Publications by authors named "Wenxi Wang"

42 Publications

Extracellular vesicles isolated by size-exclusion chromatography present suitability for RNomics analysis in plasma.

J Transl Med 2021 03 12;19(1):104. Epub 2021 Mar 12.

Research Center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, 050011, Hebei, China.

Background: Extracellular vesicles (EVs), known as cell-derived membranous structures harboring a variety of biomolecules, have been widely used in liquid biopsy. Due to the complex biological composition of plasma, plasma RNA omics analysis (RNomics) is easily affected, thus it is necessary to select an optimal strategy from exiting methods according to the performance for intended application.

Methods: In this study, four different strategies for EVs isolation were performed and compared (i.e. ultracentrifugation (UC), size exclusion chromatography (SEC), and two most frequently-used commercially available isolation kit (ExoQuick and exoEasy). We compared the yield, purity, PCR quantification of RNAs, miRNA-seq analyses and mRNA-seq analyses of RNAs from EVs isolated using four methods.

Results: The results showed that the lowest miRNA binding protein AGO2 (Argonaute-2) and the highest EVs-specific miRNA and lncRNA were observed in EVs obtained through SEC, meanwhile the content of the non-specific miRNA was the lowest. Further RNA-Seq data revealed that RNAs obtained via SEC presented more useful reads for both miRNA and mRNA. Furthermore, the mRNA delivered via SEC tended to have a concentration comparable to the ideal FPKM (Fragments Per Kilobase Million) value.

Conclusions: SEC shall be used as an optimal strategy for the isolation of EVs in plasma RNomics analysis.
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http://dx.doi.org/10.1186/s12967-021-02775-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953782PMC
March 2021

Assessment of Neuroprotective Effects of Low-Intensity Transcranial Ultrasound Stimulation in a Parkinson's Disease Rat Model by Fractional Anisotropy and Relaxation Time T2 Value.

Front Neurosci 2021 9;15:590354. Epub 2021 Feb 9.

Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China.

Low-intensity transcranial ultrasound (LITUS) may have a therapeutic effect on Parkinson's disease (PD) patients to some extent. Fractional anisotropy (FA) and relaxation time T2 that indicate the integrity of fiber tracts and iron concentrations in brain tissue have been used to evaluate the therapeutic effects of LITUS. This study aims to use FA and T2 values to evaluate the therapeutic effects of LITUS in a PD rat model. Twenty Sprague-Dawley rats were randomly divided into a hemi-PD group ( = 10) and a LITUS group ( = 10). Single-shot spin echo echo-planar imaging and fast low-angle shot T2WI sequences at 3.0 T were used. The FA and T2 values on the right side of the substantia nigra (SN) pars compacta were measured to evaluate the therapeutic effect of LITUS in the rats. One week after PD-like signs were induced in the rats, the FA value in the LITUS group was significantly larger compared with the PD group (0.214 ± 0.027 vs. 0.340 ± 0.032, = 2.864, = 0.011). At the 5th and 6th weeks, the FA values in the LITUS group were significantly smaller compared with the PD group (5th week: 0.290 ± 0.037 vs. 0.405 ± 0.027, = 2.385, = 0.030; 6th week: 0.299 ± 0.021 vs. 0.525 ± 0.028, = 6.620, < 0.0001). In the 5th and 6th weeks, the T2 values in the injected right SN of the LITUS group were significantly higher compared with the PD group (5th week, 12.169 ± 0.826 in the LITUS group vs. 7.550 ± 0.824 in the PD group; 6th week, 11.749 ± 0.615 in the LITUS group vs. 7.550 ± 0.849 in the PD group). LITUS had neuroprotective effects and can reduce the damage of 6-OHDA-induced neurotoxicity in hemi-PD rats. The combination of FA and T2 assessments can potentially serve as a new and effective method to evaluate the therapeutic effects of LITUS.
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http://dx.doi.org/10.3389/fnins.2021.590354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900573PMC
February 2021

Preparation and Biological Property Evaluation of Novel Cationic Lipid-Based Liposomes for Efficient Gene Delivery.

AAPS PharmSciTech 2021 Jan 3;22(1):22. Epub 2021 Jan 3.

Pharmacy Department, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, China.

Novel cationic lipid-based liposomes prepared using an amphiphilic cationic lipid material, N,N-dimethyl-(N',N'-di-stearoyl-1-ethyl)1,3-diaminopropane (DMSP), have been proposed to enhance the transfection of nucleic acids. Herein, we designed and investigated liposomes prepared using DMSP, soybean phosphatidylcholine, and cholesterol. This novel gene vector has high gene loading capabilities and excellent protection against nuclease degradation. An in vitro study showed that the liposomes had lower toxicity and superior cellular uptake and transfection efficiency compared with Lipofectamine 2000. An endosomal escape study revealed that the liposomes demonstrated high endosomal escape and released their genetic payload in the cytoplasm efficiently. Mechanistic studies indicated that the liposome/nucleic acid complexes entered cells through energy-dependent endocytosis that was mediated by fossa proteins. These results suggest that such cationic lipid-based liposome vectors have potential for clinical gene delivery.
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http://dx.doi.org/10.1208/s12249-020-01868-wDOI Listing
January 2021

Reconstitution of a mini-gene cluster combined with ribosome engineering led to effective enhancement of salinomycin production in Streptomyces albus.

Microb Biotechnol 2020 Dec 3. Epub 2020 Dec 3.

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.

Salinomycin, an FDA-approved polyketide drug, was recently identified as a promising anti-tumour and anti-viral lead compound. It is produced by Streptomyces albus, and the biosynthetic gene cluster (sal) spans over 100 kb. The genetic manipulation of large polyketide gene clusters is challenging, and approaches delivering reliable efficiency and accuracy are desired. Herein, a delicate strategy to enhance salinomycin production was devised and evaluated. We reconstructed a minimized sal gene cluster (mini-cluster) on pSET152 including key genes responsible for tailoring modification, antibiotic resistance, positive regulation and precursor supply. These genes were overexpressed under the control of constitutive promoter P or P . The pks operon was not included in the mini-cluster, but it was upregulated by SalJ activation. After the plasmid pSET152::mini-cluster was introduced into the wild-type strain and a chassis host strain obtained by ribosome engineering, salinomycin production was increased to 2.3-fold and 5.1-fold compared with that of the wild-type strain respectively. Intriguingly, mini-cluster introduction resulted in much higher production than overexpression of the whole sal gene cluster. The findings demonstrated that reconstitution of sal mini-cluster combined with ribosome engineering is an efficient novel approach and may be extended to other large polyketide biosynthesis.
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http://dx.doi.org/10.1111/1751-7915.13686DOI Listing
December 2020

SnpHub: an easy-to-set-up web server framework for exploring large-scale genomic variation data in the post-genomic era with applications in wheat.

Gigascience 2020 06;9(6)

Key Laboratory of Crop Heterosis and Utilization, State Key Laboratory for Agrobiotechnology, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China.

Background: The cost of high-throughput sequencing is rapidly decreasing, allowing researchers to investigate genomic variations across hundreds or even thousands of samples in the post-genomic era. The management and exploration of these large-scale genomic variation data require programming skills. The public genotype querying databases of many species are usually centralized and implemented independently, making them difficult to update with new data over time. Currently, there is a lack of a widely used framework for setting up user-friendly web servers to explore new genomic variation data in diverse species.

Results: Here, we present SnpHub, a Shiny/R-based server framework for retrieving, analysing, and visualizing large-scale genomic variation data that can be easily set up on any Linux server. After a pre-building process based on the provided VCF files and genome annotation files, the local server allows users to interactively access single-nucleotide polymorphisms and small insertions/deletions with annotation information by locus or gene and to define sample sets through a web page. Users can freely analyse and visualize genomic variations in heatmaps, phylogenetic trees, haplotype networks, or geographical maps. Sample-specific sequences can be accessed as replaced by detected sequence variations.

Conclusions: SnpHub can be applied to any species, and we build up a SnpHub portal website for wheat and its progenitors based on published data in recent studies. SnpHub and its tutorial are available at http://guoweilong.github.io/SnpHub/. The wheat-SnpHub-portal website can be accessed at http://wheat.cau.edu.cn/Wheat_SnpHub_Portal/.
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http://dx.doi.org/10.1093/gigascience/giaa060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274028PMC
June 2020

Direct Pyrolysis of Supermolecules: An Ultrahigh Edge-Nitrogen Doping Strategy of Carbon Anodes for Potassium-Ion Batteries.

Adv Mater 2020 Jun 14;32(25):e2000732. Epub 2020 May 14.

Materials Science and Engineering, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.

Most reported carbonaceous anodes of potassium-ion batteries (PIBs) have limited capacities. One approach to improve the performance of carbon anodes is edge-nitrogen doping, which effectively enhances the K-ion adsorption energy. It remains challenging to achieve high edge-nitrogen doping due to the difficulty in controlling the nitrogen dopant configuration. Herein, a new synthesis strategy is proposed to prepare carbon anodes with ultrahigh edge-nitrogen doping for high-performance PIBs. Specifically, self-assembled supermolecule precursors derived from pyromellitic acid and melamine are directly pyrolyzed. During the pyrolysis process, the amidation and imidization reactions between pyromellitic acid and melamine before carbonization enable the successful carbonization of pyromellitic acid-melamine supermolecule. The obtained 3D nitrogen-doped turbostratic carbon (3D-NTC) possesses a 3D framework composed of carbon nanosheets, turbostratic crystalline structure, and an ultrahigh edge-nitrogen-doping level up to 16.8 at% (73.7% of total 22.8 at% nitrogen doping). These features endow 3D-NTCs with remarkable performances as PIB anodes. The 3D-NTC anode displays a high capacity of 473 mAh g , robust rate capability, and a long cycle life of 500 cycles with a high capacity retention of 93.1%. This new strategy will boost the development of carbon anodes for rechargeable alkali-metal-ion batteries.
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http://dx.doi.org/10.1002/adma.202000732DOI Listing
June 2020

A Hierarchical Three-Dimensional Porous Laser-Scribed Graphene Film for Suppressing Polysulfide Shuttling in Lithium-Sulfur Batteries.

ACS Appl Mater Interfaces 2020 Apr 10;12(16):18833-18839. Epub 2020 Apr 10.

Materials Science and Engineering, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

The lithium-sulfur (Li-S) battery is a promising next-generation rechargeable battery with high energy density. Given the outstanding capacities of sulfur (1675 mAh g) and lithium metal (3861 mAh g), Li-S battery theoretically delivers an ultrahigh energy density of 2567 Wh kg. However, this energy density cannot be realized due to several factors, particularly the shuttling of polysulfide intermediates between the cathode and anode, which causes serious degradation of capacity and cycling stability of a Li-S battery. In this work, a simple and scalable route was employed to construct a freestanding laser-scribed graphene (LSG) interlayer that effectively suppresses the polysulfide shuttling in Li-S batteries. Thus, a high specific capacity (1160 mAh g) with excellent cycling stability (80.4% capacity retention after 100 cycles) has been achieved due to the unique structure of hierarchical three-dimensional pores in the freestanding LSG.
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http://dx.doi.org/10.1021/acsami.0c01135DOI Listing
April 2020

The Opposed Effects of Polyvinylpyrrolidone K30 on Dissolution and Precipitation for Indomethacin Supersaturating Drug Delivery Systems.

AAPS PharmSciTech 2020 Mar 17;21(3):107. Epub 2020 Mar 17.

College of Pharmaceutical Science, Zhejiang University of Technology, 18# Chaowang Road, Hangzhou, Zhejiang, 310014, People's Republic of China.

Amorphous solid dispersions (ASD) are one of the most important supersaturating drug delivery systems (SDDS) for poorly water-soluble drugs to improve their bioavailability. As a result of thermodynamic instability, drug molecules tend to precipitate during storage and dissolution in gastrointestinal tract. Various precipitation inhibitors (PI) have been widely used to improve the stability in the past decade. However, most studies have investigated the inhibiting capability of PI on drug precipitation, rarely considering their potential hindering effect on the drug dissolution. The present study designed an ASD of Indomethacin (IND) and Eudragit® EPO by hot melt extrusion to investigate the influence of the added PI (PVP-K30) into ASD both on dissolution and precipitation. The precipitation study by solvent shift method indicated PVP-K30 could inhibit the precipitation of IND significantly. The dissolution study in different concentrations of PVP-K30 showed when the concentration increased above 50 μg/mL, PVP-K30 displayed an acceptable precipitation inhibition without drug concentration decline but an unexpected dissolution impediment with the reduction of maximum concentration platform. The dissolution tests of physical mixtures (PMs) of ASD and PVP-K30 also showed the precipitation inhibition and dissolution impediment when more than 2% PVP-K30 in PMs. This opposed effect of PVP-K30 was strengthen in ternary systems prepared by hot melt extruding the mixtures of IND, Eudragit® EPO and PVP-K30. All of these results proved the PI may be a double-edged sword for the opposed effects of precipitation inhibition and dissolution impediment, which should be carefully considered in the design and development of SDDS.
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http://dx.doi.org/10.1208/s12249-020-01647-7DOI Listing
March 2020

Carbon Nanotubes Coupled with Metal Ion Diffusion Layers Stabilize Oxide Conversion Reactions in High-Voltage Lithium-Ion Batteries.

ACS Appl Mater Interfaces 2020 Apr 24;12(14):16276-16285. Epub 2020 Mar 24.

State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, China.

Creating new architectures combined with super diverse materials for achieving more excellent performances has attracted great attention recently. Herein, we introduce a novel dual metal (oxide) microsphere reinforced by vertically aligned carbon nanotubes (CNTs) and covered with a titanium oxide metal ion-transfer diffusion layer. The CNTs penetrate the oxide particles and buffer structural volume change while enhancing electrical conductivity. Meanwhile, the external TiO-C shell serves as a transport pathway for mobile metal ions (e.g., Li) and acts as a protective layer for the inner oxides by reducing the electrolyte/metal oxide interfacial area and minimizing side reactions. The proposed design is shown to significantly improve the stability and Coulombic efficiency (CE) of metal (oxide) anodes. For example, the as-prepared [email protected] microsphere demonstrates an extremely high capacity of 967 mA h g after 200 cycles, where a CE as high as 99% is maintained. Even at a harsh rate of 5 A g (ca. 5 C), a capacity of 389 mA h g can be maintained for thousands of cycles. The proposed oxide anode design was combined with a nickel-rich cathode to make a full-cell battery that works at high voltage and exhibits impressive stability and life span.
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http://dx.doi.org/10.1021/acsami.9b22175DOI Listing
April 2020

A Site-Selective Doping Strategy of Carbon Anodes with Remarkable K-Ion Storage Capacity.

Angew Chem Int Ed Engl 2020 Mar 29;59(11):4448-4455. Epub 2020 Jan 29.

Materials Science and Engineering, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.

The limited potassium-ion intercalation capacity of graphite hampers development of potassium-ion batteries (PIB). Edge-nitrogen doping is an effective approach to enhance K-ion storage in carbonaceous materials. One shortcoming is the lack of precise control over producing the edge-nitrogen configuration. Here, a molecular-scale copolymer pyrolysis strategy is used to precisely control edge-nitrogen doping in carbonaceous materials. This process results in defect-rich, edge-nitrogen doped carbons (ENDC) with a high nitrogen-doping level (up to 10.5 at %) and a high edge-nitrogen ratio (87.6 %). The optimized ENDC exhibits a high reversible capacity of 423 mAh g , a high initial Coulombic efficiency of 65 %, superior rate capability, and long cycle life (93.8 % retention after three months). This strategy can be extended to design other edge-heteroatom-rich carbons through pyrolysis of copolymers for efficient storage of various mobile ions.
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http://dx.doi.org/10.1002/anie.201913368DOI Listing
March 2020

Improvement of dissolution and tabletability of carbamazepine solid dispersions with high drug loading prepared by hot-melt extrusion.

Pharmazie 2019 09;74(9):523-528

Solid dispersions (SDs) have made great progress in the improvement of dissolution for poorly soluble drugs, however the low drug loading still limits their wide application. In the present paper, high carbamazepine (CBZ) loaded SDs with excellent dissolution and tabletability were prepared and characterized. The CBZ SDs were prepared with Eudragit EPO as carrier by hot-melt extrusion (HME) in the drug: carrier ratio of 4:1. Powder X-ray diffraction, differential scanning calorimetry, fourier transform infrared spectroscopy and powder dissolution was carried out to characterize the SDs. The results showed that the crystalline form the polymorph of CBZ in SDs was transformed into form I from form III after extruded at 140 °C. Wettability and microstructure of CBZ SDs were improved by the HME process, which promoted the dissolution significantly. More than 85 % drug dissolved within 5 min from CBZ SDs with even only 20 % Eudragit EPO as carrier. CBZ SDs tablets were prepared by direct tableting with a universal material testing machine at various compaction pressures. Compactibility and tabletability were enhanced significantly by the HME process. All of these results showed the CBZ SDs prepared by HME with 80 % CBZ and 20 % Eudragit EPO could improve the dissolution and tabletability significantly.
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http://dx.doi.org/10.1691/ph.2019.9008DOI Listing
September 2019

PVT1 Promotes Cancer Progression via MicroRNAs.

Front Oncol 2019 15;9:609. Epub 2019 Jul 15.

NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China.

Non-coding RNA (ncRNA) plays a regulatory role in a variety of cellular activities. And long non-coding RNA (lncRNA) is one of the important kinds of ncRNA. Previous studies have shown that various lncRNAs are involved in the progression of cancer. LncRNA plasmacytoma variant translocation 1 (PVT1) is a newly discovered oncogenic factor that has been confirmed to be overexpressed in many cancer cells. Moreover, the role of PVT1 in cancer development is closely linked to microRNAs (miRNAs). PVT1 can act as a "sponge" for miRNAs to inhibit their activities, thereby affecting proliferation, invasion, and angiogenesis of cancer. In addition, PVT1 itself can be spliced and processed into several miRNAs such as miR-1204 and miR-1207, which can also regulate the development of cancer. This review summarizes various pathways through which PVT1 regulates the progression of cancer via miRNAs. We also propose additional regulatory mechanisms of PVT1 and their potential clinical applications.
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http://dx.doi.org/10.3389/fonc.2019.00609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644598PMC
July 2019

Slp-coated liposomes for drug delivery and biomedical applications: potential and challenges.

Int J Nanomedicine 2019 20;14:1359-1383. Epub 2019 Feb 20.

Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,

Slp forms a crystalline array of proteins on the outermost envelope of bacteria and archaea with a molecular weight of 40-200 kDa. Slp can self-assemble on the surface of liposomes in a proper environment via electrostatic interactions, which could be employed to functionalize liposomes by forming Slp-coated liposomes for various applications. Among the molecular characteristics, the stability, adhesion, and immobilization of biomacromolecules are regarded as the most meaningful. Compared to plain liposomes, Slp-coated liposomes show excellent physicochemical and biological stabilities. Recently, Slp-coated liposomes were shown to specifically adhere to the gastrointestinal tract, which was attributed to the "ligand-receptor interaction" effect. Furthermore, Slp as a "bridge" can immobilize functional biomacromol-ecules on the surface of liposomes via protein fusion technology or intermolecular forces, endowing liposomes with beneficial functions. In view of these favorable features, Slp-coated liposomes are highly likely to be an ideal platform for drug delivery and biomedical uses. This review aims to provide a general framework for the structure and characteristics of Slp and the interactions between Slp and liposomes, to highlight the unique properties and drug delivery as well as the biomedical applications of the Slp-coated liposomes, and to discuss the ongoing challenges and perspectives.
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http://dx.doi.org/10.2147/IJN.S189935DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6388732PMC
April 2019

Lamellarly Stacking Porous N, P Co-Doped Mo C/C Nanosheets as High Performance Anode for Lithium-Ion Batteries.

Small 2019 Feb 30;15(8):e1805022. Epub 2019 Jan 30.

Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.

Layered stacking and highly porous N, P co-doped Mo C/C nanosheets are prepared from a stable Mo-enhanced hydrogel. The hydrogel is formed through the ultrafast cross-linking of phosphomolybdic acid and chitosan. During the reduction of the composite hydrogel framework under inert gas protection, highly porous N and P co-doped carbon nanosheets are produced with the in situ formation of ultrafine Mo C nanoparticles highly distributed throughout the nanosheets which are entangled via a hierarchical lamellar infrastructure. This unique architecture of the N, P co-doped Mo C/C nanosheets tremendously promote the electrochemical activity and operate stability with high specific capacity and extremely stable cycling. In particular, this versatile synthetic strategy can also be extended to other polyoxometalate (such as phosphotungstic acid) to provide greater opportunities for the controlled fabrication of novel hierarchical nanostructures for next-generation high performance energy storage applications.
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http://dx.doi.org/10.1002/smll.201805022DOI Listing
February 2019

Identification of a butenolide signaling system that regulates nikkomycin biosynthesis in .

J Biol Chem 2018 12 24;293(52):20029-20040. Epub 2018 Oct 24.

From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China and; the College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:

Butenolides are an emerging family of signaling molecules in They control complex physiological traits, such as morphological differentiation and antibiotic production. However, how butenolides regulate these processes is poorly investigated because of obstacles in obtaining these signaling molecules. This study reports the identification of a butenolide-type signaling system for nikkomycin biosynthesis in with distinct features. We identified a gene cluster, , consisting of three genes, , for butenolide biosynthesis and two regulator genes, and , and characterized three butenolides (SAB1, -2, and -3) by heterologous expression of disruption abolished nikkomycin production, which could be restored by the addition of SABs or by deletion of in ΔsabA. Electrophoretic mobility-shift assays and transcriptional analyses indicated that SabR1 indirectly represses the transcription of nikkomycin biosynthetic genes, but directly represses and In the presence of SABs, the SabR1 transcriptional regulator dissociated from its target genes, verifying that SabR1 is the cognate receptor of SABs. Genome-wide scanning with the conserved SabR1-binding sequence revealed another SabR1 target gene, , whose transcription was strongly repressed by SabR1. Intriguingly, CprC positively regulated the pleiotropic regulatory gene by binding to its promoter and, in turn, activated nikkomycin biosynthesis. This is the first report that butenolide-type signaling molecules and their cognate receptor SabR1 can regulate via a newly identified activator, CprC, to control nikkomycin production. These findings pave the way for further studies seeking to unravel the regulatory mechanism and functions of the butenolide signaling system in .
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http://dx.doi.org/10.1074/jbc.RA118.005667DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6311496PMC
December 2018

Circular RNAs (circRNAs) in cancer.

Cancer Lett 2018 07 3;425:134-142. Epub 2018 Apr 3.

The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha, Hunan, China; The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan, China; Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China. Electronic address:

Circular RNAs (circRNAs) are a class of non-coding RNAs that do not have 5' end caps or 3' end poly (A) tails. There are more than one hundred thousand genes that encode circRNAs. Clinical data show that there are differences in the expression of circRNAs in a variety of diseases, including cancer, suggesting that circRNA has a regulatory effect on some diseases. Further studies reveal that circRNA can be used as an endogenous competitive RNA, thereby regulating the proliferation, invasion or other physiological activities of tumor cells. In addition, some circRNAs located in the nucleus can regulate the transcription of the parental gene by binding to RNA polymerase II. circRNA can also combine with proteins to influence the cell cycle. Furthermore, recent studies have shown that circRNA can encode proteins, similarly to mRNA. circRNAs are found extensively in human cells and have tissue specificity. They have the potential to be used in clinical applications as tumor markers and therapeutic targets.
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http://dx.doi.org/10.1016/j.canlet.2018.03.035DOI Listing
July 2018

Synergistic Effects of C/α-MoC and Ag for Efficient Oxygen Reduction Reaction.

J Phys Chem Lett 2018 Feb 2;9(4):779-784. Epub 2018 Feb 2.

Department of Materials Science & Engineering, Southern University of Science and Technology , Shenzhen 518055, P. R. China.

It remains challenging to prepare highly active and stable catalysts from earth-abundant elements for the oxygen reduction reaction (ORR). Herein we report a facile method to synthesize cost-effective heterogeneous C/α-MoC/Ag electrocatalysts. Rotating disc electrode (RDE) experiments revealed that the obtained C/α-MoC/Ag exhibited much superior catalytic performance for ORR than that of C/Ag, C/α-MoC, or even the conventional Pt/C. First-principles calculations indicated that the enhanced activity could be attributed to the efficient synergistic effects between Ag and α-MoC/C by which the energy barrier for O dissociation has been substantially reduced. Furthermore, Li-air and Al-air cells were assembled to demonstrate the unprecedented electrochemical performance of C/α-MoC/Ag nanocomposites surpassing the Pt/C. Thus experimental results and theoretical calculations together showed that the heterogeneous C/α-MoC/Ag nanocomposites are a promising alternative to platinum for applications in industrial metal-air batteries.
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http://dx.doi.org/10.1021/acs.jpclett.7b03347DOI Listing
February 2018

Physicochemical characterization and gastrointestinal adhesion of S-layer proteins-coating liposomes.

Int J Pharm 2017 Aug 4;529(1-2):227-237. Epub 2017 Jul 4.

College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China.

S-layer proteins (Slps) are crystalline arrays of protein on bacterial cell surface layers. Owning to their capability to reassemble on the surface of lipid layers, Slps have been employed to modify liposomes for various profits. But the interaction information between Slps and positively charged liposomes are destitute, especially the gastrointestinal adhesion of Slps-coating liposomes is rarely reported. In the present work, the Slps extracted from Lactobacillus helveticus were reassembled on the surface of novel positively charged liposomes composed of soybean lecithin, EudragitRL100 and cholesterol. The particle size and remarkable changes of Zeta potential with various Slps/lipid weight ratios were determined by dynamic light scattering and phase analysis light scattering. Significant difference in fluorescence dequenching percentage of liposomes decorated by ODA-FITC confirmed Slps self-reassemble on the surface of liposomes. A higher integrity of vesicular membrane after the addition of Triton X-100 solution demonstrated the stability enhancement of Slps-coating liposomes. Fourier transform infrared (FTIR) spectroscopy illustrated the interaction came from non-covalent bond. The mucoadhesion of Slps-coating liposomes was evaluated by the resident FITC-LP on the gastric and intestinal tract of mice at 7h and 12h after intragastrical administration, which proved that the Slps-coating improved the gastrointestinal adhesion significantly.
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http://dx.doi.org/10.1016/j.ijpharm.2017.07.006DOI Listing
August 2017

Low-Cost and Novel Si-Based Gel for Li-Ion Batteries.

ACS Appl Mater Interfaces 2017 Mar 14;9(12):10699-10707. Epub 2017 Mar 14.

Department of Materials Science & Engineering, South University of Science and Technology of China , Shenzhen 518055, P.R. China.

Si-based nanostructure composites have been intensively investigated as anode materials for next-generation lithium-ion batteries because of their ultra-high-energy storage capacity. However, it is still a great challenge to fabricate a perfect structure satisfying all the requirements of good electrical conductivity, robust matrix for buffering large volume expansion, and intact linkage of Si particles upon long-term cycling. Here, we report a novel design of Si-based multicomponent three-dimensional (3D) networks in which the Si core is capped with phytic acid shell layers through a facile high-energy ball-milling method. By mixing the functional Si with graphene oxide and functionalized carbon nanotube, we successfully obtained a homogeneous and conductive rigid silicon-based gel through complexation. Interestingly, this Si-based gel with a fancy 3D cross-linking structure could be writable and printable. In particular, this Si-based gel composite delivers a moderate specific capacity of 2711 mA h g at a current density of 420 mA g and retained a competitive discharge capacity of more than 800.00 mA h g at the current density of 420 mA g after 700 cycles. We provide a new method to fabricate durable Si-based anode material for next-generation high-performance lithium-ion batteries.
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http://dx.doi.org/10.1021/acsami.7b00460DOI Listing
March 2017

Cationic Polymethacrylate-Modified Liposomes Significantly Enhanced Doxorubicin Delivery and Antitumor Activity.

Sci Rep 2017 02 22;7:43036. Epub 2017 Feb 22.

College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China.

Liposome (LP) encapsulation of doxorubicin (DOX) is a clinically validated method for cancer drug delivery, but its cellular uptake is actually lower than the free DOX. Therefore, we modified DOX-LP with a cationic polymer (Eudragit RL100; ER) to improve its cellular uptake and antitumor activity. The resulting DOX-ERLP was a 190 nm nanoparticle that was absorbed efficiently and caused cancer cell death in 5 hrs. Growth as measured by the MTT assay or microscopic imaging demonstrated that DOX-ERLP has at least a two-fold greater potency than the free DOX in inhibiting the growth of a DOX resistant (MCF7/adr) cell and an aggressive liver cancer H22 cell. Further, its in vivo efficacy was tested in H22-bearing mice, where four injections of DOX-ERLP reduced the tumor growth by more than 60% and caused an average of 60% tumor necrosis, which was significantly better than the DOX and DOX-LP treated groups. Our work represents the first use of polymethacrylate derivatives for DOX liposomal delivery, demonstrating the great potential of cationic polymethacrylate modified liposomes for improving cancer drug delivery.
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http://dx.doi.org/10.1038/srep43036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5320526PMC
February 2017

Supramolecular hydrogel directed self-assembly of C- and N-doped hollow CuO as high-performance anode materials for Li-ion batteries.

Chem Commun (Camb) 2017 Feb;53(13):2138-2141

Department of Materials Science & Engineering, South University of Science and Technology of China, Shenzhen, P. R. China.

A novel hollow-structured CuO derived from chitosan-coated Cu/CuO composite hollow spheres was mass produced via a supramolecular hydrogel templating method and homogeneously co-doped with C and N. Evaluation of the as-produced co-doped CuO hollow spheres as anode materials for Li ion batteries showed that they had superior electrochemical properties.
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http://dx.doi.org/10.1039/c6cc09702bDOI Listing
February 2017

Highly durable organic electrode for sodium-ion batteries via a stabilized α-C radical intermediate.

Nat Commun 2016 11 7;7:13318. Epub 2016 Nov 7.

Department of Materials Science and Engineering, South University of Science and Technology of China, Shenzhen 518055, China.

It is a challenge to prepare organic electrodes for sodium-ion batteries with long cycle life and high capacity. The highly reactive radical intermediates generated during the sodiation/desodiation process could be a critical issue because of undesired side reactions. Here we present durable electrodes with a stabilized α-C radical intermediate. Through the resonance effect as well as steric effects, the excessive reactivity of the unpaired electron is successfully suppressed, thus developing an electrode with stable cycling for over 2,000 cycles with 96.8% capacity retention. In addition, the α-radical demonstrates reversible transformation between three states: C=C; α-C·radical; and α-C anion. Such transformation provides additional Na storage equal to more than 0.83 Na insertion per α-C radical for the electrodes. The strategy of intermediate radical stabilization could be enlightening in the design of organic electrodes with enhanced cycling life and energy storage capability.
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http://dx.doi.org/10.1038/ncomms13318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5103065PMC
November 2016

Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers.

Sensors (Basel) 2016 Aug 22;16(8). Epub 2016 Aug 22.

Department of Mechanical Engineering, University of Houston, Houston, TX 77004, USA.

A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT) piezoceramic transducer with marble protection, called a smart aggregate (SA), was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this research to compute the total signal energy received by PZT sensors. Experimental results show that the energy levels of the PZT sensors can reflect the degree of grouting compactness in the duct. The proposed method has the potential to be implemented to monitor the tendon duct grouting compactness of the reinforced concrete structures with post tensioning.
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http://dx.doi.org/10.3390/s16081343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017505PMC
August 2016

Preparation and Characterization of Minoxidil Loaded Nanostructured Lipid Carriers.

AAPS PharmSciTech 2017 Feb 27;18(2):509-516. Epub 2016 Apr 27.

College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, People's Republic of China.

Nanostructured lipid carriers (NLCs) are interesting delivery systems for enhancing the penetration of an active substance through the skin after topical administration. The present paper described the development of a novel NLCs for minoxidil (MXD) topical delivery. Stearic acid and oleic acid that showed the highest solubility for MXD were selected as solid lipid and liquid lipid, respectively, and the NLCs were prepared by hot high pressure homogenization method. The minoxidil loaded NLCs prepared accordingly to the optimal formulation exhibited spherical shape with a mean diameter of 281.4 ± 7.4 nm, polydispersity of 0.207 ± 0.009, zeta potential of -32.90 ± 1.23 mV, drug entrapment efficiency of 92.48 ± 0.31%, and drug loading of 13.85 ± 0.47%. Storage stability studies demonstrated that the particle size and entrapment efficiency of the MXD-NLCs were not changed during 3 months both at 4°C and room temperature. Moreover, the release of MXD from the NLCs was faster than drug release from SLNs. In vitro skin permeability test demonstrated that MXD-NLCs had a more pronounced permeation and retention profile than MXD-SLNs. Furthermore, no erythema was observed after administration of MXD-NLCs. All these results indicated that the developed MXD-NLCs could be a promising and effective nanocarrier for topical delivery of MXD.
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http://dx.doi.org/10.1208/s12249-016-0519-xDOI Listing
February 2017

pH-Responsive Shape Memory Poly(ethylene glycol)-Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite.

ACS Appl Mater Interfaces 2015 Jun 2;7(23):12988-99. Epub 2015 Jun 2.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, People's Republic of China.

In this study, we developed a pH-responsive shape-memory polymer nanocomposite by blending poly(ethylene glycol)-poly(ε-caprolactone)-based polyurethane (PECU) with functionalized cellulose nanocrystals (CNCs). CNCs were functionalized with pyridine moieties (CNC-C6H4NO2) through hydroxyl substitution of CNCs with pyridine-4-carbonyl chloride and with carboxyl groups (CNC-CO2H) via 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated surface oxidation, respectively. At a high pH value, the CNC-C6H4NO2 had attractive interactions from the hydrogen bonding between pyridine groups and hydroxyl moieties; at a low pH value, the interactions reduced or disappeared due to the protonation of pyridine groups, which are a Lewis base. The CNC-CO2H responded to pH variation in an opposite manner. The hydrogen bonding interactions of both CNC-C6H4NO2 and CNC-CO2H can be readily disassociated by altering pH values, endowing the pH-responsiveness of CNCs. When these functionalized CNCs were added in PECU polymer matrix to form nanocomposite network which was confirmed with rheological measurements, the mechanical properties of PECU were not only obviously improved but also the pH-responsiveness of CNCs could be transferred to the nanocomposite network. The pH-sensitive CNC percolation network in polymer matrix served as the switch units of shape-memory polymers (SMPs). Furthermore, the modified CNC percolation network and polymer molecular chains also had strong hydrogen bonding interactions among hydroxyl, carboxyl, pyridine moieties, and isocyanate groups, which could be formed or destroyed through changing pH value. The shape memory function of the nanocomposite network was only dependent on the pH variation of the environment. Therefore, this pH-responsive shape-memory nancomposite could be potentially developed into a new smart polymer material.
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http://dx.doi.org/10.1021/acsami.5b02940DOI Listing
June 2015

A high performance O2 selective membrane based on [email protected] and the PMMA polymer for Li-air batteries.

Chem Commun (Camb) 2015 Mar;51(21):4364-7

Department of Materials Science & Engineering, South University of Science and Technology of China, Shenzhen, P. R. China.

A novel mixed matrix membrane (MMM) was prepared by incorporating polydopamine-coated metal organic framework (MOF) crystals of CAU-1-NH2 into a PMMA (polymethylmethacrylate) matrix. The MMM possesses the advantages of high O2 permeability, high capability of carbon dioxide capture, and excellent hydrophobic behavior. The MMM was assembled in the Li-air batteries which displayed promising electrochemical performance in the real ambient air with 30% relative humidity.
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http://dx.doi.org/10.1039/c4cc09281cDOI Listing
March 2015

Thermally activated reversible shape switch of polymer particles.

J Mater Chem B 2014 Oct 5;2(39):6855-6866. Epub 2014 Sep 5.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China.

The particles that can reversibly switch shape in response to an environmental stimulus are preferable for controlling the performance of drug carriers. In this work, we present a facile strategy towards the design and fabrication of polymer particles that can reversibly switch their shape on the basis of a biocompatible and biodegradable polymer network containing well-defined six-arm poly(ethylene glycol)-poly(ε-caprolactone) (6A PEG-PCL). These polymer particles have a capacity of reversibly changing shape from spherical to elliptical either extracellularly or intracellularly with the cyclic heating and cooling between 43 °C and 0 °C under a stress-free condition via a reversible two-way shape memory effect (2W-SME) of a polymer matrix. This study of the shape-switching particles opens up exciting possibilities for engineering dynamically shape-switching drug delivery carriers to either avoid or promote phagocytosis.
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http://dx.doi.org/10.1039/c4tb01155dDOI Listing
October 2014

Triple shape memory effect of star-shaped polyurethane.

ACS Appl Mater Interfaces 2014 May 5;6(9):6545-54. Epub 2014 May 5.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, P.R. China.

In this study, we synthesized one type of star-shaped polyurethane (SPU) with star-shaped poly(ε-caprolactone) (SPCL) containing different arm numbers as soft segment and 4,4'-diphenyl methane diisocyanate (MDI) as well as chain extender 1,4-butylene glycol (BDO) as hard segment. Proton nuclear magnetic resonance (1H-NMR) confirmed the chemical structure of the material. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) results indicated that both the melting temperature (Tm) and transition temperature (Ttrans) of SPU decreased with the hard segment composition increase. X-ray diffraction (XRD) results demonstrated that the increase of the crystallinity of SPU following the raised arm numbers endowed a high shape fixity of six-arm star-shaped polyurethane (6S-PU) and a wide melting temperature range, which resulted in an excellent triple-shape memory effect of 6S-PU. The in vitro cytotoxicity assay evaluated with osteoblasts through Alamar blue assay demonstrates that this copolymer possessed good cytocompatibility. This material can be potentially used as a new smart material in the field of biomaterials.
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http://dx.doi.org/10.1021/am5001344DOI Listing
May 2014

Multiple pqqA genes respond differently to environment and one contributes dominantly to pyrroloquinoline quinone synthesis.

J Basic Microbiol 2015 Mar 4;55(3):312-23. Epub 2013 Jul 4.

Laboratory of Microorganism Engineering, Beijing Institute of Biotechnology, Beijing, China.

Pyrroloquinoline quinone is the third redox cofactor after nicotinamide and flavin in bacteria, and its biosynthesis pathway comprise five steps initiated from a precursor peptide PqqA coded by pqqA gene. Methylovorus sp. MP688 is equipped with five copies of pqqA genes. Herein, the transcription of pqqA genes under different conditions by real-time quantitative PCR and β-galactosidase reporter genes are reported. Multiple pqqA genes were proved to play significant roles and contribute differently in PQQ synthesis. pqqA1, pqqA2, and pqqA4 were determined to be dominantly transcribed over the others, and correspondingly absence of any of the three genes caused a decrease in PQQ synthesis. Notably, pqqA was up-regulated in low pH and limited oxygen environment, and it is pqqA2 promoter that could be induced when bacteria were transferred from pH 7.0 to pH 5.5. Deletion analysis revealed a region within pqqA2 promoter inhibiting transcription. PQQ concentration was increased by overexpression of pqq genes under control of truncated pqqA2 promoter. The results not only imply there exist negative transcriptional regulators for pqqA2 but also provide us a new approach to achieve higher PQQ production by deleting the target binding sequence.
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http://dx.doi.org/10.1002/jobm.201300037DOI Listing
March 2015

Methylovorus sp. MP688 exopolysaccharides contribute to oxidative defense and bacterial survival under adverse condition.

World J Microbiol Biotechnol 2013 Dec 5;29(12):2249-58. Epub 2013 Jun 5.

Laboratory of Microorganism Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai, Beijing, 100071, China.

Methylovorus sp. MP688 is an aerobic bacterium that can grow on reduced C1 compounds such as methanol, being regarded as an attractive producer for many commercial materials including polysaccharides. The aim of the study was to learn more information about the biochemical and physiological functions of extracellular polysaccharides (EPS) produced by Methylovorus sp. MP688. Firstly, gene clusters involved in EPS synthesis were identified by whole genome sequence analysis. Then EPS produced by Methylovorus sp. MP688 were isolated and purified by centrifugation, precipitation and deproteinization. Purified EPS displayed antioxidant activity towards DPPH free radical, hydroxyl radical and superoxide anion radical. Glucose, galactose and mannose were identified to be main component monosaccharides in EPS. One mutant with defect in EPS production was obtained by knocking out epsA gene within EPS synthesis cluster. Strain with deletion of epsA exhibited compromised growth ability in the presence of oxidative stress due to the sharp reduction in EPS synthesis. Meanwhile, the intracellular antioxidant scavengers were activated to a higher level in order to counteract with the excess harmful radicals. In addition, EPS were assimilated by Methylovorus sp. MP688 to survive under disadvantage condition when the preferred carbon source was exhausted. It was reasonable to conclude that EPS produced by Methylovorus sp. MP688 contributed to oxidative defense and bacterial survival under adverse condition.
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http://dx.doi.org/10.1007/s11274-013-1391-4DOI Listing
December 2013
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