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1.
Cell ; 167(7): 1788-1802.e13, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27984727

RESUMO

More than 98% of the mammalian genome is noncoding, and interspersed transposable elements account for ∼50% of noncoding space. Here, we demonstrate that a specific interaction between the polycomb protein EZH2 and RNA made from B2 SINE retrotransposons controls stress-responsive genes in mouse cells. In the heat-shock model, B2 RNA binds stress genes and suppresses their transcription. Upon stress, EZH2 is recruited and triggers cleavage of B2 RNA. B2 degradation in turn upregulates stress genes. Evidence indicates that B2 RNA operates as a "speed bump" against advancement of RNA polymerase II, and temperature stress releases the brakes on transcriptional elongation. These data attribute a new function to EZH2 that is independent of its histone methyltransferase activity and reconcile how EZH2 can be associated with both gene repression and activation. Our study reveals that EZH2 and B2 together control activation of a large network of genes involved in thermal stress.


Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Regulação da Expressão Gênica , Resposta ao Choque Térmico , RNA não Traduzido/metabolismo , Retroelementos , Animais , Células-Tronco Embrionárias/metabolismo , Camundongos , Células NIH 3T3 , RNA Polimerase II/metabolismo , Transcrição Gênica
2.
Biochem Cell Biol ; 102(2): 145-158, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38011682

RESUMO

Histone H4 asymmetrically dimethylated at arginine 3 (H4R3me2a) is an active histone mark catalyzed by protein arginine methyltransferase 1 (PRMT1), a major arginine methyltransferase in vertebrates catalyzing asymmetric dimethylation of arginine. H4R3me2a stimulates the activity of lysine acetyltransferases such as CBP/p300, which catalyze the acetylation of H3K27, a mark of active enhancers, super-enhancers, and promoters. There are a few studies on the genomic location of H4R3me2a. In chicken polychromatic erythrocytes, H4R3me2a is found in introns and intergenic regions and binds to the globin locus control region (a super-enhancer) and globin regulatory regions. In this report, we analyzed chromatin immunoprecipitation sequencing data for the genomic location of H4R3me2a in the breast cancer cell line MCF7. As in avian cells, MCF7 H4R3me2a is present in intronic and intergenic regions. Nucleosomes with H4R3me2a and H3K27ac next to nucleosome-free regions are found at super-enhancers, enhancers, and promoter regions of expressed genes. Genes with critical roles in breast cancer cells have broad domains of nucleosomes with H4R3me2a, H3K27ac, and H3K4me3. Our results are consistent with PRMT1-mediated H4R3me2a playing a key role in the chromatin organization of regulatory regions of vertebrate genomes.


Assuntos
Histonas , Nucleossomos , Animais , Histonas/genética , Histonas/metabolismo , Arginina/genética , DNA Intergênico , Globinas/genética , Globinas/metabolismo , Cromatina , Acetilação
3.
Can J Microbiol ; 70(8): 303-335, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38696839

RESUMO

The rapid increase of antimicrobial-resistant bacteria in humans and livestock is concerning. Antimicrobials are essential for the treatment of disease in modern day medicine, and their misuse in humans and food animals has contributed to an increase in the prevalence of antimicrobial-resistant bacteria. Globally, antimicrobial resistance is recognized as a One Health problem affecting humans, animals, and environment. Enterococcal species are Gram-positive bacteria that are widely distributed in nature. Their occurrence, prevalence, and persistence across the One Health continuum make them an ideal candidate to study antimicrobial resistance from a One Health perspective. The objective of this review was to summarize the role of enterococci as an indicator of antimicrobial resistance across One Health sectors. We also briefly address the prevalence of enterococci in human, animal, and environmental settings. In addition, a 16S RNA gene-based phylogenetic tree was constructed to visualize the evolutionary relationship among enterococcal species and whether they segregate based on host environment. We also review the genomic basis of antimicrobial resistance in enterococcal species across the One Health continuum.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Enterococcus , Saúde Única , Filogenia , Enterococcus/efeitos dos fármacos , Enterococcus/genética , Humanos , Antibacterianos/farmacologia , Animais , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , RNA Ribossômico 16S/genética
4.
EMBO Rep ; 22(5): e52255, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33645898

RESUMO

Despite significant steps in our understanding of Alzheimer's disease (AD), many of the molecular processes underlying its pathogenesis remain largely unknown. Here, we focus on the role of non-coding RNAs produced by small interspersed nuclear elements (SINEs). RNAs from SINE B2 repeats in mouse and SINE Alu repeats in humans, long regarded as "junk" DNA, control gene expression by binding RNA polymerase II and suppressing transcription. They also possess self-cleaving activity that is accelerated through their interaction with certain proteins disabling this suppression. Here, we show that similar to mouse SINE RNAs, human Alu RNAs, are processed, and the processing rate is increased in brains of AD patients. This increased processing correlates with the activation of genes up-regulated in AD patients, while increased intact Alu RNA levels correlate with down-regulated gene expression in AD. In vitro assays show that processing of Alu RNAs is accelerated by HSF1. Overall, our data show that RNAs from SINE elements in the human brain show a similar pattern of deregulation during amyloid beta pathology as in mouse.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/genética , Animais , Encéfalo , Expressão Gênica , Humanos , Camundongos , Processamento Pós-Transcricional do RNA
5.
Proc Natl Acad Sci U S A ; 117(1): 415-425, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31871160

RESUMO

Transposable elements make up half of the mammalian genome. One of the most abundant is the short interspersed nuclear element (SINE). Among their million copies, B2 accounts for ∼350,000 in the mouse genome and has garnered special interest because of emerging roles in epigenetic regulation. Our recent work demonstrated that B2 RNA binds stress genes to retard transcription elongation. Although epigenetically silenced, B2s become massively up-regulated during thermal and other types of stress. Specifically, an interaction between B2 RNA and the Polycomb protein, EZH2, results in cleavage of B2 RNA, release of B2 RNA from chromatin, and activation of thermal stress genes. Although an established RNA-binding protein and histone methyltransferase, EZH2 is not known to be a nuclease. Here, we provide evidence for the surprising conclusion that B2 is a self-cleaving ribozyme. Ribozyme activity depends on Mg+2 and monovalent cations but is resistant to protease treatment. However, contact with EZH2 accelerates cleavage rate by >100-fold, suggesting that EZH2 promotes a cleavage-competent RNA conformation. B2 modification-interference analysis demonstrates that phosphorothioate changes at A and C nucleotides can substitute for EZH2. B2 nucleotides 45 to 55 and 100 to 101 are essential for activity. Finally, another family of SINEs, the human ALU element, also produces a self-cleaving RNA and is cleaved during T-cell activation as well as thermal and endoplasmic reticulum (ER) stress. Thus, B2/ALU SINEs may be classified as "epigenetic ribozymes" that function as transcriptional switches during stress. Given their high copy numbers, B2 and ALU may represent the predominant ribozyme activity in mammalian cells.


Assuntos
Elementos Alu/fisiologia , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Epigênese Genética , RNA Catalítico/metabolismo , Animais , Cromatina/metabolismo , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Proteína Potenciadora do Homólogo 2 de Zeste/isolamento & purificação , Células HeLa , Humanos , Células Jurkat , Camundongos , Conformação de Ácido Nucleico , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Células Sf9 , Transcrição Gênica/fisiologia
6.
EMBO Rep ; 15(4): 402-10, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24534129

RESUMO

Small non-coding RNAs (smRNAs) are known to be significantly enriched near the transcriptional start sites of genes. However, the functional relevance of these smRNAs remains unclear, and they have not been associated with human disease. Within the cancer genome atlas project (TCGA), we have generated small RNA datasets for many tumor types. In prior cancer studies, these RNAs have been regarded as transcriptional "noise," due to their apparent chaotic distribution. In contrast, we demonstrate their striking potential to distinguish efficiently between cancer and normal tissues and classify patients with cancer to subgroups of distinct survival outcomes. This potential to predict cancer status is restricted to a subset of these smRNAs, which is encoded within the first exon of genes, highly enriched within CpG islands and negatively correlated with DNA methylation levels. Thus, our data show that genome-wide changes in the expression levels of small non-coding RNAs within first exons are associated with cancer.


Assuntos
Neoplasias da Mama/genética , Carcinoma Ductal de Mama/genética , Pequeno RNA não Traduzido/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/mortalidade , Ilhas de CpG , Metilação de DNA , Éxons , Feminino , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Fases de Leitura Aberta , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Pequeno RNA não Traduzido/genética , Análise de Sequência de DNA , Análise de Sobrevida , Sítio de Iniciação de Transcrição , Transcriptoma
7.
EMBO J ; 30(19): 4071-83, 2011 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-21873981

RESUMO

Extinction learning refers to the phenomenon that a previously learned response to an environmental stimulus, for example, the expression of an aversive behaviour upon exposure to a specific context, is reduced when the stimulus is repeatedly presented in the absence of a previously paired aversive event. Extinction of fear memories has been implicated with the treatment of anxiety disease but the molecular processes that underlie fear extinction are only beginning to emerge. Here, we show that fear extinction initiates upregulation of hippocampal insulin-growth factor 2 (Igf2) and downregulation of insulin-growth factor binding protein 7 (Igfbp7). In line with this observation, we demonstrate that IGF2 facilitates fear extinction, while IGFBP7 impairs fear extinction in an IGF2-dependent manner. Furthermore, we identify one cellular substrate of altered IGF2 signalling during fear extinction. To this end, we show that fear extinction-induced IGF2/IGFBP7 signalling promotes the survival of 17-19-day-old newborn hippocampal neurons. In conclusion, our data suggest that therapeutic strategies that enhance IGF2 signalling and adult neurogenesis might be suitable to treat disease linked to excessive fear memory.


Assuntos
Extinção Psicológica/fisiologia , Medo/fisiologia , Regulação da Expressão Gênica , Hipocampo/metabolismo , Fator de Crescimento Insulin-Like II/metabolismo , Memória/fisiologia , Animais , Animais Recém-Nascidos , Proliferação de Células , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Neurônios/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Transdução de Sinais , Fatores de Tempo
8.
EMBO J ; 30(20): 4299-308, 2011 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-21946562

RESUMO

MicroRNAs are key regulators of transcriptome plasticity and have been implicated with the pathogenesis of brain diseases. Here, we employed massive parallel sequencing and provide, at an unprecedented depth, the complete and quantitative miRNAome of the mouse hippocampus, the prime target of neurodegenerative diseases such as Alzheimer's disease (AD). Using integrative genetics, we identify miR-34c as a negative constraint of memory consolidation and show that miR-34c levels are elevated in the hippocampus of AD patients and corresponding mouse models. In line with this, targeting miR-34 seed rescues learning ability in these mouse models. Our data suggest that miR-34c could be a marker for the onset of cognitive disturbances linked to AD and indicate that targeting miR-34c could be a suitable therapy.


Assuntos
Hipocampo/metabolismo , Transtornos da Memória/metabolismo , MicroRNAs/metabolismo , Idoso , Doença de Alzheimer/metabolismo , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transcriptoma
9.
BioData Min ; 16(1): 27, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37803453

RESUMO

Squiggle data is the numerical output of DNA and RNA sequencing by the Nanopore next generation sequencing platform. Nanopore sequencing offers expanded applications compared to previous sequencing techniques but produces a large amount of data in the form of current measurements over time. The analysis of these segments of current measurements require more complex and computationally intensive algorithms than previous sequencing technologies. The purpose of this study is to investigate in principle the potential of using quantum computers to speed up Nanopore data analysis. Quantum circuits are designed to extract major features of squiggle current measurements. The circuits are analyzed theoretically in terms of size and performance. Practical experiments on IBM QX show the limitations of the state of the art quantum computer to tackle real life squiggle data problems. Nevertheless, pre-processing of the squiggle data using the inverse wavelet transform, as experimented and analyzed in this paper as well, reduces the dimensionality of the problem in order to fit a reasonable size quantum computer in the hopefully near future.

10.
J Microbiol Methods ; 213: 106815, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37699502

RESUMO

Antimicrobial resistance genes (ARGs) can be transferred between members of a bacterial population by mobile genetic elements (MGE). Understanding the risk of these transfer events is important in monitoring and predicting antimicrobial resistance (AMR), especially in the context of a One Health Continuum. However, there is no universally accepted method for detection of ARGs and MGEs, and especially for determining their linkages. This study used publicly available shotgun metagenomic DNA short-read (Illumina, 100 bp paired-end) sequence data from samples across the One Health Continuum (including beef cattle composite feces from feedlots, catch basin water at feedlots, agricultural soil from feedlot manured surrounding fields, and urban/municipal sewage influent from two municipal wastewater treatment plants) to develop a workflow to identify and associate ARGs and MGEs. ARG- and MGE-based targeted-assemblies with available short-read data were unable to meet this analysis goal. In contrast, de novo assembly of contigs provided enough sequence context to associate ARGs and MGEs, without compromising discovery rate. However, to estimate the relative abundance of these elements, unassembled sequence data must still be used.

11.
Antibiotics (Basel) ; 12(6)2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37370279

RESUMO

Carbapenems are considered a last resort for the treatment of multi-drug-resistant bacterial infections in humans. In this study, we investigated the occurrence of carbapenem-resistant bacteria in feedlots in Alberta, Canada. The presumptive carbapenem-resistant isolates (n = 116) recovered after ertapenem enrichment were subjected to antimicrobial susceptibility testing against 12 different antibiotics, including four carbapenems. Of these, 72% of the isolates (n = 84) showed resistance to ertapenem, while 27% of the isolates (n = 31) were resistant to at least one other carbapenem, with all except one isolate being resistant to at least two other drug classes. Of these 31 isolates, 90% were carbapenemase positive, while a subset of 36 ertapenem-only resistant isolates were carbapenemase negative. The positive isolates belonged to three genera; Pseudomonas, Acinetobacter, and Stenotrophomonas, with the majority being Pseudomonas aeruginosa (n = 20) as identified by 16S rRNA gene sequencing. Whole genome sequencing identified intrinsic carbapenem resistance genes, including blaOXA-50 and its variants (P. aeruginosa), blaOXA-265 (A. haemolyticus), blaOXA-648 (A. lwoffii), blaOXA-278 (A. junii), and blaL1 and blaL2 (S. maltophilia). The acquired carbapenem resistance gene (blaPST-2) was identified in P. saudiphocaensis and P. stutzeri. In a comparative genomic analysis, clinical P. aeruginosa clustered separately from those recovered from bovine feces. In conclusion, despite the use of selective enrichment methods, finding carbapenem-resistant bacteria within a feedlot environment was a rarity.

12.
Microorganisms ; 11(12)2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38138126

RESUMO

Antimicrobial use (AMU) in the livestock industry has been associated with increased levels of antimicrobial resistance. Recently, there has been an increase in the number of "natural" feedlots in the beef cattle sector that raise cattle without antibiotics. Shotgun metagenomics was employed to characterize the impact of AMU in feedlot cattle on the microbiome, resistome, and mobilome. Sequenced fecal samples identified a decline (q < 0.01) in the genera Methanobrevibacter and Treponema in the microbiome of naturally vs. conventionally raised feedlot cattle, but this difference was not (q > 0.05) observed in catch basin samples. No differences (q > 0.05) were found in the class-level resistome between feedlot practices. In fecal samples, decreases from conventional to natural (q < 0.05) were noted in reads for the antimicrobial-resistant genes (ARGs) mefA, tet40, tetO, tetQ, and tetW. Plasmid-associated ARGs were more common in feces from conventional than natural feedlot cattle. Interestingly, more chromosomal- than plasmid-associated macrolide resistance genes were observed in both natural and conventional feedlots, suggesting that they were more stably conserved than the predominately plasmid-associated tetracycline resistance genes. This study suggests that generationally selected resistomes through decades of AMU persist even after AMU ceases in natural production systems.

13.
Microorganisms ; 11(3)2023 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-36985300

RESUMO

Enterococci are Gram-positive bacteria that can be isolated from a variety of environments including soil, water, plants, and the intestinal tract of humans and animals. Although they are considered commensals in humans, Enterococcus spp. are important opportunistic pathogens. Due to their presence and persistence in diverse environments, Enterococcus spp. are ideal for studying antimicrobial resistance (AMR) from the One Health perspective. We undertook a comparative genomic analysis of the virulome, resistome, mobilome, and the association between the resistome and mobilome of 246 E. faecium and 376 E. faecalis recovered from livestock (swine, beef cattle, poultry, dairy cattle), human clinical samples, municipal wastewater, and environmental sources. Comparative genomics of E. faecium and E. faecalis identified 31 and 34 different antimicrobial resistance genes (ARGs), with 62% and 68% of the isolates having plasmid-associated ARGs, respectively. Across the One Health continuum, tetracycline (tetL and tetM) and macrolide resistance (ermB) were commonly identified in E. faecium and E. faecalis. These ARGs were frequently associated with mobile genetic elements along with other ARGs conferring resistance against aminoglycosides [ant(6)-la, aph(3')-IIIa], lincosamides [lnuG, lsaE], and streptogramins (sat4). Study of the core E. faecium genome identified two main clades, clade 'A' and 'B', with clade A isolates primarily originating from humans and municipal wastewater and carrying more virulence genes and ARGs related to category I antimicrobials. Overall, despite differences in antimicrobial usage across the continuum, tetracycline and macrolide resistance genes persisted in all sectors.

14.
J Biol Chem ; 286(19): 17359-64, 2011 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-21454525

RESUMO

MicroRNAs (miRNAs) are emerging critical regulators of cell function that frequently reside in clusters throughout the genome. They influence a myriad of cell functions, including the generation of induced pluripotent stem cells, also termed reprogramming. Here, we have successfully delivered entire miRNA clusters into reprogramming fibroblasts using retroviral vectors. This strategy avoids caveats associated with transient transfection of chemically synthesized miRNA mimics. Overexpression of 2 miRNA clusters, 106a-363 and in particular 302-367, allowed potent increases in induced pluripotent stem cell generation efficiency in mouse fibroblasts using 3 exogenous factors (Sox2, Klf4, and Oct4). Pathway analysis highlighted potential relevant effectors, including mesenchymal-to-epithelial transition, cell cycle, and epigenetic regulators. Further study showed that miRNA cluster 302-367 targeted TGFß receptor 2, promoted increased E-cadherin expression, and accelerated mesenchymal-to-epithelial changes necessary for colony formation. Our work thus provides an interesting alternative for improving reprogramming using miRNAs and adds new evidence for the emerging relationship between pluripotency and the epithelial phenotype.


Assuntos
MicroRNAs/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Adesão Celular , Células Epiteliais/citologia , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Fator 4 Semelhante a Kruppel , Masculino , Mesoderma/citologia , Camundongos , MicroRNAs/genética , Fenótipo , Células-Tronco/citologia
15.
Front Microbiol ; 13: 859990, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35832805

RESUMO

Enterococci are commensal bacteria of the gastrointestinal tract of humans, animals, and insects. They are also found in soil, water, and plant ecosystems. The presence of enterococci in human, animal, and environmental settings makes these bacteria ideal candidates to study antimicrobial resistance in the One-Health continuum. This study focused on Enterococcus hirae isolates (n = 4,601) predominantly isolated from beef production systems including bovine feces (n = 4,117, 89.5%), catch-basin water (n = 306, 66.5%), stockpiled bovine manure (n = 24, 0.5%), and natural water sources near feedlots (n = 145, 32%), and a few isolates from urban wastewater (n = 9, 0.2%) denoted as human-associated environmental samples. Antimicrobial susceptibility profiling of a subset (n = 1,319) of E. hirae isolates originating from beef production systems (n = 1,308) showed high resistance to tetracycline (65%) and erythromycin (57%) with 50.4% isolates harboring multi-drug resistance, whereas urban wastewater isolates (n = 9) were resistant to nitrofurantoin (44.5%) and tigecycline (44.5%) followed by linezolid (33.3%). Genes for tetracycline (tetL, M, S/M, and O/32/O) and macrolide resistance erm(B) were frequently found in beef production isolates. Antimicrobial resistance profiles of E. hirae isolates recovered from different environmental settings appeared to reflect the kind of antimicrobial usage in beef and human sectors. Comparative genomic analysis of E. hirae isolates showed an open pan-genome that consisted of 1,427 core genes, 358 soft core genes, 1701 shell genes, and 7,969 cloud genes. Across species comparative genomic analysis conducted on E. hirae, Enterococcus faecalis and Enterococcus faecium genomes revealed that E. hirae had unique genes associated with vitamin production, cellulose, and pectin degradation, traits which may support its adaptation to the bovine digestive tract. E. faecium and E. faecalis more frequently harbored virulence genes associated with biofilm formation, iron transport, and cell adhesion, suggesting niche specificity within these species.

16.
Cell Stress Chaperones ; 26(1): 253-264, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33123915

RESUMO

During the integrated stress response (ISR), global translation initiation is attenuated; however, noncanonical mechanisms allow for the continued translation of specific transcripts. Eukaryotic initiation factor 5B (eIF5B) has been shown to play a critical role in canonical translation as well as in noncanonical mechanisms involving internal ribosome entry site (IRES) and upstream open reading frame (uORF) elements. The uORF-mediated translation regulation of activating transcription factor 4 (ATF4) mRNA plays a pivotal role in the cellular ISR. Our recent study confirmed that eIF5B depletion removes uORF2-mediated repression of ATF4 translation, which results in the upregulation of growth arrest and DNA damage-inducible protein 34 (GADD34) transcription. Accordingly, we hypothesized that eIF5B depletion may reprogram the transcriptome profile of the cell. Here, we employed genome-wide transcriptional analysis on eIF5B-depleted cells. Further, we validate the up- and downregulation of several transcripts from our RNA-seq data using RT-qPCR. We identified upregulated pathways including cellular response to endoplasmic reticulum (ER) stress, and mucin-type O-glycan biosynthesis, as well as downregulated pathways of transcriptional misregulation in cancer and T cell receptor signaling. We also confirm that depletion of eIF5B leads to activation of the c-Jun N-terminal kinase (JNK) arm of the mitogen-activated protein kinase (MAPK) pathway. This data suggests that depletion of eIF5B reprograms the cellular transcriptome and influences critical cellular processes such as ER stress and ISR.


Assuntos
Estresse do Retículo Endoplasmático , Fatores de Iniciação em Eucariotos/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Interferência de RNA , Transcriptoma , Ativação Enzimática , Células HEK293 , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/genética , RNA Interferente Pequeno/genética
17.
Environ Pollut ; 284: 117141, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33901984

RESUMO

Chemosensory perception is crucial for fish reproduction and survival. Direct contact of olfactory neuroepithelium to the surrounding environment makes it vulnerable to contaminants in aquatic ecosystems. Copper nanoparticles (CuNPs), which are increasingly used in commercial and domestic applications due their exceptional properties, can impair fish olfactory function. However, the molecular events underlying olfactory toxicity of CuNPs are largely unexplored. Our results suggested that CuNPs were bioavailable to olfactory mucosal cells. Using RNA-seq, we compared the effect of CuNPs and copper ions (Cu2+) on gene transcript profiles of rainbow trout (Oncorhynchus mykiss) olfactory mucosa. The narrow overlap in differential gene expression between the CuNP- and Cu2+-exposed fish revealed that these two contaminants exert their effects through distinct mechanisms. We propose a transcript-based conceptual model that shows that olfactory signal transduction, calcium homeostasis, and synaptic vesicular signaling were affected by CuNPs in the olfactory sensory neurons (OSNs). Neuroregenerative pathways were also impaired by CuNPs. In contrast, Cu2+ did not induce toxicity pathways and rather upregulated regeneration pathways. Both Cu treatments reduced immune system pathway transcripts. However, suppression of transcripts that were associated with inflammatory signaling was only observed with CuNPs. Neither oxidative stress nor apoptosis were triggered by Cu2+ or CuNPs in mucosal cells. Dysregulation of transcripts that regulate function, maintenance, and reestablishment of damaged olfactory mucosa represents critical mechanisms of toxicity of CuNPs. The loss of olfaction by CuNPs may impact survival of rainbow trout and impose an ecological risk to fish populations in contaminated environments.


Assuntos
Nanopartículas , Oncorhynchus mykiss , Poluentes Químicos da Água , Animais , Cobre/toxicidade , Ecossistema , Mucosa Olfatória/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
18.
Mol Hum Reprod ; 16(11): 793-803, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20566704

RESUMO

Cells originating from the germ cell lineage retain the remarkable property under special culture conditions to give rise to cells with embryonic stem cell (ESC) properties, such as the multipotent adult germline stem cells (maGSCs) derived from adult mouse testis. To get an insight into the mechanisms that control pluripotency and differentiation in these cells, we studied how differences observed during in vitro differentiation between ESCs and maGSCs are associated with differences at the level of microRNAs (miRNAs). In this work, we provide for a first time a connection between germ cell origin of maGSCs and their specific miRNA expression profile. We found that maGSCs express higher levels of germ cell markers characteristic for primordial germ cells (PGCs) and spermatogonia compared with ESCs. Retained expression of miR-290 cluster has been previously reported in maGSCs during differentiation and it was associated with higher Oct-4 levels. Here, we show that this property is also shared by another pluripotent cell line originating from the germ line, the embryonic germ cells. In addition, we provide proof that the specific miRNA expression profile of maGSCs has an impact on their differentiation potential. Low levels of miR-302 in maGSCs during the first 10 days of leukaemia inhibitory factor deprivation are shown to be necessary for the maintenance of high levels of early germ cell markers.


Assuntos
Diferenciação Celular , Células-Tronco Embrionárias/metabolismo , Células Germinativas/citologia , Células Germinativas/metabolismo , MicroRNAs , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Animais , Biomarcadores/metabolismo , Linhagem da Célula , Simulação por Computador , Células-Tronco Embrionárias/citologia , Perfilação da Expressão Gênica , Masculino , Camundongos , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
19.
Differentiation ; 78(2-3): 69-78, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19628328

RESUMO

We report the biological effects of miR-290 cluster via gain-of-function or loss-of-function experiments in mouse embryonic stem cells (ESCs) cultured under differentiation conditions. Under these conditions we found that overexpression of miR-290 cluster in ESCs cannot prevent downregulation of Oct-4, but inhibition results in earlier downregulation of Oct-4 compared with the negative control. In consistence with previous findings that report ectopic expression of Brachyury during gastrulation in Argonaute-2 KO mice due to impaired miRNA function, we show that miR-290 cluster regulates negatively differentiation of ESCs towards mesodermal and germ cell lineage. These results suggest that although incapable to maintain pluripotent state alone, miR-290 cluster inhibits ESC differentiation and it is involved in the pathways controlling mesoderm and primordial germ cell differentiation. Finally, we provide proofs that members of this cluster target Dkk-1 gene, a Wnt pathway inhibitor, and affect this pathway, which can partially explain why miR-290 cluster favours pluripotency against differentiation.


Assuntos
Diferenciação Celular/fisiologia , Células-Tronco Embrionárias/citologia , Células Germinativas/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , MicroRNAs/fisiologia , Proteínas Repressoras/metabolismo , Animais , Células Cultivadas , Proteínas Cromossômicas não Histona , Perfilação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/genética , Luciferases/metabolismo , Mesoderma/citologia , Mesoderma/fisiologia , Camundongos , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Células-Tronco Pluripotentes , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
20.
Can Commun Dis Rep ; 46(6): 180-185, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32673383

RESUMO

Each year, approximately one in eight Canadians are affected by foodborne illness, either through outbreaks or sporadic illness, with animals being the major reservoir for the pathogens. Whole genome sequence analyses are now routinely implemented by public and animal health laboratories to define epidemiological disease clusters and to identify potential sources of infection. Similarly, a number of bioinformatics tools can be used to identify virulence and antimicrobial resistance (AMR) determinants in the genomes of pathogenic strains. Many important clinical and phenotypic characteristics of these pathogens can now be predicted using machine learning algorithms applied to whole genome sequence data. In this overview, we compare the ability of support vector machines, gradient-boosted decision trees and artificial neural networks to predict the levels of AMR within Salmonella enterica and extended-spectrum ß-lactamase (ESBL) producing Escherichia coli. We show that minimum inhibitory concentrations (MIC) for each of 13 antimicrobials for S. enterica strains can be accurately determined, and that ESBL-producing E. coli strains can be accurately classified as susceptible, intermediate or resistant for each of seven antimicrobials. In addition to AMR and bacterial populations of greatest risk to human health, artificial intelligence algorithms hold promise as tools to predict other clinically and epidemiologically important phenotypes of enteric pathogens.

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