Metabolic dysfunction-associated steatotic liver disease (MASLD), one of the leading causes of chronic liver disorders, is characterized by hepatic lipid accumulation. MASLD causes alterations in the antioxidant defense system, lipid, and drug metabolism, resulting in impaired antioxidant status, hepatic metabolic processes, and clearance of therapeutic drugs, respectively. In the MASLD pathogenesis, dysregulated epigenetic mechanisms (e.g., histone modifications, DNA methylation, microRNAs) play a substantial role. In this study, the development of MASLD was investigated in mice fed a high-fat, high-fructose, and high-cholesterol (FFC) diet from 2 months of age, mice treated neonatally with monosodium glutamate (MSG) on a standard diet (STD), and mice treated with MSG on an FFC diet at 7 months of age and compared to control mice (C) on STD. Changes in liver histology, detoxification enzymes, epigenetic regulation, and genes involved in lipid metabolism were characterized and compared. The strong liver steatosis was observed in MSG STD, C FFC, and MSG FFC, with significant fibrosis in the latter one. Moreover, substantial alterations in hepatic lipid metabolism, epigenetic regulatory factors, and expressions and activities of various detoxification enzymes (namely superoxide dismutase, catalase, and carbonyl reductase 1) were observed in MASLD mice compared to control mice. miR-200b-3p, highly significantly upregulated in both FFC groups, could be considered as a potential diagnostic marker of MASLD. The MSG mice fed FFC seem to be a suitable model of MASLD characterized by both liver steatosis and fibrosis and substantial metabolic dysregulation.

• Keywords
• detoxification enzymes, high fat, fructose, and cholesterol (FFC) diet, metabolic dysfunction-associated steatotic liver disease (MASLD), miRNAs, mice, monosodium glutamate (MSG),
• Publication type
• Journal Article MeSH

The selection of a suitable combination of reference genes (RGs) for data normalization is a crucial step for obtaining reliable and reproducible results from transcriptional response analysis using a reverse transcription-quantitative polymerase chain reaction. This is especially so if a three-dimensional multicellular model prepared from liver tissues originating from biologically diverse human individuals is used. The mRNA and miRNA RGs stability were studied in thirty-five human liver tissue samples and twelve precision-cut human liver slices (PCLS) treated for 24 h with dimethyl sulfoxide (controls) and PCLS treated with β-naphthoflavone (10 µM) or rifampicin (10 µM) as cytochrome P450 (CYP) inducers. Validation of RGs was performed by an expression analysis of CYP3A4 and CYP1A2 on rifampicin and β-naphthoflavone induction, respectively. Regarding mRNA, the best combination of RGs for the controls was YWHAZ and B2M, while YWHAZ and ACTB were selected for the liver samples and treated PCLS. Stability of all candidate miRNA RGs was comparable or better than that of generally used short non-coding RNA U6. The best combination for the control PCLS was miR-16-5p and miR-152-3p, in contrast to the miR-16-5b and miR-23b-3p selected for the treated PCLS. Our results showed that the candidate RGs were rather stable, especially for miRNA in human PCLS.

• Keywords
• RT-qPCR, human liver, mRNA, miRNA, precision-cut liver slices, reference gene,
• MeSH
• beta 2-Microglobulin genetics   metabolism   MeSH
• beta-Naphthoflavone pharmacology   MeSH
• Cytochrome P-450 CYP1A2 genetics   metabolism   MeSH
• Cytochrome P-450 CYP3A genetics   metabolism   MeSH
• Dimethyl Sulfoxide pharmacology   MeSH
• Adult MeSH
• Liver drug effects   metabolism   MeSH
• Real-Time Polymerase Chain Reaction standards   MeSH
• Middle Aged MeSH
• Humans MeSH
• RNA, Messenger genetics   metabolism   MeSH
• MicroRNAs genetics   metabolism   MeSH
• 14-3-3 Proteins genetics   metabolism   MeSH
• Reference Standards MeSH
• Rifampin pharmacology   MeSH
• Aged MeSH
• Gene Expression Profiling standards   MeSH
• Cytochrome P-450 Enzyme System pharmacology   MeSH
• Transcriptome MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• B2M protein, human MeSH Browser
• beta 2-Microglobulin MeSH
• beta-Naphthoflavone MeSH
• CYP1A2 protein, human MeSH Browser
• CYP3A4 protein, human MeSH Browser
• Cytochrome P-450 CYP1A2 MeSH
• Cytochrome P-450 CYP3A MeSH
• Dimethyl Sulfoxide MeSH
• RNA, Messenger MeSH
• MicroRNAs MeSH
• 14-3-3 Proteins MeSH
• Rifampin MeSH
• Cytochrome P-450 Enzyme System MeSH
• YWHAZ protein, human MeSH Browser

Monoterpenes R-pulegone (PUL) and R-menthofuran (MF), abundant in the Lamiaceae family, are frequently used in herb and food products. Although their hepatotoxicity was shown in rodent species, information about their effects in human liver has been limited. The aim of our study was to test the effects of PUL, MF and acetaminophen (APAP, as a reference compound) on cell viability and microRNA (miRNA) expression in human precision-cut liver slices. Slices from five patients were used to follow up on the inter-individual variability. PUL was toxic in all liver samples (the half-maximal effective concentration was 4.0 µg/mg of tissue), while MF and surprisingly APAP only in two and three liver samples, respectively. PUL also changed miRNA expression more significantly than MF and APAP. The most pronounced effect was a marked decrease of miR-155-5p expression caused by PUL even in non-toxic concentrations in all five liver samples. Our results showed that PUL is much more toxic than MF and APAP in human liver and that miR-155-5p could be a good marker of PUL early hepatotoxicity. Marked inter-individual variabilities in all our results demonstrate the high probability of significant differences in the hepatotoxicity of tested compounds among people.

• Keywords
• acetaminophen, drug-induced liver injury, menthofuran, microRNA, precision-cut liver slices, pulegone,
• MeSH
• Biomarkers metabolism   MeSH
• Biological Variation, Individual * MeSH
• Liver drug effects   metabolism   MeSH
• Chemical and Drug Induced Liver Injury epidemiology   metabolism   MeSH
• Middle Aged MeSH
• Humans MeSH
• MicroRNAs genetics   metabolism   MeSH
• Cyclohexane Monoterpenes MeSH
• Monoterpenes toxicity   MeSH
• Acetaminophen toxicity   MeSH
• Aged MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biomarkers MeSH
• menthofuran MeSH Browser
• MicroRNAs MeSH
• MIRN155 microRNA, human MeSH Browser
• Cyclohexane Monoterpenes MeSH
• Monoterpenes MeSH
• Acetaminophen MeSH
• pulegone MeSH Browser

PURPOSE: Consumption of dietary supplements with green tea extract (GTE) is popular for weight management, but it may be accompanied by various side effects, including interactions with drugs. The aim of the present in vivo study was to evaluate the effect of defined GTE (Polyphenon 60) in three dosage schemes on insulin, leptin and drug-metabolizing enzymes in obese mice. METHODS: Experimental obesity was induced by repeated s.c. application of monosodium glutamate to newborn mice. Green tea extract was administered in three dosage schemes in chow diet. The plasmatic levels of insulin and leptin were assayed using enzyme-linked immunosorbent assay. Enzyme activities and mRNA expressions of drug-metabolizing enzymes (totally 13) were analyzed in liver and small intestine using spectrophotometric and HPLC assays and RT-PCR, respectively. RESULTS: GTE-treatment decreased insulin and leptin levels. Eleven enzymes were significantly affected by GTE-treatment. Long-term administration of 0.01% GTE caused increase in the activity and mRNA level of cytochrome P450 3A4 (CYP3A4) ortholog in the liver as well as in the small intestine. Interestingly, short-term overdose by GTE (0.1%) had more pronounced effects on enzyme activities and mRNA expressions than long-term overdose. CONCLUSIONS: GTE-mediated induction of CYP3A4 ortholog, the main drug-metabolizing enzyme, could result in decreased efficacy of simultaneously or subsequently administered drug in obese individuals.

• Keywords
• Catechins, Drug-metabolizing enzymes, Green tea extract, Metabolic syndrome, Obesity,
• MeSH
• Antioxidants pharmacology   MeSH
• Aryl Hydrocarbon Hydroxylases genetics   metabolism   MeSH
• Tea chemistry   MeSH
• Cytochrome P-450 CYP2E1 genetics   metabolism   MeSH
• Cytochrome P-450 CYP3A genetics   metabolism   MeSH
• Enzyme-Linked Immunosorbent Assay MeSH
• Sodium Glutamate adverse effects   MeSH
• Insulin blood   MeSH
• Liver drug effects   metabolism   MeSH
• Leptin blood   MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Disease Models, Animal MeSH
• Mice, Obese MeSH
• Mice MeSH
• Obesity chemically induced   drug therapy   MeSH
• Dietary Supplements * MeSH
• Cytochrome P450 Family 2 MeSH
• Plant Extracts pharmacology   MeSH
• Dose-Response Relationship, Drug MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antioxidants MeSH
• Aryl Hydrocarbon Hydroxylases MeSH
• Tea MeSH
• Cyp2a5 protein, mouse MeSH Browser
• Cytochrome P-450 CYP2E1 MeSH
• Cytochrome P-450 CYP3A MeSH
• cytochrome P450 3A4, mouse MeSH Browser
• Sodium Glutamate MeSH
• Insulin MeSH
• Leptin MeSH
• RNA, Messenger MeSH
• Cytochrome P450 Family 2 MeSH
• Plant Extracts MeSH

BACKGROUND: The repair of spontaneous and induced DNA lesions is a multistep process. Depending on the type of injury, damaged DNA is recognized by many proteins specifically involved in distinct DNA repair pathways. RESULTS: We analyzed the DNA-damage response after ultraviolet A (UVA) and γ irradiation of mouse embryonic fibroblasts and focused on upstream binding factor 1 (UBF1), a key protein in the regulation of ribosomal gene transcription. We found that UBF1, but not nucleolar proteins RPA194, TCOF, or fibrillarin, was recruited to UVA-irradiated chromatin concurrently with an increase in heterochromatin protein 1β (HP1β) level. Moreover, Förster Resonance Energy Transfer (FRET) confirmed interaction between UBF1 and HP1β that was dependent on a functional chromo shadow domain of HP1β. Thus, overexpression of HP1β with a deleted chromo shadow domain had a dominant-negative effect on UBF1 recruitment to UVA-damaged chromatin. Transcription factor UBF1 also interacted directly with DNA inside the nucleolus but no interaction of UBF1 and DNA was confirmed outside the nucleolus, where UBF1 recruitment to DNA lesions appeared simultaneously with cyclobutane pyrimidine dimers; this occurrence was cell-cycle-independent. CONCLUSIONS: We propose that the simultaneous presence and interaction of UBF1 and HP1β at DNA lesions is activated by the presence of cyclobutane pyrimidine dimers and mediated by the chromo shadow domain of HP1β. This might have functional significance for nucleotide excision repair.

• Keywords
• DNA repair, DNA-damage response, Irradiation, Live-cell studies, Nucleolus, UBF1,
• Publication type
• Journal Article MeSH