Infected HepG2 Cells Research Articles

Inhibitory Activities of Methanolic Extracts of Carica papaya, Mentha piperita and Citrullus colocynthis Against Dengue Viruses-2 viability

This study targets the methanolic extracts from the leaves of Carica papaya (Papaya) and Mentha piperita (Mint), as well as the leaves and fruit extracts of Citrullus colocynthis (Tumma plant) for their antiviral activity against dengue virus type 2 (DENV-2) in vitro, utilizing the HepG2 cell line. The antiviral activity of the plant extracts mentioned above was assessed through a plaque formation assay on the HepG2 cell line. The methanolic extracts from the leaves of C. papaya and M. piperita demonstrated lower toxicity than the fruit extract of C. colocynthis. Notably, the fruit extract of C. colocynthis maintained the normal morphology of DENV-2- infected HepG2 cells with minimal cell mortality. The cell survival rates were found to be 80-100% for 0.30mg/ml and 0.20mg/ml of C. papaya and M. piperita leaves extracts and 0.08mg/ml of C. colocynthis fruit extract. The most effective inhibition of DENV-2 was attributed to the fruit extract of C. colocynthis, exhibiting 46.55% inhibition at 0.08mg/ml. In comparison, M. Piperita and C. papaya leaf extracts demonstrated 24.14% and 23.33% inhibition against 0.20mg/ml and 0.30mg/ml, respectively. The plaque forming unit (PFU/ml) at the highest concentration ensuring 100% cell survival was calculated as 1.5×106, 1.4×106, and 1.0×106 PFU/ml for C. papaya and M. piperita leaves extracts and C. colocynthis fruit extract, respectively. The study infers that the methanolic fruit extract of C. colocynthis exhibits a high potential for inhibiting DENV-2 compared to the other two extracts.

Functional molecular characterization and the assessment of the transmission route of multidrug-resistant Helicobacter pullorum isolates from free-range and broiler chickens

BackgroundSome of the life-threatening, food-borne, and zoonotic infections are transmitted through poultry birds. Inappropriate and irrational use of antimicrobials in the livestock industry has resulted in an increased incidence of multi-drug resistant bacteria of epidemic potentials. Materials and methodsThe adhesion and invasion properties of 11 free-range and broiler chicken derived Helicobacterpullorum isolates were evaluated. To examine the biofilm formation of H. pullorum isolates, crystal violet assay was performed. A quantitative assay of invasion-associated genes was carried out after infecting HepG2 cells with two different representative (broiler and free-range chicken) H. pullorum isolates, using RT-PCR assay. Furthermore, we investigated the prevalence of H. pullorum, Campylobacter jejuni and Salmonella spp. in chicken caeca and oviducts to determine the possibility of trans-ovarian transmission. ResultsAll H. pullorum isolates adhered to HepG2 cells significantly but a notable difference towards their invasion potential was observed between free-range and broiler chicken isolates wherein broiler isolates were found to be more invasive compared to free-range isolates. Furthermore, cdtB, flhA and flaB genes of H. pullorum were upregulated post infection of HepG2 cells, in broiler chicken isolates compared to free-range chicken isolates. Moreover, all isolates of H. pullorum were found to form biofilm on the liquid-air interface of the glass coverslips and sidewalls of the wells with similar propensities. Despite presence of H. pullorum and C. jejuni in high concentrations in the caecum, they were completely absent in oviduct samples, thus ruling out the possibility of vertical transmission of these bacterial species. In contrast, Salmonella spp. was found to be present in a significant proportion in the oviduct samples of egg-laying hens suggesting its vertical transmission. ConclusionsOur findings suggest that H. pullorum, an emerging multi-drug resistant (MDR) pathogen could be transmitted from poultry sources to humans. In addition to this, its strong functional similarity with C. jejuni provides a firm basis for H. pullorum to be an emerging food-associated, MDR pathogenic bacterium that could pose risk to public health.

Synthesis and In vitro Efficacy of Tetracyclic Benzothiazepines Against Blood-Stage Plasmodium falciparum and Liver-Stage P. berghei.

A series of novel, substituted tetracyclic benzothiazepines were designed and prepared in an effort to optimize the potency of this chemical class against drug-resistant strains of the malaria parasite. Tetracyclic benzothiazepines bearing structural modification at seven distinct positions within the structure were synthesized in Knoevenagel condensation reactions followed by sequential intermolecular thio-Michael and then intramolecular imine formation reactions. Following purification and chemical characterization, the novel compounds were tested for in vitro efficacy against blood-stage P. falciparum and liver-stage P. berghei and also for in vivo efficacy against P. berghei. Benzothiazepines bearing structural modification at the sulfur atom and at the three carbocycles within the molecule were successfully synthesized. The majority of analogs inhibited bloodstage P. falciparum with submicromolar IC50 values. The potency of an 8-methoxy-substituted analog 12 exceeded that of chloroquine in all three P. falciparum strains tested. The parent benzothiazepine 1 possessed liver-stage activity, inhibiting P. berghei sporozoites infecting HepG2 cells with an IC50 of 106.4 nM and an IC90 of 408.9 nM, but failed to enhance the longevity of P. berghei infected mice compared to the controls. Compounds displayed modest toxicity toward HepG2 cells and were tolerated by mice at the highest dose tested, 640 mg/kg/dose once daily for three days. The tetracyclic benzothiazepine described, which inhibits P. berghei infected hepatic cells with an IC50 of 106.4 nM, would appear to warrant further investigation. Optimization of ADME properties may be required since the most active analogs are probably excessively lipophilic.

CtBP1 Mediates Hypoxia-Induced Sarcomatoid Transformation in Hepatocellular Carcinoma.

BackgroundSarcomatoid hepatocellular carcinoma (sHCC), a highly aggressive subtype of hepatocellular carcinoma (HCC), mostly transforms from classical hepatocellular carcinoma (cHCC). The study intended to explore the role of C-terminal binding protein 1 (CtBP1) in sarcomatoid transformation of hepatocellular carcinoma.MethodsWestern blotting and/or immunohistochemistry were used to confirm the expression of CtBP1 and other proteins in HCC cells, xenografts and clinical tissue samples. CtBP1 shRNA-expressing lentivirus was used to infect HepG2 cells to construct CtBP1 knockdown cells. Cell migration was determined by scratch wound assays and Transwell assays. Immunofluorescence was used to label the a-tubulin cytoskeleton to evaluate cell morphology. HepG2 cells were inoculated subcutaneously in nude mice to construct xenografts and beneath the liver capsule to evaluate in vivo metastasis.ResultsCompared to that in the cHCC area, CtBP1 expression was significantly upregulated in the sHCC area, as shown by immunohistochemistry. HE staining showed that cells in the sHCC area were spindle-shaped, while those in the cHCC area were polygonal. Immunohistochemically, the epithelial markers pancytokeratin (CK) and E-cadherin were partially or completely lost, while the expression of the mesenchymal marker vimentin was upregulated in the sHCC area. Moreover, HepG2, an HCC cell line with high expression of CtBP1, autonomously underwent sarcomatoid transformation, showing a sarcomatoid morphology and phenotype. HIF1a expression was upregulated in epithelial cells adjacent to the sHCC area. Hypoxia upregulated CtBP1 protein expression and induced an EMT phenotype with increased migration and a spindle-shaped morphology in HepG2 cells. Knockdown of CtBP1 partially reversed the EMT phenotype induced by hypoxia. Silencing CtBP1 completely blocked the sarcomatoid transformation of subcutaneous xenografts and decreased lung metastasis in subcapsular xenografts of the liver in nude mice.ConclusionCtBP1 plays a key role in hypoxia-induced EMT and sarcomatoid transformation in HCC and could be a candidate target for the management of sHCC.

Liraglutide Alleviates Hepatic Steatosis by Activating the TFEB-Regulated Autophagy-Lysosomal Pathway.

Liraglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), has been demonstrated to alleviate non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanism has not been fully elucidated. Increasing evidence suggests that autophagy is involved in the pathogenesis of hepatic steatosis. In this study, we examined whether liraglutide could alleviate hepatic steatosis through autophagy-dependent lipid degradation and investigated the underlying mechanisms. Herein, the effects of liraglutide on NAFLD were evaluated in a high-fat diet (HFD)-induced mouse model of NAFLD as well as in mouse primary and HepG2 hepatocytes exposed to palmitic acid (PA). The expression of the GLP-1 receptor (GLP-1R) was measured in vivo and in vitro. Oil red O staining was performed to detect lipid accumulation in hepatocytes. Electron microscopy was used to observe the morphology of autophagic vesicles and autolysosomes. Autophagic flux activity was measured by infecting HepG2 cells with mRFP-GFP-LC3 adenovirus. The roles of GLP-1R and transcription factor EB (TFEB) in autophagy-lysosomal activation were explored using small interfering RNA. Liraglutide treatment alleviated hepatic steatosis in vivo and in vitro. In models of hepatic steatosis, microtubule-associated protein 1B light chain-3-II (LC3-II) and SQSTM1/P62 levels were elevated in parallel to blockade of autophagic flux. Liraglutide treatment restored autophagic activity by improving lysosomal function. Furthermore, treatment with autophagy inhibitor chloroquine weakened liraglutide-induced autophagy activation and lipid degradation. TFEB has been identified as a key regulator of lysosome biogenesis and autophagy. The protein levels of nuclear TFEB and its downstream targets CTSB and LAMP1 were decreased in hepatocytes treated with PA, and these decreases were reversed by liraglutide treatment. Knockdown of TFEB expression compromised the effects of liraglutide on lysosome biogenesis and hepatic lipid accumulation. Mechanistically, GLP-1R expression was decreased in HFD mouse livers as well as PA-stimulated hepatocytes, and liraglutide treatment reversed the downregulation of GLP-1R expression in vivo and in vitro. Moreover, GLP-1R inhibition could mimic the effect of the TFEB downregulation-mediated decrease in lysosome biogenesis. Thus, our findings suggest that liraglutide attenuated hepatic steatosis via restoring autophagic flux, specifically the GLP-1R-TFEB-mediated autophagy-lysosomal pathway.

The CCCTC-binding factor CTCF represses hepatitis B virus enhancer I and regulates viral transcription.

Hepatitis B virus (HBV) infection is of global importance with over 2 billion people exposed to the virus during their lifetime and at risk of progressive liver disease, cirrhosis and hepatocellular carcinoma. HBV is a member of the Hepadnaviridae family that replicates via episomal copies of a covalently closed circular DNA (cccDNA) genome. The chromatinization of this small viral genome, with overlapping open reading frames and regulatory elements, suggests an important role for epigenetic pathways to regulate viral transcription. The chromatin-organising transcriptional insulator protein, CCCTC-binding factor (CTCF), has been reported to regulate transcription in a diverse range of viruses. We identified two conserved CTCF binding sites in the HBV genome within enhancer I and chromatin immunoprecipitation (ChIP) analysis demonstrated an enrichment of CTCF binding to integrated or epi-somal copies of the viral genome. siRNA knock-down of CTCF results in a significant increase in pre-genomic RNA levels in de novo infected HepG2 cells and those supporting episomal HBV DNA replication. Furthermore, mutation of these sites in HBV DNA minicircles abrogated CTCF binding and increased pre-genomic RNA levels, providing evidence of a direct role for CTCF in repressing HBV transcription.

A Plasmodium homolog of ER tubule‐forming proteins is required for parasite virulence

Reticulon and REEP family of proteins stabilize the high curvature of endoplasmic reticulum (ER) tubules. Plasmodium berghei Yop1 (PbYop1) is a REEP5 homolog in Plasmodium. Here, we characterize its function using a gene-knockout (Pbyop1∆). Pbyop1∆ asexual stage parasites display abnormal ER architecture and an enlarged digestive vacuole. The erythrocytic cycle of Pbyop1∆ parasites is severely attenuated and the incidence of experimental cerebral malaria is significantly decreased in Pbyop1∆-infected mice. Pbyop1∆ sporozoites have reduced speed, are slower to invade host cells but give rise to equal numbers of infected HepG2 cells, as WT sporozoites. We propose that PbYOP1's disruption may lead to defects in trafficking and secretion of a subset of proteins required for parasite development and invasion of erythrocytes. Furthermore, the maintenance of ER morphology in different parasite stages is likely to depend on different proteins.

Heterologous Expression and Functional Characterization of Novel CYP2C9 Variants Identified in the Alaska Native People.

CYP2C9 is a major form of human liver cytochrome P450 that is responsible for the oxidative metabolism of several widely used low-therapeutic index drugs, including (S)-warfarin and phenytoin. In a cohort of Alaska Native people, ultrarare or novel CYP2C9 protein variants, M1L (rs114071557), N218I (rs780801862), and P279T (rs182132442, CYP2C9*29), are expressed with higher frequencies than the well characterized CYP2C9*2 and CYP2C9*3 alleles. We report here on their relative expression in lentivirus-infected HepG2 cells and the functional characterization of purified reconstituted enzyme variants expressed in Escherichia coli toward (S)-warfarin, phenytoin, flurbiprofen, and (S)-naproxen. In the infected HepG2 cells, robust mRNA and protein expression were obtained for wild-type, N218I, and P279T variants, but as expected, the M1L variant protein was not translated in this liver-derived cell line. His-tagged wild-type protein and the N218I and P279T variants, but not M1L, expressed well in E. coli and were highly purified after affinity chromatography. Upon reconstitution with cytochrome P450 oxidoreductase and cytochrome b5, the N218I and P279T protein variants metabolized (S)-warfarin, phenytoin, flurbiprofen, and (S)-naproxen to the expected monohydroxylated or O-demethylated metabolites. Steady-state kinetic analyses revealed that the relative catalytic efficiency ratios of (S)-warfarin metabolism by the P279T and N218I variants were 87% and 24%, respectively, of wild-type CYP2C9 protein. A similar rank ordering was observed for metabolism of phenytoin, flurbiprofen, and (S)-naproxen. We conclude that carriers of the variant N218I and, especially, the M1L alleles would be at risk of exacerbated therapeutic effects from drugs that rely on CYP2C9 for their metabolic clearance. SIGNIFICANCE STATEMENT: Novel gene variants of CYP2C9-M1L, and N218I, along with P279T (CYP2C9*29)-are expressed in Alaska Native people at relatively high frequencies. In vitro characterization of their functional effects revealed that each variant confers reduced catalytic efficiency toward several substrates, including the low-therapeutic index drugs (S)-warfarin and phenytoin. These data provide the first functional information for new, common CYP2C9 variants in this understudied population. The data may help guide dose adjustments in allele carriers, thus mitigating potential healthcare disparities.

Effect of recombinant adenovirus Ad-mir-22 on glucose uptake in HepG2 cells

The recombinant adenoviruses expressing miR-22 (Ad-miR-22) was constructed and the effect of Ad-miR-22 on insulin signal pathway and glucose uptake in HepG2 cells was analyzed. MiR-22 gene was amplified by PCR from human hepatocytes and cloned into the pAdTrack-CMV vector to generate the shuttle plasmid pAdT-22. The positive colonies were confirmed by PCR and sequencing. The resultant shuttle plasmid was linearized with Pme I, followed by co-transformation into competent BJ5183 cells containing an adenoviral backbone plasmid (pAdEasy-1) to create the recombinant plasmid pAd-miR-22. After digested with Pac I, the linearized pAd-miR-22 was transfected into 293A packaging cell line to generate recombinant adenoviruses Ad-miR-22. HepG2 cells were infected with Ad-miR-22 or control Ad-GFP (adenoviruses expressing green fluorescent protein), and then the miR-22 expression levels were analyzed by qPCR. The result shows that adenovirus-mediated overexpression of miR-22 significantly decreased insulin-induced glucose uptake in HepG2 cells. Moreover, overexpression of miR-22 markedly decreased insulin-induced phosphorylation of GSK-3β. miR-22 also increased the mRNA levels of gluconeogenic genes in HepG2 cells. Furthermore, Western blotting results indicate that the protein expression of SIRT1 decreased in Ad-miR-22 infected HepG2 cells as compared with Ad-GFP infected HepG2 cells. In summary, overexpressing of miR-22 significantly increased gluconeogenesis while decreased glucose uptake in HepG2 cells. The effect of miR-22 on glucose metabolism may be mediated by SIRT1.

Endothelial lipase increases eNOS activating capacity of high-density lipoprotein

Endothelial lipase (EL) changes structural and functional properties of high-density lipoprotein (HDL). HDL is a relevant modulator of endothelial nitric oxide synthase (eNOS) activity, but the effect of EL on HDL induced eNOS-activation has not yet been investigated. Here, we examined the impact of EL-modified HDL (EL-HDL) on eNOS activity, subcellular trafficking, and eNOS- dependent vasorelaxation. EL-HDL and empty virus (EV)-HDL as control were isolated from human serum incubated with EL-overexpressing or EV infected HepG2 cells. EL-HDL exhibited higher capacity to induce eNOS phosphorylation at Ser1177 and eNOS activity in EA.hy 926 cells, as well as eNOS-dependent vasorelaxation of mouse aortic rings compared to control HDL. As revealed by confocal and structured illumination-microscopy EL-HDL-driven induction of eNOS was accompanied by an increased eNOS-GFP targeting to the plasma membrane and a lower eNOS-GFP colocalization with Golgi and mitochondria. Widefield microscopy of filipin stained cells revealed that EL-HDL lowered cellular free cholesterol (FC) and as found by thin-layer chromatography increased cellular cholesterol ester (CE) content. Additionally, cholesterol efflux capacity, acyl-coenzyme A: cholesterol acyltransferase activity, and HDL particle uptake were comparable between EL-HDL and control HDL. In conclusion, EL increases eNOS activating capacity of HDL, a phenomenon accompanied by an enrichment of the plasma membrane eNOS pool, a decreased cell membrane FC and increased cellular CE content.

Phytochemical profiling and antiviral activity of Ajuga bracteosa, Ajuga parviflora, Berberis lycium and Citrus lemon against Hepatitis C Virus

Hepatitis C is a serious health issue and cause liver disorders in millions of people. Available therapeutic agents require long term administration with numerous side effects. Therefore, there is a dire need to find alternative treatment options for this disease. Since ancient times, medicinal plants are widely used to cure various diseases with no or less harmful effects. Therefore, this study was designed to find out phytochemicals and investigate antiviral activity of methanol extract of Ajuga bracteosa, Ajuga parviflora, Berberis lycium and Citrus lemon against Hepatitis C Virus (HCV infection). Phytochemical analysis of the plant extract was performed using various chemical tests. Toxicity of the plant extract was determined against using trypan blue exclusion method. Antiviral activity of the selected plant extract was find out against HCV infected HepG2 cells. For this purpose, HepG2 cells were seeded with HCV positive and negative serum and nontoxic doses of plant extract for 24 and 48 h. After this RNA was extracted and viral load was determined using Real-time PCR. Phytochemical analysis showed the presence of flavonoids and phenols in all plant extracts while amino acids, alkaloids and tannins were present in B. lycium and saponins were detected in C. lemon. Toxicity assay showed that all plant extracts were nontoxic at maximum concentration of 200 μg/ml except B. lycium, which showed mild toxicity at 40 μg/ml and were extremely toxic at 60 μg/ml and above doses. Real-time PCR quantitation result revealed that after 24 h treatments A. parviflora showed highest antiviral activity, followed by A. bracteosa, while B. lycium extract had low (35%) and C. lemon has no antiviral effects. The 48 h treatments showed an increase antiviral activity by A. bracteosa followed by A. parviflora and B. lycium while C. lemon showed negative effect. Our results depicted that mentioned plants might be used as an alternative therapeutic regime or in combination with existing treatments against HCV.

MiR199a-5p inhibits hepatic insulin sensitivity via suppression of ATG14-mediated autophagy

MicroRNAs (miRNAs) are known to contribute to many metabolic diseases, including diabetes. In this study, we investigated the role of miR199a-5p in the regulation of hepatic insulin sensitivity. Ad-anti-miR199a-5p adenoviruses were injected into male C57BL/6J WT mice fed a high-fat diet to inhibit miR199a-5p expression before the glucose levels and insulin resistance were assessed. Similarly, Ad-miR199a-5p adenoviruses were injected into male C57BL/6J WT mice to cause the overexpression of miR199a-5p. To investigate the roles of autophagy-related protein 14 (ATG14) and miR199a-5p in the regulation of insulin sensitivity, we injected Ad-miR199a-5p with or without Ad-ATG14 viruses into WT C57BL/6J mice before performing functional assays. Moreover, we infected HepG2 cells or primary hepatocytes with Ad-anti-miR199a-5p or Ad-miR199a-5p viruses to determine the effect of miR199a-5p on insulin resistance in vitro. Finally, we explored the clinical relevance of miR199a-5p by examining the expression level of miR199a-5p in liver samples derived from diabetes patients. We first demonstrated that knocking down miR199a-5p led to decreased glucose tolerance and clearance in vivo, whereas the overexpression of miR199a-5p had the opposite effect. We further identified ATG14 as the target of miR199a-5p, and ATG14 partially rescued miR199a-5p-potentiated glucose and insulin tolerance. In addition, transmission electron microscopy data and western blot data regarding ATG14, LC3 and BECLIN1 illustrated that miR199a-5p regulates autophagy via ATG14. Knocking down miR199a-5p in primary hepatocytes and HepG2 cells suppressed the insulin-stimulated phosphorylation of insulin receptor β, glycogen synthase kinase 3β and protein kinase B, whereas the overexpression of miR199a-5p further potentiated their phosphorylation. Finally, we detected upregulated miR199a-5p levels, which were correlated with reduced ATG14 mRNA levels and downregulated autophagy in liver samples obtained from diabetes patients. Our study uncovered a novel biological role of miR199a-5p in the regulation of hepatic insulin sensitivity via ATG14-mediated autophagy.

Comparative proteomics reveals that YK51, a 4-Hydroxypandurantin-A analogue, downregulates the expression of proteins associated with dengue virus infection.

Dengue is endemic throughout tropical and subtropical regions of the world. Currently, there is no clinically approved therapeutic drug available for this acute viral infection. Although the first dengue vaccine Dengvaxia has been approved for use in certain countries, it is limited to those without a previous dengue infection while the safety and efficacy of the vaccine in those elderly and younger children still need to be identified. Therefore, it is becoming increasingly important to develop therapeutics/drugs to combat dengue virus (DENV) infection. YK51 is a synthetic analogue of 4-Hydroxypandurantin A (a compound found in the crude extract of the rhizomes of Boesenbergia rotunda) that has been extensively studied by our research group. It has been shown to possess outstanding antiviral activity due to its inhibitory activity against NS2B/NS3 DENV2 protease. However, it is not known how YK51 affects the proteome of DENV infected cells. Therefore, we performed a comparative proteomics analysis to identify changes in protein expression in DENV infected HepG2 cells treated with YK51. Classical two-dimensional gel electrophoresis followed by protein identification using tandem mass spectrometry was employed in this study. Thirty proteins were found to be down-regulated with YK51 treatment. In silico analysis predicted that the down-regulation of eight of these proteins may inhibit viral infection. Our results suggested that apart from inhibiting the NS2B/NS3 DENV2 protease, YK51 may also be causing the down-regulation of a number of proteins that may be responsible in, and/or essential to virus infection. However, functional characterization of these proteins will be necessary before we can conclusively determine their roles in DENV infection.

Dengue virus induced changes in Ca2+ homeostasis in human hepatic cells that favor the viral replicative cycle

The role of Ca2+ during dengue virus (DENV) replication is unknown; thus, changes in Ca2+ homeostasis in DENV infected human hepatic HepG2 and Huh-7 cells were analyzed. Infected HepG2 cells, but not Huh-7 cells, showed a significant increase in plasma membrane permeability to Ca2+, while both cell lines showed marked reduced levels of Ca2+ stored in the endoplasmic reticulum. While the expression levels of STIM1 and ORAI1 showed no changes, STIM1 and ORAI1 were shown to co-localized in infected cells, indicating activation of the store-operated Ca2+ entry (SOCE) pathway. Finally, manipulation in the infected cells of the intra and extracellular Ca2+ levels by chelators (BAPTA-AM and EGTA), SOC inhibitor (SKF96365), IP3 Receptor antagonist (2APB) or increase of extracellular [Ca2+], significantly reduced DENV yield, but not vesicular stomatitis virus yield, used as a control. These results show that DENV infection alters cell Ca2+ homeostasis and that such changes favor viral replication.

Effect of health foods on cytochrome P450-mediated drug metabolism

BackgroundHealth foods have been widely sold and consumed in Japan. There has been an increase in reports of adverse effects in association with the expanding health food market. While health food-drug interactions are a particular concern from the viewpoint of safe and effective use of health foods, information regarding such interactions is limited owing to the lack of established methods to assess the effects of health food products on drug metabolism. We therefore developed cells that mimicked the activities of cytochrome P450 1A2 (CYP1A2), CYP2C9, CYP2C19, CYP2D6, and CYP3A4, which strongly contribute to drug metabolism in human hepatocytes, and established a system to assess the inhibitory activity of health foods toward P450-mediated metabolism.MethodsWe simultaneously infected HepG2 cells with five P450-expressing adenoviruses (Ad-CYP1A2, Ad-CYP2C9, Ad-CYP2C19, Ad-CYP2D6, and Ad-CYP3A4) to mimic the activity levels of these P450s in human hepatocytes, and named them Ad-P450 cells. The activity levels of P450s in Ad-P450 cells and human hepatocytes were calculated via simultaneous liquid chromatography/tandem mass spectrometry analysis utilizing a P450 substrate cocktail.ResultsWe established Ad-P450 cells mimicking the activity levels of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 in human hepatocytes. We determined the Km values of P450 substrates and IC50 values of P450 inhibitors in Ad-P450 cells. These values were approximately equivalent to those obtained in previous studies. We investigated the inhibitory effects of 172 health foods that were recently in circulation in Japan on P450-mediated metabolism using Ad-P450 cells. Of the 172 health foods, five products (two products having dietary effects, one turmeric-based product, one collagen-based product, and one propolis-containing product) simultaneously inhibited the five P450s by more than 50%. Another 29 products were also confirmed to inhibit one or more P450s.ConclusionsWe established a comprehensive assessment system to elucidate the effects of health foods on P450-mediated metabolism and identified the inhibitory activity of 34 of 172 health foods toward the drug-metabolizing P450s. Our results may provide useful information to predict health food-drug interactions.

Oxidative stress in Mayaro virus infection

Mayaro virus (MAYV) is a neglected tropical arbovirus that causes a febrile syndrome that is sometimes accompanied by incapacitating arthritis/arthralgia. The pathogenesis of MAYV has not been completely defined and oxidative stress mediated by an increase in reactive oxygen species (ROS) and/or depletion of antioxidant defences has been found to contribute to several aspects of viral disease. To investigate whether MAYV induced oxidative stress in host cells, we monitored ROS production, oxidative stress markers and antioxidant defences at different time points after infection. Our results show that MAYV induced significant oxidative stress in infected HepG2 cells, as indicated by the increase of malondialdehyde (MDA) and protein carbonyl levels, and by a significant decrease of the reduced versus oxidized glutathione (GSH/GSSG) ratio. Generally, MAYV-infected HepG2 cells also showed an increase in antioxidant defences. We observed an increase in the superoxide dismutase (SOD) and catalase (CAT) activities and the total glutathione content. To determine whether similar effects occurred in other cell types, we evaluated the ROS, MDA and SOD activity levels in J774 cells after MAYV infection. Similar to our observations in HepG2 cells, the J774 cells showed an increase in ROS, MDA and total SOD activity following MAYV infection. Thus, since the cellular redox environment is influenced by the production and removal of ROS, we hypothesize that the overproduction of ROS was responsible for the oxidative stress in response to the MAYV infection despite the increase in the antioxidant status. This study is the first report on the involvement of oxidative stress during MAYV infection. Collectively, our data shed light on some mechanisms that are operational in host cells following exposure to MAYV.

Antiviral activity of Faramea bahiensis leaves on dengue virus type-2 and characterization of a new antiviral flavanone glycoside

Dengue virus infection is a neglected disease prevalent in most tropical and subtropical areas. Currently there is no any antiviral drug indicated for the routine treatment of dengue patients. As part of our ongoing search for potential anti-dengue virus agents we have investigated the methanol extract of Faramea bahiensis (Rubiaceae) leaves. This species is endemic in Brazil, and there are no reports on its chemical composition or therapeutic potential. Its crude MeOH extract showed in vitro non-cytotoxicity and anti-dengue virus serotype 2 (DENV-2) activity in human hepatocarcinoma cell lineage (HepG2). A marked reduction on viral load (100%) was observed. Sequential fractionation of the bioactive crude extract led to the isolation of a bioactive new flavanone glycoside: 5-hydroxy-4′-methoxy-flavanone-7-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside, the known 5,4′-dihydroxy-flavanone-7-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside and a diateroisomeric epimer pair of the known 5,3′,5′-trihydroxy-flavanone-7-O-ß-d-glucopyranoside. The treatment of DENV-2 infected HepG2 cells with the new flavanone was able to control viral replication promoting a reduction of the number of infected cells (12%), together with a decrease of infectious particles in the culture supernatant (97%) and of the number of RNA copies of DENV-2 in HepG2 cells (67%). Structural determinations were made by NMR techniques in one and two dimensions (1H NMR, 13C NMR, COSY, HSQC and HMBC), HRMS, UV, OR and CD.

PEG10 is imperative for TGF-β1-induced epithelial-mesenchymal transition in hepatocellular carcinoma

Substantial evidence indicates that transforming growth factor-beta 1 (TGF-β1) plays a vital role in epithelial-mesenchymal transition (EMT). PEG10 has been shown involved in invasion and metastasis of tumors. The present study investigated the role of PEG10 in TGF-β1-triggered EMT in hepatocellular carcinoma (HCC) progression. Immunohistochemistry and real-time PCR were used to measure the expression level of PEG10 in clinical HCC tissues with or without lymph node metastasis, and normal tissues. The results showed that PEG10 expression is higher in HCC tissues and associated with overall survival (OS) and lymph node metastasis. Moreover, PEG10 expression level was remarkably higher in hepatic cancer cells than the normal hepatic cell line L02. In the present study, we constructed an adenovirus vector containing the coding area of PEG10 (Ad-PEG10) and infected HepG2 cells and found that overexpression of PEG10 promoted the cell migration, invasion ability and EMT of HepG2 cells. TGF-β1 acted on HepG2 cells by enhancing cell migration, invasion, EMT and upregulating PEG10 expression level. However, cells pretreated with adenovirus vector of PEG10 shRNAs (Ad-shRNA1 and Ad-shRNA2) did not occur EMT prior to TGF-β1 stimulation. Moreover, TGF-β1 did not increase the migration and invasion of cells with PEG10 knockdown and overexpression of PEG10 confers chemoresistance to HepG2 cells. Accordingly, sufficient PEG10 expression level is essential for TGF-β1 induced EMT and associated with the chemoresistance in HepG2 cells.

Cell-type specific variation in the induction of ER stress and downstream events in chikungunya virus infection

Over the last decade infections with the mosquito transmitted chikungunya virus (CHIKV) have become a major worldwide concern, and considerable efforts have been made in understanding the interaction of this virus with the host cell machinery. Studies have documented the induction of the unfolded protein response (UPR), as well as the induction of apoptosis and autophagy in response to CHIKV infection. This study comparatively analysed these three processes in two cell lines, Hela and HepG2. Infection of Hela cells was characterized by activation of the PERK/eIF2α branch of the UPR, the induction of autophagy and early apoptosis, while infection of HepG2 cells was characterized by activation of the IRE/XBP1 branch of the UPR, limited or no activation of autophagy and comparatively later apoptosis. These results show that the specific cell context is an important mediator of the host cell response to CHIKV infection.

Anticancer effect of 20(S)-ginsenoside Rh2 on HepG2 liver carcinoma cells: Activating GSK-3β and degrading β-catenin.

20(S)-ginsenoside Rh2[(S)Rh2] possesses potential to prevent cancer invitro aswellas invivo, but the underlying mechanism is still unknown. First, we infected HepG2 cells with lentivirus which carries β‑catenin. We detected the pharmacological effects of (S)Rh2 on HepG2 and HepG2‑β‑catenin cells and found that the IC50 of (S)Rh2 exposure on HepG2-β-catenin cells was higher than HepG2 cells. Flow cytometry(FCM) indicated that (S)Rh2 could be arrested in G0/G1 phase and induce early apoptosis in HepG2 and HepG2‑β‑catenin cells. Second, ELISA kit was used to check the activity of glycogen synthase kinase‑3β(GSK‑3β), which was upregulated by (S)Rh2. GSK‑3β inhibitor BIO, was used to verify that (S)Rh2 activated GSK‑3β. PCR and western blotting results indicated that (S)Rh2 could degrade the expression of β‑catenin, which combined with TCF in the nucleus and activate transcription of Wnt target genes, such as Bax, Bcl‑2, cyclin D1, MMP3, which were checked by chromatin immunoprecipitation(ChIP), PCR and western blotting. The results showed that the expression of Bax mRNA and proteins increased, while the cyclinD1, Bcl‑2, MMP3 mRNA and proteins were downregulated in HepG2 and HepG2‑β‑catenin cells which was induced by (S)Rh2. By contrast, with the HepG2-β-catenin+(S)Rh2 group, the expression of other mRNA and proteins in HepG2+(S)Rh2 group changed significantly. Invivo, experiments were performed using a nude mouse xenograft model to investigate the (S)Rh2 effect. So these results suggested that (S)Rh2 could suppress proliferation, promote apoptosis and inhibit metastasis of HepG2, decrease weight of tumor by downregulating β‑catenin through activating GSK‑3β and the pharmacological effect of (S)Rh2 on HepG2 cells might be weakened by overexpression of β‑catenin.