Evaluation of genetic response of mesenchymal stem cells to nanosecond pulsed electric fields by whole transcriptome sequencing

BACKGROUND Mesenchymal stem cells(MSCs)modulated by various exogenous signals have been applied extensively in regenerative medicine research.Notably,nanosecond pulsed electric fields(nsPEFs),characterized by short duration and high strength,significantly influence cell phenotypes and regulate MSCs differentiation via multiple pathways.Consequently,we used transcriptomics to study changes in messenger RNA(mRNA),long noncoding RNA(lncRNA),microRNA(miRNA),and circular RNA expression during nsPEFs application.AIM To explore gene expression profiles and potential transcriptional regulatory mechanisms in MSCs pretreated with nsPEFs.METHODS The impact of nsPEFs on the MSCs transcriptome was investigated through whole transcriptome sequencing.MSCs were pretreated with 5-pulse nsPEFs(100 ns at 10 kV/cm,1 Hz),followed by total RNA isolation.Each transcript was normalized by fragments per kilobase per million.Fold change and difference significance were applied to screen the differentially expressed genes(DEGs).Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to elucidate gene functions,complemented by quantitative polymerase chain reaction verification.RESULTS In total,263 DEGs were discovered,with 92 upregulated and 171 downregulated.DEGs were predominantly enriched in epithelial cell proliferation,osteoblast differentiation,mesenchymal cell differentiation,nuclear division,and wound healing.Regarding cellular components,DEGs are primarily involved in condensed chromosome,chromosomal region,actin cytoskeleton,and kinetochore.From aspect of molecular functions,DEGs are mainly involved in glycosaminoglycan binding,integrin binding,nuclear steroid receptor activity,cytoskeletal motor activity,and steroid binding.Quantitative real-time polymerase chain reaction confirmed targeted transcript regulation.CONCLUSION Our systematic investigation of the wide-ranging transcriptional pattern modulated by nsPEFs revealed the differential expression of 263 mRNAs,2 miRNAs,and 65 lncRNAs.Our study demonstrates that nsPEFs may affect stem cells through several signaling pathways,which are involved in vesicular transport,calcium ion transport,cytoskeleton,and cell differentiation.

Application of a Pulsed Electric Field to Modify the Free Energy of the Active Site of an Azoreductase

The Gibbs free energy is strongly related to the stability and catalytic function of an enzyme through the energetic changes that occur in the chemical reactions the enzyme catalyzes. In this in silico study, a pulsed electric field was applied to an azoreductase, and its effect on the Gibbs free energy of molecular docking with two dyes was measured. We propose that certain stimuli from a pulsed electric field favor the structural stability of the enzyme by promoting an arrangement in the active site, potentially leading to an enhancement of enzymatic activity overall.

Demulsification Behavior, Characteristics, and Performance of Surfactant Stabilized Oil-in-Water Emulsion under Bidirectional Pulsed Electric Field

As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.

Recent progress in pulsed electric field ablation for liver cancer

The number of liver cancer patients is likely to continue to increase in the coming decades due to the aging of the population and changing risk factors.Traditional treatments cannot meet the needs of all patients.New treatment methods evolved from pulsed electric field ablation are expected to lead to breakthroughs in the treatment of liver cancer.This paper reviews the safety and efficacy of irreversible electroporation in clinical studies,the methods to detect and evaluate its ablation effect,the improvements in equipment and its antitumor effect,and animal and clinical trials on electrochemotherapy.We also summarize studies on the most novel nanosecond pulsed electric field ablation techniques in vitro and in vivo.These research results are certain to promote the progress of pulsed electric field in the treatment of liver cancer.

Removal of phenol by activated alumina bed in pulsed high-voltage electric field

A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2＋. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2＋ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

Effects of High-voltage Pulse Electric Field Treatment on the Structure Stability of Konjac Glucomannan

Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.

Tumor ablation with nanosecond pulsed electric fields

Liver cancer is one of the most malignant cancers. It is reported that 600 000 patients died from liver cancer every year. [1,2] Hepatocellular carcinoma (HCC) is a particular problem because symptoms are not evident until the disease has progressed and hepatitis B, which is prominent specific regions of Asia, is a common precursor of the disease. There are many liver cancer

Design and Experiments of the High Voltage Pulsed Electric Fields Sterilization System

This experiment designed the pulsed electric fields （PEF） of high intensity of 100 kV· cm^-1 sterilization system. Fluorescent pseudomonas as target cell was operated 180 s in the PEF. By observing the difference of the bacteria before and after the disposal by TEM, it is found that the cell walls of the treated bacteria were broken. Irreversible perforations were formed on the cell membrane. The cell inclusions and cell fragments were leaked. The cell died as a result. The results showed that the PEF sterilization system designed can be used for liquid food sterilization experiments.

Influence of pulsed electric field on enzymes, bacteria and volatile flavor compounds of unpasteurized sake

A pulsed electric field(PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect.The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.

Treatment time influences the effects of a low-frequency pulsed electric field on synthesis of tyrosine hydroxylase and dopamine in PC12 cells

BACKGROUND： Electromagnetic radiation can influence dopamine （DA） synthesis in brain tissues or ceils, but electromagnetic frequencies, intensities, and radiation time can produce different effects. In addition, the signal pathway by which electromagnetic radiation influences DA synthesis remains controversial. OBJECTIVE： To determine tyrosine hydroxylase （TH） expression in PC12 cells and DA levels in cell culture media after different periods of low-frequency pulsed electric field （LF-PEF） stimulation, and to determine how LF-PEF signaling stimulates TH synthesis using inhibitors. DESIGN, TIME AND SETTING： A parallel, controlled, cell experiment was performed at the Laboratory of Cell Biology, School of Life Science, East China Normal University, between January and October 2006. MATERIALS： PC12 cells were purchased from the Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China. Nerve growth factor was purchased from PeproTech, USA. The protein kinase A inhibitor, H-89, and mitogen-activated protein kinase kinase inhibitor, U0126, were purchased from Sigma, USA. METHODS： （1） Following routine culture in Dulbecco＇s modified eagle medium, primary PC12 cells were stimulated under LF-PEF （pulse frequency 50.Hz, pulse width 20 μs, peak field strength 1 V/m） for 5, 10, 15, 20, and 30 minutes. （2） Inhibitors （H-89 or U0126, 1 μmol/L） were added 30 minutes before LF-PEF stimulation for 10 minutes. MAIN OUTCOME MEASURES： （1） TH expression was determined by Western blot in PC12 cells at 0.5, 1,2, 3, and 4 days after LF-PEF stimulation. Similarly, DA was measured by high-performance liquid chromatography in media at 2, 3, 4, or 5 days after LF-PEE （2） TH expression was detected 1 day after H-89 or U0126 treatment and LF-PEE RESULTS： （1） Short-term LF-PEF stimulation （5 and 10 minutes） increased TH expression and media DA levels after short-term culture （2 days） （P 〈 0.01）, but both parameters decreased with longer culture （3 4 days） （P 〈 0.01）. Long-term LF-PEF stimulation （15, 20, or 30 minutes） decreased TH and DA synthesis, followed by a rapid increase （P 〈 0.01）. （2） H89 could completely inhibit TH expression in PC12 cells stimulated by LF-PEF for 10 minutes, while the inhibition rate of U0126 was 53.2%. CONCLUSION： Short-term LF-PEF first promotes then inhibits, while long-term LF-PEF first inhibits then promotes, TH and DA synthesis. LF-PEF stimulation regulates TH expression primarily by activating protein kinase A to regulate DA synthesis.

STUDY ON THE MECHANISM OF GRAPHITIZATION IN MOLTEN CAST IRON PROMOTED BY ELECTROPULSE DISCHARGE

From the points of both molten cast iron structure and the appearing ratio of electrons in outer-layer of different atoms, analysis on enhancement mechanism of graphitization ability after processing of the iron by pulse electric discharge has been made, and the theory has been proofed by corresponding experiments. The results show that when the molten cast iron is being processed by pulse electric discharge, both the size of crystal embryos that composed by Fe and C atoms as well as the number of clusters can be reduced, even be separated by such discharging; consequently results in the segre- gation of C atoms in the molten cast iron near the cathode of discharging. The nucleation of graphite in these areas of the iron has been promoted at the discharging temperature; even though such degree has not been reached, the most favorable nucleation conditions of graphite can be at least created. Under the preconditions of not breaking up the graphite crystal embryos, with proper adjustment of discharging frequency, the stronger of the electric field and the longer of the pulsation treatment time are, the more graphitization ability of the molten cast iron is. The theoretical analysis on the above rules consists well with experimental results.

The latest research progress on minimally invasive treatments for hepatocellular carcinoma

Background:Hepatocellular carcinoma(HCC)is the fourth leading cause of cancer-related death worldwide.Due to the high prevalence of hepatitis B virus(HBV)infection in China,the incidence of HCC in China is high,and liver cirrhosis caused by chronic hepatitis also brings great challenges to treatment.This paper reviewed the latest research progress on minimally invasive treatments for HCC,including percutaneous thermal ablation and new nonthermal ablation techniques,and introduced the principles,advantages,and clinical applications of various therapeutic methods in detail.Data sources:The data of treatments for HCC were systematically collected from the Pub Med,Science Direct,American Chemical Society and Web of Science databases published in English,using“minimally invasive”and“hepatocellular carcinoma”or“liver cancer”as the keywords.Results:Percutaneous thermal ablation is still a first-line strategy for the minimally invasive treatment of HCC.The effect of microwave ablation(MWA)on downgrading treatment before liver transplantation is better than that of radiofrequency ablation(RFA),while RFA is more widely used in the clinical practice.High-intensity focused ultrasound(HIFU)is mainly used for the palliative treatment of advanced liver cancer.Electrochemotherapy(ECT)delivers chemotherapeutic drugs to the target cells while reducing the blood supply around HCC.Irreversible electroporation(IRE)uses a microsecond-pulsed electric field that induces apoptosis and necrosis and triggers a systemic immune response.The nanosecond pulsed electric field(ns PEF)has achieved a good response in the ablation of mice with HCC,but it has not been reported in China for the treatment of human HCC.Conclusions:A variety of minimally invasive treatments provide a sufficient survival advantage for HCC patients.Nonthermal ablation will lead to a new wave with its unique advantage of antitumor recurrence and metastasis.

Activation of Anti-tumor Immune Response by Ablation of HCC with Nanosecond Pulsed Electric Field

Locoregional therapy is playing an increasingly important role in the non-surgical management of hepatocellular carcinoma(HCC).The novel technique of non-thermal electric ablation by nanosecond pulsed electric field has been recognized as a potential locoregional methodology for indicated HCC.This manuscript explores the most recent studies to indicate its unique anti-tumor immune response.The possible immune mechanism,termed as nano-pulse stimulation,was also analyzed.

Nanosecond pulsed electric fields prime mesenchymal stem cells to peptide ghrelin and enhance chondrogenesis and osteochondral defect repair in vivo

Mesenchymal stem cells(MSCs) are important cell sources in cartilage tissue development and homeostasis,and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting cartilage regeneration.Here we report the effects of combining nanosecond pulsed electric fields(ns PEFs) followed by treatment with ghrelin(a hormone that stimulates release of growth hormone) to regulate chondrogenesis of MSCs.ns PEFs and ghrelin were observed to separately enhance the chondrogenesis of MSCs,and the effects were significantly enhanced when the bioelectric stimulation and hormone were combined,which in turn improved osteochondral tissue repair of these cells within Sprague Dawley rats.We further found that ns PEFs can prime MSCs to be more receptive to subsequent stimuli of differentiation by upregulated Oct4/Nanog and activated JNK signaling pathway.Ghrelin initiated chondrogenic differentiation by activation of ERK1/2 signaling pathway,and RNA-seq results indicated 243 genes were regulated,and JAK-STAT signaling pathway was involved.Interestingly,the sequential order of applying these two stimuli is critical,with ns PEFs pretreatment followed by ghrelin enhanced chondrogenesis of MSCs in vitro and subsequent cartilage regeneration in vivo,but not vice versa.This synergistic prochondrogenic effects provide us new insights and strategies for future cell-based therapies.

Immune response triggered by the ablation of hepatocellular carcinoma with nanosecond pulsed electric field

Nanosecond pulsed electric field(nsPEF)is a novel,nonthermal,and minimally invasive modality that can ablate solid tumors by inducing apoptosis.Recent animal experiments show that nsPEF can induce the immunogenic cell death of hepatocellular carcinoma(HCC)and stimulate the host’s immune response to kill residual tumor cells and decrease distant metastatic tumors.nsPEF-induced immunity is of great clinical importance because the nonthermal ablation may enhance the immune memory,which can prevent HCC recurrence and metastasis.This review summarized the most advanced research on the effect of nsPEF.The possible mechanisms of how locoregional nsPEF ablation enhances the systemic anticancer immune responses were illustrated.nsPEF stimulates the host immune system to boost stimulation and prevail suppression.Also,nsPEF increases the dendritic cell loading and inhibits the regulatory responses,thereby improving immune stimulation and limiting immunosuppression in HCC-bearing hosts.Therefore,nsPEF has excellent potential for HCC treatment.

Effects of high intensity pulsed electric fields on yield and chemical composition of rose essential oil

High intensity pulsed electric fields(PEF)combined with distillation was used to extract essential oil from rose.Three main parameters,namely electric field intensity,pulse number and distillation times,which can affect the efficiency of extraction,were optimized.Then,in order to demonstrate the feasibility of the method,oil obtained under optimal conditions was compared quantitatively and qualitatively with that obtained by conventional hydro distillation.Considering the extraction yield,the optimal parameters combination was obtained with electric field intensity of 20 kV/cm,pulse number of 8 and distillation time of 2 h.PEF treatment had no significant influence on the quality of essential oils.However,there was an increase in methyl eugenol percentage,which is a disadvantage from qualitative point of view.

Explore the mechanism of pulsed electric field technology on improving the antioxidant activity of Leu-Tyr-Gly-Ala-Leu-Gly-Leu

In this study,the synthetic peptide Leu-Tyr-Gly-Ala-Leu-Gly-Leu(LYGALGL)derived from egg white was used as the research object.The structure-activity relationship was elucidated by cell experiment and structure determination.The results of cell experiment showed that the superoxide dismutase(SOD)activity and mitochondrial membrane potential(MMP)of LYGALGL were significantly increased by pulsed electric field(PEF)treatment,especially by 10 kV/cm field intensity treatment(P<0.05).However,the content of reactive oxygen species(ROS)decreased significantly(P<0.05).LYGALG treated with 10 kV/cm showed the highest antioxidant activity.The results of structure determination showed that theβ-turn of LYGALGL increased,the random coil decreased,and the active hydrogen sites moved under 10 kV/cm treatment.The structure of LYGALGL was changed and the active site was exposed by PEF,thus improving the antioxidant activity of LYGALGL.

Review on Non-thermal Technologies for the Preservation of Fruit Juices

Liquid food industries use different preservation methods to extend the shelf life of products by reducing both enzymatic and microorganism activities.Emerging non-thermal pasteurization techniques are applied in order to avoid thermal processes maintaining the microbial safety and quality of liquid foods.Non-thermal preservation technologies used in the liquid food industry include high-pressure processing(HPP),pulsed electric field(PEF),ultraviolet light(UV-C)and ultra-sonication(US).HPP is a method to target specific organisms by applying a pressure range of 100-1,000 MPa.PEF uses short pulses of a strong electric field applied to a flowing liquid food which affects the whole cell membrane of the organism.UV-C treatment at 253.7 nm has been proven to be appropriate for maintaining liquid quality and minimal deterioration of nutrients.US is applied to liquid foods in a lower frequency range of 20-100 kHz and a higher sound intensity of 10-1,000 W/cm2 to the breakdown of cells.According to scientific literature,those methods have been applied to fruit juices like orange,apple,pear,coconut water,etc.Most of the non-thermal methods achieved the Food and Drug Administration(FDA)requirement of a 5-log reduction of microorganisms without deteriorating the sensory and nutritional attributes of fruit juices.Some of these methods have already been commercialized and others are still in a pilot scale.This study gives a comprehensive overview of published literature regarding the potential for using non-thermal pasteurization methods to extend the shelf life of different fruit juices with minimal deterioration of nutritional and sensory quality.

Recent advances in extraction of antioxidants from plant by-products processing industries

The by-products obtained from plant processing industries are the cheap source of bioactive compounds especially antioxidants.Extraction of bioactive compounds can be obtained by using conventional and non-conventional methods.Extraction efficiency of any conventional method mainly depends on the choice of solvents.The major challenges of conventional extraction are longer extraction time,requirement of costly and high purity solvent,evaporation of the huge amount of solvent,low extraction selectivity,and thermal decomposition of thermolabile compounds.To overcome these limitations of conventional extraction methods,new and promising extraction techniques are introduced.These techniques are referred as non-conventional extraction techniques.Therefore,in this review,some of the most promising techniques such as ultrasoundassisted extraction,pulsed electric field extraction,enzyme-assisted extraction,microwave-assisted extraction,pressurized liquid extraction,supercritical fluid extraction,pressurized low-polarity water extraction,and molecular distillation were discussed.The process systems along with industrial applications for non-conventional method of antioxidants extraction were discussed,and the comparative efficacies of different extraction methods were highlighted.Replacing conventional technologies by non-conventional ones for the extraction of valuable compounds from plant by-products processing industries has several advantages,which includes reduction of the processing time,energy consumption,and the uses of harmful and expensive solvents and increase in the extraction yields.Incorporation and development of hybrid methods should be investigated,while considering plant material characteristics and choice of compounds in future.Proper choice of standard methods also influences the measurement of extraction efficiency.The increasing economic significance of bioactive compounds and commodities rich in these bioactive compounds may lead to find out more sophisticated extraction methods in future.