Exposed HepG2 Cells Research Articles

The Role of PNPLA3_rs738409 Gene Variant, Lifestyle Factors, and Bioactive Compounds in Nonalcoholic Fatty Liver Disease: A Population-Based and Molecular Approach towards Healthy Nutrition.

This study aimed to investigate the impact of a common non-synonymous gene variant (C>G, rs738409) in patatin-like phospholipase domain-containing 3 (PNPLA3), leading to the substitution of isoleucine with methionine at position 148 (PNPLA3-I148M), on susceptibility to nonalcoholic fatty liver disease (NAFLD) and explore potential therapeutic nutritional strategies targeting PNPLA3. It contributed to understanding sustainable dietary practices for managing NAFLD, recently referred to as metabolic-dysfunction-associated fatty liver. NAFLD had been diagnosed by ultrasound in a metropolitan hospital-based cohort comprising 58,701 middle-aged and older Korean individuals, identifying 2089 NAFLD patients. The interaction between PNPLA3 and lifestyle factors was investigated. In silico analyses, including virtual screening, molecular docking, and molecular dynamics simulations, were conducted to identify bioactive compounds from foods targeting PNPLA3(I148M). Subsequent cellular experiments involved treating oleic acid (OA)-exposed HepG2 cells with selected bioactive compounds, both in the absence and presence of compound C (AMPK inhibitor), targeting PNPLA3 expression. Carriers of the risk allele PNPLA3_rs738409G showed an increased association with NAFLD risk, particularly with adherence to a plant-based diet, avoidance of a Western-style diet, and smoking. Delphinidin 3-caffeoyl-glucoside, pyranocyanin A, delta-viniferin, kaempferol-7-glucoside, and petunidin 3-rutinoside emerged as potential binders to the active site residues of PNPLA3, exhibiting a reduction in binding energy. These compounds demonstrated a dose-dependent reduction in intracellular triglyceride and lipid peroxide levels in HepG2 cells, while pretreatment with compound C showed the opposite trend. Kaempferol-7-glucoside and petunidin-3-rutinoside showed potential as inhibitors of PNPLA3 expression by enhancing AMPK activity, ultimately reducing intrahepatic lipogenesis. In conclusion, there is potential for plant-based diets and specific bioactive compounds to promote sustainable dietary practices to mitigate NAFLD risk, especially in individuals with genetic predispositions.

Daily exposure to low concentrations Tetrabromobisphenol A interferes with the thyroid hormone pathway in HepG2 cells

Tetrabromobisphenol A (TBBPA) is a flame retardant that adversely affects the environment and human health. The present study exposed HepG2 cells to low concentrations of TBBPA daily to investigate the changes in gene regulation, mainly related to pathways associated with the endocrine system. The quantitative polymerase chain reaction (qPCR) confirmed that prolonged exposure gradually activated the thyroid hormone and parathyroid hormone signaling pathways. The expression levels of genes related to the thyroid hormone signaling pathway were upregulated (1.15−8.54 times) after five generations of exposure to 1 and 81 nM TBBPA. Furthermore, co-exposure to 81 nM TBBPA and 0.5 nM thyroid hormone receptor antagonist for five generations significantly reduced the expression of thyroid hormone and parathyroid hormone receptors. Meanwhile, 81 nM TBBPA inhibited the activation of the Ras pathway and downregulated Ras gene expression level (3.7 times), indicating the association between the toxic effect and thyroid hormone receptors. Additionally, our experiments revealed that the thyroid hormone pathway regulated the induction of the Ras signaling pathway by TBBPA. The study thus proves that daily exposure to TBBPA interferes with the thyroid hormone signaling pathway and subsequently the endocrine system.

BDE-47, -99, -209 and Their Ternary Mixture Disrupt Glucose and Lipid Metabolism of Hepg2 Cells at Dietary Relevant Concentrations: Mechanistic Insight through Integrated Transcriptomics and Proteomics Analysis.

Polybrominated diphenyl ethers (PBDEs) are persistent organic chemicals implied as flame retardants. Humans are mainly exposed to BDE-47, -99, and -209 congeners by diet. PBDEs are metabolic disruptors with the liver as the main target organ. To investigate their mode of action at a human-relevant concentration, we exposed HepG2 cells to these congeners and their mixture at 1 nM, analyzing their transcriptomic and proteomic profiles. KEGG pathways and GSEA Hallmarks enrichment analyses evidenced that BDE-47 disrupted the glucose metabolism and hypoxia pathway; all the congeners and the MIX affected lipid metabolism and signaling Hallmarks regulating metabolism as mTORC1 and PI3K/AKT/MTOR. These results were confirmed by glucose secretion depletion and increased lipid accumulation, especially in BDE-47 and -209 treated cells. These congeners also affected the EGFR/MAPK signaling; further, BDE-47 enriched the estrogen pathway. Interestingly, BDE-209 and the MIX increased ERα gene expression, whereas all the congeners and the MIX induced ERβ and PPARα. We also found that PBDEs modulated several lncRNAs and that HNRNAP1 represented a central hub in all the four interaction networks. Overall, the PBDEs investigated affected glucose and lipid metabolism with different underlying modes of action, as highlighted by the integrated omics analysis, at a dietary relevant concentration. These results may support the mechanism-based risk assessment of these compounds in relation to liver metabolism disruption.

Biological and Proteomic Characterization of the Anti-Cancer Potency of Aqueous Extracts from Cell-Free Coelomic Fluid of Arbacia lixula Sea Urchin in an In Vitro Model of Human Hepatocellular Carcinoma

Echinoderms are an acknowledged source of bioactive compounds exerting various beneficial effects on human health. Here, we examined the potential in vitro anti-hepatocarcinoma effects of aqueous extracts of the cell-free coelomic fluid obtained from the sea urchin Arbacia lixula using the HepG2 cell line as a model system. This was accomplished by employing a combination of colorimetric, microscopic and flow cytometric assays to determine cell viability, cell cycle distribution, the possible onset of apoptosis, the accumulation rate of acidic vesicular organelles, mitochondrial polarization, cell redox state and cell locomotory ability. The obtained data show that exposed HepG2 cells underwent inhibition of cell viability with impairment of cell cycle progress coupled to the onset of apoptotic death, the induction of mitochondrial depolarization, the inhibition of reactive oxygen species production and acidic vesicular organelle accumulation, and the block of cell motile attitude. We also performed a proteomic analysis of the coelomic fluid extract identifying a number of proteins that are plausibly responsible for anti-cancer effects. Therefore, the anti-hepatocarcinoma potentiality of A. lixula’s preparation can be taken into consideration for further studies aimed at the characterization of the molecular mechanism of cytotoxicity and the development of novel prevention and/or treatment agents.

Quantitative phosphoproteomics reveal cellular responses from caffeine, coumarin and quercetin in treated HepG2 cells

Protein phosphorylation is the most common type of post-translational modification where serine, threonine or tyrosine are reversibly bound to the phosphate group of ATP in a reaction catalyzed by protein kinases. Phosphorylation plays an important role in regulation of cell homeostasis, including but not limited to signal perception and transduction, gene expression and function of proteins. Protein phosphorylation happens on a fast time scale and represents an energy-efficient way for the cell to adapt to exposure to chemical stressors. To understand the cascade of cellular signaling induced by exposure to chemicals, we have exposed HepG2 cells to three chemicals with different modes of action, namely, caffeine, coumarin, and quercetin in a concentration and time response manner. Significantly upregulated and downregulated phosphosites were screened to analyze the activation/deactivation of signaling pathways by protein kinases. In total, 69, 44 and 12 signaling pathways were found enriched in caffeine, coumarin and quercetin treated cells, respectively, of which 9 pathways were co-enriched with 11 jointly responded kinases. Among identified co-responded kinases, CDK1, MAPK1 and MAPK3 play important roles in cell cycle and insulin signaling pathways. Quantitative phosphoproteomics can sensitively distinguish the effects of different chemicals on cells, allowing the assessment of chemical safety through changes in substrates and metabolic pathways at the cellular level, which is important for the development of non-animal approaches for chemical safety assessment.

Tris(2-butoxyethyl) phosphate (TBEP): A flame retardant in solid waste display hepatotoxic and carcinogenic risks for humans

Recent reports have confirmed that tris(2-butoxyethyl) phosphate (TBEP), an organophosphorous flame retardants (OPFRs), profoundly detected in the dust from solid waste (SW), e-waste dumping sites, landfills, and wastewater treatment facilities. Herein, we evaluated the hepatotoxic and carcinogenic potential of TBEP in human liver cells (HepG2). HepG2 cells exhibited cytotoxicity after 3 days of exposure, especially at greater concentrations (100–400 μM). TBEP induced severe DNA damage and cell cycle disturbances that trigger apoptosis in HepG2. TBEP treated cells showed an elevated level of esterase, nitric oxide (NO), reactive oxygen species (ROS), and influx of Ca2+ in exposed cells. Thereby, causing oxidative stress and proliferation inhibition. TBEP exposed HepG2 cells exhibited dysfunction in mitochondrial membrane potential (ΔΨm). Immunofluorescence analysis demonstrated cytoplasmic and nucleolar localization of DNA damage (P53) and apoptotic (caspase 3 and 9) proteins in HepG2 grown in the presence of TBEP for 3 days. Within the cohort of 84 genes of cancer pathway, 10 genes were upregulated and 3 genes were downregulated. The transcriptomic and toxicological data categorically emphasize that TBEP is hepatotoxic, and act as a putative carcinogenic agent. Thereby, direct or indirect ingestion of TBEP containing dusts by workers involved in handling and disposal of SW, as well as residents living nearby the disposal areas are prone to its adverse health risks.

Counteracting Action of Curcumin on High Glucose-Induced Chemoresistance in Hepatic Carcinoma Cells.

Along with direct anticancer activity, curcumin hinders the onset of chemoresistance. Among many, high glucose condition is a key driving factor for chemoresistance. However, the ability of curcumin remains unexplored against high glucose-induced chemoresistance. Moreover, chemoresistance is major hindrance in effective clinical management of liver cancer. Using hepatic carcinoma HepG2 cells, the present investigation demonstrates that high glucose induces chemoresistance, which is averted by the simultaneous presence of curcumin. Curcumin obviated the hyperglycemia-induced modulations like elevated glucose consumption, lactate production, and extracellular acidification, and diminished nitric oxide and reactive oxygen species (ROS) production. Modulated molecular regulators are suggested to play a crucial role as curcumin pretreatment also prevented the onset of chemoresistance by high glucose. High glucose instigated suppression in the intracellular accumulation of anticancer drug doxorubicin and drug-induced chromatin compactness along with declined expression of drug efflux pump MDR-1 and transcription factors and signal transducers governing the survival, aggressiveness, and apoptotic cell death (p53, HIF-1α, mTOR, MYC, STAT3). Curcumin alleviated the suppression of drug retention and nuclear condensation along with hindering the high glucose-induced alterations in transcription factors and signal transducers. High glucose-driven resistance in cancer cells was associated with elevated expression of metabolic enzymes HKII, PFK1, GAPDH, PKM2, LDH-A, IDH3A, and FASN. Metabolite transporters and receptors (GLUT-1, MCT-1, MCT-4, and HCAR-1) were also found upregulated in high glucose exposed HepG2 cells. Curcumin inhibited the elevated expression of these enzymes, transporters, and receptors in cancer cells. Curcumin also uplifted the SDH expression, which was inhibited in high glucose condition. Taken together, the findings of the present investigation first time demonstrate the ability of curcumin against high glucose-induced chemoresistance, along with its molecular mechanism. This will have implication in therapeutic management of malignancies in diabetic conditions.

Long Non-Coding RNAs Involved in Progression of Non-Alcoholic Fatty Liver Disease to Steatohepatitis.

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease and is characterized by different stages varying from benign fat accumulation to non-alcoholic steatohepatitis (NASH) that may progress to cirrhosis and liver cancer. In recent years, a regulatory role of long non-coding RNAs (lncRNAs) in NAFLD has emerged. Therefore, we aimed to characterize the still poorly understood lncRNA contribution to disease progression. Transcriptome analysis in 60 human liver samples with various degrees of NAFLD/NASH was combined with a functional genomics experiment in an in vitro model where we exposed HepG2 cells to free fatty acids (FFA) to induce steatosis, then stimulated them with tumor necrosis factor alpha (TNFα) to mimic inflammation. Bioinformatics analyses provided a functional prediction of novel lncRNAs. We further functionally characterized the involvement of one novel lncRNA in the nuclear-factor-kappa B (NF-κB) signaling pathway by its silencing in Hepatoma G2 (HepG2) cells. We identified 730 protein-coding genes and 18 lncRNAs that responded to FFA/TNFα and associated with human NASH phenotypes with consistent effect direction, with most being linked to inflammation. One novel intergenic lncRNA, designated lncTNF, was 20-fold up-regulated upon TNFα stimulation in HepG2 cells and positively correlated with lobular inflammation in human liver samples. Silencing lncTNF in HepG2 cells reduced NF-κB activity and suppressed expression of the NF-κB target genes A20 and NFKBIA. The lncTNF we identified in the NF-κB signaling pathway may represent a novel target for controlling liver inflammation.

Inhibition of NOX4 by Cissus quadrangularis extract protects from Type 2 diabetes induced-steatohepatitis

BackgroundCissus quadrangularis L. is commonly known as hadjod and traditionally used as a medicinal plant for the treatment of osteoporosis, dyspepsia, tumors, chronic ulcers, and hepatic diseases. Existing studies have proclaimed the proinflammatory property of NOX4 through instigating ROS and oxidative stress, which is considered to be one of the instrumental causes of steatohepatitis. PurposeTo investigate the protective effect of ethanolic extract of C. quadrangularis (EECQ) on the steatohepatitis associated with type 2 diabetes (DM) through inhibition of NOX4. MethodsAn experimental DM-induced steatohepatitis was developed by feeding a high-fat diet for 12 weeks in Sprague Dawley rats. Treatment of EECQ was given at a dose of 200 mg/kg (po), for six weeks. Glucose and insulin tolerance test was conducted. Hematoxylin and eosin and picrosirius red staining of liver sections was done. Steatosis and lobular inflammation were scored, and hepatocyte ballooning was assessed to confirm the NASH. qPCR, Immunofluorescence, and Immunoblotting determined the mRNA and protein expression of NOX4. ResultsNASH group rats manifested features of DM, marked by aggravated glucose and insulin tolerance tests. Moreover, the DM rats exhibited the presence of steatohepatitis, characterized by elevated serum lipid content, aminotransferases, and presence of steatosis, lobular inflammation, and ballooning in the liver section. Nevertheless, EECQ treatment prevented all of these abnormalities. Besides, the level of AGEs and the expression of its receptor, RAGE was found to be increased in DM rats. Parallelly, the expression of NOX4 and the accompanying level of ROS, oxidative stress markers, and inflammatory cytokines were determined to be surged in palmitic acid exposed HepG2 cells and DM rats. However, EECQ treatment exemplified safeguards from the soared level of the aforementioned markers. ConclusionCollectively, the above findings propounded the protective effect of EECQ against steatohepatitis. Nonetheless, further studies on humans necessitate to scrutinize and reinforce its therapeutic potential so that it may be employed as a remedy for DM-induced steatohepatitis.

Desmodium gyrans dc modulates lipid trafficking in cultured macrophages and improves functional high-density lipoprotein in male wistar rats.

OBJECTIVE:High-density lipoprotein (HDL) cholesterol-mediated atherosclerotic plaque regression has gained wide therapeutic attention. The whole plant methanolic extract of the medicinal plant Desmodium gyrans Methanolic Extract (DGM) has shown to mitigate hyperlipidemia in high fat- and-cholesterol fed rats and rabbits with significant HDL enhancing property. The study aimed to assess the functionality and mechanistic basis of HDL promoting effect of DGM.MATERIALS AND METHODS:Macrophage cholesterol efflux and foam cell formation assays were performed in THP-1 macrophages. Male Wistar rats were given DGM extract over 1 month and assessed the serum HDL, Apolipoprotein A1 (Apo-A1), and paraoxonase activity. Quantitative Polymerase chain reaction was carried out to assess the expression level of Apo-A1, SR-B1 (Scavenger receptor B1), and Cholesteryl ester transfer protein (CETP) on cDNA of HepG2 cells exposed to DGM.RESULTS:Pretreatment of DGM inhibited uptake of oxidized lipids and enhanced the lipid efflux by THP-1-derived macrophages. Oral administration of DGM (100 and 250 mg/kg) progressively enhanced the serum HDL, Apo-A1 level, and associated paraoxonase activity in normal male Wistar rats. In support to this, DGM exposed HepG2 cells documented dose-dependent increase in the expression of SR-B1 and Apo-A1 mRNA, while reduced the CETP expression.CONCLUSION:Overall the results indicated that DGM modulates lipid trafficking and possesses functional HDL enhancing potential through increased Apo-A1 levels and paraoxonase activity. Further, reduced CETP expression and increased expression of SR-B1 suggest the reverse cholesterol transport promoting role of DGM.

Hepatoprotective activity assessment of amino acids derivatives of picroside I and II

Picrorhiza kurroa has a long medicinal history as a traditional medicinal plant in China and India that is widely used in clinical treatments. It is a common treatment for liver diseases, fever, diarrhoea, indigestion, and some other diseases. Modern pharmacological studies proved that P.kurroa rhizomes have high levels of picroside I and II, which were identified as main constituents with anti-inflammatory and hepatoprotective activities. In our study, we used picroside I and II as the lead compounds to generate derivatives by reactions with Boc-valine or Boc-proline, which underwent dehydration and condensation with the hydroxyl groups in the lead compounds in the presence of coupling reagent N,N'-dicyclohexylcarbodiimide. We synthesized 11 derivatives and examined their hepatoprotective effects in vitro by assessing the proliferation rates of H2 O2 -exposed HepG2 cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We found that some derivatives promoted higher proliferation rates in HepG2 cells than the natural compounds before derivatization, suggesting that those derivatives possessed an improved hepatoprotective capacity. The novel derivatization strategy for picrosides had the additional benefit that the esterification of their hydroxyl groups created derivatives not only with increased stability but also with improved pharmacokinetic properties and potentially prolonged half-life.

Protective effects of Lactobacillus acidophilus NX2-6 against oleic acid-induced steatosis, mitochondrial dysfunction, endoplasmic reticulum stress and inflammatory responses

Lactobacillus acidophilus NX2-6 protected against oleic acid-induced steatosis through improving lipid metabolism, mitochondrial dysfunction, endoplasmic reticulum stress and inflammatory responses. • The cell-free extract of Lactobacillus acidophilus NX2-6 improved lipid profile. • The cell-free extract regulated lipid metabolism at the genetic and protein level. • The cell-free extract alleviated oxidative stress and endoplasmic reticulum stress. • The cell-free extract attenuated mitochondrial dysfunction. The cell-free extract (CFE) of Lactobacillus acidophilus NX2-6 was used to treat oleic acid (OA)-exposed HepG2 cells. Biochemical analysis showed that CFE could reduce high levels of triglyceride, LDL-c, LDH, and MDA caused by OA treatment. RT-PCR and western blot analysis revealed that CFE distinctly decreased levels of Srebp-1c and FAS but elevated expression of CPT1. Fluorimetric analysis showed that CFE augmented mitochondrial membrane potential and mitochondrial content, and reduced ROS production induced by OA. Meanwhile, RT-PCR analysis also exhibited that CFE contributed to mitochondrial respiration by increasing expressions of respiratory complex subunits MTND1 , MTCO1 , MTATP6 and MTCYB . CFE also downregulated GRP58 , ATF6 , IREα , XBP1 and CHOP to alleviate ERS. Results also showed that CFE inhibited inflammatory responses through decreasing the levels of IL-1β and IL-6 and downregulating expression of NF-κB . Therefore, L. acidophilus possessed potentials to improve lipid metabolism, oxidative stress, mitochondrial dysfunction, ERS and inflammation in hepatocytes.

The Root of Polygonum multiflorum Thunb. Alleviates Non-Alcoholic Steatosis and Insulin Resistance in High Fat Diet-Fed Mice

Non-alcoholic steatosis and insulin resistance are critical health problems and cause metabolic complications worldwide. In this study, we investigated the molecular mechanism of Polygonum multiflorum Thunb. (PM) against hepatic lipid accumulation and insulin resistance by using in vitro and in vivo models. PM extract significantly attenuated the accumulation of lipid droplets and hepatic triglyceride in free fatty acid (FFA)-exposed HepG2 cells. PM extract increased the AMPK and ACC phosphorylation and GLUT4 expression, whose levels were downregulated in FFA-exposed cells. PM extract also decreased precursor and mature forms of SREBP-1 in FFA-exposed cells. C57BL/6 mice fed with normal diet (ND) or high-fat diet (HFD) were administered PM extract (100 mg/kg) or vehicle orally for 16 weeks. PM extract attenuated the increases of the epididymal and perirenal fats on HFD feeding. PM extract markedly reduced hepatic lipid accumulation and fasting glucose levels, and improved glucose and insulin sensitivity in HFD-fed mice. HFD-fed mice decreased the AMPK and ACC phosphorylation and GLUT4 expression, and increased precursor and mature forms of SREBP-1; these changes were significantly restored by PM extract. In conclusion, PM extract alleviates non-alcoholic steatosis and insulin resistance through modulating the expression of proteins on lipid metabolism and glucose transport in the liver.

HEPATOPROTECTIVE ACTIVITY OF ETHANOLIC STEM BARK EXTRACT OF KNEMA ATTENUATA (HOO K. F. AND THOMSON) WARB

Objective: To investigate the hepatoprotective activity of ethanolic stem bark extract (ESBE) of Knema attenuata against carbon tetrachloride (CCl4) induced hepatotoxicity in Wistar rats using both in vivo and in vitro models.
 Methods: Animals were treated orally with ESBE (250 mg kg-1 and 500 mg kg-1) once daily for 6 d and CCl4 on the 4th d. On the 7th d, animals were sacrificed and the blood samples were collected to measure the serum levels of biochemical parameters, whereas the liver homogenates were utilized for estimating the antioxidant defense. The hepatoprotective efficacy of the extract was further ensured in vitro using human liver hepatocellular carcinoma (HepG2) cell line against CCl4 induced toxicity. The cell line viability was determined using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.
 Results: ESBE effectively reduced (p<0.001) the elevated serum levels of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), and Alkaline phosphatase (ALP) when compared to the toxicant control group. ESBE 500 mg kg-1significantly raised the antioxidant defense (p<0.0001) by reducing the malondialdehyde (MDA) level and enhancing hepatic reduced glutathione (GSH) level in comparison to the CCl4 control group. The in vitro effect was investigated using CCl4 exposed HepG2 cells. Pretreatment with ESBE showed a dose-dependent increase in percentage cell viability ranged between 44 to 57% at 12.5-100 μg ml-1concentrations (p<0.001, when compared to the control cells). 
 Conclusion: Present study confirms the hepatoprotective activity of the stem bark extract of K. attenuata against CCl4‑induced liver damage.

Berbamine induced AMPK activation regulates mTOR/SREBP-1c axis and Nrf2/ARE pathway to allay lipid accumulation and oxidative stress in steatotic HepG2 cells

Non-alcoholic fatty liver disease is emanating as a global cataclysm. This study was designed to investigate the antioxidative, anti-inflammatory and fat metabolism-regulating potential of berbamine (BBM), a natural bis-benzylisoquinoline alkaloid. BBM attenuated intracellular lipid accumulation in oleic-acid exposed HepG2 cells (0.5 mM) by inhibiting fatty acid uptake, lipogenesis, and promoting fatty acid β-oxidation by activating AMP-activated kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)-α. Berbamine (5 μM) induced AMPK activation (P < 0.001) via LKB1 (Ser-428) and elevated AMP:ATP ratio (P < 0.001). AMPK activation negatively regulated mTOR and also constrained the nuclear translocation of SREBP-1c and inhibited the lipogenic proteins, stearoyl-CoA desaturase-1 (SCD-1) and fatty acid synthase (FAS) (P < 0.001). BBM stimulated nuclear translocation of redox-sensitive nuclear factor erythroid-2-related factor-2 (Nrf2) and increased hepatic expression of Nrf2 responsive enzymes, HO-1 and Nqo-1. BBM treatment reduced the oxidative burst and pro-inflammatory responses by significantly enhancing hepatic antioxidant defenses [SOD (P < 0.001), catalase (P < 0.001) and cellular glutathione (P < 0.01)] and diminishing NF-κB regulated pro-inflammatory cytokines (TNF-α, and IL-6) levels respectively. TEM analysis confirmed the disruption of mitochondrial structure and reduction in mitochondrial size (50.97%, P < 0.001) in steatotic HepG2 cells which was significantly prevented by 5 μM BBM treatment (71.84% as compared to control, P < 0.01). Pre-treatment of Compound C (AMPK inhibitor, 25 μM) greatly repressed the anti-steatotic properties exhibited by BBM confirming the involvement of AMPK signaling pathway. In summary, the results manifest that BBM reduces intracellular lipid accumulation via AMPK/mTOR/SREBP-1c axis mediated regulation of lipid metabolism and upsurged nuclear stability of Nrf2 by promoting AMPK/Nrf2 association to ameliorate oxidative stress/proinflammatory response.

Protective potency of ascorbic acid supplementation against cytotoxicity and DNA fragmentation induced by triphenyltin on human liver carcinoma cells.

Agrochemicals are one the most significant sources of environmental pollution. Cytotoxicity and genotoxicity are the serious side effects of fungicide. In the current study, I have evaluated acute cytotoxicity and genotoxicity of triphenyltin (TPT) on human hepatic carcinoma (HepG2) cells and the ameliorating effect of ascorbic acid for 24h. In this experiment, I have exposed HepG2 cells to ascorbic acids (50, 100, and 200μM) simultaneously and 24h prior triphenyltin (TPT, 400ng/ml) exposure for 24h to determine the protective effect of ascorbic acid by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and NRU (neutral red uptake) assays. Oxidative stress, such as intracellular reactive oxygen species and glutathione levels, was measured in HepG2 cells. The intracellular reactive oxygen species was evaluated using fluorescent probe DCFDA (6-carboxy-2',7' dichloro-dihydrofluorescein diacetate). Apoptosis and genotoxicity effects of TPT in HepG2 cells were determined using flow cytometry and comet assay. The result of these experiments showed that the TPT compound (400ng/ml) induced cytotoxicity, oxidative stress and apoptosis, and DNA damage in HepG2 cells.Ascorbic acid reduced cytotoxicity, oxidative stress, apoptosis, and genotoxicity induced by TPT. Thus, ascorbic acid is a potent antioxidant, and it showed a significant protective effect against toxicity induced by TPT in HepG2 cells.

Lemon Balm and Its Constituent, Rosmarinic Acid, Alleviate Liver Damage in an Animal Model of Nonalcoholic Steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) ranges in severity from hepatic steatosis to cirrhosis. Lemon balm and its major constituent, rosmarinic acid (RA), effectively improve the liver injury and obesity; however, their therapeutic effects on nonalcoholic steatohepatitis (NASH) are unknown. In this study, we investigated the effects of RA and a lemon balm extract (LBE) on NAFLD and liver fibrosis and elucidated their mechanisms. Palmitic acid (PA)-exposed HepG2 cells and db/db mice fed a methionine- and choline-deficient (MCD) diet were utilized to exhibit symptoms of human NASH. LBE and RA treatments alleviated the oxidative stress by increasing antioxidant enzymes and modulated lipid metabolism-related gene expression by the activation of adenosine monophosphate-activated protein kinase (AMPK) in vitro and in vivo. LBE and RA treatments inhibited the expression of genes involved in hepatic fibrosis and inflammation in vitro and in vivo. Together, LBE and RA could improve liver damage by non-alcoholic lipid accumulation and may be promising medications to treat NASH.

The uricosuric benzbromarone disturbs the mitochondrial redox homeostasis and activates the NRF2 signaling pathway in HepG2 cells

The uricosuric benzbromarone is a mitochondrial toxicant associated with severe liver injury in patients treated with this drug. Since dysfunctional mitochondria can increase mitochondrial superoxide (O2•−) production, we investigated the consequences of benzbromarone-induced mitochondrial oxidative stress on the hepatic antioxidative defense system. We exposed HepG2 cells (a human hepatocellular carcinoma cell line) to increasing concentrations of benzbromarone (1-100 μM) for different durations (2-24 h), and investigated markers of antioxidative defense and oxidative damage. At high concentrations (≥50 μM), benzbromarone caused accumulation of mitochondrial superoxide (O2•−) and cellular reactive oxygen species (ROS). At concentrations >50 μM, benzbromarone increased the mitochondrial and cellular GSSG/GSH ratio and increased the oxidized portion of the mitochondrial thioredoxin 2. Benzbromarone stabilized the transcription factor NRF2 and caused its translocation into the nucleus. Consequently, the expression of the NRF2-regulated antioxidative proteins superoxide dismutase 1 (SOD1) and 2 (SOD2), glutathione peroxidase 1 (GPX1) and 4 (GPX4), as well as thioredoxin 1 (TRX1) and 2 (TRX2) increased. Finally, upregulation of NRF2 by siRNA-mediated knock-down of KEAP1 partially protected HepG2 cells from benzbromarone-induced membrane damage and ATP depletion. In conclusion, benzbromarone increased mitochondrial O2•− accumulation and activates the NRF2 signaling pathway in HepG2 cells, thereby strengthening the cytosolic and mitochondrial antioxidative defense. Impaired antioxidative defense may represent a risk factor for benzbromarone-induced hepatotoxicity.

Chemical Constituents from Albiziae Cortex and Their Ability to Ameliorate Steatosis and Promote Proliferation and Anti-Oxidation In Vitro.

This study describes the chemical constituents of Albiziae Cortex and their ability to ameliorate steatosis and promote proliferation and anti-oxidation in vitro. Together, five known lignan glycosides, (7S,8R)-erythro-syringylglycerol-β–O-4′-sinapyl ether 9-O-β-D-glucopyranoside (1), (+)-lyoniresinol-9′-O-gluco-side (2), (−)-lyoniresinol-9′-O-glucoside (3), picraquassioside C (4), and icariside E5 (5), were isolated from the Albiziae Cortex. Their structures were elucidated by extensive NMR and high-resolution mass spectrometry analysis and compared with reported data. Oil Red O staining results revealed that compounds 1, 2, and 3 attenuated lipid accumulation and lipid metabolic disorders in FFAs (oleate/palmitate, 2:1 ratio, 0.3 mM)-exposed HepG2 cells. The Cell Counting Kit 8 (CCK-8) assay results revealed that compounds 1 and 5 can significantly promote human umbilical vein endothelial cell (HUVEC) proliferation; meanwhile, these compounds did not exhibit significant cytotoxicity against HUVECs. In addition, 2′,7′-dichlorofluorescein diacetate (DCFH-DA) staining results revealed that high glucose (HG)-induced reactive oxygen species (ROS) production was abolished by compounds 1, 2, and 3. This is the first report of the isolation of lignan skeletons from the genus Albizzia julibrissin with the ability to ameliorate steatosis and promote proliferation and anti-oxidation activities.

Lemon Balm Extract and Its Major Chemical Compound, Rosmarinic Acid, Alleviate Damages of Liver in an Animal Model of Nonalcoholic Steatohepatitis (NASH) (P06-093-19)

ObjectivesThe non-alcoholic fatty liver disease (NAFLD) comprises the broad histopathological states of liver, that ranging from asymptomatic hepatic steatosis to non-alcoholic steatohepatitis (NASH) and liver cirrhosis. In some studies, they suppose that almost 25–30% of world population is underlying NAFLD. Lemon balm (Melissa officinalis) is the herb that has some traditional medicinal usages. Also rosmarinic acid (RA; O-caffeoyl-3,4-dihydroxyphenyl lactic acid), the major chemical compound of lemon balm, already reported that it has the potency on anti-obesity and -inflammatory. Hence, we evaluate the whether lemon balm extract (LBE) and RA could suppress the pathogenesis of NASH using an in vitro and in vivo model. MethodsIn vitro model: The palmitic acid (PA) exposed HepG2 hepatocellular carcinoma cells can imitate the lipid accumulation in hepatocytes. PA exposed HepG2 cells were exposed with or without LBE or RA.In vivo model: The methionine- and choline-deficient (MCD) diet fed db/db C57BL/6 J mice model was used. This model is known as it can mimic well symptoms of human NAFLD. The LBE or RA were treated by oral gavage. ResultsWith the MCD diet only, the severe liver damage was caused by progression of NASH in animal model. LBE and RA treatments alleviated the oxidative stress in the MCD diet-fed db/db mice and PA-exposed HepG2 cells by increasing the expression of antioxidant enzymes (NRF2, SOD) and augmented lipolysis-related gene (PPARα, PGC-1α, CPT-1 L) expression. In addition, LBE and RA treatments inhibited the expression of genes involved in hepatic fibrosis (α-SMA, COL1A1) and fatty acid synthesis (SREBP-1c, CPT-1 L) and activated AMP-activated protein kinase in vitro and in vivo. Also, the histopathological results were ameliorated by treatment of LBE or RA. ConclusionsLBE and RA modulate lipid metabolism via AMPK activation and suppress inflammation via changes in NRF2 and NF-κB signalling. Importantly, the extract of lemon balm obtained with 20% EtOH showed effectiveness similar to that of RA at high concentrations. Therefore, LBE may be a good candidate for the treatment and prevention of NASH. Funding SourcesThis work was supported by the National Research Council of Science & Technology (NST) funded by the Korea Government (MSIP) (grant No. CRC-15-01-KIST). Supporting Tables, Images and/or Graphs▪