Several plants have the potential to protect essential reproductive processes such as spermatogenesis or steroidogenesis, however, effective concentrations and main mechanisms of action are still unknown. This in vitro study was aimed to assess the effects of Apium graveolens L., Levisticum officinale, and Calendula officinalis L. extracts on the structural integrity, functional activity and gap junctional intercellular communication (GJIC) in mice Leydig cells. TM3 cells were grown in the presence of experimental extracts (37.5; 75; 150 and 300 µg/ml) for 24 h. For the present study, high-performance liquid chromatography analysis was used to quantify flavonoids or phenolic acids. Subsequently, Leydig cell viability was assessed by alamarBlue assay, while the cell membrane integrity was detected by 5-carboxyfluorescein diacetate-acetoxymethyl ester. The level of steroid hormones production was determined by enzyme-linked immunosorbent assay. Additionally, GJIC was assessed by scalpel loading/dye transfer assay. According to our results, Apium graveolens L. significantly increased the viability and cell membrane integrity at 75 µg/ml (109.0±4.3%) followed by a decline at 300 µg/ml (89.4±2.3%). In case of Levisticum officinale and Calendula officinalis L. was observed significant decrease at 150 µg/ml (88.8±11.66%; 87.4±6.0%) and 300 µg/ml (86.2±9.3%; 84.1±4.6%). Furthermore, Apium graveolens L. significantly increased the progesterone and testosterone production (75 and 150 µg/ml) however, Levisticum officinale and Calendula officinalis L. significantly reduced steroid hormones synthesis at 150 and 300 µg/ml. Finally, the disturbance of GJIC was significantly affected at 300 µg/ml of Levisticum officinale (82.5±7.7%) and Calendula officinalis L. (79.8±7.0%). The balanced concentration ratio may support the Leydig cell function, steroidogenesis as well as all essential parameters that may significantly improve reproductive functions.

• MeSH
• Apium * chemie   MeSH
• buněčná membrána účinky léků   patologie   MeSH
• buněčné linie MeSH
• Leydigovy buňky účinky léků   metabolismus   patologie   MeSH
• libeček * chemie   MeSH
• měsíček * chemie   MeSH
• mezerový spoj účinky léků   metabolismus   patologie   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• pohlavní steroidní hormony biosyntéza   MeSH
• rostlinné extrakty izolace a purifikace   farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• pohlavní steroidní hormony MeSH
• rostlinné extrakty MeSH

Inhalation exposures to polycyclic aromatic hydrocarbons (PAHs) have been associated with various adverse health effects, including chronic lung diseases and cancer. Using human bronchial epithelial cell line HBE1, we investigated the effects of structurally different PAHs on tissue homeostatic processes, namely gap junctional intercellular communication (GJIC) and MAPKs activity. Rapid (<1 h) and sustained (up to 24 h) inhibition of GJIC was induced by low/middle molecular weight (MW) PAHs, particularly by those with a bay- or bay-like region (1- and 9-methylanthracene, fluoranthene), but also by fluorene and pyrene. In contrast, linear low MW (anthracene, 2-methylanthracene) or higher MW (chrysene) PAHs did not affect GJIC. Fluoranthene, 1- and 9-methylanthracene induced strong and sustained activation of MAPK ERK1/2, whereas MAPK p38 was activated rather nonspecifically by all tested PAHs. Low/middle MW PAHs can disrupt tissue homeostasis in human airway epithelium via structure-dependent nongenotoxic mechanisms, which can contribute to their human health hazards.

• Klíčová slova
• Gap junctional intercellular communication, Human bronchial epithelial cell line, Methylated anthracenes, Mitogen-activated protein kinases, Nongenotoxic mechanisms, Polycyclic aromatic hydrocarbons,
• MeSH
• bronchy cytologie   MeSH
• buněčné linie MeSH
• epitelové buňky účinky léků   fyziologie   MeSH
• lidé MeSH
• mezerový spoj účinky léků   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• polycyklické aromatické uhlovodíky toxicita   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• mitogenem aktivované proteinkinasy MeSH
• polycyklické aromatické uhlovodíky MeSH

Acute excessive ethyl alcohol (ethanol) consumption alters cardiac electrophysiology and can evoke cardiac arrhythmias, e.g., in 'holiday heart syndrome'. Ethanol acutely modulates numerous targets in cardiomyocytes, including ion channels, Ca2+-handling proteins and gap junctions. However, the mechanisms underlying ethanol-induced arrhythmogenesis remain incompletely understood and difficult to study experimentally due to the multiple electrophysiological targets involved and their potential interactions with preexisting electrophysiological or structural substrates. Here, we employed cellular- and tissue-level in-silico analyses to characterize the acute effects of ethanol on cardiac electrophysiology and arrhythmogenesis. Acute electrophysiological effects of ethanol were incorporated into human atrial and ventricular cardiomyocyte computer models: reduced INa, ICa,L, Ito, IKr and IKur, dual effects on IK1 and IK,ACh (inhibition at low and augmentation at high concentrations), and increased INCX and SR Ca2+ leak. Multiscale simulations in the absence or presence of preexistent atrial fibrillation or heart-failure-related remodeling demonstrated that low ethanol concentrations prolonged atrial action-potential duration (APD) without effects on ventricular APD. Conversely, high ethanol concentrations abbreviated atrial APD and prolonged ventricular APD. High ethanol concentrations promoted reentry in tissue simulations, but the extent of reentry promotion was dependent on the presence of altered intercellular coupling, and the degree, type, and pattern of fibrosis. Taken together, these data provide novel mechanistic insight into the potential proarrhythmic interactions between a preexisting substrate and acute changes in cardiac electrophysiology. In particular, acute ethanol exposure has concentration-dependent electrophysiological effects that differ between atria and ventricles, and between healthy and diseased hearts. Low concentrations of ethanol can have anti-fibrillatory effects in atria, whereas high concentrations promote the inducibility and maintenance of reentrant atrial and ventricular arrhythmias, supporting a role for limiting alcohol intake as part of cardiac arrhythmia management.

• Klíčová slova
• Arrhythmia, Atrial fibrillation, Cardiac electrophysiology, Computational modeling, Ethanol,
• MeSH
• akční potenciály účinky léků   MeSH
• elektrofyziologické jevy účinky léků   MeSH
• ethanol škodlivé účinky   MeSH
• fibróza MeSH
• iontové kanály metabolismus   MeSH
• kardiomyocyty účinky léků   metabolismus   MeSH
• lidé MeSH
• mezerový spoj účinky léků   metabolismus   MeSH
• počítačová simulace MeSH
• remodelace cév účinky léků   MeSH
• srdce účinky léků   patofyziologie   MeSH
• srdeční arytmie patologie   patofyziologie   MeSH
• srdeční síně účinky léků   patologie   patofyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ethanol MeSH
• iontové kanály MeSH

Humans are exposed to phthalates released from plastics, cosmetics, or food on a daily basis. Phthalates have low acute liver toxicity, but their chronic exposures could induce molecular and cellular effects linked to adverse health outcomes, such as liver tumor promotion or chronic liver diseases. The alternation of gap junctional intercellular communication (GJIC) and MAPK-Erk1/2 pathways in liver progenitor or oval cells can disrupt liver tissue homeostatic mechanisms and affect the development and severity of these adverse outcomes. Our study with 20 different phthalates revealed their structurally dependent effects on liver GJIC and MAPK-Erk1/2 signaling in rat liver WB-F344 cell line with characteristics of liver oval cells. The phthalates with a medium-length side chain (3-6 C) were the most potent dysregulators of GJIC and activators of MAPK-Erk1/2. The effects occurred rapidly, suggesting the activation of non-genomic (non-transcriptional) mechanisms directly by the parental compounds. Short-chain phthalates (1-2 C) did not dysregulate GJIC even after longer exposures and did not activate MAPK-Erk1/2. Longer chain (≥7 C) phthalates, such as DEHP or DINP, moderately activated MAPK-Erk1/2, but inhibited GJIC only after prolonged exposures (>12 h), suggesting that GJIC dysregulation occurs via genomic mechanisms, or (bio)transformation. Overall, medium-chain phthalates rapidly affected the key tissue homeostatic mechanisms in the liver oval cell population via non-genomic pathways, which might contribute to the development of chronic liver toxicity and diseases.

• Klíčová slova
• MAP-kinases Erk1/2 activation, gap junctional intercellular communication, gap junctions, hepatotoxicity, non-genomic mechanism, oval cells, phthalates, progenitor cells,
• MeSH
• buněčné linie MeSH
• játra cytologie   účinky léků   metabolismus   MeSH
• krysa rodu Rattus MeSH
• kyseliny ftalové aplikace a dávkování   chemie   toxicita   MeSH
• MAP kinasový signální systém účinky léků   MeSH
• mezerový spoj účinky léků   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyseliny ftalové MeSH

Ambient air pollution and smoking are well-documented risk factors for male infertility. Prevalent air pollutants and cigarette smoke components, polycyclic aromatic hydrocarbons (PAHs), are environmental and occupational toxicants that act as chemicals disrupting endocrine regulation and reproductive potential in males. Testicular gap junctional intercellular communication (GJIC) is critical for normal development and function of testicular tissue, thus we assessed GJIC as a process potentially targeted by PAHs in testes. Lower MW PAHs with a bay or bay-like region rapidly dysregulated GJIC in Leydig TM3 cells by relocalization of major testicular gap junctional protein connexin 43 (Cx43) from plasma membrane to cytoplasm. This was associated with colocalization between Cx43 and ubiquitin in intracellular compartments, but without any effect on Cx43 degradation rate or steady-state Cx43 mRNA levels. A longer exposure to active PAHs decreased steady-state levels of full-length Cx43 protein and its 2 N-truncated isoforms. Inhibition of GJIC by PAHs, similarly to a prototypic GJIC-inhibitor TPA, was mediated via the MAP kinase-Erk1/2 and PKC pathways. Polycyclic aromatic hydrocarbon-induced GJIC dysregulation in testes was cell-type-specific because neither PAH dysregulated GJIC in Sertoli TM4 cells, despite PAHs were rapidly taken up by both Leydig TM3 as well as Sertoli TM4 cells. Because TPA effectively dysregulated GJIC in both testicular cell types, a unique regulator of GJIC targeted by PAHs might exist in Leydig TM3 cells. Our results indicate that PAHs could be a potential etiological agent contributing to reproductive dysfunctions in males through an impairment of testicular GJIC and junctional and/or nonjunctional functions of Cx43.

• Klíčová slova
• Cx43 truncated isoforms, connexins, endocrine disruptors, gap junctional intercellular communication, polycyclic aromatic hydrocarbons, testicular cells,
• MeSH
• buněčné linie MeSH
• endokrinní disruptory chemie   toxicita   MeSH
• fosforylace MeSH
• konexin 43 genetika   metabolismus   MeSH
• Leydigovy buňky účinky léků   metabolismus   patologie   MeSH
• mezerový spoj účinky léků   metabolismus   patologie   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• myši MeSH
• polycyklické aromatické uhlovodíky chemie   toxicita   MeSH
• Sertoliho buňky účinky léků   metabolismus   patologie   MeSH
• signální transdukce MeSH
• viabilita buněk účinky léků   MeSH
• zátoková oblast polycyklických aromatických uhlovodíků MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• endokrinní disruptory MeSH
• GJA1 protein, mouse MeSH Prohlížeč
• konexin 43 MeSH
• mitogenem aktivované proteinkinasy MeSH
• polycyklické aromatické uhlovodíky MeSH

The non-dioxin-like environmental toxicant 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153), member of a group of persistent organic pollutants wide-spread throughout the environment, reduces gap junction intercellular communication (GJIC), an event possibly associated with tumor promotion. Since very few studies have investigated the signaling effectors and mode(s) of action of PCB153, and it is known that the gap junction (GJ) protein Cx43 can be regulated by the bioactive sphingolipid (SL) sphingosine 1-phosphate (S1P), this in vitro study mainly addresses whether SL metabolism is affected by PCB153 in rat liver epithelial WB-F344 cells. PCB153 treatment obtained significant changes in the S1P/ceramide (Cer) ratio, known to be crucial in determining cell fate. In particular, an increase in S1P at 30 min and a decrease of the bioactive lipid at 3 h were observed, whereas Cer level increased at 1 h and 24 h. Notably, a time-dependent modulation of sphingosine kinase (SphK), the enzyme responsible for S1P synthesis, and of its regulators, ERK1/2 and protein phosphatase PP2A, supports the involvement of these signaling effectors in PCB153 toxicity. Electrophysiological analyses, furthermore, indicated that the lipophilic environmental toxicant significantly reduced GJ biophysical properties, affecting both voltage-dependent (such as those formed by Cx43 and/or Cx32) and voltage-independent channels, thereby demonstrating that PCB153 may act differently on GJs formed by distinct Cx isoforms. SphK down-regulation alone induced GJIC impairment, and, when combined with PCB153, the acute effect on GJ suppression was additive. Moreover, after enzyme-specific gene silencing, the SphK1 isoform appears to be responsible for down-regulating Cx43 expression, while being the target of PCB153 at short-term exposure. In conclusion, we provide the first evidence of novel effectors in PCB153 toxic action in rat liver stem-like cells, leading us to consider SLs as potential markers for preventing GJIC deregulation and, thus, the tumorigenic action elicited by this environmental toxicant.

• Klíčová slova
• Connexin 43, Environmental toxicant non-dioxin-like PCB153, Gap junctions, PP2A, Sphingosine-1-phosphate,
• MeSH
• dioxiny toxicita   MeSH
• elektrofyziologie metody   MeSH
• fosfotransferasy s alkoholovou skupinou jako akceptorem antagonisté a inhibitory   genetika   metabolismus   MeSH
• játra cytologie   účinky léků   MeSH
• konexin 43 metabolismus   MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lysofosfolipidy metabolismus   MeSH
• mezerový spoj účinky léků   fyziologie   MeSH
• mitogenem aktivovaná proteinkinasa 3 metabolismus   MeSH
• polychlorované bifenyly toxicita   MeSH
• proteinfosfatasa 2 genetika   metabolismus   MeSH
• sfingolipidy metabolismus   MeSH
• sfingosin analogy a deriváty   metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2,4,5,2',4',5'-hexachlorobiphenyl MeSH Prohlížeč
• dioxiny MeSH
• fosfotransferasy s alkoholovou skupinou jako akceptorem MeSH
• Gja1 protein, rat MeSH Prohlížeč
• konexin 43 MeSH
• lysofosfolipidy MeSH
• mitogenem aktivovaná proteinkinasa 3 MeSH
• polychlorované bifenyly MeSH
• proteinfosfatasa 2 MeSH
• sfingolipidy MeSH
• sfingosin MeSH
• sphingosine 1-phosphate MeSH Prohlížeč
• sphingosine kinase MeSH Prohlížeč

Methoxychlor (MXC) and vinclozolin (VIN) are well-recognized endocrine disrupting chemicals known to alter epigenetic regulations and transgenerational inheritance; however, non-endocrine disruption endpoints are also important. Thus, we determined the effects of MXC and VIN on the dysregulation of gap junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) in WB-F344 rat liver epithelial cells. Both chemicals induced a rapid dysregulation of GJIC at non-cytotoxic doses, with 30 min EC50 values for GJIC inhibition being 10 µM for MXC and 126 µM for VIN. MXC inhibited GJIC for at least 24 h, while VIN effects were transient and GJIC recovered after 4 h. VIN induced rapid hyperphosphorylation and internalization of gap junction protein connexin43, and both chemicals also activated MAPK ERK1/2 and p38. Effects on GJIC were not prevented by MEK1/2 inhibitor, but by an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), resveratrol, and in the case of VIN, also, by a p38 inhibitor. Estrogen (ER) and androgen receptor (AR) modulators (estradiol, ICI 182,780, HPTE, testosterone, flutamide, VIN M2) did not attenuate MXC or VIN effects on GJIC. Our data also indicate that the effects were elicited by the parental compounds of MXC and VIN. Our study provides new evidence that MXC and VIN dysregulate GJIC via mechanisms involving rapid activation of PC-PLC occurring independently of ER- or AR-dependent genomic signaling. Such alterations of rapid intercellular and intracellular signaling events involved in regulations of gene expression, tissue development, function and homeostasis, could also contribute to transgenerational epigenetic effects of endocrine disruptors.

• Klíčová slova
• endocrine disruptors, epigenetic toxicity, gap junctional intercellular communication, mitogen-activated protein kinases, non-genomic signaling., phosphatidylcholine-specific phospholipase C,
• MeSH
• androgenní receptory metabolismus   MeSH
• buněčné linie MeSH
• insekticidy toxicita   MeSH
• játra cytologie   účinky léků   metabolismus   MeSH
• kmenové buňky účinky léků   metabolismus   MeSH
• konexin 43 metabolismus   MeSH
• krysa rodu Rattus MeSH
• MAP kinasový signální systém účinky léků   MeSH
• methoxychlor toxicita   MeSH
• mezerový spoj účinky léků   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• oxazoly toxicita   MeSH
• potkani inbrední F344 MeSH
• receptory pro estrogeny metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• androgenní receptory MeSH
• insekticidy MeSH
• konexin 43 MeSH
• methoxychlor MeSH
• mitogenem aktivované proteinkinasy p38 MeSH
• oxazoly MeSH
• receptory pro estrogeny MeSH
• vinclozolin MeSH Prohlížeč

Altered gap junctional intercellular communication (GJIC) has been associated with chemical carcinogenesis, where both chemical tumor promoters and chemopreventive agents (CPAs) are known to conversely modulate GJIC. The aim of this study was to investigate whether attenuation of chemically inhibited GJIC represents a common outcome induced by different CPAs, which could be effectively evaluated using in vitro methods. Rat liver epithelial cells WB-F344 were pretreated with a CPA for either 30 min or 24 h, and then exposed to GJIC-inhibiting concentration of a selected tumor promoter or environmental toxicant [12-O-tetradecanoylphorbol-13-acetate (TPA), lindane, fluoranthene, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), perfluorooctanoic acid (PFOA), or pentachlorophenol]. Out of nine CPAs tested, quercetin and silibinin elicited the most pronounced effects, preventing the dysregulation of GJIC by all the GJIC inhibitors, but DDT. Metformin and curcumin attenuated the effects of three GJIC inhibitors, whereas the other CPAs prevented the effects of two (diallyl sulfide, emodin) or one (indole-3-carbinol, thymoquinone) GJIC inhibitor. Significant attenuation of chemically induced inhibition of GJIC was observed in 27 (50%) out of 54 possible combinations of nine CPAs and six GJIC inhibitors. Our data demonstrate that in vitro evaluation of GJIC can be used as an effective screening tool for identification of chemicals with potential chemopreventive activity.

• MeSH
• antikarcinogenní látky farmakologie   MeSH
• DDT toxicita   MeSH
• epitelové buňky účinky léků   MeSH
• fluoreny toxicita   MeSH
• fluorokarbony toxicita   MeSH
• hexachlorcyklohexan toxicita   MeSH
• játra cytologie   účinky léků   MeSH
• kapryláty toxicita   MeSH
• karcinogeny toxicita   MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• kurkumin farmakologie   MeSH
• metformin farmakologie   MeSH
• mezerový spoj účinky léků   metabolismus   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• potkani inbrední F344 MeSH
• tetradekanoylforbolacetát toxicita   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antikarcinogenní látky MeSH
• DDT MeSH
• fluoranthene MeSH Prohlížeč
• fluoreny MeSH
• fluorokarbony MeSH
• hexachlorcyklohexan MeSH
• kapryláty MeSH
• karcinogeny MeSH
• kurkumin MeSH
• metformin MeSH
• perfluorooctanoic acid MeSH Prohlížeč
• tetradekanoylforbolacetát MeSH

UNLABELLED: Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. IN CONCLUSION: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap junction channels are closed by toxicants vary. Thus, accurate assessments of risk posed by toxic agents, and the role of dietary phytochemicals play in preventing or reversing the effects of these agents must take into account the specific mechanisms involved in the cancer process.

• MeSH
• analýza hlavních komponent MeSH
• buněčné linie MeSH
• butadieny farmakologie   MeSH
• fosfatidylcholiny metabolismus   MeSH
• fosfolipasy typu C metabolismus   MeSH
• krysa rodu Rattus MeSH
• mezerový spoj účinky léků   metabolismus   MeSH
• nitrily farmakologie   MeSH
• norbornany MeSH
• potkani inbrední F344 MeSH
• přemostěné cyklické sloučeniny farmakologie   MeSH
• resveratrol MeSH
• stilbeny farmakologie   MeSH
• thiokarbamáty MeSH
• thioketony farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• butadieny MeSH
• fosfatidylcholiny MeSH
• fosfolipasy typu C MeSH
• nitrily MeSH
• norbornany MeSH
• phosphatidylcholine-specific phospholipase C MeSH Prohlížeč
• přemostěné cyklické sloučeniny MeSH
• resveratrol MeSH
• stilbeny MeSH
• thiokarbamáty MeSH
• thioketony MeSH
• tricyclodecane-9-yl-xanthogenate MeSH Prohlížeč
• U 0126 MeSH Prohlížeč

Polycyclic aromatic hydrocarbons (PAHs) with lower molecular weight exhibit lesser genotoxicity and carcinogenicity than highly carcinogenic PAHs with a higher number of benzene rings. Nevertheless, they elicit specific effects linked with tumor promotion, such as acute inhibition of gap junctional intercellular communication (GJIC). Although inflammatory reaction may alter bioactivation and toxicity of carcinogenic PAHs, little is known about the impact of pro-inflammatory cytokines on toxic effects of the low-molecular-weight PAHs. Here, we investigated the impact of a pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α), on the effects associated with tumor promotion and with induction of the aryl hydrocarbon receptor (AhR)-dependent gene expression in rat liver epithelial cells. We found that a prolonged incubation with TNF-α induced a down-regulation of GJIC, associated with reduced expression of connexin 43 (Cx43), a major connexin isoform found in liver epithelial cells. The Cx43 down-regulation was partly mediated by the activity of the mitogen-activated protein (MAP) p38 kinase. Independently of GJIC modulation, or p38 activation, TNF-α potentiated the AhR-dependent proliferative effect of a model low-molecular-weight PAH, fluoranthene, on contact-inhibited cells. In contrast, this pro-inflammatory cytokine repressed the fluoranthene-induced expression of a majority of model AhR gene targets, such as Cyp1a1, Ahrr or Tiparp. The results of the present study indicate that inflammatory reaction may differentially modulate various toxic effects of low-molecular-weight PAHs; the exposure to pro-inflammatory cytokines may both strengthen (inhibition of GJIC, disruption of contact inhibition) and repress (expression of a majority of AhR-dependent genes) their impact on toxic endpoints associated with carcinogenesis.

• Klíčová slova
• Aryl hydrocarbon receptor, Cell proliferation, Gap junctions, Inflammation, PAHs,
• MeSH
• aktivace enzymů MeSH
• buněčné linie MeSH
• časové faktory MeSH
• epitelové buňky účinky léků   metabolismus   patologie   MeSH
• fluoreny toxicita   MeSH
• genetická transkripce účinky léků   MeSH
• játra účinky léků   metabolismus   patologie   MeSH
• konexin 43 genetika   metabolismus   MeSH
• krysa rodu Rattus MeSH
• mezerový spoj účinky léků   metabolismus   patologie   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• molekulová hmotnost MeSH
• nádorová transformace buněk chemicky indukované   metabolismus   patologie   MeSH
• nádory jater chemicky indukované   metabolismus   patologie   MeSH
• proliferace buněk účinky léků   MeSH
• receptory aromatických uhlovodíků agonisté   genetika   metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• TNF-alfa toxicita   MeSH
• transkripční faktory bHLH agonisté   genetika   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zánět chemicky indukované   genetika   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Ahr protein, rat MeSH Prohlížeč
• fluoranthene MeSH Prohlížeč
• fluoreny MeSH
• Gja1 protein, rat MeSH Prohlížeč
• konexin 43 MeSH
• mitogenem aktivované proteinkinasy p38 MeSH
• receptory aromatických uhlovodíků MeSH
• TNF-alfa MeSH
• transkripční faktory bHLH MeSH