Lymphomas driven by Epstein-Barr virus nuclear antigen-1 (EBNA1) are dependant upon Mdm2

Epstein-Barr virus (EBV)-associated Burkitt's lymphoma is characterised by the deregulation of c-Myc expression and a restricted viral gene expression pattern in which the EBV nuclear antigen-1 (EBNA1) is the only viral protein to be consistently expressed. EBNA1 is required for viral genome propagation and segregation during latency. However, it has been much debated whether the protein plays a role in viral-associated tumourigenesis. We show that the lymphomas which arise in EµEBNA1 transgenic mice are unequivocally linked to EBNA1 expression and that both C-Myc and Mdm2 deregulation are central to this process. Tumour cell survival is supported by IL-2 and there is a skew towards CD8-positive T cells in the tumour environment, while the immune check-point protein PD-L1 is upregulated in the tumours. Additionally, several isoforms of Mdm2 are upregulated in the EµEBNA1 tumours, with increased phosphorylation at ser166, an expression pattern not seen in Eµc-Myc transgenic tumours. Concomitantly, E2F1, Xiap, Mta1, C-Fos and Stat1 are upregulated in the tumours. Using four independent inhibitors of Mdm2 we demonstrate that the EµEBNA1 tumour cells are dependant upon Mdm2 for survival (as they are upon c-Myc) and that Mdm2 inhibition is not accompanied by upregulation of p53, instead cell death is linked to loss of E2F1 expression, providing new insight into the underlying tumourigenic mechanism. This opens a new path to combat EBV-associated disease

Epstein-Barr Virus Nuclear Antigen-1, Action and Reaction as an Oncogene

The herpesvirus Epstein-Barr virus (EBV) leads to a life-long persistent infection and greater than 90% of the adult population of the world are seropositive. EBV is the causative agent of infectious mononucleosis, but in addition, the virus is associated with certain tumours of B-cell and epithelia cell origin (as well as some rare T-cell tumours). EBV nuclear antigen 1 (EBNA1) is an essential viral protein, required for the maintenance, replication and mitotic segregation of viral genome episomes. EBNA1 is a DNA binding protein and also interacts with several cellular proteins, thereby affecting host cell-signalling pathways and in so doing may contribute to cell survival and proliferation. EBNA1 is the only latent protein that is expressed in all EBV-associated malignancies and is thought to play a significant role in viral tumourigenesis. In order to explore the oncogenic mechanism of EBNA1, B-cell lymphoma samples from transgenic mice expressing EBNA1 (EµEBNA1 mice) and/or c-Myc (Eµc-Myc mice) were analysed by immunoblotting. Several candidate cellular proteins likely involved in the tumourigenic process were examined, including C-myc, Mdm2, p53, PTEN, Akt and others. Overexpression of specific MDM2 isoforms were detected in all EBNA1 tumour samples, not detected in c-Myc tumour samples, or in pre-tumour or transgene negative samples. Thus there is a specific correlation of the overexpression of Mdm2, with EBNA1-induced tumourigenesis, likely reflecting the underlying mechanism. In addition, C-Myc was overexpressed in EBNA1 tumours, supporting our previous observations regarding the cooperation of these two proteins in tumourigenesis

Epstein-Barr Virus Nuclear Antigen-1, in a Preclinical Model for BL

No abstract available

Epstein-Barr Virus Nuclear Antigen-1, Action and Reaction as an Oncogene

The herpesvirus Epstein-Barr virus (EBV) leads to a life-long persistent infection and greater than 90% of the adult population of the world are seropositive. EBV is the causative agent of infectious mononucleosis, but in addition, the virus is associated with certain tumours of B-cell and epithelia cell origin (as well as some rare T-cell tumours). EBV nuclear antigen 1 (EBNA1) is an essential viral protein, required for the maintenance, replication and mitotic segregation of viral genome episomes. EBNA1 is a DNA binding protein and also interacts with several cellular proteins, thereby affecting host cell-signalling pathways and in so doing may contribute to cell survival and proliferation. EBNA1 is the only latent protein that is expressed in all EBV-associated malignancies and is thought to play a significant role in viral tumourigenesis. In order to explore the oncogenic mechanism of EBNA1, B-cell lymphoma samples from transgenic mice expressing EBNA1 (EµEBNA1 mice) and/or c-Myc (Eµc-Myc mice) were analysed by immunoblotting. Several candidate cellular proteins likely involved in the tumourigenic process were examined, including C-myc, Mdm2, p53, PTEN, Akt and others. Overexpression of specific MDM2 isoforms were detected in all EBNA1 tumour samples, not detected in c-Myc tumour samples, or in pre-tumour or transgene negative samples. Thus there is a specific correlation of the overexpression of Mdm2, with EBNA1-induced tumourigenesis, likely reflecting the underlying mechanism. In addition, C-Myc was overexpressed in EBNA1 tumours, supporting our previous observations regarding the cooperation of these two proteins in tumourigenesis

Epstein-Barr Virus Nuclear Antigen-1, Action and Reaction as an Oncogene

The herpesvirus Epstein-Barr virus (EBV) leads to a life-long persistent infection and greater than 90% of the adult population of the world are seropositive. EBV is the causative agent of infectious mononucleosis, but in addition, the virus is associated with certain tumours of B-cell and epithelia cell origin (as well as some rare T-cell tumours). EBV nuclear antigen 1 (EBNA1) is an essential viral protein, required for the maintenance, replication and mitotic segregation of viral genome episomes. EBNA1 is a DNA binding protein and also interacts with several cellular proteins, thereby affecting host cell-signalling pathways and in so doing may contribute to cell survival and proliferation. EBNA1 is the only latent protein that is expressed in all EBV-associated malignancies and is thought to play a significant role in viral tumourigenesis. In order to explore the oncogenic mechanism of EBNA1, B-cell lymphoma samples from transgenic mice expressing EBNA1 (EµEBNA1 mice) and/or c-Myc (Eµc-Myc mice) were analysed by immunoblotting. Several candidate cellular proteins likely involved in the tumourigenic process were examined, including C-myc, Mdm2, p53, PTEN, Akt and others. Overexpression of specific MDM2 isoforms were detected in all EBNA1 tumour samples, not detected in c-Myc tumour samples, or in pre-tumour or transgene negative samples. Thus there is a specific correlation of the overexpression of Mdm2, with EBNA1-induced tumourigenesis, likely reflecting the underlying mechanism. In addition, C-Myc was overexpressed in EBNA1 tumours, supporting our previous observations regarding the cooperation of these two proteins in tumourigenesis

Epstein-Barr Virus Nuclear Antigen-1, Action and Reaction as an Oncogene

The herpesvirus Epstein-Barr virus (EBV) leads to a life-long persistent infection and greater than 90% of the adult population of the world are seropositive. EBV is the causative agent of infectious mononucleosis, but in addition, the virus is associated with certain tumours of B-cell and epithelia cell origin (as well as some rare T-cell tumours). EBV nuclear antigen 1 (EBNA1) is an essential viral protein, required for the maintenance, replication and mitotic segregation of viral genome episomes. EBNA1 is a DNA binding protein and also interacts with several cellular proteins, thereby affecting host cell-signalling pathways and in so doing may contribute to cell survival and proliferation. EBNA1 is the only latent protein that is expressed in all EBV-associated malignancies and is thought to play a significant role in viral tumourigenesis. In order to explore the oncogenic mechanism of EBNA1, B-cell lymphoma samples from transgenic mice expressing EBNA1 (EµEBNA1 mice) and/or c-Myc (Eµc-Myc mice) were analysed by immunoblotting. Several candidate cellular proteins likely involved in the tumourigenic process were examined, including C-myc, Mdm2, p53, PTEN, Akt and others. Overexpression of specific MDM2 isoforms were detected in all EBNA1 tumour samples, not detected in c-Myc tumour samples, or in pre-tumour or transgene negative samples. Thus there is a specific correlation of the overexpression of Mdm2, with EBNA1-induced tumourigenesis, likely reflecting the underlying mechanism. In addition, C-Myc was overexpressed in EBNA1 tumours, supporting our previous observations regarding the cooperation of these two proteins in tumourigenesis

Inhibition of ITK Signaling Causes Amelioration in Sepsis-Associated Neuroinflammation and Depression-like State in Mice

Sepsis affects millions of people worldwide and is associated with multiorgan dysfunction that is a major cause of increased morbidity and mortality. Sepsis is associated with several morbidities, such as lung, liver, and central nervous system (CNS) dysfunction. Sepsis-associated CNS dysfunction usually leads to several mental problems including depression. IL-17A is one of the crucial cytokines that is expressed and secreted by Th17 cells. Th17 cells are reported to be involved in the pathogenesis of depression and anxiety in humans and animals. One of the protein tyrosine kinases that plays a key role in controlling the development/differentiation of Th17 cells is ITK. However, the role of ITK in sepsis-associated neuroinflammation and depression-like symptoms in mice has not been investigated earlier. Therefore, this study investigated the efficacy of the ITK inhibitor, BMS 509744, in sepsis-linked neuroinflammation (ITK, IL-17A, NFkB, iNOS, MPO, lipid peroxides, IL-6, MCP-1, IL-17A) and a battery of depression-like behavioral tests, such as sucrose preference, tail suspension, and the marble burying test. Further, the effect of the ITK inhibitor on anti-inflammatory signaling (Foxp3, IL-10, Nrf2, HO-1, SOD-2) was assessed in the CNS. Our data show that sepsis causes increased ITK protein expression, IL-17A signaling, and neuroinflammatory mediators in the CNS that are associated with a depression-like state in mice. ITK inhibitor-treated mice with sepsis show attenuated IL-17A signaling, which is associated with the upregulation of IL-10/Nrf2 signaling and the amelioration of depression-like symptoms in mice. Our data show, for the first time, that the ITK inhibition strategy may counteract sepsis-mediated depression through a reduction in IL-17A signaling in the CNS

Oxyphenbutazone ameliorates carfilzomib induced cardiotoxicity in rats via inhibition of oxidative free radical burst and NF-κB/IκB-α pathway

Carfilzomib (CFZ), a chemotherapeutic agent used for multiple myeloma treatments reported to cause high incidence of cardiac events either new onset and/or exacerbate formerly diagnosed heart failure with ventricular and myocardial dysfunction.Purpose: Current research designed to explore and examine the preventive effect of oxyphenbutazone in the CFZ -instigated cardiotoxicity. Methodology: Female Wistar Rats weighing 200–250 g selected randomly and grouped as follows: Group 1 designated as the Normal control and receive normal saline only. Group 2 served toxic control and exposed to CFZ (4 mg/kg, intraperitoneally [i.p.]). Group 3 & 4 served as treatment groups and administered with CFZ concomitantly orally fed with oxyphenbutazone at doses of 35 and 70 mg/kg/three times a week, respectively. The total duration of experimental protocol was of 21 days. After completion of the experiments animals subjected to blood collection using light ether anesthesia and serum was separated for biochemical analysis further. The serum levels of Mg+2, Ca+2 and cardiac enzymes (aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase-MB (CK-MB) levels were estimated. Later animals sacrificed and heart tissue isolated for further examinations. Intracellular proteins NFkB and IkBα were estimated by western blot. Results: The serum analysis revealed that CFZ administration significantly elevated the levels of LDH, CK and CKMB in CFZ exposed animals when compared to normal animals while administration of oxyphenbutazone significantly reduced these biochemical changes, Intracellular antioxidant enzymes and NF-kB in treatment groups as compared to disease control animals. Conclusion: Findings of the research protocol suggests significant injuries to cardiac tissues when animals exposed to CFZ and Oxyphenbutazone protected the cardiac tissues

Thioredoxin 1 and Thioredoxin Reductase 1 Redox System Is Dysregulated in Neutrophils of Subjects with Autism: In Vitro Effects of Environmental Toxicant, Methylmercury

Autism spectrum disorder (ASD) is a complex developmental disorder in children that results in abnormal communicative and verbal behaviors. Exposure to heavy metals plays a significant role in the pathogenesis or progression of ASD. Mercury compounds pose significant risk for the development of ASD as children are more exposed to environmental toxicants. Increased concentration of mercury compounds has been detected in different body fluids/tissues in ASD children, which suggests an association between mercury exposure and ASD. Thioredoxin1 (Trx1) and thioredoxin reductase1 (TrxR1) redox system plays a crucial role in detoxification of oxidants generated in different immune cells. However, the effect of methylmercury and the Nrf2 activator sulforaphane on the Trx1/TrxR1 antioxidant system in neutrophils of ASD subjects has not been studied previously. Therefore, this study examined the effect of methylmercury on Trx1/TrxR1 expression, TrxR activity, nitrotyrosine, and ROS in neutrophils of ASD and TDC subjects. Our study shows that Trx1/TrxR1 protein expression is dysregulated in ASD subjects as compared to the TDC group. Further, methylmercury treatment significantly inhibits the activity of TrxR in both ASD and TDC groups. Inhibition of TrxR by mercury is associated with upregulation of the Trx1 protein in TDC neutrophils but not in ASD neutrophils. Furthermore, ASD neutrophils have exaggerated ROS production after exposure to methylmercury, which is much greater in magnitude than TDC neutrophils. Sulforaphane reversed methylmercury-induced effects on neutrophils through Nrf2-mediated induction of the Trx1/TrxR1 system. These observations suggest that exposure to the environmental toxicant methylmercury may elevate systemic oxidative inflammation due to a dysregulated Trx1/TrxR1 redox system in the neutrophils of ASD subjects, which may play a role in the progression of ASD

Bio-Guided Isolation of SARS-CoV-2 Main Protease Inhibitors from Medicinal Plants: In Vitro Assay and Molecular Dynamics

Since the emergence of the pandemic of the coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the discovery of antiviral phytoconstituents from medicinal plants against SARS-CoV-2 has been comprehensively researched. In this study, thirty-three plants belonging to seventeen different families used traditionally in Saudi Arabia were tested in vitro for their ability to inhibit the SARS-CoV-2 main protease (MPRO). Major constituents of the bio-active extracts were isolated and tested for their inhibition potential against this enzyme; in addition, their antiviral activity against the SARS-CoV-2 Egyptian strain was assessed. Further, the thermodynamic stability of the best active compounds was studied through focused comparative insights for the active metabolites regarding ligand–target binding characteristics at the molecular level. Additionally, the obtained computational findings provided useful directions for future drug optimization and development. The results revealed that Psiadia punctulata, Aframomum melegueta, and Nigella sativa extracts showed a high percentage of inhibition of 66.4, 58.7, and 31.5%, against SARS-CoV-2 MPRO, respectively. The major isolated constituents of these plants were identified as gardenins A and B (from P. punctulata), 6-gingerol and 6-paradol (from A. melegueta), and thymoquinone (from N. sativa). These compounds are the first to be tested invitro against SARS-CoV-2 MPRO. Among the isolated compounds, only thymoquinone (THY), gardenin A (GDA), 6-gingerol (GNG), and 6-paradol (PAD) inhibited the SARS-CoV-2 MPRO enzyme with inhibition percentages of 63.21, 73.80, 65.2, and 71.8%, respectively. In vitro assessment of SARS-CoV-2 (hCoV-19/Egypt/NRC-03/2020 (accession number on GSAID: EPI_ISL_430820) revealed a strong-to-low antiviral activity of the isolated compounds. THY showed relatively high cytotoxicity and was anti-SARS-CoV-2, while PAD demonstrated a cytotoxic effect on the tested VERO cells with a selectivity index of CC50/IC50 = 1.33 and CC50/IC50 = 0.6, respectively. Moreover, GNG had moderate activity at non-cytotoxic concentrations in vitro with a selectivity index of CC50/IC50 = 101.3/43.45 = 2.3. Meanwhile, GDA showed weak activity with a selectivity index of CC50/IC50 = 246.5/83.77 = 2.9. The thermodynamic stability of top-active compounds revealed preferential stability and SARS-CoV-2 MPRO binding affinity for PAD through molecular-docking-coupled molecular dynamics simulation. The obtained results suggest the treating potential of these plants and/or their active metabolites for COVID-19. However, further in-vivo and clinical investigations are required to establish the potential preventive and treatment effectiveness of these plants and/or their bio-active compounds in COVID-19