Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Theranostics ; 10(6): 2859-2871, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32194840

RESUMO

Rationale: Mesenchymal cell-derived osteosarcoma is a rare malignant bone tumor affecting children and adolescents. PTEN down-regulation or function-loss mutation is associated with the aggressive of osteosarcoma. Explicating the regulatory mechanism of PTEN might highlight new targets for improving the survival rate of osteosarcoma patients. Methods: The clinical relevance of FGD1 was examined by the TCGA data set, Western blotting and immunohistochemistry of osteosarcoma microarray slides. Functional assays, such as the MTS assay, colony formation assay and xenografts, were used to determine the biological role of FGD1 in osteosarcoma. The protein-protein interaction between FGD1 and PTEN was detected via co-immunoprecipitation. The relationship between FGD1 and PD-L1 was examined by Western blot analysis, RT-qPCR and immunohistochemistry. Results: In this study, analysis of the TCGA data set of sarcomas revealed that FGD1 was over-expressed with the highest P values. Then, we demonstrated that FGD1 was also abnormally up-regulated in osteosarcoma with unfavorable prognosis. Aberrant expressed FGD1 promoted the osteosarcoma tumor cell proliferation and invasion. Moreover, we found that FGD1 was participated in activating PI3K/AKT signaling pathway by interacting with PTEN. Finally, we showed that FGD1 was capable of regulating the tumor immune response via the PTEN/PD-L1 axis in osteosarcoma. Conclusions: Our data suggested that abnormally over-expressed FGD1 functions as an oncogenic protein to promote osteosarcoma progression through inhibiting PTEN activity and activating PI3K/AKT signaling. Notably, FGD1 increased PD-L1 expression in a PTEN dependent manner and modulated the sensitivity of immune checkpoint-based immunotherapy in osteosarcoma. Thus, FGD1 might be a potential target for improving the survival rate of osteosarcomas.

2.
Connect Tissue Res ; : 1-13, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32180463

RESUMO

Purpose: Reactive oxygen species (ROS) are related to compression stress-induced nucleus pulposus (NP) cell autophagy, but the specific mechanism is unknown in compression stress-induced intervertebral disc degeneration (IVDD). Here, we discuss the specific molecular mechanism and explore whether ROS scavengers could be employed as specific drugs to inhibit compression stress-induced IVDD.Methods: Rat NP cells were exposed to 1.0 MPa compression and pretreatment with the ROS scavenger N-acetylcysteine (NAC) or the JNK-selective inhibitor SP600125 not. Intracellular ROS production was monitored by confocal microscopy. Autophagy was detected by observing the NP cell ultrastructural features using TEM and examining autophagic vacuoles by flow cytometry. The levels of autophagy-associated molecules, the JNK pathway and the PI3K/AKT/mTOR pathway were analyzed by western blotting.Results: Compression-mediated autophagy in rat NP cells was implicated in ROS generation. The ROS scavenger NAC could protect compression-induced NP cell injures by inhibiting ROS production. And SP600125, a JNK inhibitor, attenuated compression-induced NP cell autophagy. Additionally, this is the first report showing that compression induces autophagy in rat NP cells by impeding the compression-induced ROS dependent PI3K/AKT/mTOR pathway and the ROS independent activation of JNK pathway. And the involvement of JNK pathway was in different mechanism of action that when inhibited leaded to increased cell death, increased generation of ROS but decreased autophagy.Conclusions: These results show a new regulatory mechanism involving ROS-mediated autophagy in rat NP cells, which may provide ideas for drug development to improve compression stress-induced IVDD and help avoid eventual surgical treatment of IVD herniation.

3.
Food Microbiol ; 89: 103452, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32138998

RESUMO

The use of whole genome sequencing (WGS) data generated by short-read sequencing technologies such as the Illumina sequencing platforms has been shown to provide reliable results for Salmonella serotype prediction. Emerging long-read sequencing platforms developed by Oxford Nanopore Technologies (ONT) provide an alternative WGS method to meet the needs of industry for rapid and accurate Salmonella confirmation and serotype classification. Advantages of the ONT sequencing platforms include portability, real-time base-calling and long-read sequencing. To explore whether WGS data generated by an ONT sequencing platform could accurately predict Salmonella serotypes, 38 Salmonella strains representing 34 serotypes were sequenced using R9.4 flow cells on an ONT sequencer for up to 2 h. The downstream bioinformatics analysis was performed using pipelines with different assemblers including Canu, Wdbtg2 combined with Racon, or Miniasm combined with Racon. In silico serotype prediction programs were carried out using both SeqSero2 (raw reads and genome assemblies) and SISTR (genome assemblies). The WGS data of the same strains were also obtained from Illumina Hiseq (200 x depth of coverage per genome) as a benchmark of accurate serotype prediction. Predictions using WGS data generated after 30 min, 45 min, 1 h, and 2 h of ONT sequencing time all matched the prediction results from Illumina WGS data. This study demonstrated the comparable accuracy of WGS-based serotype prediction between ONT and Illumina sequencing platforms. This study also sets a start point for future validation of ONT WGS as a rapid Salmonella confirmation and serotype classification tool for the food industry.

4.
Microbiologyopen ; : e1012, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107876

RESUMO

ß-Glucosidase production by Aspergillus niger is accompanied by an inevitable temperature increase in the industrial fermentation environment. Hence, the synthetic process of ß-glucosidase is negatively affected. However, our understanding of the heat stress response (HSR) mechanism in A. niger is still incomplete. The current study explored the intracellular proteome profile of A. niger 3.316 in group T (50°C stress) and group C (30°C control) using two proteomic approaches (isobaric tags for relative and absolute quantitation [iTRAQ] and label-free) and examined the expression of four proteins using a parallel reaction monitoring (PRM) approach. Based on the result of the iTRAQ proteomic analysis, 1,025 proteins were differentially expressed in group T compared to group C. Using the label-free approach, we only focused on 77 proteins with significant changes in their protein expression levels. In addition, we performed bioinformatics analysis on all these proteins and obtained detailed gene ontology (GO) enrichment and Kyoto encyclopedia of genes and genomes (KEGG) pathway results. Under heat stress conditions, the relative expression levels of proteins with protection and repair functions were upregulated in A. niger 3.316. These proteins were involved in metabolic pathways, oxidative phosphorylation, porphyrin and chlorophyll metabolism, pyruvate metabolism, and the citrate cycle (TCA cycle). The insights obtained from the presented proteomics and bioinformatics analyses can be used to further explore the HSR mechanism of A. niger.

5.
Food Microbiol ; 88: 103396, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31997755

RESUMO

The common use of gloves in retail practices represents a potential route for cross contamination of foodborne pathogens in fresh-cut produce. Using fresh-cut cantaloupe as a food model, we investigated factors that may influence glove-mediated cross contamination by Listeria monocytogenes and developed mathematical models to illustrate the patterns of transfer during fresh-cutting practices. Contact time (2, 5, 10 s), contact pressure (0.05, 0.18, 0.37 psi), and glove type (nitrile, polyvinyl chloride, polyethylene) did not have a significant effect on transfer of L. monocytogenes from cantaloupe rind to flesh, or from flesh to flesh. However, glove type appeared to affect L. monocytogenes transfer from the stem scar tissue to cantaloupe flesh (P = 0.0371). Transfer from rind pieces that had been washed with water was significantly higher than transfer from pieces that had not been washed (P = 0.0006). Predictive modeling and experimental validation suggested that transfer of L. monocytogenes on cantaloupe flesh persists over 85 pieces through consecutive contacts with a gloved hand. Findings of the study provide new scientific data to aid researchers, retailers, and caterers in safety risk assessments of fresh-cut practices used to prepare cantaloupes and other produce items.

6.
ACS Appl Mater Interfaces ; 12(4): 4265-4275, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31903741

RESUMO

Conventional therapeutic approaches to treat malignant tumors such as surgery, chemotherapy, or radiotherapy often lead to poor therapeutic results, great pain, economic burden, and risk of recurrence and may even increase the difficulty in treating the patient. Long-term drug administration and systemic drug delivery for cancer chemotherapy would be accompanied by drug resistance or unpredictable side effects. Thus, the use of photothermal therapy, a relatively rapid tumor elimination technique that regulates autophagy and exerts an antitumor effect, represents a novel solution to these problems. Heat shock protein 90 (HSP90), a protein that reduces photothermal or hypothermic efficacy, is closely related to AKT (protein kinase B) and autophagy. Therefore, it was hypothesized that autophagy could be controlled to eliminate tumors by combining exogenous light with a selective HSP90 inhibitor, for example, SNX-2112. In this study, an efficient tumor-killing strategy using graphene oxide loaded with SNX-2112 and folic acid for ultrafast low-temperature photothermal therapy (LTPTT) is reported. A unique mechanism that achieves remarkable therapeutic performance was discovered, where overactivated autophagy induced by ultrafast LTPTT led to direct apoptosis of tumors and enabled functional recovery of T cells to promote natural immunity for actively participating in the attack against tumors. This LTPTT approach resulted in residual tumor cells being rendered in an "injured" state, opening up the possibility of concurrent antitumor and antirecurrence treatment.

7.
BMC Bioinformatics ; 21(1): 20, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941435

RESUMO

BACKGROUND: Antibiotic resistance genes (ARGs) can spread among pathogens via horizontal gene transfer, resulting in imparities in their distribution even within the same species. Therefore, a pan-genome approach to analyzing resistomes is necessary for thoroughly characterizing patterns of ARGs distribution within particular pathogen populations. Software tools are readily available for either ARGs identification or pan-genome analysis, but few exist to combine the two functions. RESULTS: We developed Pan Resistome Analysis Pipeline (PRAP) for the rapid identification of antibiotic resistance genes from various formats of whole genome sequences based on the CARD or ResFinder databases. Detailed annotations were used to analyze pan-resistome features and characterize distributions of ARGs. The contribution of different alleles to antibiotic resistance was predicted by a random forest classifier. Results of analysis were presented in browsable files along with a variety of visualization options. We demonstrated the performance of PRAP by analyzing the genomes of 26 Salmonella enterica isolates from Shanghai, China. CONCLUSIONS: PRAP was effective for identifying ARGs and visualizing pan-resistome features, therefore facilitating pan-genomic investigation of ARGs. This tool has the ability to further excavate potential relationships between antibiotic resistance genes and their phenotypic traits.

8.
IEEE Trans Neural Netw Learn Syst ; 31(2): 488-501, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30990197

RESUMO

The pulse-coupled neural network (PCNN) model is a third-generation artificial neural network without training that uses the synchronous pulse bursts of neurons to process digital images, but the lack of in-depth theoretical research limits its extensive application. By analyzing the working mechanism of the PCNN, we present an expression for the fire-extinguishing time of neurons that fire in the second iteration and an expression for the firing time of neurons that extinguish in the second iteration. In addition, we find a phenomenon of the PCNN and name it mathematically coupled fire extinguishing. Based on the above analysis, we propose a new working mode for the PCNN, where the refiring of fire-extinguishing neurons is only allowed when all firing neurons are extinguished. We also work out the constraint conditions of the parameter settings under this mode. Furthermore, we analyze the relationship between the network parameters and mathematically coupled fire extinguishing, the coupling of neighboring neurons, and the convergence rate of the PCNN, respectively. In addition, we demonstrate the essential regularity of extinguished neuron in the PCNN and then propose an optimal parameter setting to achieve the best comprehensive performance of the PCNN.

9.
Front Microbiol ; 10: 2554, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31781065

RESUMO

Salmonella is one of the most common causes of food-borne diseases worldwide. While Salmonella molecular subtyping by Whole Genome Sequencing (WGS) is increasingly used for outbreak and source tracking investigations, serotyping remains as a first-line characterization of Salmonella isolates. The traditional phenotypic method for serotyping is logistically challenging, as it requires the use of more than 150 specific antisera and well trained personnel to interpret the results. Consequently, it is not a routine method for the majority of laboratories. Several rapid molecular methods targeting O and H loci or surrogate genomic markers have been developed as alternative solutions. With the expansion of WGS, in silico Salmonella serotype prediction using WGS data is available. Here, we compared a microarray method using molecular markers, the Check and Trace Salmonella assay (CTS) and a WGS-based serotype prediction tool that targets molecular determinants of serotype (SeqSero) to the traditional phenotypic method using 100 strains representing 45 common and uncommon serotypes. Compared to the traditional method, the CTS assay correctly serotyped 97% of the strains, four strains gave a double serotype prediction. Among the inconclusive data, one strain was not predicted and two strains were incorrectly identified. SeqSero was evaluated with two versions (SeqSero 1 and the alpha test version of SeqSero 2). The correct antigenic formula was predicted by SeqSero 1 for 96 and 95% of strains using raw reads and assembly, respectively. However, 34 and 33% of these predictions included multiple serotypes by raw reads and assembly. With raw reads, one strain was not identified and three strains were discordant with phenotypic serotyping result. With assembly, three strains were not predicted and two strains were incorrectly predicted. While still under development, SeqSero 2 maintained the accuracy of antigenic formula prediction at 98% and reduced multiple serotype prediction rate to 13%. One strain had no prediction and one strain was incorrectly predicted. Our study indicates that the CTS assay is a good alternative for routine laboratories as it is an easy to use method with a short turn-around-time. SeqSero is a reliable replacement for phenotypic serotyping if WGS is routinely implemented.

10.
ACS Appl Mater Interfaces ; 11(44): 41758-41769, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31610117

RESUMO

Bone repair and regeneration are greatly influenced by the local immune microenvironment. In this regard, the immunomodulatory capability of biomaterials should be considered when evaluating their osteogenic effects. In this study, we investigated the modulatory effects of gold nanoparticle (AuNP)-loaded mesoporous silica nanoparticles (Au-MSNs) on macrophages and the subsequent effects on the behavior of osteoblastic lineage cells. The results demonstrate that Au-MSNs could generate a favorable immune microenvironment by stimulating an anti-inflammatory response and promoting the secretion of osteogenic cytokines by macrophages. As a result, there is an enhancement of osteogenic differentiation in preosteoblastic MC3T3 cells as assessed by the increased expression of osteogenic markers, alkaline phosphatase (ALP) production, and calcium deposition. The immunomodulatory effects and direct osteogenic stimulation by Au-MSNs synergistically increased the osteogenic differentiation capability of MC3T3 cells as a result of crosstalk between Au-MSN-conditioned macrophages and Au-MSN-treated osteoblasts in a coculture system. An in vivo study further revealed that Au-MSNs could accelerate new bone formation in a critical-sized cranial defect site in rats based on computed tomography analysis and histological examination. Together, this novel Au-MSNs could significantly promote osteogenic activity by modulating the immune microenvironment, showing its therapeutic potential for bone tissue repair and regeneration.

11.
Appl Environ Microbiol ; 85(24)2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31585993

RESUMO

Single-nucleotide polymorphisms (SNPs) are widely used for whole-genome sequencing (WGS)-based subtyping of foodborne pathogens in outbreak and source tracking investigations. Mobile genetic elements (MGEs) are commonly present in bacterial genomes and may affect SNP subtyping results if their evolutionary history and dynamics differ from that of the bacterial chromosomes. Using Salmonella enterica as a model organism, we surveyed major categories of MGEs, including plasmids, phages, insertion sequences, integrons, and integrative and conjugative elements (ICEs), in 990 genomes representing 21 major serotypes of S. enterica We evaluated whether plasmids and chromosomal MGEs affect SNP subtyping with 9 outbreak clusters of different serotypes found in the United States in 2018. The median total length of chromosomal MGEs accounted for 2.5% of a typical S. enterica chromosome. Of the 990 analyzed S. enterica isolates, 68.9% contained at least one assembled plasmid sequence. The median total length of assembled plasmids in these isolates was 93,671 bp. Plasmids that carry high densities of SNPs were found to substantially affect both SNP phylogenies and SNP distances among closely related isolates if they were present in the reference genome for SNP subtyping. In comparison, chromosomal MGEs were found to have limited impact on SNP subtyping. We recommend the identification of plasmid sequences in the reference genome and the exclusion of plasmid-borne SNPs from SNP subtyping analysis.IMPORTANCE Despite increasingly routine use of WGS and SNP subtyping in outbreak and source tracking investigations, whether and how MGEs affect SNP subtyping has not been thoroughly investigated. Besides chromosomal MGEs, plasmids are frequently entangled in draft genome assemblies and yet to be assessed for their impact on SNP subtyping. This study provides evidence-based guidance on the treatment of MGEs in SNP analysis for Salmonella to infer phylogenetic relationship and SNP distance between isolates.

12.
Cancer Med ; 8(17): 7345-7358, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31631559

RESUMO

Patients with osteosarcoma exhibiting resistance to chemotherapy or presenting with metastasis usually have a poor prognosis. Osteosarcoma stem cells (OSCs) are a potential cause of tumor metastasis, relapse, and chemotherapy resistance. Therefore, it is necessary to develop novel therapeutic drugs, which not only kill osteosarcoma cells but also target OSCs. This study aims to explore the anti-osteosarcoma effects of Bruceine D (BD), a natural compound derived from Brucea javanica, and investigate its underlying mechanisms. Results demonstrated that BD could significantly inhibit cell proliferation and migration, induce cell cycle arrest, and promote apoptosis in osteosarcoma cells. Besides, BD could also suppress the sphere-forming and self-renewal ability of OSCs. Mechanistically, the inhibitory role of BD on osteosarcoma cell growth and migration including OSC stemness was partially executed through the inhibition of STAT3 signaling pathway. More importantly, BD showed significant anti-osteosarcoma activity without obvious side effects in vivo. Collectively, the results of this study demonstrated that BD exerts a strong inhibitory effect on tumor growth and stem cell like traits of osteosarcoma which may be partially due to STAT3 inhibition, suggesting that BD maybe a promising therapeutic candidate against osteosarcoma.

13.
Appl Environ Microbiol ; 85(23)2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31540993

RESUMO

SeqSero, launched in 2015, is a software tool for Salmonella serotype determination from whole-genome sequencing (WGS) data. Despite its routine use in public health and food safety laboratories in the United States and other countries, the original SeqSero pipeline is relatively slow (minutes per genome using sequencing reads), is not optimized for draft genome assemblies, and may assign multiple serotypes for a strain. Here, we present SeqSero2 (github.com/denglab/SeqSero2; denglab.info/SeqSero2), an algorithmic transformation and functional update of the original SeqSero. Major improvements include (i) additional sequence markers for identification of Salmonella species and subspecies and certain serotypes, (ii) a k-mer based algorithm for rapid serotype prediction from raw reads (seconds per genome) and improved serotype prediction from assemblies, and (iii) a targeted assembly approach for specific retrieval of serotype determinants from WGS for serotype prediction, new allele discovery, and prediction troubleshooting. Evaluated using 5,794 genomes representing 364 common U.S. serotypes, including 2,280 human isolates of 117 serotypes from the National Antimicrobial Resistance Monitoring System, SeqSero2 is up to 50 times faster than the original SeqSero while maintaining equivalent accuracy for raw reads and substantially improving accuracy for assemblies. SeqSero2 further suggested that 3% of the tested genomes contained reads from multiple serotypes, indicating a use for contamination detection. In addition to short reads, SeqSero2 demonstrated potential for accurate and rapid serotype prediction directly from long nanopore reads despite base call errors. Testing of 40 nanopore-sequenced genomes of 17 serotypes yielded a single H antigen misidentification.IMPORTANCE Serotyping is the basis of public health surveillance of Salmonella It remains a first-line subtyping method even as surveillance continues to be transformed by whole-genome sequencing. SeqSero allows the integration of Salmonella serotyping into a whole-genome-sequencing-based laboratory workflow while maintaining continuity with the classic serotyping scheme. SeqSero2, informed by extensive testing and application of SeqSero in the United States and other countries, incorporates important improvements and updates that further strengthen its application in routine and large-scale surveillance of Salmonella by whole-genome sequencing.

14.
Int J Nanomedicine ; 14: 6151-6163, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31447557

RESUMO

Background: Precise control and induction of the differentiation of stem cells to osteoblasts by artificial biomaterials are a promising strategy for rapid bone regeneration and reconstruction. Purpose: In this study, gold nanoparticles (AuNPs)-loaded hydroxyapatite (HA-Au) nanocomposites were designed to guide the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) through the synergistic effects of both AuNPs and HA. Materials and methods: The HA-Au nanoparticles were synthesized and characterized by several analytical techniques. Cell viability and proliferation of hMSCs were characterized by CCK-8 test. Cellular uptake of nanoparticles was observed by transmission electron microscope. For the evaluation of osteogenic differentiation, alkaline phosphatase (ALP) activity and staining, Alizarin red staining, and a quantitative real-time polymerase chain reaction (RT-PCR) analysis were performed. In order to examine specific signaling pathways, RT-PCR and Western blotting assay were performed. Results: The results confirmed the successful synthesis of HA-Au nanocomposites. The HA-Au nanoparticles showed good cytocompatibility and internalized into hMSCs at the studied concentrations. The increased level of ALP production, deposition of calcium mineralization, as well as the expression of typical osteogenic genes, indicated the enhancement of osteogenic differentiation of hMSCs. Moreover, the incorporation of Au could activate the Wnt/ß-catenin signaling pathway, which seemed to be the molecular mechanism underlying the osteoinductive capability of HA-Au nanoparticles. Conclusion: The HA-Au nanoparticles exerted a synergistic effect on accelerating osteogenic differentiation of hMSCs, suggesting they may be potential candidates for bone repair and regeneration.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Durapatita/farmacologia , Ouro/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Nanopartículas Metálicas/química , Osteogênese , Via de Sinalização Wnt/efeitos dos fármacos , Fosfatase Alcalina/metabolismo , Cálcio/metabolismo , Diferenciação Celular/genética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/enzimologia , Nanopartículas Metálicas/ultraestrutura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética
15.
ACS Infect Dis ; 5(8): 1306-1316, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31267737

RESUMO

Toxin-antitoxin (TA) modules widely exist in bacteria, and their activities are associated with the persister phenotype of the pathogen Mycobacterium tuberculosis (M. tb). M. tb causes tuberculosis, a contagious and severe airborne disease. There are 10 MazEF TA systems in M. tb that play important roles in stress adaptation. How the antitoxins antagonize toxins in M. tb or how the 10 TA systems crosstalk to each other are of interest, but the detailed molecular mechanisms are largely unclear. MazEF-mt9 is a unique member among the MazEF family due to its tRNase activity, which is usually carried out by the VapC toxins. Here, we present the cocrystal structure of the MazEF-mt9 complex at 2.7 Å. By characterizing the association mode between the TA pairs through various techniques, we found that MazF-mt9 bound not only its cognate antitoxin but also the noncognate antitoxin MazE-mt1, a phenomenon that could be also observed in vivo. Based on our structural and biochemical work, we propose that the cognate and heterologous interactions among different TA systems work together in vivo to relieve the toxicity of MazF-mt9 toward M. tb cells.

16.
Med Sci Monit ; 25: 5613-5620, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31353362

RESUMO

BACKGROUND The number of patients with spinal cord injury caused by motor vehicle accidents, violent injuries, and other types of trauma increases year by year, and bone marrow mesenchymal stem cell (BMSC) transplants are being widely investigated to treat this condition. However, the success rate of BMSCs transplants is relatively low due to the presence of oxidative stress in the new microenvironment. Our main goals in the present study were to evaluate the damaging effects of H2O2 on BMSCs and to develop a model of "stemness loss" using rat BMSCs. MATERIAL AND METHODS Bone marrow-derived mesenchymal stem cells were obtained from the bone marrow of young rats reared under sterile conditions. The stem cells were used after 2 passages following phenotypic identification. BMSCs were divided into 4 groups to evaluate the damaging effects of H2O2: A. blank control; B. 100 uM H2O2; C. 200 uM H2O2 and D. 300 uM H2O2. The ability of the BMSCs to differentiate into 3 cell lineages and their colony formation and migration capacities were analyzed by gene expression, colony formation, and scratch assays. RESULTS The cells we obtained complied with international stem cell standards demonstrated by their ability to differentiate into 3 cell lineages. We found that 200-300 uM H2O2 had a significant effect on the biological behavior of BMSCs, including their ability to differentiate into 3 cell lineages, the expression of stemness-related proteins, and their migration and colony formation capacities. CONCLUSIONS H2O2 can damage the stemness ability of BMSCs at a concentration of 200-300 uM.


Assuntos
Peróxido de Hidrogênio/efeitos adversos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/efeitos dos fármacos , Animais , Medula Óssea/metabolismo , Células da Medula Óssea/metabolismo , Técnicas de Cultura de Células/métodos , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Peróxido de Hidrogênio/metabolismo , Masculino , Células-Tronco Mesenquimais/metabolismo , Ratos , Ratos Sprague-Dawley
17.
J Oncol ; 2019: 7254534, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354821

RESUMO

Graphene nanocomposite is an inorganic nanocomposite material, which has been widely used in the treatment of tumor at present due to its ability of drug loading, modifiability, photothermal effect, and photodynamic effect. However, the application of graphene nanocomposite is now limited due to the fact that the functions mentioned above are not well realized. This is mainly because people do not have a systematic understanding of the physical and chemical properties of GO nanomolecules, so that we cannot make full use of GO nanomolecules to make the most suitable materials for the use of medicine. Here, we are the first to discuss the influence of the physicochemical properties of graphene nanocomposite on the various functions related to their antitumor effects. The relationship between some important physicochemical properties of graphene nanocomposite such as diameter, shape, and surface chemistry and their functions related to antitumor effects was obtained through analysis, which provides evidence for the application of related materials in the future.

18.
Poult Sci ; 98(12): 6973-6979, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31347691

RESUMO

We evaluated the combination of immunomagnetic separation (IMS), multiple displacement amplification (MDA), and real-time PCR to detect Salmonella from poultry environmental samples. The limits of detection (LODs) of IMS-MDA real-time PCR with different culture enrichment hours (0, 4, 6, and 8 h) were determined in artificially inoculated litter samples from a specific pathogen-free (SPF) poultry farm. In addition, Salmonella detection rate of IMS-MDA real-time PCR with 8-h culture enrichment was compared with that of conventional real-time PCR and culture-based detection by analyzing 174 poultry environmental samples (boot swabs, drag swabs, and litter), and the levels of Salmonella in the samples were quantified using the most probably number method. The LODs of IMS-MDA real-time PCR with 0, 4 to 6, and 8-h enrichment were 10, 1, and 0.1 CFU/g, respectively. Salmonella was detected in 25 of the 174 environmental samples (14.4%) by IMS-MDA real-time PCR, compared with 24 (13.8%) by conventional real-time PCR and 19 (10.9%) by culturing. Cohen's kappa index indicated strong concordance (0.79) between IMS-MDA real-time PCR and culture detection. We demonstrated the potential of the IMS-MDA real-time PCR assay as a faster and more sensitive alternative to culture-based Salmonella detection from poultry environmental samples.

19.
Connect Tissue Res ; : 1-9, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31203667

RESUMO

Purpose: Recently, nucleus pulposus-derived mesenchymal stem cells (NPMSCs) have been identified and have shown good prospects for the repair of degenerative intervertebral discs. However, there is no consensus about the methods for the isolation and purification of NPMSCs. Therefore, a reliable and efficient isolation and purification method is potentially needed. We aimed to compare different methods and to identify an optimal method for isolating and purifying NPMSCs. Methods: NPMSCs were isolated and purified using two common methods (a low-density culture (LD) method and a mesenchymal stem cell complete medium culture (MSC-CM) method) and two novel methods (a cloning cylinder (CC) method and a combination of the CC and MSC-CM methods (MSC-CM+CC)). The morphology, MSC-specific surface markers (CD44, CD73, CD90, CD105, CD34 and HLA-DR), multiple-lineage differentiation potential, colony formation ability, and stemness gene (Oct4, Nanog, and Sox2) expression were evaluated and compared. Results: NPMSCs isolated from nucleus pulposus (NP) tissues via the four methods met the criteria stated by the International Society of Cell Therapy (ISCT) for MSCs, including adherent growth ability, MSC-specific surface antigen expression, and multi-lineage differentiation potential. In particular, the MSC-CM+CC method yielded a relatively higher quality of NPMSCs in terms of cell surface markers, multiple-lineage differentiation potential, colony formation ability, and stemness gene expression. Conclusions: Our results indicated that NPMSCs can be obtained via all four methods and that the MSC-CM+CC method is more reliable and efficient than the other three methods. The findings from this study provide an alternative option for isolating and purifying NPMSCs.

20.
J Cancer ; 10(8): 1825-1832, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31205539

RESUMO

Purpose: Circular RNAs (circRNAs) as prognostic biomarkers have spurred considerable interest in several types of tumors. In the present study, we aimed to elucidate the clinicopathological and prognostic values of circRNAs in human cancer. Methods: We systematically searched PubMed Central (PMC), PubMed, Web of Science, EMBASE, Scopus, CBM and the Cochrane Library databases up to Nov 29, 2018. Eligible studies reporting on the association between circRNAs expression and clinicopathological and prognostic outcomes in cancer were incorporated. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess clinicopathological parameters, and hazard ratios (HRs) and 95% CIs to estimate overall survival (OS). Results: Thirty-two studies involving 4529 patients were incorporated into our meta-analysis. Pooled results showed that high expression of oncogenic circRNAs was significantly associated with poor clinicopathological characteristics (tumor size: OR=1.29, 95%Cl: 1.10-1.51; TNM stage: OR=1.62, 95%Cl: 1.41-1.87; differentiation grade: OR=1.41, 95%Cl: 1.11-1.78; lymph node metastasis: OR=1.69; 95%Cl: 1.34-2.13; distant metastasis: OR=2.75; 95%Cl: 1.92-3.95) and a poor prognosis (OS: HR=2.75; 95%Cl: 2.34-3.15). Furthermore, we found that high expression of tumor-suppressor circRNAs was correlated with improved clinical characteristics (tumor size: OR=0.72; 95%Cl: 0.56-0.92; TNM stage: OR=0.77, 95%Cl: 0.68-0.88) and longer survival times (OS: HR=0.49; 95%Cl: 0.42-0.56). Subgroup analyses based on cancer types and circRNA types were also performed. Conclusion: Our study indicates that circRNAs may serve as important biomarkers for clinicopathologic features and prognosis in human cancer.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA