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1.
Cell ; 164(5): 974-84, 2016 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-26919432

RESUMO

Piwi-interacting RNAs (piRNAs) engage Piwi proteins to suppress transposons and are essential for fertility in diverse organisms. An interesting feature of piRNAs is that, while piRNA lengths are stereotypical within a species, they can differ widely between species. For example, piRNAs are mainly 29 and 30 nucleotides in humans, 24 to 30 nucleotides in D. melanogaster, and uniformly 21 nucleotides in C. elegans. However, how piRNA length is determined and whether length impacts function remains unknown. Here, we show that C. elegans deficient for PARN-1, a conserved RNase, accumulate untrimmed piRNAs with 3' extensions. Surprisingly, these longer piRNAs are stable and associate with the Piwi protein PRG-1 but fail to robustly recruit downstream silencing factors. Our findings identify PARN-1 as a key regulator of piRNA length in C. elegans and suggest that length is regulated to promote efficient transcriptome surveillance.


Assuntos
Caenorhabditis elegans/metabolismo , Exorribonucleases/metabolismo , Processamento Pós-Transcricional do RNA , Sequência de Aminoácidos , Animais , Proteínas Argonautas/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Exorribonucleases/química , Redes e Vias Metabólicas , Dados de Sequência Molecular , Mutação , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência , Transcriptoma
2.
Mol Cell ; 81(4): 845-858.e8, 2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33406384

RESUMO

Mammalian genomes contain long domains with distinct average compositions of A/T versus G/C base pairs. In a screen for proteins that might interpret base composition by binding to AT-rich motifs, we identified the stem cell factor SALL4, which contains multiple zinc fingers. Mutation of the domain responsible for AT binding drastically reduced SALL4 genome occupancy and prematurely upregulated genes in proportion to their AT content. Inactivation of this single AT-binding zinc-finger cluster mimicked defects seen in Sall4 null cells, including precocious differentiation of embryonic stem cells (ESCs) and embryonic lethality in mice. In contrast, deletion of two other zinc-finger clusters was phenotypically neutral. Our data indicate that loss of pluripotency is triggered by downregulation of SALL4, leading to de-repression of a set of AT-rich genes that promotes neuronal differentiation. We conclude that base composition is not merely a passive byproduct of genome evolution and constitutes a signal that aids control of cell fate.


Assuntos
Composição de Bases , Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Neurônios/metabolismo , Fatores de Transcrição/metabolismo , Animais , Linhagem Celular , Proteínas de Ligação a DNA/genética , Regulação para Baixo , Camundongos , Camundongos Mutantes , Células-Tronco Embrionárias Murinas/citologia , Mutação , Neurônios/citologia , Fatores de Transcrição/genética , Regulação para Cima , Dedos de Zinco
3.
Cell ; 150(1): 78-87, 2012 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-22738724

RESUMO

Piwi Argonautes and Piwi-interacting RNAs (piRNAs) mediate genome defense by targeting transposons. However, many piRNA species lack obvious sequence complementarity to transposons or other loci; only one C. elegans transposon is a known piRNA target. Here, we show that, in mutants lacking the Piwi Argonaute PRG-1 (and consequently its associated piRNAs/21U-RNAs), many silent loci in the germline exhibit increased levels of mRNA expression with a concomitant depletion of RNA-dependent RNA polymerase (RdRP)-derived secondary small RNAs termed 22G-RNAs. Sequences depleted of 22G-RNAs are proximal to potential target sites that base pair imperfectly but extensively to 21U-RNAs. We show that PRG-1 is required to initiate, but not to maintain, silencing of transgenes engineered to contain complementarity to endogenous 21U-RNAs. Our findings support a model in which C. elegans piRNAs utilize their enormous repertoire of targeting capacity to scan the germline transcriptome for foreign sequences, while endogenous germline-expressed genes are actively protected from piRNA-induced silencing.


Assuntos
Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Genoma Helmíntico , RNA de Helmintos/metabolismo , RNA Interferente Pequeno/metabolismo , Animais , Proteínas Argonautas/metabolismo , Inativação Gênica , Células Germinativas
4.
Cell ; 151(7): 1488-500, 2012 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-23260138

RESUMO

Piwi-interacting (pi) RNAs are germline-expressed small RNAs linked to epigenetic programming. C. elegans piRNAs are thought to be transcribed as independent gene-like loci. To test this idea and to identify potential transcription start (TS) sites for piRNA precursors, we developed CapSeq, an efficient enzymatic method for 5' anchored RNA profiling. Using CapSeq, we identify candidate TS sites, defined by 70-90 nt sequence tags, for >50% of annotated Pol II loci. Surprisingly, however, these CapSeq tags failed to identify the overwhelming majority of piRNA loci. Instead, we show that the likely piRNA precursors are ∼26 nt capped small (cs) RNAs that initiate precisely 2 nt upstream of mature piRNAs and that piRNA processing or stability requires a U at the csRNA +3 position. Finally, we identify a heretofore unrecognized class of piRNAs processed from csRNAs that are expressed at promoters genome wide, nearly doubling the number of piRNAs available for genome surveillance.


Assuntos
Caenorhabditis elegans/genética , Perfilação da Expressão Gênica/métodos , Capuzes de RNA/genética , Processamento Pós-Transcricional do RNA , RNA de Helmintos/genética , RNA Interferente Pequeno/genética , Sítio de Iniciação de Transcrição , Animais , Proteínas Argonautas/metabolismo , Caenorhabditis elegans/metabolismo , Estudo de Associação Genômica Ampla , Camundongos , Motivos de Nucleotídeos , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo
5.
Cell ; 150(1): 65-77, 2012 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-22738726

RESUMO

Organisms employ a fascinating array of strategies to silence invasive nucleic acids such as transposons and viruses. Although evidence exists for several pathways that detect foreign sequences, including pathways that sense copy number, unpaired DNA, or aberrant RNA (e.g., dsRNA), in many cases, the mechanisms used to distinguish "self" from "nonself" nucleic acids remain mysterious. Here, we describe an RNA-induced epigenetic silencing pathway that permanently silences single-copy transgenes. We show that the Piwi Argonaute PRG-1 and its genomically encoded piRNA cofactors initiate permanent silencing, and maintenance depends on chromatin factors and the WAGO Argonaute pathway. Our findings support a model in which PRG-1 scans for foreign sequences and two other Argonaute pathways serve as epigenetic memories of "self" and "nonself" RNAs. These findings suggest how organisms can utilize RNAi-related mechanisms to detect foreign sequences not by any molecular signature, but by comparing the foreign sequence to a memory of previous gene expression.


Assuntos
Caenorhabditis elegans/genética , Epigenômica , RNA de Helmintos/metabolismo , RNA Interferente Pequeno/metabolismo , Animais , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Inativação Gênica , Células Germinativas/metabolismo , Interferência de RNA
6.
EMBO Rep ; 25(3): 1130-1155, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38291337

RESUMO

The correct establishment of DNA methylation patterns is vital for mammalian development and is achieved by the de novo DNA methyltransferases DNMT3A and DNMT3B. DNMT3B localises to H3K36me3 at actively transcribing gene bodies via its PWWP domain. It also functions at heterochromatin through an unknown recruitment mechanism. Here, we find that knockout of DNMT3B causes loss of methylation predominantly at H3K9me3-marked heterochromatin and that DNMT3B PWWP domain mutations or deletion result in striking increases of methylation in H3K9me3-marked heterochromatin. Removal of the N-terminal region of DNMT3B affects its ability to methylate H3K9me3-marked regions. This region of DNMT3B directly interacts with HP1α and facilitates the bridging of DNMT3B with H3K9me3-marked nucleosomes in vitro. Our results suggest that DNMT3B is recruited to H3K9me3-marked heterochromatin in a PWWP-independent manner that is facilitated by the protein's N-terminal region through an interaction with a key heterochromatin protein. More generally, we suggest that DNMT3B plays a role in DNA methylation homeostasis at heterochromatin, a process which is disrupted in cancer, aging and Immunodeficiency, Centromeric Instability and Facial Anomalies (ICF) syndrome.


Assuntos
Metilação de DNA , Face/anormalidades , Heterocromatina , Doenças da Imunodeficiência Primária , Animais , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA Metiltransferase 3A , Mutação , Mamíferos/genética , Mamíferos/metabolismo
7.
Mol Cell ; 71(4): 606-620.e7, 2018 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-30118680

RESUMO

Metformin has been reported to possess antitumor activity and maintain high cytotoxic T lymphocyte (CTL) immune surveillance. However, the functions and detailed mechanisms of metformin's role in cancer immunity are not fully understood. Here, we show that metformin increases CTL activity by reducing the stability and membrane localization of programmed death ligand-1 (PD-L1). Furthermore, we discover that AMP-activated protein kinase (AMPK) activated by metformin directly phosphorylates S195 of PD-L1. S195 phosphorylation induces abnormal PD-L1 glycosylation, resulting in its ER accumulation and ER-associated protein degradation (ERAD). Consistently, tumor tissues from metformin-treated breast cancer patients exhibit reduced PD-L1 levels with AMPK activation. Blocking the inhibitory signal of PD-L1 by metformin enhances CTL activity against cancer cells. Our findings identify a new regulatory mechanism of PD-L1 expression through the ERAD pathway and suggest that the metformin-CTLA4 blockade combination has the potential to increase the efficacy of immunotherapy.


Assuntos
Antineoplásicos/farmacologia , Antígeno B7-H1/genética , Antígeno CTLA-4/genética , Regulação Neoplásica da Expressão Gênica , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/imunologia , Animais , Antígeno B7-H1/imunologia , Antígeno CTLA-4/imunologia , Linhagem Celular Tumoral , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Degradação Associada com o Retículo Endoplasmático , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Feminino , Glicosilação , Humanos , Glândulas Mamárias Humanas/citologia , Glândulas Mamárias Humanas/efeitos dos fármacos , Glândulas Mamárias Humanas/imunologia , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos NOD , Fosforilação , Serina/metabolismo , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/efeitos dos fármacos , Linfócitos T Citotóxicos/imunologia
8.
RNA ; 29(5): 557-569, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36737102

RESUMO

PIWI-interacting RNAs (piRNAs) protect genome integrity by silencing transposon mRNAs and some endogenous mRNAs in various animals. However, C. elegans piRNAs only trigger gene silencing at select predicted targeting sites, suggesting additional cellular mechanisms regulate piRNA silencing. To gain insight into possible mechanisms, we compared the transcriptome-wide predicted piRNA targeting sites to the in vivo piRNA binding sites. Surprisingly, while sequence-based predicted piRNA targeting sites are enriched in 3' UTRs, we found that C. elegans piRNAs preferentially bind to coding regions (CDS) of target mRNAs, leading to preferential production of secondary silencing small RNAs in the CDS. However, our analyses suggest that this CDS binding preference cannot be explained by the action of antisilencing Argonaute CSR-1. Instead, our analyses imply that CSR-1 protects mRNAs from piRNA silencing through two distinct mechanisms-by inhibiting piRNA binding across the entire CSR-1 targeted transcript, and by inhibiting secondary silencing small RNA production locally at CSR-1 bound sites. Together, our work identifies the CDS as the critical region that is uniquely competent for piRNA binding in C. elegans. We speculate the CDS binding preference may have evolved to allow the piRNA pathway to maintain robust recognition of RNA targets in spite of genetic drift. Together, our analyses revealed that distinct mechanisms are responsible for restricting piRNA binding and silencing to achieve proper transcriptome surveillance.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , RNA de Interação com Piwi , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transcriptoma , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , RNA de Cadeia Dupla/metabolismo , Sítios de Ligação , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo
9.
J Biol Chem ; 298(4): 101817, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35278434

RESUMO

Expression of the receptor tyrosine kinase ephrin receptor A10 (EphA10), which is undetectable in most normal tissues except for the male testis, has been shown to correlate with tumor progression and poor prognosis in several malignancies, including triple-negative breast cancer (TNBC). Therefore, EphA10 could be a potential therapeutic target, likely with minimal adverse effects. However, no effective clinical drugs against EphA10 are currently available. Here, we report high expression levels of EphA10 in tumor regions of breast, lung, and ovarian cancers as well as in immunosuppressive myeloid cells in the tumor microenvironment. Furthermore, we developed anti-EphA10 monoclonal antibodies (mAbs) that specifically recognize cell surface EphA10, but not other EphA family isoforms, and target tumor regions precisely in vivo with no apparent accumulation in other organs. In syngeneic TNBC mouse models, we found that anti-EphA10 mAb clone #4 enhanced tumor regression, therapeutic response rate, and T cell-mediated antitumor immunity. Notably, the chimeric antigen receptor T cells derived from clone #4 significantly inhibited TNBC cell viability in vitro and tumor growth in vivo. Together, our findings suggest that targeting EphA10 via EphA10 mAbs and EphA10-specific chimeric antigen receptor-T cell therapy may represent a promising strategy for patients with EphA10-positive tumors.


Assuntos
Anticorpos Monoclonais , Receptores de Antígenos Quiméricos , Receptores da Família Eph , Linfócitos T , Neoplasias de Mama Triplo Negativas , Animais , Anticorpos Monoclonais/metabolismo , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Camundongos , Receptores da Família Eph/imunologia , Linfócitos T/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Clin Infect Dis ; 75(1): e432-e439, 2022 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34849615

RESUMO

BACKGROUND: The role of favipiravir in preventing disease progression in coronavirus disease 2019 (COVID-19) remains uncertain. We aimed to determine its effect in preventing disease progression from nonhypoxia to hypoxia among high-risk COVID-19 patients. METHODS: This was an open-label, randomized clinical trial conducted at 14 public hospitals across Malaysia (February-July 2021) among 500 symptomatic, RT-PCR-confirmed COVID-19 patients, aged ≥50 years with ≥1 comorbidity, and hospitalized within first 7 days of illness. Patients were randomized 1:1 to favipiravir plus standard care or standard care alone. Favipiravir was administered at 1800 mg 2×/day on day 1 followed by 800 mg 2×/day until day 5. The primary endpoint was rate of clinical progression from nonhypoxia to hypoxia. Secondary outcomes included rates of mechanical ventilation, intensive care unit (ICU) admission, and in-hospital mortality. RESULTS: Of 500 patients randomized (mean [SD] age, 62.5 [8.0] years; 258 women [51.6%]; 251 [50.2%] had COVID-19 pneumonia), 487 (97.4%) patients completed the trial. Clinical progression to hypoxia occurred in 46 (18.4%) patients on favipiravir plus standard care and 37 (14.8%) on standard care alone (OR, 1.30; 95% CI: .81-2.09; P = .28). All 3 prespecified secondary endpoints were similar between both groups. Mechanical ventilation occurred in 6 (2.4%) vs 5 (2.0%) (OR, 1.20; 95% CI: .36-4.23; P = .76), ICU admission in 13 (5.2%) vs 12 (4.8%) (OR, 1.09; 95% CI: .48-2.47; P = .84), and in-hospital mortality in 5 (2.0%) vs 0 (OR, 12.54; 95% CI: .76-207.84; P = .08) patients. CONCLUSIONS: Among COVID-19 patients at high risk of disease progression, early treatment with oral favipiravir did not prevent their disease progression from nonhypoxia to hypoxia. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov (NCT04818320).


Assuntos
Tratamento Farmacológico da COVID-19 , Amidas , Progressão da Doença , Feminino , Humanos , Hipóxia , Pessoa de Meia-Idade , Pirazinas , SARS-CoV-2 , Resultado do Tratamento
11.
Mol Cancer ; 21(1): 185, 2022 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-36163179

RESUMO

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy using brexucabtagene autoleucel (BA) induces remission in many patients with mantle cell lymphoma (MCL), and BA is the only CAR T-cell therapy approved by the FDA for MCL. However, development of relapses to BA is recognized with poor patient outcomes. Multiple CAR T-cell therapies have been approved for other lymphomas and the resistance mechanisms have been investigated. However, the mechanisms underlying BA relapse in MCL have not been investigated and whether any previously reported resistance mechanisms apply to BA-relapsed patients with MCL is unknown. METHODS: To interrogate BA resistance mechanisms in MCL, we performed single-cell RNA sequencing on 39 longitudinally collected samples from 15 BA-treated patients, and multiplex cytokine profiling on 80 serial samples from 20 patients. RESULTS: We demonstrate that after BA relapse, the proportion of T cells, especially cytotoxic T cells (CTLs), decreased among non-tumor cells, while the proportion of myeloid cells correspondingly increased. TIGIT, LAG3, and CD96 were the predominant checkpoint molecules expressed on exhausted T cells and CTLs; only TIGIT was significantly increased after relapse. CTLs expanded during remission, and then contracted during relapse with upregulated TIGIT expression. Tumor cells also acquired TIGIT expression after relapse, leading to the enhanced interaction of tumor cell TIGIT with monocyte CD155/PVR. In myeloid cells, post-relapse HLA-II expression was reduced relative to pretreatment and during remission. Myeloid-derived suppressor cells (MDSCs) were enriched after relapse with elevated expression of activation markers, including CLU (clusterin) and VCAN (versican). Extracellular chemokines (CCL4, CXCL9, CXCL13), soluble checkpoint inhibitors (sPD-L1, sTIM3, s4-1BB), and soluble receptors (sIL-2R, sTNFRII) were decreased during remission but elevated after relapse. CONCLUSIONS: Our data demonstrate that multiple tumor-intrinsic and -extrinsic factors are associated with T-cell suppression and BA relapse. Among these, TIGIT appears to be the central player given its elevated expression after BA relapse in not only CTLs but also MCL cells. The acquisition of TIGIT expression on tumor cells is MCL-specific and has not been reported in other CAR T-treated diseases. Together, our data suggest that co-targeting TIGIT may prevent CAR T relapses and thus promote long-term progression-free survival in MCL patients.


Assuntos
Linfoma de Célula do Manto , Receptores de Antígenos Quiméricos , Adulto , Antígenos CD , Clusterina , Citocinas/metabolismo , Humanos , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/terapia , Recidiva Local de Neoplasia , Receptores Imunológicos/genética , Linfócitos T , Versicanas
12.
Int J Mol Sci ; 23(15)2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35955678

RESUMO

The serum neutralization (SN) test has been regarded as the "gold standard" for seroconversion following foot-and-mouth disease virus (FMDV) vaccination, although a high-level biosafety laboratory is necessary. ELISA is one alternative, and its format is constantly being improved. For instance, standard polyclonal antisera have been replaced by monoclonal antibodies (MAbs) for catching and detecting antibodies, and inactive viruses have been replaced by virus-like particles (VLPs). To the best of current knowledge, however, no researchers have evaluated the performances of different MAbs as tracers. In previous studies, we successfully identified site 1 and site 2 MAbs Q10E and P11A. In this study, following the established screening platform, the VLPs of putative escape mutants from sites 1 to 5 were expressed and used to demonstrate that S11B is a site 3 MAb. Additionally, the vulnerability of VLPs prompted us to assess another diagnostic antigen: unprocessed polyprotein P1. Therefore, we established and evaluated the performance of blocking ELISA (bELISA) systems based on VLPs and P1, pairing them with Q10E, P11A, S11B, and the non-neutralizing TSG MAb as tracers. The results indicated that the VLP paired with S11B demonstrated the highest correlation with the SN titers (R2 = 0.8071, n = 63). Excluding weakly positive serum samples (SN = 16-32, n = 14), the sensitivity and specificity were 95.65% and 96.15% (kappa = 0.92), respectively. Additionally, the P1 pairing with Q10E also demonstrated a high correlation (R2 = 0.768). We also discovered that these four antibodies had steric effects on one another to varying degrees, despite recognizing distinct antigenic sites. This finding indicated that MAbs as tracers could not accurately detect specific antibodies, possibly because MAbs are bulky compared to a protomeric unit. However, our results still provide convincing support for the application of two pairs of bELISA systems: VLP:S11B-HRP and P1:Q10E-HRP.


Assuntos
Antineoplásicos Imunológicos , Vírus da Febre Aftosa , Febre Aftosa , Animais , Anticorpos Monoclonais , Anticorpos Antivirais , Ensaio de Imunoadsorção Enzimática/métodos , Febre Aftosa/diagnóstico , Febre Aftosa/prevenção & controle , Suínos
13.
J Hepatol ; 74(4): 907-918, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33031845

RESUMO

BACKGROUND & AIMS: There are currently limited therapeutic options for hepatocellular carcinoma (HCC), particularly when it is diagnosed at advanced stages. Herein, we examined the pathophysiological role of ROS1 and assessed the utility of ROS1-targeted therapy for the treatment of HCC. METHODS: Recombinant ribonucleases (RNases) were purified, and the ligand-receptor relationship between RNase7 and ROS1 was validated in HCC cell lines by Duolink, immunofluorescence, and immunoprecipitation assays. Potential interacting residues between ROS1 and RNase7 were predicted using a protein-protein docking approach. The oncogenic function of RNase7 was analyzed by cell proliferation, migration and invasion assays, and a xenograft mouse model. The efficacy of anti-ROS1 inhibitor treatment was evaluated in patient-derived xenograft (PDX) and orthotopic models. Two independent patient cohorts were analyzed to evaluate the pathological relevance of RNase7/ROS1. RESULTS: RNase7 associated with ROS1's N3-P2 domain and promoted ROS1-mediated oncogenic transformation. Patients with HCC exhibited elevated plasma RNase7 levels compared with healthy individuals. High ROS1 and RNase7 expression were strongly associated with poor prognosis in patients with HCC. In both HCC PDX and orthotopic mouse models, ROS1 inhibitor treatment markedly suppressed RNase7-induced tumorigenesis, leading to decreased plasma RNase7 levels and tumor shrinkage in mice. CONCLUSIONS: RNase7 serves as a high-affinity ligand for ROS1. Plasma RNase7 could be used as a biomarker to identify patients with HCC who may benefit from anti-ROS1 treatment. LAY SUMMARY: Receptor tyrosine kinases are known to be involved in tumorigenesis and have been targeted therapeutically for a number of cancers, including hepatocellular carcinoma. ROS1 is the only such receptor with kinase activity whose ligand has not been identified. Herein, we show that RNase7 acts as a ligand to activate ROS1 signaling. This has important pathophysiological and therapeutic implications. Anti-ROS1 inhibitors could be used to treatment patients with hepatocellular carcinoma and high RNase7 levels.


Assuntos
Carcinogênese , Carcinoma Hepatocelular , Crizotinibe/farmacologia , Neoplasias Hepáticas , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Ribonucleases/metabolismo , Animais , Biomarcadores Tumorais/metabolismo , Carcinogênese/efeitos dos fármacos , Carcinogênese/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Ensaios de Migração Celular/métodos , Proliferação de Células/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Ligantes , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Camundongos , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Nucleic Acids Res ; 47(D1): D181-D187, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30357353

RESUMO

PIWI-interacting RNAs (piRNAs) are a class of small noncoding RNAs that guard animal genomes against mutation by silencing transposons. In addition, recent studies have reported that piRNAs silence various endogenous genes. Tens of thousands of distinct piRNAs made in animals do not pair well to transposons and currently the functions and targets of piRNAs are largely unexplored. piRTarBase provides a user-friendly interface to access both predicted and experimentally identified piRNA targeting sites in Caenorhabditis elegans. The user can input genes of interest and retrieve a list of piRNA targeting sites on the input genes. Alternatively, the user can input a piRNA and retrieve a list of its mRNA targets. Additionally, piRTarBase integrates published mRNA and small RNA sequencing data, which will help users identify biologically relevant targeting events. Importantly, our analyses suggest that the piRNA sites found by both predictive and experimental approaches are more likely to exhibit silencing effects on their targets than each method alone. Taken together, piRTarBase offers an integrative platform that will help users to identify functional piRNA target sites by evaluating various information. piRTarBase is freely available for academic use at http://cosbi6.ee.ncku.edu.tw/piRTarBase/.


Assuntos
Sítios de Ligação , Bases de Dados Genéticas , Regulação da Expressão Gênica , Inativação Gênica , Interferência de RNA , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Software , Navegador , Fluxo de Trabalho
15.
J Biomed Sci ; 27(1): 77, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620165

RESUMO

N-linked glycosylation is one of the most abundant posttranslational modifications of membrane-bound proteins in eukaryotes and affects a number of biological activities, including protein biosynthesis, protein stability, intracellular trafficking, subcellular localization, and ligand-receptor interaction. Accumulating evidence indicates that cell membrane immune checkpoint proteins, such as programmed death-ligand 1 (PD-L1), are glycosylated with heavy N-linked glycan moieties in human cancers. N-linked glycosylation of PD-L1 maintains its protein stability and interaction with its cognate receptor, programmed cell death protein 1 (PD-1), and this in turn promotes evasion of T-cell immunity. Studies have suggested targeting PD-L1 glycosylation as a therapeutic option by rational combination of cancer immunotherapies. Interestingly, structural hindrance by N-glycan on PD-L1 in fixed samples impedes its recognition by PD-L1 diagnostic antibodies. Notably, the removal of N-linked glycosylation enhances PD-L1 detection in a variety of bioassays and more accurately predicts the therapeutic efficacy of PD-1/PD-L1 inhibitors, suggesting an important clinical implication of PD-L1 N-linked glycosylation. A detailed understanding of the regulatory mechanisms, cellular functions, and diagnostic limits underlying PD-L1 N-linked glycosylation could shed new light on the clinical development of immune checkpoint inhibitors for cancer treatment and deepen our knowledge of biomarkers to identify patients who would benefit the most from immunotherapy. In this review, we highlight the effects of protein glycosylation on cancer immunotherapy using N-linked glycosylation of PD-L1 as an example. In addition, we consider the potential impacts of PD-L1 N-linked glycosylation on clinical diagnosis. The notion of utilizing the deglycosylated form of PD-L1 as a predictive biomarker to guide anti-PD-1/PD-L1 immunotherapy is also discussed.


Assuntos
Antígeno B7-H1/metabolismo , Imunoterapia , Neoplasias/diagnóstico , Neoplasias/terapia , Nitrogênio/metabolismo , Glicosilação , Humanos
16.
Nucleic Acids Res ; 46(W1): W43-W48, 2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29897582

RESUMO

pirScan is a web-based tool for identifying C. elegans piRNA-targeting sites within a given mRNA or spliced DNA sequence. The purpose of our tool is to allow C. elegans researchers to predict piRNA targeting sites and to avoid the persistent germline silencing of transgenes that has rendered many constructs unusable. pirScan fulfills this purpose by first enumerating the predicted piRNA-targeting sites present in an input sequence. This prediction can be exported in a tabular or graphical format. Subsequently, pirScan suggests silent mutations that can be introduced to the input sequence that would allow the modified transgene to avoid piRNA targeting. The user can customize the piRNA targeting stringency and the silent mutations that he/she wants to introduce into the sequence. The modified sequences can be re-submitted to be certain that any previously present piRNA-targeting sites are now absent and no new piRNA-targeting sites are accidentally generated. This revised sequence can finally be downloaded as a text file and/or visualized in a graphical format. pirScan is freely available for academic use at http://cosbi4.ee.ncku.edu.tw/pirScan/.


Assuntos
Caenorhabditis elegans/genética , Internet , RNA Interferente Pequeno/genética , Software , Animais , Biologia Computacional/tendências , RNA Interferente Pequeno/química
17.
Int J Sports Med ; 41(11): 776-782, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32485777

RESUMO

This study determined the effect of divided attention on controlling postural stability during a drop vertical jump task. In total, 30 participants were tested for drop vertical jumps from a 30-cm high platform and landing on a single leg with or without divided attention tasks. Three-dimensional marker trajectories and ground reaction forces were collected simultaneously. Vertical ground reaction force, loading rate, and dynamic postural stability index were analyzed with or without divided attention tasks. The paired sample t test indicated a significantly low knee flexion angle, high vertical ground reaction force, and increased loading rate in the divided attention task. Moreover, participants showed an increased vertical stability index and dynamic postural stability index in the divided attention task than in the nondivided attention task. Thus, results demonstrated that the divided attention task could affect posture control, leading to poor dynamic posture stability and possibly increasing lower extremity injury risk. The influence of the divided attention task on movement quality likely indicates that an athlete can no longer focus his attention on the bounce drop jump maneuver. Therefore, the bounce drop jump combined with dynamic postural stability index could be used in posture stability screening.


Assuntos
Atenção/fisiologia , Exercício Pliométrico/psicologia , Equilíbrio Postural , Fenômenos Biomecânicos , Cognição/fisiologia , Humanos , Joelho/fisiologia , Perna (Membro)/fisiologia , Movimento/fisiologia , Análise e Desempenho de Tarefas
18.
BMC Plant Biol ; 19(1): 470, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31690276

RESUMO

BACKGROUND: Legitimacy in breeding and commercial crop production depends on optimised protocols to ensure purity of crosses and correct field planting of material. In oil palm, the presence of three fruit forms permits these assumptions to be tested, although only after field planting. The presence of incorrect fruit forms in a cross is a clear sign of illegitimacy. Given that tenera forms produce 30% more oil for the same weight of fruit as dura, the presence of low levels of dura contamination can have major effect during the economic lifespan of an oil palm, which is around 25 years. We evaluated two methods for legitimacy test 1) The use of SHELL markers to the gene that determines the shell-thickness trait 2) The use of SNP markers, to determine the legitimacy of the cross. RESULTS: Our results indicate that the SHELL markers can theoretically reduce the major losses due to dura contamination of tenera planting material. However, these markers cannot distinguish illegitimate tenera, which reduces the value of having bred elite tenera for commercial planting and in the breeding programme, where fruit form is of limited utility, and incorrect identity could lead to significant problems. We propose an optimised approach using SNPs for routine quality control. CONCLUSIONS: Both dura and tenera contamination can be identified and removed at or before the nursery stage. An optimised legitimacy assay using SNP markers coupled with a suitable sampling scheme is now ready to be deployed as a standard control for seed production and breeding in oil palm. The same approach will also be an effective solution for other perennial crops, such as coconut and date palm.


Assuntos
Arecaceae/crescimento & desenvolvimento , Arecaceae/genética , Genoma de Planta , Melhoramento Vegetal , Sementes/crescimento & desenvolvimento , Marcadores Genéticos , Óleo de Palmeira , Melhoramento Vegetal/métodos , Polimorfismo de Nucleotídeo Único
19.
J Sports Sci Med ; 18(4): 653-662, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31827349

RESUMO

This study analyzed landing strategies used by athletes with chronic ankle instability (CAI) and copers compared to uninjured controls. Thirty participants were asked to perform a single-leg forward jump followed by a single-leg landing. Compared to uninjured controls, those with CAI athletes had significantly greater hip flexion and ankle eversion angles at initial landing, suggesting preference for using hip movements and extra ankle eversion angles to avoid ankle inversion when landing. CAI athletes were also found to have significantly decreased peroneus longus activation and higher ankle inversion velocity were both found during descending phase. And these were potential contributors to cause ankle inversion injury as there were likely many others. Based on these findings, CAI athletes may need to utilize more multi-joint or multi-muscle strategies during landing to maintain stability and prevent re-injury.


Assuntos
Traumatismos do Tornozelo/fisiopatologia , Articulação do Tornozelo/fisiopatologia , Instabilidade Articular/fisiopatologia , Extremidade Inferior/fisiologia , Exercício Pliométrico , Traumatismos do Tornozelo/prevenção & controle , Fenômenos Biomecânicos , Eletromiografia , Feminino , Quadril/fisiologia , Humanos , Instabilidade Articular/etiologia , Masculino , Movimento/fisiologia , Músculo Esquelético/fisiologia , Recidiva , Entorses e Distensões/fisiopatologia , Adulto Jovem
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