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.

• Klíčová slova
• detoxification enzymes, high fat, fructose, and cholesterol (FFC) diet, metabolic dysfunction-associated steatotic liver disease (MASLD), miRNAs, mice, monosodium glutamate (MSG),
• Publikační typ
• časopisecké články 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.

• Klíčová slova
• RT-qPCR, human liver, mRNA, miRNA, precision-cut liver slices, reference gene,
• MeSH
• beta-2-mikroglobulin genetika   metabolismus   MeSH
• beta-naftoflavon farmakologie   MeSH
• cytochrom P-450 CYP1A2 genetika   metabolismus   MeSH
• cytochrom P-450 CYP3A genetika   metabolismus   MeSH
• dimethylsulfoxid farmakologie   MeSH
• dospělí MeSH
• játra účinky léků   metabolismus   MeSH
• kvantitativní polymerázová řetězová reakce normy   MeSH
• lidé středního věku MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• mikro RNA genetika   metabolismus   MeSH
• proteiny 14-3-3 genetika   metabolismus   MeSH
• referenční standardy MeSH
• rifampin farmakologie   MeSH
• senioři MeSH
• stanovení celkové genové exprese normy   MeSH
• systém (enzymů) cytochromů P-450 farmakologie   MeSH
• transkriptom MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• B2M protein, human MeSH Prohlížeč
• beta-2-mikroglobulin MeSH
• beta-naftoflavon MeSH
• CYP1A2 protein, human MeSH Prohlížeč
• CYP3A4 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A2 MeSH
• cytochrom P-450 CYP3A MeSH
• dimethylsulfoxid MeSH
• messenger RNA MeSH
• mikro RNA MeSH
• proteiny 14-3-3 MeSH
• rifampin MeSH
• systém (enzymů) cytochromů P-450 MeSH
• YWHAZ protein, human MeSH Prohlížeč

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.

• Klíčová slova
• acetaminophen, drug-induced liver injury, menthofuran, microRNA, precision-cut liver slices, pulegone,
• MeSH
• biologické markery metabolismus   MeSH
• individuální biologická variabilita * MeSH
• játra účinky léků   metabolismus   MeSH
• lékové postižení jater epidemiologie   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• monoterpeny s cyklohexanovým kruhem MeSH
• monoterpeny toxicita   MeSH
• paracetamol toxicita   MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery MeSH
• menthofuran MeSH Prohlížeč
• mikro RNA MeSH
• MIRN155 microRNA, human MeSH Prohlížeč
• monoterpeny s cyklohexanovým kruhem MeSH
• monoterpeny MeSH
• paracetamol MeSH
• pulegone MeSH Prohlížeč

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.

• Klíčová slova
• Catechins, Drug-metabolizing enzymes, Green tea extract, Metabolic syndrome, Obesity,
• MeSH
• antioxidancia farmakologie   MeSH
• aromatické hydroxylasy genetika   metabolismus   MeSH
• čaj chemie   MeSH
• cytochrom P-450 CYP2E1 genetika   metabolismus   MeSH
• cytochrom P-450 CYP3A genetika   metabolismus   MeSH
• ELISA MeSH
• glutamát sodný škodlivé účinky   MeSH
• inzulin krev   MeSH
• játra účinky léků   metabolismus   MeSH
• leptin krev   MeSH
• messenger RNA genetika   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• myši obézní MeSH
• myši MeSH
• obezita chemicky indukované   farmakoterapie   MeSH
• potravní doplňky * MeSH
• rodina 2 cytochromů P450 MeSH
• rostlinné extrakty farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• aromatické hydroxylasy MeSH
• čaj MeSH
• Cyp2a5 protein, mouse MeSH Prohlížeč
• cytochrom P-450 CYP2E1 MeSH
• cytochrom P-450 CYP3A MeSH
• cytochrome P450 3A4, mouse MeSH Prohlížeč
• glutamát sodný MeSH
• inzulin MeSH
• leptin MeSH
• messenger RNA MeSH
• rodina 2 cytochromů P450 MeSH
• rostlinné extrakty 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.

• Klíčová slova
• DNA repair, DNA-damage response, Irradiation, Live-cell studies, Nucleolus, UBF1,
• Publikační typ
• časopisecké články MeSH