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1.
Sci Rep ; 12(1): 7592, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35534544

RESUMO

Height identification of water-permeable fractured zone (WPFZ) is one of the decisive influence factors for mining safety, especially in some specific conditions, such as mining under aquifer. In order to demonstrate the formation process of the WPFZ, the scaling model experiment is carried out. Through the analysis of movement and breaking in overlying strata, the WPFZ height is significantly affected by mining range, movement characteristics of key strata and its follow-up strata. Based on the research findings, a new theoretical method, " overlying strata synchronous movement method " (OSSM) is established to predict the WPFZ height. Taking 3301 mining face of Zhujiamao Coal Mine in China as the engineering background, the WPFZ height is estimated by OSSM. Additionally, the field detection is carried out by the downhole segmented water injection method combined with borehole camera method. By comparing the results of different methods, the accuracy of OSSM is verified and the WPFZ height is determined finally. What´s more, various methods for determining WPFZ height are evaluated.


Assuntos
Minas de Carvão , Água Subterrânea , Carvão Mineral/análise , Engenharia , Água/análise
3.
Gene Ther ; 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35534612

RESUMO

With the development of basic research, some genetic-based methods have been found to treat Duchenne muscular dystrophy (DMD) with large deletion mutations and nonsense mutations. Appropriate therapeutic approaches for repairing multiple duplications are limited. We used the CRISPR (clustered regularly interspaced short palindromic repeat)/Cas9 system with patient-derived primary myoblasts to correct multiple duplications of the dystrophin gene. Muscle tissues from a patient carrying duplications of dystrophin were obtained, and tissue-derived primary cells were cultured. Myoblasts were purified with an immunomagnetic sorting system using CD56 microbeads. After transduction by lentivirus with a designed single guide RNA (sgRNA) targeting a duplicated region, myoblasts were allowed to differentiate for 7 days. Copy number variations in the exons of the patient's myotubes were quantified by real-time PCR before and after genetic editing. Western blot analysis was performed to detect the full-length dystrophin protein before and after genetic editing. The ten sequences predicted to be the most likely off-targets were determined by Sanger sequencing. The patient carried duplications of exon 18-25, dystrophin protein expression was completely abrogated. Real-time PCR showed that the copy number of exon 25 in the patient's myotubes was 2.015 ± 0.079 compared with that of the healthy controls. After editing, the copy number of exon 25 in the patient's modified myotubes was 1.308 ± 0.083 compared with that of the healthy controls (P < 0.001). Western blot analysis revealed no expression of the dystrophin protein in the patient's myotubes before editing. After editing, the patient's myotubes expressed the full-length dystrophin protein at a level that was ~6.12% of that in the healthy control samples. Off-target analysis revealed no abnormal editing at the ten sites predicted to be the most likely off-target sites. The excision of multiple duplications by the CRISPR/Cas9 system restored the expression of full-length dystrophin. This study provides proof of evidence for future genome-editing therapy in patients with DMD caused by multiple duplication mutations.

4.
Int J Food Microbiol ; 372: 109692, 2022 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-35504161

RESUMO

The convergence of blaNDM and tet(X4) in a single strain has been sporadically detected in diverse pathogens from different sources, causing widespread concerns. However, the genomic characterization of blaNDM-positive or blaNDM- and tet(X4)-coharboring Enterobacteriaceae in the pork production chain, as well as how they emerged, remains mostly unclear. In this study, forty blaNDM-positive Enterobacteriaceae, including eleven tet(X4)- and blaNDM-coharboring isolates, were isolated from a pig slaughterhouse and a retail pork market in Yangzhou, China. This is the first report presenting the coexistence of blaNDM and tet(X4) in Enterobacter hormaechei, and it was demonstrated that they could spread clonally from the slaughterhouse to the retail market. Furthermore, we also discovered that the slaughterhouse served as a possible reservoir for blaNDM-positive ST48 E. coli strains. The blaNDM-bearing IncX3 plasmid was found in twenty blaNDM-positive strains as well as all blaNDM-5- and tet(X4)-coharboring strains, and most of them (30/31) were conjugative. In Klebsiella aerogenes NTT31XS, blaNDM was found on a nonconjugative ~17 kb IncX3 plasmid. When compared to the typical IncX3 plasmid, it deleted large-scale regions, which might imply a low fitness cost dissemination strategy for the IncX3 plasmid. Despite being from different species, tet(X4)-bearing plasmids carried by all blaNDM-5- and tet(X4)-coharboring strains were nonconjugative and had identical architectures. Phylogenetic analysis suggested that the formation of K. aerogenes NTT31XS may have been mediated by translocation of tet(X4)-positive circular intermediates and recombination events of regions in typical blaNDM-bearing IncX3 plasmids. Overall, this study expounded the prevalence and transmission characteristics of blaNDM-positive Enterobacteriaceae strains in the two links of pork production chain before they were exposed to humans, and expanded our knowledge of the molecular features and evolutionary history of tet(X4)- and blaNDM-5-coharboring strains. Strict control measures should be implemented to prevent the spread of such pathogens along food production chains.


Assuntos
Carne de Porco , Carne Vermelha , Animais , Antibacterianos/farmacologia , China , Enterobacter , Enterobacteriaceae/genética , Escherichia coli/genética , Testes de Sensibilidade Microbiana , Filogenia , Plasmídeos , Suínos , beta-Lactamases/genética
5.
J Transl Med ; 20(1): 220, 2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35562740

RESUMO

BACKGROUND: An increasing number of studies have demonstrated that long non-coding RNAs (lncRNAs) serve as key regulators in tumor development and progression. However, only a few lncRNAs have been functionally characterized in gastric cancer (GC). METHODS: Bioinformatics analysis was conducted to find lncRNAs that are associated with GC metastasis. RNA FISH, RIP, and RNA pull down assays were used to study the complementary binding of LINC01564 complementary to the 3'UTR of transcription factor POU2F1. The transcription activation of LINC01564 by POU2F1 as a transcription factor was examined by ChIP assay. In vitro assays such as MTT, cell invasion assay, and clonogenic assay were conducted to examined the impacts of LINC01564 and POU2F1 on GC cell proliferation and invasion. Experiments in vivo were performed to access the impacts of LINC01564 and POU2F1 on GC metastasis. RESULTS: The results showed that LINC01564 complementary bound to the 3'UTR of POU2F1 to form an RNA duplex, whereby stabilizing POU2F1 mRNA and increasing the enrichment in cells. The level of LINC01564 was also increased by POU2F1 through transcription activation. In vitro assays showed that LINC01564 promoted the proliferation, invasion and migration of GC cells through increasing POU2F1. In vivo experiments indicate the promotion of GC proliferation and metastasis by the interaction between LINC01564 and POU2F1. CONCLUSION: Taken together, our results indicate that the interaction between LINC01564 and POU2F1 promotes the proliferation, migration and invasion of GC cells.

6.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 51(1): 62-72, 2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35576115

RESUMO

To explore the mechanism of ovarian toxicity of Hook. F. (TwHF) by network pharmacology and molecular docking. The candidate toxic compounds and targets of TwHF were collected by the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and the Comparative Toxicogenomics Database (CTD). Then, the potential ovarian toxic targets were obtained from CTD, and the target genes of ovarian toxicity of TwHF were analyzed using the STRING database. The protein-protein interaction (PPI) network was established by Cytoscape and analyzed by the cytoHubba plug-in to identify hub genes. Additionally, the target genes of ovarian toxicity of TwHF were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses by using the R software. Finally, Discovery Studio software was used for molecular docking verification of the core toxic compounds and the hub genes. Nine candidate toxic compounds of TwHF and 56 potential ovarian toxic targets were identified in this study. Further network analysis showed that the core ovarian toxic compounds of TwHF were triptolide, kaempferol and tripterine, and the hub ovarian toxic genes included , , , , , , , , and . Besides, the GO and KEGG analysis indicated that TwHF caused ovarian toxicity through oxidative stress, reproductive system development and function, regulation of cell cycle, response to endogenous hormones and exogenous stimuli, apoptosis regulation and aging. The docking studies suggested that 3 core ovarian toxic compounds of TwHF were able to fit in the binding pocket of the 10 hub genes. TwHF may cause ovarian toxicity by acting on 10 hub genes and 140 signaling pathways.

7.
J Environ Manage ; 316: 115211, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35561491

RESUMO

Over the past decade, biochar-supported nZVI composites (nZVI/biochar) have been developed and applied to treat various pollutants due to their excellent physical and chemical properties, especially in the field of chromium (VI) removal. This paper reviewed the factors influencing the preparation and experiments of nZVI/biochar composites, optimization methods, column experimental studies and the mechanism of Cr(VI) removal. The results showed that the difference in raw materials and preparation temperature led to the difference in functional groups and electron transfer capabilities of nZVI/biochar materials. In the experimental process, pH and test temperature can affect the surface chemical properties of materials and involve the electron transfer efficiency. Elemental doping and microbial coupling can effectively improve the performance of nZVI/biochar composites. In conclusion, biochar can stabilize nZVI and enhance electron transfer in nZVI/biochar materials, enabling the composite materials to remove Cr(VI) efficiently. The study of column experiments provides a theoretical basis for applying nZVI/biochar composites in engineering. Finally, the future work prospects of nZVI/biochar composites for heavy metal removal are introduced, and the main challenges and further research directions are proposed.

8.
Front Nutr ; 9: 862773, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35520284

RESUMO

Dryopteris crassirhizoma rhizome (DCR) inhibits melanin production in B16F10 melanoma cells and tyrosinase activity. The melanin content and tyrosinase activity of DCR-treated zebrafish embryos were determined to evaluate the in vivo inhibitory effect of DCR on melanogenesis. Moreover, an off-line hyphenated method combining the high-speed counter-current chromatography, affinity-based ultrafiltration, and liquid chromatography-tandem mass spectrometry was used to identify and characterize the DCR compounds with tyrosinase inhibitory activity. Our results indicated that DCR significantly decreased the melanin content and tyrosinase activity in zebrafish embryos in a dose-dependent manner; moreover, 22 compounds in DCR presented tyrosinase inhibitory activity. In silico molecular docking prediction data indicated that the 22 compounds in DCR can form stable conformations in the active site pocket of tyrosinase.

9.
Commun Biol ; 5(1): 396, 2022 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-35484199

RESUMO

Aging of hematopoietic stem cells (HSCs) is linked to various blood disorders and malignancies. SIRT1 has been implicated in healthy aging, but its role in HSC aging is poorly understood. Surprisingly, we found that Sirt1 knockout improved the maintenance of quiescence of aging HSCs and their functionality as well as mouse survival in serial bone marrow transplantation (BMT) recipients. The majority of secondary and tertiary BMT recipients of aging wild type donor cells developed B/myeloid mixed phenotype acute leukemia (MPAL), which was markedly inhibited by Sirt1 knockout. SIRT1 inhibition also reduced the growth and survival of human B/myeloid MPAL cells. Sirt1 knockout suppressed global gene activation in old HSCs, prominently the genes regulating protein synthesis and oxidative metabolism, which may involve multiple downstream transcriptional factors. Our results demonstrate an unexpected role of SIRT1 in promoting HSC aging and age-dependent MPAL and suggest SIRT1 may be a new therapeutic target for modulating functions of aging HSCs and treatment of MPAL.


Assuntos
Leucemia , Sirtuína 1 , Envelhecimento/genética , Animais , Células-Tronco Hematopoéticas/metabolismo , Leucemia/genética , Leucemia/metabolismo , Camundongos , Fenótipo , Sirtuína 1/genética , Sirtuína 1/metabolismo
10.
Front Microbiol ; 13: 778659, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35401428

RESUMO

Advancement of novel sequencing technologies facilitates modern life science and medicine unprecedentedly. Exploring complete genome sequences of bacteria by long-read sequencing technology is significant for microbial genomics research. However, third-generation long-read sequencing technologies are available with limited choices, which generate technological barrier to scientific research. Recently, a novel QitanTech nanopore long-read sequencing technology has emerged in China, but the potential application and performance were unexplored. Herein, we comprehensively evaluated the feasibility of the emerging sequencing technology in assembling complete genomes of MDR pathogens. The results showed that 500 Mbp QitanTech nanopore sequencing data could be generated within 8 h in one flow cell with the standard library preparation method. The mean read length, longest read length, and mean read-level accuracy of QitanTech sequencing data were 6,041 bp, 57,037 bp, and 81.50% (LAST)/81.40% (Minimap2), respectively. Two routine assembly strategies including long-read assembly and hybrid assembly enable the achievement of complete bacterial genomes. The accuracy of assembled draft bacterial genomes with QitanTech long-read data could be improved up to 99.9% dramatically by polishing using accurate short-read data. Furthermore, the assembled bacterial genomes cover accurate structures of complex resistance plasmids harboring critical resistance genes such as tet(X), tmexCD-toprJ, and bla VIM-2, even the complex fusion MDR plasmid generated from homologous recombination. In conclusion, QitanTech nanopore sequencing, as a nanopore long-read sequencing technology launched in China, could be a good option for investigation of complex bacterial genomes. More potential applications based on this novel platform warrant investigations.

11.
Explore (NY) ; 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35469747

RESUMO

BACKGROUND: Immune checkpoint inhibitors (ICIs) have changed the landscape of advanced cancer treatment. However, immune checkpoint inhibitors can trigger effector T cells against self-antigens as well as tumor antigens, resulting in immune-related toxicities in normal organs, referred to as immune-related adverse events (irAEs). CASE SUMMARY: A 56-year-old man with undifferentiated gastric carcinoma received sintilimab plus paclitaxel and tegafur therapy. After five cycles of treatment, the patient was referred to the hospital for sudden onset urinary frequency, micturition pain, and urinary incontinence. Cystoscopy revealed the entire bladder mucosa was red and edematous but there was no evidence of tumor. Oral administration of Chai-Ling-Tang (Sairei-To) alleviated lower urinary tract symptoms (LUTS). Histological analysis revealed numerous infiltrates of CD3-positive and CD8-positive cells into the urothelium but no atypia, indicating a diagnosis of immune-related cystitis. Interestingly, the urothelial epithelium infiltrated by lymphocytes and subepithelial inflammatory cells strongly expressed cell boundary PD-L1. The dose of Chai-Ling-Tang was maintained and stopped 2 months later without recurrence of LUTS. Since recovering from cystitis, the patient remains alive with no disease progression. CONCLUSION: This report shows that Chai-Ling-Tang is safe and effective for treating immune-related cystitis. The detailed mechanism of action requires further investigation.

13.
Int J Biol Macromol ; 209(Pt B): 1848-1857, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35487380

RESUMO

In this work, sustainable cellulose-g-poly(lauryl acrylate-co-acrylamide) [Cell-g-P(LA-co-AM)] bottlebrush copolymer elastomers derived from cellulose and plant oil were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Differential scanning calorimeter (DSC) results indicate that these thermally stable Cell-g-P(LA-co-AM) bottlebrush copolymer elastomers show adjustable melting temperatures. Monotonic and cyclic tensile tests suggest that the mechanical properties, including tensile strength, extensibility, Young's modulus, and elasticity, can be conveniently controlled by changing the LA/AM feed ratio and cellulose content. In such kind of bottlebrush copolymer elastomers, the rigid cellulose backbones act as cross-linking points to provide tensile strength. The incorporated PAM segments can form additional network structure via hydrogen bonding, resulting in enhanced tensile strength but decreased extensibility when more PAM segments are introduced. This versatile strategy can promote the development of sustainable cellulose-based bottlebrush copolymer elastomers from renewable resources.

15.
Sci China Life Sci ; 2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35366153

RESUMO

Mammalian individuals differ in their somatic cell cloning efficiency, but the mechanisms leading to this variation is poorly understood. Here we found that high cloning efficiency buffalo fetal fibroblasts (BFFs) displayed robust energy metabolism, looser chromatin structure, high H3K9 acetylation and low heterochromatin protein 1α (HP1α) expression. High cloning efficiency BFFs had more H3K9ac regions near to the upstream of glycolysis genes by ChIP-seq, and involved more openness loci related to glycolysis genes through ATAC-seq. The expression of these glycolysis genes was also found to be higher in high cloning efficiency BFFs by qRT-PCR. Two key enzymes of glycolysis, PDKs and LDH, were confirmed to be associated with histone acetylation and chromatin openness of BFFs. Treatment of low cloning efficiency BFFs with PS48 (activator of PDK1) resulted in an increase in the intracellular lactate production and H3K9 acetylation, decrease in histone deacetylase activity and HP1α expression, less condensed chromatin structure and more cloning embryos developing to blastocysts. These results indicate that the cloning efficiency of buffalo somatic cells is associated with their glycolytic metabolism and chromatin structure, and can be improved by increasing glycolytic metabolism.

16.
Cancer Gene Ther ; 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35370291

RESUMO

Alternative splicing (AS) is a gene regulatory mechanism that drives protein diversity and dysregulation of AS plays a significant role in tumorigenesis. This study aimed to develop a prognostic signature based on AS and elucidate the role in tumor immune microenvironment (TIME) in clear cell renal cell carcinoma (ccRCC). The prognosis-related AS events were analyzed by univariate Cox regression analysis. Gene set enrichment analyses (GSEA) were performed for functional annotation. Prognostic signatures were identified and validated using univariate and multivariate Cox regression, LASSO regression, Kaplan-Meier survival analysis, and proportional hazards model. The context of TIME in ccRCC was also analyzed. Gene and protein expression data of C4orf19 were obtained from ONCOMINE website and Human Protein Altas. Splicing factors (SFs) regulatory networks were visualized. 4431 survival-related AS events in ccRCC were screened. Based on splicing subtypes, eight AS prognostic signatures were constructed. A nomogram with good prognostic prediction was generated. Furthermore, the prognostic signatures were significantly correlated with TIME diversity and immune checkpoint inhibitor (ICI)-related genes. C4orf19 was the only gene whose expression levels were downregulated among the prognostic AS-related genes, which is considered as a promising prognostic factor in ccRCC. Potential functions of SFs were determined by splicing regulatory networks. In our study, AS patterns of novel indicators for prognostic prediction of ccRCC were explored. The AS-SF networks provide information of regulatory mechanisms. Players of AS events related to TIME were investigated, which contribute to prognosis monitoring of ccRCC.

17.
Carbohydr Polym ; 288: 119381, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35450643

RESUMO

In this work, a chitin-based macromolecular chain transfer agent (Chitin-CTA) was designed to graft polymers from chitin at the molecular level. Homogeneous reversible addition-fragmentation chain transfer (RAFT) polymerization was performed to prepare branched MA elastomers, chitin-graft-poly(methyl acrylate) (Chitin-g-PMA) copolymers, which were thermally stable and showed tunable glass transition temperatures. These ultra-stretchable branched MA elastomers exhibit unique strain-hardening behavior and significantly enhanced mechanical properties. Mechanical tests indicate that the chitin backbones in branched MA elastomers can act as cross-linking points to improve the tensile strength, toughness, and elasticity simultaneously. The macroscopic performance of branched MA elastomers c be further promoted by introducing hydrogen bonding as non-covalent interaction to form an additional reversible physical network. This robust and versatile grafting strategy can provide new opportunities to prepare chitin-based branched MA elastomers with extraordinary mechanical properties.


Assuntos
Quitina , Elastômeros , Polimerização , Polímeros , Resistência à Tração
18.
Microbiol Spectr ; 10(2): e0019622, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35311537

RESUMO

Emergence of pathogens harboring multiple resistance genes incurs great concerns. Cooccurrence of mobile resistance genes conferring resistance to tigecycline, colistin, and carbapenems in Escherichia coli has not been investigated. This study aimed to characterize three E. coli isolates coharboring tet(X4), mcr-1, and blaNDM-5. Isolates coharboring tet(X4), mcr-1, and blaNDM-5 were identified and characterized by PCR, Sanger sequencing, antimicrobial susceptibility testing, conjugation assays, Illumina sequencing, nanopore sequencing, and bioinformatic analysis. Three E. coli isolates carrying tet(X4), mcr-1, and blaNDM-5 were identified from pigeons in China. They were resistant to almost all antimicrobials except enrofloxacin. tet(X4) and blaNDM-5 could be conjugated into E. coli C600, but mcr-1 was nontransferable in three isolates. Three isolates belonged to sequence type 6775 (ST6775), and clonal dissemination of isolates carrying tet(X4), mcr-1, and blaNDM-5 existed in the pigeon farm. Genetic analysis revealed that mcr-1 mediated by the Tn6330 was located on the chromosome, tet(X4) was located on the IncFII plasmid, and blaNDM-5 was located on the IncX3 plasmid. We first characterized the E. coli isolates carrying tet(X4), mcr-1, and blaNDM-5 simultaneously. Relevant measures should be taken to decrease the prevalence of pathogens carrying tet(X4), mcr-1, and blaNDM-5. IMPORTANCE Tigecycline and colistin are regarded as vital antimicrobials to treat multidrug-resistant (MDR) bacterial infections, such as that caused by carbapenemase-producing Enterobacteriaceae (CPE). Cooccurrence of mobile resistance genes conferring resistance to last-resort antimicrobials in E. coli remains unknown. Here, we characterized E. coli strains coharboring tet(X4), mcr-1, and blaNDM-5 phenotypically and genetically. Resistance genes tet(X4), mcr-1, and blaNDM-5 were located on transposons or plasmids that were mobile genetic elements related to the capture, accumulation, and dissemination of such important resistance genes. The emergence of E. coli isolates carrying tet(X4), mcr-1, and blaNDM-5 highlights the importance of monitoring the coexistence of novel mobile resistance genes in different settings with a One Health approach. Risk of transmission of such MDR pathogens from animals to humans should be evaluated comprehensively.


Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Animais , Antibacterianos/farmacologia , Colistina , Farmacorresistência Bacteriana/genética , Escherichia coli , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Tigeciclina , beta-Lactamases/genética
19.
Hepatology ; 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35243663

RESUMO

BACKGROUND AND AIMS: IL-10-producing regulatory B cells (IL-10+ B cells), a dominant regulatory B cell (Breg) subset, foster tumor progression. However, the mechanisms underlying their generation in HCC are poorly understood. Ten-eleven translocation-2 (TET2), a predominant epigenetic regulatory enzyme in B cells, regulates gene expression by catalyzing demethylation of 5-methylcytosine into 5-hydroxymethyl cytosine (5hmC). In this study, we investigated the role of TET2 in IL-10+ B cell generation in HCC and its prospects for clinical application. APPROACH AND RESULTS: TET2 activation in B cells triggered by oxidative stress from the HCC microenvironment promoted IL-10 expression, whereas adoptive transfer of Tet2-deficient B cells suppressed HCC progression. The aryl hydrocarbon receptor is required for TET2 to hydroxylate Il10. In addition, high levels of IL-10, TET2, and 5hmc in B cells indicate poor prognosis in patients with HCC. Moreover, we determined TET2 activity using 5hmc in B cells to evaluate the efficacy of anti-programmed death 1 (anti-PD-1) therapy. Notably, TET2 inhibition in B cells facilitates antitumor immunity to improve anti-PD-1 therapy for HCC. CONCLUSIONS: Our findings propose a TET2-dependent epigenetic intervention targeting IL-10+ B cell generation during HCC progression and identify the inhibition of TET2 activity as a promising combination therapy with immune checkpoint inhibitors for HCC.

20.
Microbiol Spectr ; 10(2): e0216021, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35230128

RESUMO

Horizontal gene transfer (HGT) plays a significant role in the spread of antibiotic resistance genes (ARGs). Most reported compounds promote HGT by increasing the cell membrane permeability. Colistin has been reported to increase the cell membrane permeability when exhibiting its antibacterial effect. Therefore, this study aimed to investigate the potential role of colistin in facilitating the dissemination of ARGs via plasmid conjugation by establishing an in vitro mating model. Three strains Escherichia coli (E. coli) DH5α, E. coli L65, and E. coli LD67-1 carrying plasmid RP4-7, blaNDM-5 positive IncX3 plasmid, and mcr-1 positive IncI2 plasmid, respectively, were regarded as the donor strains and E. coli J53 as the recipient strain. Exposure to subinhibitory concentrations of colistin (1/4, 1/8, 1/16 MIC) significantly stimulated the conjugation frequency of RP-4 plasmid, wide-type IncI2 and IncX3 plasmid. Scanning electron microscopy revealed the shrunken cell membrane after colistin treatment, whereas propidium iodide dye and 1-N-Phenylnaphthylamine fluorescent probe showed the increased cell membrane permeability. Additionally, the expression level of the outer membrane proteins (ompF and ompC) was increased. These results indicate a break in the membrane barrier. The expression of the mating pair formation gene (trbBp) was promoted and the expression of the global regulatory genes (korA, trbA), which downregulates trbBp expression, was inhibited. Thus, the production of the mating pairing machine could be elevated after colistin exposure. These findings aid in understanding the hidden risks of colistin on the spread of antimicrobial resistance. IMPORTANCE Antimicrobial resistance (AMR) dissemination is a growing global threat. As a last-resort treatment against multidrug-resistant and extensively drug-resistant Gram-negative bacteria, colistin has been used for prophylactic and therapeutic purposes in veterinary medicine. Previous studies have reported the presence of colistin residues in the intestinal tract and feces. The role of colistin in facilitating the conjugation frequency of mcr-1- and blaNDM-5-positive plasmids was confirmed in this study along with elucidating its potential mechanisms. This study raises awareness of the potential AMR dissemination roles induced by colistin in environmental settings.


Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Antibacterianos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos/genética
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