Micro arc oxidation(MAO)coatings were formed on magnesium alloy AZ31B to improve the corrosion resistance using environmental friendly electrolyte solution under single-polar pulse power supply.The effect of electrica...Micro arc oxidation(MAO)coatings were formed on magnesium alloy AZ31B to improve the corrosion resistance using environmental friendly electrolyte solution under single-polar pulse power supply.The effect of electrical parameters of pulse frequency on the coating performance was studied at frequencies of 2.5 Hz,25 Hz and 250 Hz.The coating performance at different frequencies was characterized by scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS)and potentiodynamic polarization testing method.It was found that the corrosion resistance of the MAO coatings was improved when increasing the pulse frequencies from 2.5 Hz to 250 Hz.The corrosion current in 250 Hz case decreased by three orders of magnitude as compared with bare Mg alloy and the corrosion impedance also increased remarkably,means significantly enhanced corrosion resistance than bare Mg alloy.The results give us more insight in the optimization of electrical parameters to improve the MAO coating performance.The MAO technology is attractive for application on magnesium and other light alloys for surface protection in automotive and space industries.展开更多
Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify ...Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify the differential proteins and expected to elucidate the mechanism of EBV. Altered protein expressions were found between 293 cell (HEK293) and EBV infected cell (293-EBV). In this study, we separated differential expressed proteins using 2D-DIGE method while matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry (MALDI-TOF-MS) method was used to identify proteins. The results showed that 14 proteins were up regulated and 3 proteins were down regulated in 293-EBV cells. Bioinformatic analysis showed that these proteins are involved in cell proliferation, metastasis, apoptosis, metabolism, and signal transduction. Western blotting analysis was further carried out to verify the MS results. Thus, EBV may exert its functions by mediating differential expression of these proteins.展开更多
Herpesviruses are remarkable pathogens that have evolved multiple mechanisms to evade host immunity, ensuring their proliferation and egress. Among these mechanisms, herpesviruses utilize elaborate extracellular vesic...Herpesviruses are remarkable pathogens that have evolved multiple mechanisms to evade host immunity, ensuring their proliferation and egress. Among these mechanisms, herpesviruses utilize elaborate extracellular vesicles, including exosomes, for the intricate interplay between infected host and recipient cells. Herpesviruses incorporate genome expression products and direct cellular products into exosomal cargoes. These components alter the content and function of exosomes released from donor cells, thus affecting the downstream signalings of recipient cells. In this way, herpesviruses hijack exosomal pathways to ensure their survival and persistence, and exosomes are emerging as critical mediators for virus infection-associated intercellular communication and microenvironment alteration. In this review, the function and effects of exosomes in herpesvirus infection will be discussed, so that we will have a better understanding about the pathogenesis of herpesviruses.展开更多
Epstein-Barr virus(EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategie...Epstein-Barr virus(EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that micro RNAs(mi RNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes mi RNAs for immune evasion. EBV encodes mi RNAs targeting both viral and host genes involved in the immune response. The mi RNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4^+ and CD8^+ T cell response of infected cells. These reports strongly indicate that EBV mi RNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host mi RNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated mi RNAs and viral proteins contributes to the construction and modification of the inflammatory tumor microenvironment.During EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of mi RNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.展开更多
Epstein-Barr virus(EBV)is an important human dsDNA virus,which has been shown to be associated with several malignancies including about 10%of gastric carcinomas.How EBV enters an epithelial cell has been an interesti...Epstein-Barr virus(EBV)is an important human dsDNA virus,which has been shown to be associated with several malignancies including about 10%of gastric carcinomas.How EBV enters an epithelial cell has been an interesting project for investigation."Cell-in-cell"infection was recently reported an efficient way for the entry of EBV into nasopharynx epithelial cells.The present approach was to explore the feasibility of this mode for EBV infection in gastric epithelial cells and the dynamic change of host inflammatory reaction.The EBV-positive lymphoblastic cells of Akata containing a GFP tag in the viral genome were co-cultured with the gastric epithelial cells(GES-1).The infection situation was observed under fluorescence and electron microscopies.Real-time quantitative PCR and Western-blotting assay were employed to detect the expression of a few specific cytokines and inflammatory factors.The results demonstrated that EBV could get into gastric epithelial cells by"cell-in-cell"infection but not fully successful due to the host fighting.IL-1β,IL-6 and IL-8 played prominent roles in the cellular response to the infection.The activation of NF-κB and HSP70 was also required for the host antiviral response.The results imply that the gastric epithelial cells could powerfully resist the virus invader via cell-in-cell at the early stage through inflammatory and innate immune responses.展开更多
The AKT/mTOR and NF-κB signalings are crucial pathways activated in cancers including nasopharyngeal carcinoma(NPC), which is prevalent in southern China and closely related to Epstein-Barr virus(EBV) infection.How t...The AKT/mTOR and NF-κB signalings are crucial pathways activated in cancers including nasopharyngeal carcinoma(NPC), which is prevalent in southern China and closely related to Epstein-Barr virus(EBV) infection.How these master pathways are persistently activated in EBV-associated NPC remains to be investigated. Here we demonstrated that EBV-encoded latent membrane protein 1(LMP1) promoted cyclophilin A(CYPA) expression through the activation of NF-κB. The depletion of CYPA suppressed cell proliferation and facilitated apoptosis.CYPA was able to bind to AKT1, thus activating AKT/mTOR/NF-κB signaling cascade. Moreover, the use of mTOR inhibitor, rapamycin, subverted the activation of the positive feedback loop, NF-κB/CYPA/AKT/mTOR. It is reasonable that LMP1 expression derived from initial viral infection is enough to assure the constant potentiation of AKT/mTOR and NF-κB signalings. This may partly explain the fact that EBV serves as a tumor-promoting factor with minimal expression of the viral oncoprotein LMP1 in malignancies. Our findings provide new insight into the understanding of causative role of EBV in tumorigenicity during latent infection.展开更多
基金This work performed by the author was financially sup-ported by Singapore Ministry of Education innovation Fund(MOE2010-IF-027).
文摘Micro arc oxidation(MAO)coatings were formed on magnesium alloy AZ31B to improve the corrosion resistance using environmental friendly electrolyte solution under single-polar pulse power supply.The effect of electrical parameters of pulse frequency on the coating performance was studied at frequencies of 2.5 Hz,25 Hz and 250 Hz.The coating performance at different frequencies was characterized by scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS)and potentiodynamic polarization testing method.It was found that the corrosion resistance of the MAO coatings was improved when increasing the pulse frequencies from 2.5 Hz to 250 Hz.The corrosion current in 250 Hz case decreased by three orders of magnitude as compared with bare Mg alloy and the corrosion impedance also increased remarkably,means significantly enhanced corrosion resistance than bare Mg alloy.The results give us more insight in the optimization of electrical parameters to improve the MAO coating performance.The MAO technology is attractive for application on magnesium and other light alloys for surface protection in automotive and space industries.
文摘Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify the differential proteins and expected to elucidate the mechanism of EBV. Altered protein expressions were found between 293 cell (HEK293) and EBV infected cell (293-EBV). In this study, we separated differential expressed proteins using 2D-DIGE method while matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry (MALDI-TOF-MS) method was used to identify proteins. The results showed that 14 proteins were up regulated and 3 proteins were down regulated in 293-EBV cells. Bioinformatic analysis showed that these proteins are involved in cell proliferation, metastasis, apoptosis, metabolism, and signal transduction. Western blotting analysis was further carried out to verify the MS results. Thus, EBV may exert its functions by mediating differential expression of these proteins.
基金supported by the National Natural Science Foundations of China (81372139, 31670171, 81728011)the National Key Research and Development Program of China (2017YFC1200204)the Hunan Provincial Natural Science Foundation of China (2015JJ2149)
文摘Herpesviruses are remarkable pathogens that have evolved multiple mechanisms to evade host immunity, ensuring their proliferation and egress. Among these mechanisms, herpesviruses utilize elaborate extracellular vesicles, including exosomes, for the intricate interplay between infected host and recipient cells. Herpesviruses incorporate genome expression products and direct cellular products into exosomal cargoes. These components alter the content and function of exosomes released from donor cells, thus affecting the downstream signalings of recipient cells. In this way, herpesviruses hijack exosomal pathways to ensure their survival and persistence, and exosomes are emerging as critical mediators for virus infection-associated intercellular communication and microenvironment alteration. In this review, the function and effects of exosomes in herpesvirus infection will be discussed, so that we will have a better understanding about the pathogenesis of herpesviruses.
基金supported by the National Natural Science Foundations of China(81372139,31670171)the Hunan Provincial Natural Science Foundation of China(2015JJ2149)the Hunan Provincial Innovation Foundation for Postgraduates(CX2016B055)
文摘Epstein-Barr virus(EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that micro RNAs(mi RNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes mi RNAs for immune evasion. EBV encodes mi RNAs targeting both viral and host genes involved in the immune response. The mi RNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4^+ and CD8^+ T cell response of infected cells. These reports strongly indicate that EBV mi RNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host mi RNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated mi RNAs and viral proteins contributes to the construction and modification of the inflammatory tumor microenvironment.During EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of mi RNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.
基金supported by the National Key Research & Development ProgramNational Natural Science Foundations of China (2017YFC1200204, 31670171, 81728011)Innovation Foundations for Postgraduates of Central South University (2018zzts817)
文摘Epstein-Barr virus(EBV)is an important human dsDNA virus,which has been shown to be associated with several malignancies including about 10%of gastric carcinomas.How EBV enters an epithelial cell has been an interesting project for investigation."Cell-in-cell"infection was recently reported an efficient way for the entry of EBV into nasopharynx epithelial cells.The present approach was to explore the feasibility of this mode for EBV infection in gastric epithelial cells and the dynamic change of host inflammatory reaction.The EBV-positive lymphoblastic cells of Akata containing a GFP tag in the viral genome were co-cultured with the gastric epithelial cells(GES-1).The infection situation was observed under fluorescence and electron microscopies.Real-time quantitative PCR and Western-blotting assay were employed to detect the expression of a few specific cytokines and inflammatory factors.The results demonstrated that EBV could get into gastric epithelial cells by"cell-in-cell"infection but not fully successful due to the host fighting.IL-1β,IL-6 and IL-8 played prominent roles in the cellular response to the infection.The activation of NF-κB and HSP70 was also required for the host antiviral response.The results imply that the gastric epithelial cells could powerfully resist the virus invader via cell-in-cell at the early stage through inflammatory and innate immune responses.
基金supported by the Natural Science Foundations of China(81974427)Graduate Research and Innovation Projects of Central South University(2021zzts0931)
文摘The AKT/mTOR and NF-κB signalings are crucial pathways activated in cancers including nasopharyngeal carcinoma(NPC), which is prevalent in southern China and closely related to Epstein-Barr virus(EBV) infection.How these master pathways are persistently activated in EBV-associated NPC remains to be investigated. Here we demonstrated that EBV-encoded latent membrane protein 1(LMP1) promoted cyclophilin A(CYPA) expression through the activation of NF-κB. The depletion of CYPA suppressed cell proliferation and facilitated apoptosis.CYPA was able to bind to AKT1, thus activating AKT/mTOR/NF-κB signaling cascade. Moreover, the use of mTOR inhibitor, rapamycin, subverted the activation of the positive feedback loop, NF-κB/CYPA/AKT/mTOR. It is reasonable that LMP1 expression derived from initial viral infection is enough to assure the constant potentiation of AKT/mTOR and NF-κB signalings. This may partly explain the fact that EBV serves as a tumor-promoting factor with minimal expression of the viral oncoprotein LMP1 in malignancies. Our findings provide new insight into the understanding of causative role of EBV in tumorigenicity during latent infection.