JEV replication and the production of progeny viruses at 48 hpi. Mechanically, JEV triggered a considerable increase in the innate immune response of METTL3 knockdown neuro2a cells compared to the control cells. Our study has revealed the distinctive m6A signatures of both the virus and host in neuro2a cells infected with JEV, illustrating the positive role of m6A modification in JEV infection. Our study further enhances understanding of the role of m6A modification in Flaviviridae viruses.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Animais , Camundongos , Vírus da Encefalite Japonesa (Espécie)/genética , Metiltransferases/genética , Metiltransferases/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Imunidade Inata , Replicação Viral/genética
3.
Org Biomol Chem ; 22(24): 4968-4972, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38825973

RESUMO

Visible light-induced aza-6π electrocyclization was developed for the synthesis of aza-arenes from nitroarenes with diverse aldehydes. This protocol allows the reduction of nitroarenes by B2nep2 and subsequent 6π-electrocyclization of the in situ formed imine under visible light. An array of 6- and multi-substituted phenanthridines were constructed in moderate to good yields under purple LEDs at room temperature. A wide scope of substrates with diverse functional groups were well tolerated. In addition, the synthetic utility of this methodology was further demonstrated in the late-stage functionalization of celecoxib.

4.
Org Biomol Chem ; 22(14): 2819-2823, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38511315

RESUMO

An efficient method was developed for the one-pot construction of C-B and C-I via visible light-induced transformation of nitroarenes. This protocol relies on the photochemical properties of nitroarenes under visible light, followed by reduction with B2pin2 and diazotization with tBuONO. An array of arylboronates and iodobenzenes were constructed smoothly after excitation with purple LEDs at room temperature. In addition, the synthetic utility of this method was further demonstrated in the late-stage modification of a drug molecule. The advantages of this strategy include metal-free system, mild reaction conditions and acceptable substrate scope.

5.
Mikrochim Acta ; 191(3): 143, 2024 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-38368295

RESUMO

An enzyme immunoassay was developed based on the coulometric measurement of immunoglobulin M (IgM) against Hantaan viruses (HTNV) by using virus-like particles (VLPs) as recognition molecules. The surface functionalization of screen-printed carbon electrodes (SPCEs) was achieved through paste-exfoliated graphene that was modified with a COOH group and a thionine mediator through supramolecular-covalent scaffolds, on SPCEs by using the binder contained in the ink. After the covalent immobilization of the antibody, the sensor was used for the sandwich enzyme immunoassay of IgM against HTNV. By using HTNV VLPs as the second recognization molecules, the resulting sensor efficiently monitored the reaction of IgM against HTNV and anti-IgM antibody with high specificity. By attaching HTNV nucleocapsid protein antibody conjugate with horseradish peroxidase (HRP) onto VLPs, the signal response of the assay was derived from the coulometric measurement of H2O2 reduction mediated by thionine on the electrode surface after the application of a potential (- 0.2 V vs. Ag/AgCl). The ratio of charges measured before or after H2O2 addition was used to quantify IgM because these charges could be used as background charges or total charges, respectively. The ratio exhibited good agreement with IgM concentration within a range 0.1 to 1000 pg mL-1, and a detection limit of 0.06 pg mL-1 was obtained. The assay demonstrated high sensitivity and specificity toward HTNV-specific IgM in serum.


Assuntos
Técnicas Biossensoriais , Grafite , Fenotiazinas , Grafite/química , Carbono/química , Imunoensaio/métodos , Técnicas Biossensoriais/métodos , Peróxido de Hidrogênio/química , Imunoglobulina M , Eletrodos
6.
J Virol ; 96(3): e0171321, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-34787453

RESUMO

Rift Valley fever virus (RVFV) belongs to the order Bunyavirales and is the type species of genus Phlebovirus, which accounts for over 50% of family Phenuiviridae species. RVFV is mosquito-borne and causes severe diseases in both humans and livestock, and consists of three segments (S, M, L) in the genome. The L segment encodes an RNA-dependent RNA polymerase (RdRp, L protein) that is responsible for facilitating the replication and transcription of the virus. It is essential for the virus and has multiple drug targets. Here, we established an expression system and purification procedures for full-length L protein, which is composed of an endonuclease domain, RdRp domain, and cap-binding domain. A cryo-EM L protein structure was reported at 3.6 Å resolution. In this first L protein structure of genus Phlebovirus, the priming loop of RVFV L protein is distinctly different from those of other L proteins and undergoes large movements related to its replication role. Structural and biochemical analyses indicate that a single template can induce initiation of RNA synthesis, which is notably enhanced by 5' viral RNA. These findings help advance our understanding of the mechanism of RNA synthesis and provide an important basis for developing antiviral inhibitors. IMPORTANCE The zoonosis RVF virus (RVFV) is one of the most serious arbovirus threats to both human and animal health. RNA-dependent RNA polymerase (RdRp) is a multifunctional enzyme catalyzing genome replication as well as viral transcription, so the RdRp is essential for studying the virus and has multiple drug targets. In our study, we report the structure of RVFV L protein at 3.6 Å resolution by cryo-EM. This is the first L protein structure of genus Phlebovirus. Strikingly, a single template can initiate RNA replication. The structure and assays provide a comprehensive and in-depth understanding of the catalytic and substrate recognition mechanism of RdRp.


Assuntos
Modelos Moleculares , Conformação Proteica , RNA Polimerase Dependente de RNA/química , Vírus da Febre do Vale do Rift/enzimologia , Motivos de Aminoácidos , Domínio Catalítico , Fenômenos Químicos , Sequência Conservada , Microscopia Crioeletrônica , Domínios e Motivos de Interação entre Proteínas , RNA Polimerase Dependente de RNA/metabolismo , Proteínas Recombinantes de Fusão , Proteínas Virais/química
7.
J Org Chem ; 88(7): 4345-4351, 2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-36898142

RESUMO

Direct C-H amidation of α-ketoesters was accomplished using various organic azides as the amino source through the combination of transient directing group strategy and iridium catalysis. Excellent functional group tolerance and wide substrate scope were explored under simple and mild conditions. Importantly, it was found that the steric hindrance of the ester moiety played a pivotal role for the reaction efficacy. In addition, the reaction could be enlarged to gram scale, and several useful heterocycles were readily constructed via one-step late-stage derivatization.

8.
Nucleic Acids Res ; 49(15): 8556-8572, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34329471

RESUMO

Dysfunction of Tumour Suppressor Genes (TSGs) is a common feature in carcinogenesis. Epigenetic abnormalities including DNA hypermethylation or aberrant histone modifications in promoter regions have been described for interpreting TSG inactivation. However, in many instances, how TSGs are silenced in tumours are largely unknown. Given that miRNA with low expression in tumours is another recognized signature, we hypothesize that low expression of miRNA may reduce the activity of TSG related enhancers and further lead to inactivation of TSG during cancer development. Here, we reported that low expression of miRNA in cancer as a recognized signature leads to loss of function of TSGs in breast cancer. In 157 paired breast cancer and adjacent normal samples, tumour suppressor gene GPER1 and miR-339 are both downregulated in Luminal A/B and Triple Negative Breast Cancer subtypes. Mechanistic investigations revealed that miR-339 upregulates GPER1 expression in breast cancer cells by switching on the GPER1 enhancer, which can be blocked by enhancer deletion through the CRISPR/Cas9 system. Collectively, our findings reveal novel mechanistic insights into TSG dysfunction in cancer development, and provide evidence that reactivation of TSG by enhancer switching may be a promising alternative strategy for clinical breast cancer treatment.


Assuntos
Neoplasias da Mama/genética , Metilação de DNA/genética , MicroRNAs/genética , Receptores de Estrogênio/genética , Receptores Acoplados a Proteínas G/genética , Proteínas Supressoras de Tumor/genética , Neoplasias da Mama/patologia , Carcinogênese/genética , Elementos Facilitadores Genéticos/genética , Epigenômica , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Inativação Gênica , Humanos , Regiões Promotoras Genéticas/genética , RNA Neoplásico/genética , Sequências Reguladoras de Ácido Nucleico/genética
9.
Int J Mol Sci ; 24(19)2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37834012

RESUMO

Triple-negative breast cancer (TNBC) is the most fatal subtype of breast cancer; however, effective treatment strategies for TNBC are lacking. Therefore, it is important to explore the mechanism of TNBC metastasis and identify its therapeutic targets. Dysregulation of ETHE1 leads to ethylmalonic encephalopathy in humans; however, the role of ETHE1 in TNBC remains elusive. Stable cell lines with ETHE1 overexpression or knockdown were constructed to explore the biological functions of ETHE1 during TNBC progression in vitro and in vivo. Mass spectrometry was used to analyze the molecular mechanism through which ETHE1 functions in TNBC progression. ETHE1 had no impact on TNBC cell proliferation and xenograft tumor growth but promoted TNBC cell migration and invasion in vitro and lung metastasis in vivo. The effect of ETHE1 on TNBC cell migratory potential was independent of its enzymatic activity. Mechanistic investigations revealed that ETHE1 interacted with eIF2α and enhanced its phosphorylation by promoting the interaction between eIF2α and GCN2. Phosphorylated eIF2α in turn upregulated the expression of ATF4, a transcriptional activator of genes involved in cell migration and tumor metastasis. Notably, inhibition of eIF2α phosphorylation through ISRIB or ATF4 knockdown partially abolished the tumor-promoting effect of ETHE1 overexpression. ETHE1 has a functional and mechanistic role in TNBC metastasis and offers a new therapeutic strategy for targeting ETHE1-propelled TNBC using ISRIB.


Assuntos
Neoplasias de Mama Triplo Negativas , Humanos , Neoplasias de Mama Triplo Negativas/patologia , Fator de Iniciação 2 em Eucariotos/metabolismo , Linhagem Celular Tumoral , Transdução de Sinais , Proliferação de Células/genética , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Mitocondriais/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo
10.
Cell Commun Signal ; 20(1): 127, 2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-35986334

RESUMO

BACKGROUND: N-acetyltransferase 10 (NAT10), an abundant nucleolar protein with both lysine and RNA cytidine acetyltransferase activities, has been implicated in Hutchinson-Gilford progeria syndrome and human cancer. We and others recently demonstrated that NAT10 is translocated from the nucleolus to the nucleoplasm after DNA damage, but the underlying mechanism remains unexplored. METHODS: The NAT10 and PARP1 knockout (KO) cell lines were generated using CRISPR-Cas9 technology. Knockdown of PARP1 was performed using specific small interfering RNAs targeting PARP1. Cells were irradiated with γ-rays using a 137Cs Gammacell-40 irradiator and subjected to clonogenic survival assays. Co-localization and interaction between NAT10 and MORC2 were examined by immunofluorescent staining and immunoprecipitation assays, respectively. PARylation of NAT10 and translocation of NAT10 were determined by in vitro PARylation assays and immunofluorescent staining, respectively. RESULTS: Here, we provide the first evidence that NAT10 underwent covalent PARylation modification following DNA damage, and poly (ADP-ribose) polymerase 1 (PARP1) catalyzed PARylation of NAT10 on three conserved lysine (K) residues (K1016, K1017, and K1020) within its C-terminal nucleolar localization signal motif (residues 983-1025). Notably, mutation of those three PARylation residues on NAT10, pharmacological inhibition of PARP1 activity, or depletion of PARP1 impaired NAT10 nucleoplasmic translocation after DNA damage. Knockdown or inhibition of PARP1 or expression of a PARylation-deficient mutant NAT10 (K3A) attenuated the co-localization and interaction of NAT10 with MORC family CW-type zinc finger 2 (MORC2), a newly identified chromatin-remodeling enzyme involved in DNA damage response, resulting in a decrease in DNA damage-induced MORC2 acetylation at lysine 767. Consequently, expression of a PARylation-defective mutant NAT10 resulted in enhanced cellular sensitivity to DNA damage agents. CONCLUSION: Collectively, these findings indicate that PARP1-mediated PARylation of NAT10 is key for controlling its nucleoplasmic translocation and function in response to DNA damage. Moreover, our findings provide novel mechanistic insights into the sophisticated paradigm of the posttranslational modification-driven cellular response to DNA damage. Video Abstract.


Assuntos
Acetiltransferases , Poli ADP Ribosilação , Núcleo Celular , Dano ao DNA , Humanos , Lisina , Acetiltransferases N-Terminal , Poli(ADP-Ribose) Polimerase-1/genética , Fatores de Transcrição
11.
J Org Chem ; 87(16): 10807-10814, 2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-35921192

RESUMO

An expeditious construction of an unsymmetrical tertiary 9-fluorenol skeleton was accomplished starting from readily available α-ketoester and aryl iodide. Inexpensive commercially available substituted aniline was utilized as a potent monodentate transient directing group (TDG) to assist palladium-catalyzed direct ortho-C-H arylation and tandem dual C-H activation of α-ketoesters to form two carbon-carbon bonds. To demonstrate practical applications, the reaction was enlarged to the gram scale, and subsequent one-step derivatization allowed facile access to structurally diversified useful derivatives. A series of control experiments were carried out to shed light on the possible catalytic mechanism.


Assuntos
Carbono , Paládio , Carbono/química , Catálise , Estrutura Molecular , Paládio/química
12.
Nucleic Acids Res ; 48(7): 3638-3656, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32112098

RESUMO

MORC family CW-type zinc finger 2 (MORC2) is an oncogenic chromatin-remodeling enzyme with an emerging role in DNA repair. Here, we report a novel function for MORC2 in cell-cycle checkpoint control through an acetylation-dependent mechanism. MORC2 is acetylated by the acetyltransferase NAT10 at lysine 767 (K767Ac) and this process is counteracted by the deacetylase SIRT2 under unperturbed conditions. DNA-damaging chemotherapeutic agents and ionizing radiation stimulate MORC2 K767Ac through enhancing the interaction between MORC2 and NAT10. Notably, acetylated MORC2 binds to histone H3 phosphorylation at threonine 11 (H3T11P) and is essential for DNA damage-induced reduction of H3T11P and transcriptional repression of its downstream target genes CDK1 and Cyclin B1, thus contributing to DNA damage-induced G2 checkpoint activation. Chemical inhibition or depletion of NAT10 or expression of an acetylation-defective MORC2 (K767R) forces cells to pass through G2 checkpoint, resulting in hypersensitivity to DNA-damaging agents. Moreover, MORC2 acetylation levels are associated with elevated NAT10 expression in clinical breast tumor samples. Together, these findings uncover a previously unrecognized role for MORC2 in regulating DNA damage-induced G2 checkpoint through NAT10-mediated acetylation and provide a potential therapeutic strategy to sensitize breast cancer cells to DNA-damaging chemotherapy and radiotherapy by targeting NAT10.


Assuntos
Neoplasias da Mama/enzimologia , Dano ao DNA , Pontos de Checagem da Fase G2 do Ciclo Celular , Acetiltransferases N-Terminal/metabolismo , Fatores de Transcrição/metabolismo , Acetilação , Antineoplásicos , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Proteína Quinase CDC2/genética , Proteína Quinase CDC2/metabolismo , Linhagem Celular Tumoral , Ciclina B1/genética , Ciclina B1/metabolismo , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Histonas/metabolismo , Humanos , Lisina/metabolismo , Radiação Ionizante , Sirtuína 2/metabolismo , Fatores de Transcrição/química
13.
Int J Mol Sci ; 23(21)2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36361605

RESUMO

ATP-dependent chromatin-remodeling complexes can reorganize and remodel chromatin and thereby act as important regulator in various cellular processes. Based on considerable studies over the past two decades, it has been confirmed that the abnormal function of chromatin remodeling plays a pivotal role in genome reprogramming for oncogenesis in cancer development and/or resistance to cancer therapy. Recently, exciting progress has been made in the identification of genetic alteration in the genes encoding the chromatin-remodeling complexes associated with tumorigenesis, as well as in our understanding of chromatin-remodeling mechanisms in cancer biology. Here, we present preclinical evidence explaining the signaling mechanisms involving the chromatin-remodeling misregulation-induced cancer cellular processes, including DNA damage signaling, metastasis, angiogenesis, immune signaling, etc. However, even though the cumulative evidence in this field provides promising emerging molecules for therapeutic explorations in cancer, more research is needed to assess the clinical roles of these genetic cancer targets.


Assuntos
Montagem e Desmontagem da Cromatina , Neoplasias , Humanos , Cromatina/genética , Fatores de Transcrição/metabolismo , Dano ao DNA , Neoplasias/tratamento farmacológico , Neoplasias/genética
14.
J Cell Mol Med ; 25(22): 10663-10673, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34698450

RESUMO

The proliferation of pulmonary artery smooth muscle cells (PASMCs) is an important cause of pulmonary vascular remodelling in hypoxia-induced pulmonary hypertension (HPH). However, its underlying mechanism has not been well elucidated. Connexin 43 (Cx43) plays crucial roles in vascular smooth muscle cell proliferation in various cardiovascular diseases. Here, the male Sprague-Dawley (SD) rats were exposed to hypoxia (10% O2 ) for 21 days to induce rat HPH model. PASMCs were treated with CoCl2 (200 µM) for 24 h to establish the HPH cell model. It was found that hypoxia up-regulated the expression of Cx43 and phosphorylation of Cx43 at Ser 368 in rat pulmonary arteries and PASMCs, and stimulated the proliferation and migration of PASMCs. HIF-1α inhibitor echinomycin attenuated the CoCl2 -induced Cx43 expression and phosphorylation of Cx43 at Ser 368 in PASMCs. The interaction between HIF-1α and Cx43 promotor was also identified using chromatin immunoprecipitation assay. Moreover, Cx43 specific blocker (37,43 Gap27) or knockdown of Cx43 efficiently alleviated the proliferation and migration of PASMCs under chemically induced hypoxia. Therefore, the results above suggest that HIF-1α, as an upstream regulator, promotes the expression of Cx43, and the HIF-1α/Cx43 axis regulates the proliferation and migration of PASMCs in HPH.


Assuntos
Conexina 43/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Miócitos de Músculo Liso/metabolismo , Animais , Proliferação de Células , Células Cultivadas , Conexina 43/agonistas , Conexina 43/genética , Hipóxia/genética , Hipóxia/metabolismo , Imuno-Histoquímica , Modelos Biológicos , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Fosforilação , Regiões Promotoras Genéticas , Ligação Proteica , Artéria Pulmonar/citologia , Artéria Pulmonar/metabolismo , Ratos
15.
J Org Chem ; 86(23): 17244-17248, 2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34807586

RESUMO

The development of a novel environmental benign and sustainable synthetic method for highly efficient construction and direct C-H functionalization of N-heterocycles remains a pivotal central research topic for organic and medicinal chemistry. Herein, a novel visible-light-enabled biomimetic aza-6π electrocyclization for efficient assembly of diverse pyridines and further tandem Minisci-type reaction were developed. A broad spectrum of polysubstituted picolinaldehydes were readily constructed with high efficacy and good functional group tolerance under metal- and oxidant-free conditions.


Assuntos
Luz , Piridinas , Catálise , Metais
16.
Ecotoxicol Environ Saf ; 226: 112825, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34571421

RESUMO

As an essential plant micronutrient, copper (Cu) is required as a component of several enzymes, but it can be highly toxic to plants when present in excess quantities. Nitrogen (N) application can help to alleviate the phytotoxic effects of heavy metals, including Cu, and different N forms significantly affect the uptake and accumulation of heavy metals in plants. The aim of this study was to determine the effects of different N forms, i.e., ammonium (NH4+) and nitrate (NO3-), on Cu detoxification in wheat seedlings. The inhibition of seedling growth under excess Cu was more obvious in wheat plants supplied with NO3- than in those supplied with NH4+. This growth inhibition was directly induced by excess Cu accumulation and reduced absorption of other mineral nutrients by the plants. Compared with seedlings treated with NO3-, those treated with NH4+ showed a decrease in Cu-induced toxicity as a result of increased antioxidant capacity in the leaves and a lower redox potential in the rhizosphere. Furthermore, treatment with NH4+ decreased the loss of mineral nutrients in wheat seedlings exposed to excess Cu. In conclusion, compared with supplying NO3-, supplying NH4+ to wheat seedlings under Cu stress improved their ability to maintain their nutritional and redox balance and increased their antioxidant capacity, thereby preventing a decline in photosynthesis. According to our results, NH4+ is more effective than NO3- in reducing Cu phytotoxicity in wheat seedlings.


Assuntos
Compostos de Amônio , Plântula , Cobre/toxicidade , Homeostase , Nitratos/toxicidade , Nitrogênio , Oxirredução , Fotossíntese , Raízes de Plantas , Triticum
17.
Biochem Biophys Res Commun ; 527(1): 297-304, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32446384

RESUMO

During replication, numerous viral RNAs are modified by N6-methyladenosine (m6A), the most abundant internal RNA modification. m6A is believed to regulate elements of RNA metabolism, such as splicing, stability, translation, secondary structure formation, and viral replication. In this study, we assessed the occurrence of m6A modification of the EV71 genome in human cells and revealed a preferred, conserved modification site across diverse viral strains. A single m6A modification at the 5' UTR-VP4 junction was shown to perform a protranslational function. Depletion of the METTL3 methyltransferase or treatment with 3-deazaadenosine significantly reduced EV71 replication. Specifically, METTL3 colocalized with the viral dsRNA replication intermediate in the cytoplasm during EV71 infection. As a nuclear resident protein, METTL3 relies on the binding of the nuclear import protein karyopherin to its nuclear localization signal (NLS) for nuclear translocation. We observed that EV71 2A and METTL3 share nuclear import proteins. The results of this study revealed an inner mechanism by which EV71 2A regulates the subcellular location of METTL3 to amplify its own gene expression, providing an increased understanding of RNA epitranscriptomics during the EV71 replication cycle.


Assuntos
Adenosina/análogos & derivados , Citoplasma/metabolismo , Enterovirus Humano A/efeitos dos fármacos , Metiltransferases/metabolismo , Adenosina/farmacologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Enterovirus Humano A/genética , Enterovirus Humano A/metabolismo , Humanos , Metilação/efeitos dos fármacos , Estrutura Molecular , RNA Viral/efeitos dos fármacos , RNA Viral/genética , RNA Viral/metabolismo , Relação Estrutura-Atividade
18.
Virol J ; 17(1): 146, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33028368

RESUMO

BACKGROUND: An effective vaccine that prevents disease caused by hantaviruses is a global public health priority, but up to now, no vaccine has been approved for worldwide use. Therefore, novel vaccines with high prophylaxis efficacy are urgently needed. METHODS: Herein, we designed and synthesized Hantaan virus (HTNV) linear multi-epitope peptide consisting of HLA-A*02-restricted HTNV cytotoxic T cell (CTL) epitope and pan HLA-DR-binding epitope (PADRE), and evaluated the immunogenicity, as well as effectiveness, of multi-epitope peptides in HLA-A2.1/Kb transgenic mice with interferon (IFN)-γ enzyme-linked immunospot assay, cytotoxic mediator detection, proliferation assay and HTNV-challenge test. RESULTS: The results showed that a much higher frequency of specific IFN-γ-secreting CTLs, high levels of granzyme B production, and a strong proliferation capacity of specific CTLs were observed in splenocytes of mice immunized with multi-epitope peptide than in those of a single CTL epitope. Moreover, pre-immunization of multi-epitope peptide could reduce the levels of HTNV RNA loads in the liver, spleen and kidneys of mice, indicating that specific CTL responses induced by multi-epitope peptide could reduce HTNV RNA loads in vivo. CONCLUSIONS: This study may provide an important foundation for the development of novel peptide vaccines for HTNV prophylaxis.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/imunologia , Antígeno HLA-A2/genética , Antígeno HLA-A2/imunologia , Vírus Hantaan/imunologia , Febre Hemorrágica com Síndrome Renal/prevenção & controle , Vacinas Antimaláricas/imunologia , Animais , Antígenos Virais/genética , Antígenos Virais/imunologia , Epitopos de Linfócito T/genética , Vírus Hantaan/genética , Imunização , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/genética , Masculino , Camundongos , Camundongos Transgênicos , Linfócitos T Citotóxicos/imunologia , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologia
19.
J Org Chem ; 84(20): 13104-13111, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31497964

RESUMO

Commercially available 3,5-bis(trifluoromethyl)aniline was found to be a highly efficient monodentate transient directing group (MonoTDG) for the palladium-catalyzed direct dehydrogenative cross-coupling of benzaldehydes with arenes. A diverse set of symmetrical and unsymmetrical 9-fluorenones was readily obtained in yields of 32-72% along with excellent regioselectivities and broad functional group compatibility as well as high atom economy under mild conditions via a dual carbon-hydrogen (C-H) bond activation sequence.

20.
J Virol ; 91(9)2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28202761

RESUMO

Hantavirus infection, which causes zoonotic diseases with a high mortality rate in humans, has long been a global public health concern. Over the past decades, accumulating evidence suggests that long noncoding RNAs (lncRNAs) play key regulatory roles in innate immunity. However, the involvement of host lncRNAs in hantaviral control remains uncharacterized. In this study, we identified the lncRNA NEAT1 as a vital antiviral modulator. NEAT1 was dramatically upregulated after Hantaan virus (HTNV) infection, whereas its downregulation in vitro or in vivo delayed host innate immune responses and aggravated HTNV replication. Ectopic expression of NEAT1 enhanced beta interferon (IFN-ß) production and suppressed HTNV infection. Further investigation suggested that NEAT1 served as positive feedback for RIG-I signaling. HTNV infection activated NEAT1 transcription through the RIG-I-IRF7 pathway, whereas NEAT1 removed the transcriptional inhibitory effects of the splicing factor proline- and glutamine-rich protein (SFPQ) by relocating SFPQ to paraspeckles, thus promoting the expression of RIG-I and DDX60. RIG-I and DDX60 had synergic effects on IFN production. Taken together, our findings demonstrate that NEAT1 modulates the innate immune response against HTNV infection, providing another layer of information about the role of lncRNAs in controlling viral infections.IMPORTANCE Hantaviruses have attracted worldwide attention as archetypal emerging pathogens. Recently, increasing evidence has highlighted long noncoding RNAs (lncRNAs) as key regulators of innate immunity; however, their roles in hantavirus infection remain unknown. In the present work, a new unexplored function of lncRNA NEAT1 in controlling HTNV replication was found. NEAT1 promoted interferon (IFN) responses by acting as positive feedback for RIG-I signaling. This lncRNA was induced by HTNV through the RIG-I-IRF7 pathway in a time- and dose-dependent manner and promoted HTNV-induced IFN production by facilitating RIG-I and DDX60 expression. Intriguingly, NEAT1 relocated SFPQ and formed paraspeckles after HTNV infection, which might reverse inhibitive effects of SFPQ on the transcription of RIG-I and DDX60. To the best of our knowledge, this is the first study to address the regulatory role of the lncRNA NEAT1 in host innate immunity after HTNV infection. In summary, our findings provide additional insights regarding the role of lncRNAs in controlling viral infections.


Assuntos
Proteína DEAD-box 58/metabolismo , Vírus Hantaan/genética , Vírus Hantaan/imunologia , Infecções por Hantavirus/imunologia , Imunidade Inata/genética , RNA Longo não Codificante/genética , Células A549 , Animais , Linhagem Celular Tumoral , Chlorocebus aethiops , RNA Helicases DEAD-box/metabolismo , Células HEK293 , Vírus Hantaan/crescimento & desenvolvimento , Infecções por Hantavirus/virologia , Células HeLa , Células Endoteliais da Veia Umbilical Humana , Humanos , Interferon beta/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator de Processamento Associado a PTB/metabolismo , Interferência de RNA , RNA Longo não Codificante/biossíntese , RNA Interferente Pequeno/genética , Receptores Imunológicos , Transdução de Sinais/genética , Células Vero , Replicação Viral/genética
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