Publications by authors named "Meiting Chen"

9 Publications

  • Page 1 of 1

Wobble Editing of -box by Unspecific CRISPR/Cas9 Causes CCR Release and Phenotypic Changes in .

Front Chem 2021 9;9:717609. Epub 2021 Aug 9.

Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, China.

CRISPR-associated Cas9 endonuclease (CRISPR/Cas9) systems are widely used to introduce precise mutations, such as knocking in/out at targeted genomic sites. Herein, we successfully disrupted the transcription of multiple genes in LG3145 using a series of unspecific guide RNAs (gRNAs) and UgRNA:Cas9 system-assisted -box editing. The bases used as gRNAs shared 30-70% similarity with a consensus sequence, a acting element (-box) mediating carbon catabolite repression (CCR) of many genes in . This triggers -crRNA:Cas9 complex wobble cleavage up/downstream of sites in the promoters of multiple genes (up to 7), as confirmed by Sanger sequencing and next-generation sequencing (NGS). LG3145 displayed an obvious CCR release phenotype, including numerous secondary metabolites released into the culture broth, ∼ 1.67 g/L white flocculent protein, pigment overflow causing orange-coloured broth (absorbance = 309 nm), polysaccharide capsules appearing outside cells, improved sugar tolerance, and a two-fold increase in cell density. We assessed the relationship between carbon catabolite pathways and phenotype changes caused by unspecific UgRNA-directed site wobble editing. We propose a novel strategy for editing consensus targets at operator sequences that mediates transcriptional regulation in bacteria.
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http://dx.doi.org/10.3389/fchem.2021.717609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8381255PMC
August 2021

HO-1 nuclear accumulation and interaction with NPM1 protect against stress-induced endothelial senescence independent of its enzymatic activity.

Cell Death Dis 2021 Jul 26;12(8):738. Epub 2021 Jul 26.

Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Guangdong Engineering Laboratory of Druggability and New Drug Evaluation, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, China.

Heme oxygenase-1 (HO-1) has attracted accumulating attention for its antioxidant enzymatic activity. However, the exact regulatory role of its non-enzymatic activity in the cardiovascular system remains unaddressed. Here, we show that HO-1 was accumulated in the nuclei of stress-induced senescent endothelial cells, and conferred protection against endothelial senescence independent of its enzymatic activity. Overexpression of ΔHO-1, a truncated HO-1 without transmembrane segment (TMS), inhibited HO-induced endothelial senescence. Overexpression of ΔHO-1, the catalytically inactive form of ΔHO-1, also exhibited anti-senescent effect. In addition, infection of recombinant adenovirus encoding ΔHO-1 with three nuclear localization sequences (NLS), alleviated endothelial senescence induced by knockdown of endogenous HO-1 by CRISPR/Cas9. Moreover, repression of HO-1 nuclear translocation by silencing of signal peptide peptidase (SPP), which is responsible for enzymatic cleavage of the TMS of HO-1, exacerbated endothelial senescence. Mechanistically, nuclear HO-1 interacted with NPM1 N-terminal portion, prevented NPM1 translocation from nucleolus to nucleoplasm, thus disrupted NPM1/p53/MDM2 interactions and inhibited p53 activation by NPM1, finally resisted endothelial senescence. This study provides a novel understanding of HO-1 as a promising therapeutic strategy for vascular senescence-related cardiovascular diseases.
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http://dx.doi.org/10.1038/s41419-021-04035-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313700PMC
July 2021

[Construction of sepsis-associated competing endogenous RNA network based on Gene Expression Omnibus datasets and bioinformatic analysis].

Zhonghua Wei Zhong Bing Ji Jiu Yi Xue 2021 Apr;33(4):427-432

Department of Emergency Medicine, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, Guangdong, China.

Objective: To analyze the sepsis related long non-coding RNA (lncRNA) and mRNA expression profiles based on Gene Expression Omnibus (GEO) datasets and bioinformatic analysis, and to analyze the sepsis-associated competing endogenous RNA (ceRNA) network based on microRNA (miRNA) database.

Methods: The sepsis-related lncRNA dataset was downloaded from the GEO database, and the differential expression analysis was conducted by Bioconductor on the sepsis dataset to obtain differentially expressed lncRNA (DElncRNA) and differentially expressed mRNA (DEmRNA), and cluster heat map was drawn. miRNA combined with DElncRNA were predicted by miRcode. mRNA targeted by miRNA was simultaneously met by three databases: TargetScan, miRDB, and mirTarBase. The interaction relationship of lncRNA-miRNA-mRNA was obtained. The regulatory network visualization software CytoScape was used to draw ceRNA networks. DEmRNA in the ceRNA networks were imported into the Search Tool for the Retrieval of Interacting Genes Database (STRING) online database to draw the protein-protein interaction (PPI) map. The gene ontology (GO) function annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEmRNA were performed.

Results: Dataset GSE89376 and GSE145227 were found from GEO database. Difference analysis showed there were 14 DElncRNA and 359 DEmRNA in the elderly group of GSE89376; 8 DElncRNA and 153 DEmRNA in the adult group of GSE89376; 1 232 DElncRNA and 1 224 DEmRNA in the children group of GSE145227. Clustering heatmap showed that there were significant differences in the expression of lncRNA and mRNA between the sepsis group and the control group. The ceRNA networks were constructed with miRNA. Several DElncRNA and multiple DEmRNA participated in the ceRNA network of sepsis. The PPI diagram demonstrated that several genes encoding proteins interacted with each other and form a multi-node interaction network with multiple genes encoding proteins. Functional annotation and enrichment analysis demonstrated that there might be a crosstalk mechanism on functionally related genes such as nuclear receptor activity, ligand-activated transcription factor activity, and steroid hormone receptor activity, and played a role in the occurrence and development of diseases through forkhead box transcription factor O (FoxO) signaling pathway, Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway, p53 signaling pathway, and phosphateidylinositol 3-kinase (PI3K)/Akt signaling pathway.

Conclusions: Through sepsis-related lncRNA-miRNA-mRNA ceRNA network and combining with KEGG pathway analysis, there were several lncRNA and mRNA participating in the ceRNA network related sepsis, which played an important role in several signal pathways.
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http://dx.doi.org/10.3760/cma.j.cn121430-20210205-00211DOI Listing
April 2021

KIF15 is involved in development and progression of Burkitt lymphoma.

Cancer Cell Int 2021 May 13;21(1):261. Epub 2021 May 13.

Department of Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, and Collaborative Innovation Center of Cancer Medicine, 651 Dong feng East Road, Guangzhou, 510060, Guangdong, China.

Background: Burkitt lymphoma (BL) is a highly aggressive, fast-growing B-cell non-Hodgkin's lymphoma, manifested in several subtypes, including sporadic, endemic, and immunodeficiency-related forms, the mechanism of which is still not clear. Abundant evidence reported that KIF15 was involved in the progression of human cancer. The emphasis of this study is to explore the functions of KIF15 in the development of BL.

Methods: Firstly, tumor and normal tissues were collected for detecting expression of KIF15 in BL. Lentivirus-mediated shRNA knockdown of KIF15 was used to construct BL cell model, which was verified by qRT-PCR and Western Blot. The cell proliferation was detected by CCK8 assay, cell apoptosis and cell cycle were measured through flow cytometry. Transwell assay was conducted to detect the migration.

Results: We first found that KIF15 is highly expressed in BL. Knockdown of KIF15 can inhibit proliferation and migration, promote apoptosis and arrest the cell cycle. Moreover, KIF15 is involved in BL cell activity through regulating expression of apoptosis-related proteins (Caspase3, Caspase8, HTRA, IGFBP-6, p53, SMAC, sTNF-R1, TNF-β and Bcl-2) and downstream pathways, such as p-Akt, CCND1, CDK6 and PIK3CA.

Conclusions: These findings justify the search for small molecule inhibitors targeting KIF15 as a novel therapeutic strategy in BL.
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http://dx.doi.org/10.1186/s12935-021-01967-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117549PMC
May 2021

Ambient marine shipping emissions determined by vessel operation mode along the East China Sea.

Sci Total Environ 2021 May 20;769:144713. Epub 2021 Jan 20.

State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, PR China.

Marine shipping emissions exert important air quality and climate impacts. This study characterized the ambient pollutants predominant by emissions from a variety of marine vessel types near the mid-latitude East China Sea. Two discernible primary shipping emissions were identified by factorization analysis on detailed mass spectra of organic aerosol (OA), as emissions in maneuvering and cruise, highly linked with NO (and less oxidized OA, black carbon, BC) or CO (and more oxidized OA), respectively. Using radio-recorded quantities and activities of 3566 vessels mixed with slow and high-speed diesel engines, we found emission of NO or BC per vessel was positively correlated with vessel speed, while CO emission peaked at moderate speed. The approach here based on vessel operation mode directly linked the vessel activities to ambient concentrations of pollutants from marine shipping emission, and may synthesize the complex vessel types in shipping emission inventory.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144713DOI Listing
May 2021

Chemotherapy Plus Radiotherapy Chemotherapy Alone for Patients With Peripheral T-Cell Lymphoma, Not Otherwise Specified.

Front Oncol 2021 18;11:607145. Epub 2021 Feb 18.

Department of Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in Southern China, and Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.

Purpose: Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is a clinically and biologically heterogeneous disease with poor prognosis. As the role of radiation therapy (RT) is still unclear, we carried out this study to evaluate the potential efficacy of RT in PTCL-NOS.

Methods: Patients diagnosed with PTCL-NOS between 2000 and 2016 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching was used to balance the characteristics between patients who received radiotherapy and those who did not receive radiotherapy. In addition, we validated the findings in an external validation cohort retrospectively recruited from two high-capacity cancer center in China between 2006 and 2016. Kaplan-Meier curves and Cox regression models were used for survival analysis.

Results: Of the 2,768 patients with chemotherapy records in the SEER cohort, 27.6% of 844 patients with early-stage disease and 6.8% of 1,924 patients with advanced-stage disease received RT. The application of RT was significantly associated with an improvement in overall survival (5-year OS rate 58.5 35.1%, P <0.001) and disease-specific survival (5-year DSS rate 66.3 44.0%, P <0.001) in the early-stage subgroup, while no apparent survival benefit of adding RT was identified in patients with advanced-stage disease (5-year OS rate 28.7 24.4%, P = 0.089; 5-year DSS rate 32.9 31.3%, P = 0.223). After adjustment, a matched cohort of 1,044 patients (348 in the RT combined with CT group and 696 in the CT alone group) was created. And RT was still significantly associated with a survival benefit in the early-stage subset, but not in the advanced-stage disease group. In the validation cohort with more comprehensive data, RT also significantly improved the survival of early-stage PTCL-NOS patients.

Conclusion: Adding RT was associated with significant improvement in survival in early-stage PTCL-NOS, but the survival benefit of RT was not obvious in advanced-stage disease. The incorporation of RT for treatment in early-stage PTCL-NOS should be highly considered. Further prospective studies with more comprehensive data are needed to evaluate the effectiveness and toxicity of RT in PTCL-NOS.
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http://dx.doi.org/10.3389/fonc.2021.607145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930486PMC
February 2021

A proposal for a prognostic index for non-nasal type natural killer/T cell lymphoma after asparaginase-based treatment.

Ann Hematol 2020 Dec 25;99(12):2811-2819. Epub 2020 Sep 25.

Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in Southern China, and Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.

In the era of asparaginase-based therapy for extranodal natural killer/T cell lymphoma (ENKTL), the clinical outcomes of ENKTL have notably improved. However, as a rare subtype of ENKTL, the therapeutic effect and prognostic factors of non-nasal type ENKTL remain unclear. Thus, we performed this study to analyze the clinical characteristics and to establish a prognostic model specifically for the non-nasal disease. We performed a retrospective study of consecutive patients newly diagnosed with non-nasal type ENKTL and mainly received asparaginase-based therapy at Sun Yat-sen University Cancer Center (SYSUCC) between January 2011 and December 2019, to analyze the prognostic factors and to propose a prognostic model. We validated the prognostic model in an independent cohort. In total, 98 non-nasal type ENKTL patients were included in the training cohort. Multivariate analyses showed that prognostic factors for OS were elevated LDH levels, involvement of bone marrow and serum total protein (TP) < 60 g/L. We developed a new prognostic model named the non-nasal type ENKTL prognostic index (NPI) by grouping the prognostic factors: group 1, no risk factors; group 2, one risk factor; and group 3, two or three risk factors, which were associated with 3-year OS rates of 84.1% (95% CI, 70.9-97.2), 46.8% (27.7-65.8), and 14.9% (0-32.9), respectively (P < 0.001). These results were validated and confirmed in an independent cohort. The new model is efficient in distinguishing non-nasal-type ENKTL patients with various outcomes in the contemporary era of asparaginase-based therapy.
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http://dx.doi.org/10.1007/s00277-020-04278-xDOI Listing
December 2020

Length-dependent flagellar growth of revealed by real time fluorescent imaging.

Elife 2017 01 18;6. Epub 2017 Jan 18.

Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan.

Bacterial flagella are extracellular filaments that drive swimming in bacteria. During motor assembly, flagellins are transported unfolded through the central channel in the flagellum to the growing tip. Here, we applied in vivo fluorescent imaging to monitor in real time the polar flagella growth. The flagellar growth rate is found to be highly length-dependent. Initially, the flagellum grows at a constant rate (50 nm/min) when shorter than 1500 nm. The growth rate decays sharply when the flagellum grows longer, which decreases to ~9 nm/min at 7500 nm. We modeled flagellin transport inside the channel as a one-dimensional diffusive process with an injection force at its base. When the flagellum is short, its growth rate is determined by the loading speed at the base. Only when the flagellum grows longer does diffusion of flagellin become the rate-limiting step, dramatically reducing the growth rate. Our results shed new light on the dynamic building process of this complex extracellular structure.
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http://dx.doi.org/10.7554/eLife.22140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300704PMC
January 2017
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