Cellular senescence, induced by genotoxic or replication stress, is accompanied by defects in nuclear morphology and nuclear membrane-heterochromatin disruption. In this work, we analyzed cytological and molecular changes in the linker of nucleoskeleton and cytoskeleton (LINC) complex proteins in senescence triggered by γ-irradiation. We used human mammary carcinoma and osteosarcoma cell lines, both original and shRNA knockdown clones targeting lamin B receptor (LBR) and leading to LBR and lamin B (LB1) reduction. The expression status and integrity of LINC complex proteins (nesprin-1, SUN1, SUN2), lamin A/C, and emerin were analyzed by immunodetection using confocal microscopy and Western blot. The results show frequent mislocalization of these proteins from the nuclear membrane to cytoplasm and micronuclei and, in some cases, their fragmentation and amplification. The timing of these changes clearly preceded the onset of senescence. The LBR deficiency triggered neither senescence nor changes in the LINC protein distribution before irradiation. However, the cytological changes following irradiation were more pronounced in shRNA knockdown cells compared to original cell lines. We conclude that mislocalization of LINC complex proteins is a significant characteristic of cellular senescence phenotypes and may influence complex events at the nuclear membrane, including trafficking and heterochromatin attachment.
- MeSH
- časoprostorová analýza MeSH
- jaderný obal metabolismus MeSH
- lidé MeSH
- membránové proteiny metabolismus MeSH
- receptory cytoplazmatické a nukleární genetika MeSH
- stárnutí buněk genetika MeSH
- záření gama terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hepatocellular carcinoma (HCC) remains a highly prevalent and deadly disease, being among the top causes of cancer-related deaths worldwide. Despite the fact that the liver is the major site of biotransformation, studies on drug metabolizing enzymes in HCC are scarce. It is known that malignant transformation of hepatocytes leads to a significant alteration of their metabolic functions and overall deregulation of gene expression. Advanced stages of the disease are thus frequently associated with liver failure, and severe alteration of drug metabolism. However, the impact of dysregulation of metabolic enzymes on therapeutic efficacy and toxicity in HCC patients is largely unknown. Here we demonstrate a significant down-regulation in European Caucasian patients of cytochromes P450 (CYPs), the major xenobiotic-metabolizing enzymes, in HCC tumour samples as compared to their surrounding non-cancerous (reference) tissue. Moreover, we report for the first time the association of the unique CYP profiles with specific transcriptome changes, and interesting correlations with expression levels of nuclear receptors and with the histological grade of the tumours. Integrated analysis has suggested certain co-expression profiles of CYPs with lncRNAs that need to be further characterized. Patients with large tumours with down-regulated CYPs could be more vulnerable to drug toxicity; on the other hand, such tumours would eliminate drugs more slowly and should be more sensitive to pharmacotherapy (except in the case of pro-drugs where activation is necessary).
- MeSH
- dospělí MeSH
- hepatocelulární karcinom enzymologie patologie MeSH
- hepatocyty metabolismus MeSH
- játra metabolismus MeSH
- kohortové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- metabolická inaktivace genetika MeSH
- nádory jater enzymologie patologie MeSH
- receptory cytoplazmatické a nukleární genetika metabolismus MeSH
- regulace genové exprese enzymů * MeSH
- senioři MeSH
- stanovení celkové genové exprese MeSH
- stupeň nádoru MeSH
- systém (enzymů) cytochromů P-450 genetika 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
Infantile spasms (IS) is a developmental and epileptic encephalopathy with heterogeneous etiologies including many genetic causes. Genetic studies have identified pathogenic variants in over 30 genes as causes of IS. Many of these genetic causes are extremely rare, with only one reported incidence in an individual with IS. To better understand the genetic landscape of IS, we used targeted sequencing to screen 42 candidate IS genes and 53 established developmental and epileptic encephalopathy genes in 92 individual with IS. We identified a genetic diagnosis for 7.6% of our cohort, including pathogenic variants in KCNB1 (n = 2), GNAO1 (n = 1), STXBP1 (n = 1), SLC35A2 (n = 1), TBL1XR1 (n = 1), and KIF1A (n = 1). Our data emphasize the genetic heterogeneity of IS and will inform the diagnosis and management of individuals with this devastating disorder.
- MeSH
- draslíkové kanály Shab genetika MeSH
- kineziny genetika MeSH
- kojenec MeSH
- křeče u dětí diagnóza genetika MeSH
- lidé MeSH
- mutace genetika MeSH
- předškolní dítě MeSH
- proteiny přenášející monosacharidy genetika MeSH
- proteiny vázající GTP - alfa-podjednotky Gi-Go genetika MeSH
- receptory cytoplazmatické a nukleární genetika MeSH
- represorové proteiny genetika MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- předškolní dítě MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The constitutive androstane receptor(CAR) activation is connected with mitogenic effects leading to liver hyperplasia and tumorigenesis in rodents. CAR activators, including phenobarbital, are considered rodent non-genotoxic carcinogens. Recently, trans-3,4,5,4´-tetramethoxystilbene(TMS), a potential anticancer drug (DMU-212), have been shown to alleviate N-nitrosodiethylamine/phenobarbital-induced liver carcinogenesis. We studied whether TMS inhibits mouse Car to protect from the PB-induced tumorigenesis. Unexpectedly, we identified TMS as a murine CAR agonist in reporter gene experiments, in mouse hepatocytes, and in C57BL/6 mice in vivo. TMS up-regulated Car target genes Cyp2b10, Cyp2c29 and Cyp2c55 mRNAs, but down-regulated expression of genes involved in gluconeogenesis and lipogenesis. TMS did not change or down-regulate genes involved in liver proliferation or apoptosis such as Mki67, Foxm1, Myc, Mcl1, Pcna, Bcl2, or Mdm2, which were up-regulated by another Car ligand TCPOBOP. TMS did not increase liver weight and had no significant effect on Ki67 and Pcna labeling indices in mouse liver in vivo. In murine hepatic AML12 cells, we confirmed a Car-independent proapoptotic effect of TMS. We conclude that TMS is a Car ligand with limited effects on hepatocyte proliferation, likely due to promoting apoptosis in mouse hepatic cells, while controlling Car target genes involved in xenobiotic and endobiotic metabolism.
- MeSH
- antikarcinogenní látky metabolismus farmakologie MeSH
- apoptóza účinky léků MeSH
- aromatické hydroxylasy genetika metabolismus MeSH
- buňky Hep G2 MeSH
- glukoneogeneze účinky léků genetika MeSH
- hepatocyty účinky léků metabolismus patologie MeSH
- játra účinky léků metabolismus MeSH
- lidé MeSH
- lipogeneze účinky léků genetika MeSH
- myši inbrední C57BL MeSH
- nádory jater enzymologie genetika patologie prevence a kontrola MeSH
- proliferace buněk účinky léků MeSH
- pyridiny farmakologie MeSH
- receptory cytoplazmatické a nukleární agonisté genetika metabolismus MeSH
- regulace genové exprese enzymů účinky léků MeSH
- rodina 2 cytochromů P450 genetika metabolismus MeSH
- signální transdukce účinky léků MeSH
- simulace molekulového dockingu MeSH
- steroidhydroxylasy genetika metabolismus MeSH
- stilbeny metabolismus farmakologie MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The aim of current study was to evaluate the effect of the most common anthocyanidins (cyanidin, delphinidin, malvidin, pelargonidin, and peonidin) on the transcriptional activity of steroid and nuclear receptors. The activities of steroid receptors - progesterone receptor (PR), estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), and nuclear receptors - vitamin D receptor (VDR), retinoid X receptor (RXR), retinoic acid receptor (RAR), pregnane X receptor (PXR), and thyroid receptor (TR) were assessed using either stable transfected luciferase gene reporter cell lines or transiently transfected cell lines. The cytotoxicity assays and gene reporter assays were performed after the 24-h treatment of cells with increasing range of concentrations (10 nM to 50 µM) of selected anthocyanidins. The results of experiments indicate that none of the examined anthocyanidins in all tested concentrations caused remarkable changes of transcriptional activity of studied steroid receptors, but their increasing concentrations slightly inhibited transcriptional activity of nuclear receptors induced by model agonists.
- MeSH
- anthokyaniny farmakologie MeSH
- genetická transkripce účinky léků MeSH
- lidé MeSH
- nádorové buňky kultivované MeSH
- receptory cytoplazmatické a nukleární genetika MeSH
- steroidní receptory genetika MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Cholestasis is characterised by impaired bile secretion and accumulation of bile salts in the organism. Hereditary cholestasis is a heterogeneous group of rare autosomal recessive liver disorders, which are characterised by intrahepatic cholestasis, pruritus, and jaundice and caused by defects in genes related to the secretion and transport of bile salts and lipids. Phenotypic manifestation is highly variable, ranging from progressive familial intrahepatic cholestasis (PFIC)-with onset in early infancy and progression to end-stage liver disease-to a milder intermittent mostly nonprogressive form known as benign recurrent intrahepatic cholestasis (BRIC). Cases have been reported of initially benign episodic cholestasis that subsequently transitions to a persistent progressive form of the disease. Therefore, BRIC and PFIC seem to represent two extremes of a continuous spectrum of phenotypes that comprise one disease. Thus far, five representatives of PFIC (named PFIC1-5) caused by pathogenic mutations present in both alleles of ATP8B1, ABCB11, ABCB4, TJP2, and NR1H4 have been described. In addition to familial intrahepatic cholestasis, partial defects in ATP8B1, ABCB11, and ABCB4 predispose patients to drug-induced cholestasis and intrahepatic cholestasis in pregnancy. This review summarises the current knowledge of the clinical manifestations, genetics, and molecular mechanisms of these diseases and briefly outlines the therapeutic options, both conservative and invasive, with an outlook for future personalised therapeutic strategies.
- MeSH
- ABC transportér, podrodina B, člen 11 genetika MeSH
- adenosintrifosfatasy genetika MeSH
- intrahepatální cholestáza genetika metabolismus MeSH
- komplikace těhotenství genetika MeSH
- lidé MeSH
- P-glykoproteiny nedostatek genetika MeSH
- proteiny přenášející anionty metabolismus MeSH
- receptory cytoplazmatické a nukleární genetika metabolismus MeSH
- žlučové kyseliny a soli biosyntéza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Analyzing mixture toxicity requires an in-depth understanding of the mechanisms of action of its individual components. Substances with the same target organ, same toxic effect and same mode of action (MoA) are believed to cause additive effects, whereas substances with different MoAs are assumed to act independently. Here, we tested 2 triazole fungicides, propiconazole, and tebuconazole (Te), for individual and combined effects on liver toxicity-related endpoints. Both triazoles are proposed to belong to the same cumulative assessment group and are therefore thought to display similar and additive behavior. Our data show that Te is an antagonist of the constitutive androstane receptor (CAR) in rats and humans, while propiconazole is an agonist of this receptor. Both substances activate the pregnane X-receptor (PXR) and further induce mRNA expression of CYP3A4. CYP3A4 enzyme activity, however, is inhibited by propiconazole. For common targets of PXR and CAR, the activation of PXR by Te overrides CAR inhibition. In summary, propiconazole and Te affect different hepatotoxicity-relevant cellular targets and, depending on the individual endpoint analyzed, act via similar or dissimilar mechanisms. The use of molecular data based on research in human cell systems extends the picture to refine cumulative assessment group grouping and substantially contributes to the understanding of mixture effects of chemicals in biological systems.
- MeSH
- buněčné kultury MeSH
- fungicidy průmyslové farmakologie MeSH
- hepatocyty účinky léků metabolismus MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- pregnanový X receptor agonisté genetika MeSH
- receptory cytoplazmatické a nukleární agonisté antagonisté a inhibitory genetika MeSH
- simulace molekulového dockingu MeSH
- substrátová specifita MeSH
- synergismus léků MeSH
- systém (enzymů) cytochromů P-450 genetika metabolismus MeSH
- transfekce MeSH
- triazoly farmakologie MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The Pregnane X (PXR), Vitamin D (VDR) and Farnesoid X (FXR) nuclear receptors have been shown to be receptors of bile acids controlling their detoxification or synthesis. Chenodeoxycholic (CDCA) and lithocholic (LCA) acids are ligands of FXR and VDR, respectively, whereas 3-keto and acetylated derivates of LCA have been described as ligands for all three receptors. In this study, we hypothesized that oxidation or acetylation at position 3, 7 and 12 of bile acids DCA (deoxycholic acid), LCA, CA (cholic acid), and CDCA by detoxification enzymes or microbiome may have an effect on the interactions with bile acid nuclear receptors. We employed reporter gene assays in HepG2 cells, the TR-FRET assay with recombinant PXR and RT-PCR to study the effects of acetylated and keto bile acids on the nuclear receptors activation and their target gene expression in differentiated hepatic HepaRG cells. We demonstrate that the DCA 3,12-diacetate and CA 3,7,12-triacetate derivatives are ligands of PXR and DCA 3,12-diacetate induces PXR target genes such as CYP3A4, CYP2B6 and ABCB1/MDR1. In conclusion, we found that acetylated DCA and CA are potent ligands of PXR. Whether the acetylated bile acid derivatives are novel endogenous ligands of PXR with detoxification or physiological functions should be further studied in ongoing experiments.
- MeSH
- acetylace MeSH
- buněčné kultury MeSH
- buňky Hep G2 MeSH
- cytochrom P-450 CYP3A genetika MeSH
- cytochrom P450 CYP2B6 genetika MeSH
- hepatocyty účinky léků enzymologie metabolismus MeSH
- kyselina cholová chemie metabolismus farmakologie MeSH
- kyselina deoxycholová chemie metabolismus farmakologie MeSH
- lidé MeSH
- ligandy MeSH
- myši MeSH
- oxidace-redukce MeSH
- P-glykoprotein genetika MeSH
- plazmidy MeSH
- receptory cytoplazmatické a nukleární chemie genetika metabolismus MeSH
- receptory kalcitriolu chemie genetika metabolismus MeSH
- reportérové geny MeSH
- simulace molekulového dockingu MeSH
- steroidní receptory chemie genetika metabolismus MeSH
- techniky dvojhybridového systému MeSH
- transfekce MeSH
- vazba proteinů MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Cellular transition to senescence is associated with extensive chromatin reorganization and changes in gene expression. Recent studies appear to imply an association of lamin B1 (LB1) reduction with chromatin rearrangement in human fibroblasts promoted to senescence, while the mechanisms and structural features of these relationships have not yet been clarified. In this work, we examined the functions of LB1 and the lamin B receptor (LBR) in human cancer cells. We found that both LB1 and LBR tend to deplete during cancer cell transfer to senescence by γ-irradiation. A functional study employing silencing of LBR by small hairpin ribonucleic acid (shRNA) constructs revealed reduced LB1 levels suggesting that the regulation of both proteins is interrelated. The reduced expression of LBR resulted in the relocation of centromeric heterochromatin (CSH) from the inner nuclear membrane (INM) to the nucleoplasm and is associated with its unfolding. This indicates that LBR tethers heterochromatin to INM in cycling cancer cells and that LB1 is an integral part of this tethering. Down-regulation of LBR and LB1 at the onset of senescence are thus necessary for the release of heterochromatin binding to lamina, resulting in changes in chromatin architecture and gene expression. However, the senescence phenotype was not manifested in cell lines with reduced LBR and LB1 expression suggesting that other factors, such as deoxyribonucleic acid (DNA) damage, are needed to trigger senescence. We conclude that the primary response of cells to various stresses leading to senescence consists of the down-regulation of LBR and LB1 to attain reversal of the chromatin architecture.
- MeSH
- centromera metabolismus účinky záření ultrastruktura MeSH
- heterochromatin metabolismus účinky záření ultrastruktura MeSH
- jaderný obal metabolismus účinky záření ultrastruktura MeSH
- lamin typ B genetika metabolismus MeSH
- lidé MeSH
- malá interferující RNA genetika metabolismus MeSH
- MFC-7 buňky MeSH
- nádorové buněčné linie MeSH
- osteoblasty metabolismus patologie účinky záření MeSH
- receptory cytoplazmatické a nukleární antagonisté a inhibitory genetika metabolismus MeSH
- regulace genové exprese u nádorů * MeSH
- signální transdukce MeSH
- stárnutí buněk účinky záření MeSH
- záření gama MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
