The iron-containing protein, acireductone dioxygenase 1 (ADI1), is a dioxygenase important for polyamine synthesis and proliferation. Using differential proteomics, the studies herein demonstrated that ADI1 was significantly down-regulated by cellular iron depletion. This is important, since ADI1 contains a non-heme, iron-binding site critical for its activity. Examination of multiple human cell-types demonstrated a significant decrease in ADI1 mRNA and protein after incubation with iron chelators. The decrease in ADI1 after iron depletion was reversible upon incubation of cells with the iron salt, ferric ammonium citrate (FAC). A significant decrease in ADI1 mRNA levels was observed after 14 h of iron depletion. In contrast, the chelator-mediated reduction in ADI1 protein occurred earlier after 10 h of iron depletion, suggesting additional post-transcriptional regulation. The proteasome inhibitor, MG-132, prevented the iron chelator-mediated decrease in ADI1 expression, while the lysosomotropic agent, chloroquine, had no effect. These results suggest an iron-dependent, proteasome-mediated, degradation mechanism. Poly r(C)-binding protein (PCBPs) 1 and 2 act as iron delivery chaperones to other iron-containing dioxygenases and were shown herein for the first time to be regulated by iron levels. Silencing of PCBP1, but not PCBP2, led to loss of ADI1 expression. Confocal microscopy co-localization studies and proximity ligation assays both demonstrated decreased interaction of ADI1 with PCBP1 and PCBP2 under conditions of iron depletion using DFO. These data indicate PCBP1 and PCBP2 interact with ADI1, but only PCBP1 plays a role in ADI1 expression. In fact, PCBP2 appeared to play an accessory role, being involved as a potential co-chaperone.

• MeSH
• buněčné linie MeSH
• dioxygenasy genetika   metabolismus   MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• down regulace MeSH
• inhibitory proteasomu farmakologie   MeSH
• leupeptiny MeSH
• lidé MeSH
• membránový potenciál mitochondrií MeSH
• molekulární chaperony účinky léků   metabolismus   MeSH
• proteiny vázající RNA genetika   metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• vazebná místa MeSH
• železo metabolismus   MeSH
• zinek metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Desmoglein-3 (Dsg3), the Pemphigus Vulgaris (PV) antigen (PVA), plays an essential role in keratinocyte cell-cell adhesion and regulates various signaling pathways involved in the progression and metastasis of cancer where it is upregulated. We show here that expression of Dsg3 impacts on the expression and function of p53, a key transcription factor governing the responses to cellular stress. Dsg3 depletion increased p53 expression and activity, an effect enhanced by treating cells with UVB, mechanical stress and genotoxic drugs, whilst increased Dsg3 expression resulted in the opposite effects. Such a pathway in the negative regulation of p53 by Dsg3 was Dsg3 specific since neither E-cadherin nor desmoplakin knockdown caused similar effects. Analysis of Dsg3-/- mouse skin also indicated an increase of p53/p21WAF1/CIP1 and cleaved caspase-3 relative to Dsg3+/- controls. Finally, we evaluated whether this pathway was operational in the autoimmune disease PV in which Dsg3 serves as a major antigen involved in blistering pathogenesis. We uncovered increased p53 with diffuse cytoplasmic and/or nuclear staining in the oral mucosa of patients, including cells surrounding blisters and the pre-lesional regions. This finding was verified by in vitro studies where treatment of keratinocytes with PV sera, as well as a characterized pathogenic antibody specifically targeting Dsg3, evoked pronounced p53 expression and activity accompanied by disruption of cell-cell adhesion. Collectively, our findings suggest a novel role for Dsg3 as an anti-stress protein, via suppression of p53 function, and this pathway is disrupted in PV.

• MeSH
• desmoglein 3 nedostatek   metabolismus   MeSH
• desmozomy metabolismus   MeSH
• fyziologický stres * MeSH
• kaspasa 3 metabolismus   MeSH
• keratinocyty metabolismus   MeSH
• kultivované buňky MeSH
• kůže metabolismus   MeSH
• leupeptiny farmakologie   MeSH
• lidé MeSH
• myši MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• pemfigus krev   imunologie   patologie   MeSH
• proteolýza MeSH
• protilátky imunologie   MeSH
• psi MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Bidirectional interactions between astrocytes and neurons have physiological roles in the central nervous system and an altered state or dysfunction of such interactions may be associated with neurodegenerative diseases, such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). Astrocytes exert structural, metabolic and functional effects on neurons, which can be either neurotoxic or neuroprotective. Their neurotoxic effect is mediated via the senescence-associated secretory phenotype (SASP) involving pro-inflammatory cytokines (e.g., IL-6), while their neuroprotective effect is attributed to neurotrophic growth factors (e.g., NGF). We here demonstrate that the p53 isoforms Δ133p53 and p53β are expressed in astrocytes and regulate their toxic and protective effects on neurons. Primary human astrocytes undergoing cellular senescence upon serial passaging in vitro showed diminished expression of Δ133p53 and increased p53β, which were attributed to the autophagic degradation and the SRSF3-mediated alternative RNA splicing, respectively. Early-passage astrocytes with Δ133p53 knockdown or p53β overexpression were induced to show SASP and to exert neurotoxicity in co-culture with neurons. Restored expression of Δ133p53 in near-senescent, otherwise neurotoxic astrocytes conferred them with neuroprotective activity through repression of SASP and induction of neurotrophic growth factors. Brain tissues from AD and ALS patients possessed increased numbers of senescent astrocytes and, like senescent astrocytes in vitro, showed decreased Δ133p53 and increased p53β expression, supporting that our in vitro findings recapitulate in vivo pathology of these neurodegenerative diseases. Our finding that Δ133p53 enhances the neuroprotective function of aged and senescent astrocytes suggests that the p53 isoforms and their regulatory mechanisms are potential targets for therapeutic intervention in neurodegenerative diseases.

• MeSH
• alternativní sestřih MeSH
• Alzheimerova nemoc metabolismus   patologie   MeSH
• amyotrofická laterální skleróza metabolismus   patologie   MeSH
• astrocyty cytologie   účinky léků   metabolismus   MeSH
• autofagie účinky léků   MeSH
• genetické vektory genetika   metabolismus   MeSH
• interleukin-6 genetika   metabolismus   MeSH
• kokultivační techniky MeSH
• kultivované buňky MeSH
• leupeptiny farmakologie   MeSH
• lidé MeSH
• malá interferující RNA metabolismus   MeSH
• mozek metabolismus   patologie   MeSH
• nádorový supresorový protein p53 antagonisté a inhibitory   genetika   metabolismus   MeSH
• neurony cytologie   metabolismus   MeSH
• neuroprotekce fyziologie   MeSH
• protein - isoformy antagonisté a inhibitory   genetika   metabolismus   MeSH
• RNA interference MeSH
• sekvestosom 1 antagonisté a inhibitory   genetika   metabolismus   MeSH
• serin-arginin sestřihové faktory antagonisté a inhibitory   genetika   metabolismus   MeSH
• stárnutí buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Porcine oocyte-cumulus complexes (OCCs) form an expanded cumulus extracellular matrix (ECM) in response to gonadotropins during meiotic maturation. Essential components of ECM are hyaluronan (HA), tumor necrosis factor α-induced protein 6 (TNFAIP6) and heavy chains (HC) of interalpha-trypsin inhibitor. To form expanded cumulus ECM, intermediate complexes (TNFAIP6-HC) must bind to HA to allow HC transfer onto HA. Protein turnover by the ubiquitin-proteasome pathway is poorly characterized in this process. It is known that the specific proteasomal inhibitor MG132 prevents cumulus expansion and formation of ECM. To determine whether inhibition of proteasomal proteolysis with MG132 affects cumulus cell steroidogenesis and expression of the cumulus expansion-related components (hyaluronan synthase type 2, HAS2, TNFAIP6) we cultured porcine OCCs and granulosa cells (GCs) in a medium supplemented with FSH/LH. Methods performed included real-time reverse transcription PCR, immunofluorescence and RIAs. The expression of TNFAIP6 and HAS2 transcripts increased significantly after the stimulation of OCCs and GCs with FSH/LH. In contrast, treatment with MG132 reduced the expression of TNFAIP6 and HAS2. Hyaluronan was detected with biotinylated HA-binding proteins within FSH/LH-stimulated expanded OCCs but not in those treated with MG132. Progesterone production, although increased almost three times after OCCs stimulation with FSH/LH, was significantly suppressed by MG132. The FSH/LH-stimulated a 40-fold increase in progesterone secretion by GCs was inhibited in the presence of MG132. In conclusion, MG132 affects progesterone secretion and expression of cumulus expansion-related components by cumulus and GCs, suggesting the requirement of ubiquitin-proteasome pathway-regulated protein turnover for formation of ECM during cumulus expansion in the preovulatory period in the pig.

• MeSH
• extracelulární matrix účinky léků   metabolismus   MeSH
• inhibitory cysteinových proteinas farmakologie   MeSH
• inhibitory proteasomu MeSH
• kumulární buňky účinky léků   metabolismus   MeSH
• kvantitativní polymerázová řetězová reakce veterinární   MeSH
• leupeptiny farmakologie   MeSH
• messenger RNA biosyntéza   genetika   MeSH
• molekuly buněčné adheze biosyntéza   MeSH
• oocyty účinky léků   metabolismus   MeSH
• prasata MeSH
• progesteron biosyntéza   MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Small ubiquitin-related modifiers 1, 2 and 3 (SUMO-1, -2, -3), members of the ubiquitin-like protein family, can be conjugated to various cellular proteins. Conjugates of SUMO-2 and SUMO-3 (SUMO-2/3) accumulate in cells exposed to various stress stimuli or to MG132 treatment. Although the proteins modified by SUMO-2/3 during heat shock or under MG132 treatment have been identified, the significance of this modification remains unclear. Our data show that the inhibition of translation by puromycin or cycloheximide blocks both the heat shock and MG132 induced accumulation of SUMO-2/3 conjugates in HEK 293T and U2OS cells. However, the heat shock induced accumulation of SUMO-2/3 conjugates was restored by proteasome inhibition, which suggests that the inhibition of translation did not abolish SUMOylation itself. Furthermore, we show that some of the proteins truncated due to the treatment by low concentration of puromycin are SUMOylated in HEK 293T cells. We suggest that the SUMO-2/3 conjugates accumulating under the heat shock or MG132 treatment result largely from new protein synthesis and that portion of them is incorrectly folded.

• MeSH
• benzochinony farmakologie   MeSH
• biologické modely MeSH
• cykloheximid farmakologie   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• inhibitory syntézy proteinů farmakologie   MeSH
• leupeptiny farmakologie   MeSH
• lidé MeSH
• makrocyklické laktamy farmakologie   MeSH
• malé modifikační proteiny související s ubikvitinem metabolismus   MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• proteosyntéza účinky léků   MeSH
• puromycin farmakologie   MeSH
• reakce na tepelný šok účinky léků   MeSH
• sumoylace účinky léků   MeSH
• ubikvitiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

One of the toxic effects of non-dioxin-like polychlorinated biphenyls (NDL-PCBs) is the acute inhibition of gap junctional intercellular communication (GJIC), an event possibly associated with tumor promotion. The model NDL-PCB-2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153)-induces a sustained GJIC inhibition in rat liver epithelial WB-F344 cells. As this effect might be related to deregulation of connexin 43 (Cx43) synthesis, trafficking, or degradation, we investigated the impact of PCB 153 on these events. Although PCB 153 had no effect on Cx43 mRNA levels, it induced a gradual loss of Cx43 protein and significantly decreased the amount of gap junction plaques in plasma membrane. PCB 153 contributed to extracellular signal-regulated kinases 1 and 2 (ERK1/2)-dependent accumulation of hyperphosphorylated Cx43-P3 form, thus indicating that ERK1/2 activation by PCB 153 might contribute to its effects on Cx43 internalization or degradation. Inhibition of either proteasomes or lysosomes with their specific inhibitors largely restored total Cx43 protein levels, thus suggesting that both proteasomes and lysosomes may participate in the PCB 153-enhanced Cx43 internalization and degradation. However, neither the proteasomal nor the lysosomal inhibitors restored normal GJIC or number/size of gap junction plaques. Finally, PCB 153 also interfered with restoration of gap junction plaques following the inhibition of Cx43 transport to plasma membrane. Taken together, multiple modes of action seem to contribute to downregulation of Cx43 in PCB 153-treated rat liver epithelial cells. The enhanced degradation of Cx43, together with persistent inhibition of GJIC, might contribute to tumor-promoting effects of NDL-PCBs.

• MeSH
• analýza rozptylu MeSH
• buněčná membrána účinky léků   MeSH
• buněčné linie MeSH
• extracelulárním signálem regulované MAP kinasy antagonisté a inhibitory   metabolismus   MeSH
• inhibitory proteasomu MeSH
• játra metabolismus   MeSH
• konexin 43 genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• leupeptiny farmakologie   MeSH
• lyzozomy metabolismus   účinky léků   MeSH
• metabolické sítě a dráhy účinky léků   MeSH
• mezerový spoj metabolismus   účinky léků   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• polychlorované bifenyly farmakologie   MeSH
• proteasomový endopeptidasový komplex účinky léků   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

The toxic modes of action of non-dioxin-like polychlorinated biphenyls (PCBs) in liver cells are still only partially understood. Several recent studies have indicated that PCBs may interfere with cell membrane protein functions. Therefore, we analyzed in the present study the effects of di-ortho-substituted 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) on proteins involved in the formation of adherens junctions in a model of rat liver progenitor cells - WB-F344 cell line. PCB 153, at micromolar concentrations, induced a gradual degradation of E-cadherin, beta-catenin or plakoglobin (gamma-catenin) proteins. This effect was not due to changes in gene expression, as PCB 153 had no effect on mRNA levels of the above mentioned proteins. Moreover, apart from the reduction of total beta-catenin pool, PCB 153 also decreased levels of the active beta-catenin form, dephosphorylated at residues Ser37 and Thr41, which is the key co-activator of Wnt-induced TCF/LEF-dependent gene expression. Therefore, we also evaluated the impact of PCB 153 on expression of Axin2, a known transcriptional target of canonical Wnt signaling. PCB 153 reduced basal Axin2 mRNA levels and it inhibited induction of Axin2 expression by recombinant mouse Wnt3a. Nevertheless, PCB 153 had no effect on phosphorylation of glycogen synthase kinase-3beta (GSK-3beta), which is supposed to target beta-catenin for its proteasomal degradation. This suggested that GSK-3beta activity is not modulated by PCB 153 and, consequently, not involved in the observed PCB 153-induced decrease of both total and active beta-catenin levels. Protein levels of E-cadherin and beta-catenin were partially restored with lysosomal inhibitor leupeptin, thus suggesting a possible role of lysosomes in the observed degradation of adherens junction proteins. Taken together, the present data suggest that PCB 153 may interfere with functions of adherens junction proteins involved in both cell-to-cell communication and intracellular signaling. Such mechanisms might be involved in the effects of non-dioxin-like PCBs contributing to liver tumor promotion.

• MeSH
• adhezní spoje metabolismus   účinky léků   MeSH
• beta-katenin antagonisté a inhibitory   biosyntéza   genetika   MeSH
• buněčné linie MeSH
• epitelové buňky cytologie   metabolismus   účinky léků   MeSH
• fosforylace účinky léků   MeSH
• gama-katenin biosyntéza   genetika   metabolismus   MeSH
• genetická transkripce účinky léků   MeSH
• inhibitory cysteinových proteinas farmakologie   MeSH
• játra cytologie   metabolismus   účinky léků   MeSH
• kadheriny biosyntéza   genetika   metabolismus   MeSH
• kinasa 3 glykogensynthasy metabolismus   MeSH
• kmenové buňky cytologie   metabolismus   účinky léků   MeSH
• krysa rodu rattus MeSH
• leupeptiny farmakologie   MeSH
• lyzozomy metabolismus   MeSH
• messenger RNA biosyntéza   genetika   MeSH
• polychlorované bifenyly toxicita   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• represorové proteiny biosyntéza   genetika   metabolismus   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Cellular signaling by glucocorticoid receptor and aryl hydrocarbon receptor is restricted by microtubules interfering agents (MIAs). This leads to down-regulation of drug metabolizing enzymes and drug interactions. Here we investigated the effects of all-trans-retinoic acid (ATRA) and MIAs, i.e. colchicine, nocodazole and taxol on the regulation of retinoic acid receptor (RAR) genes in primary cultures of rat hepatocytes. ATRA (1microM) down-regulated RARalpha and RARgamma mRNAs (decrease 23% and 41%, respectively) whereas it up-regulated RARbeta mRNA (4.3-fold induction). All MIAs diminished the expression of RARs in dose-dependent manner; the potency of MIAs increased in order NOC

• MeSH
• financování organizované MeSH
• genetická transkripce účinky záření   MeSH
• HeLa buňky cytologie   metabolismus   účinky léků   MeSH
• inhibitory proteasomu MeSH
• katalýza účinky léků   MeSH
• kolchicin farmakologie   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• leupeptiny farmakologie   MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• mikrotubuly účinky léků   MeSH
• modulátory tubulinu farmakologie   MeSH
• proteasomový endopeptidasový komplex MeSH
• receptory kyseliny retinové genetika   metabolismus   MeSH
• regulace genové exprese účinky záření   MeSH
• termodynamika MeSH
• transglutaminasy metabolismus   MeSH
• tretinoin farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH

Proteasome inhibitors are novel therapeutic agents which may be used in treatment of cancer and other severe disorders. We studied the effect of proteasome inhibitor MG-132 on protein and amino acid metabolism. In MG-132-treated rats we observed a significant decrease in proteasome-dependent proteolysis in skeletal muscle and an increase in whole-body protein turnover (i.e., increase in whole-body proteolysis and protein synthesis). Proteasome-dependent proteolysis was activated in the liver and kidney, protein synthesis increased in skeletal muscle, liver, and kidney. Insignificant changes were found in jejunum and colon. MG-132 administration induced a significant increase in concentration of several amino acids in blood plasma and their decrease in jejunum and colon. We conclude that administration of MG-132 affects both protein anabolic and protein catabolic pathways via the direct effect on proteasome-dependent proteolysis and indirect effect on proteolysis and protein synthesis via unidentified mediators.

• MeSH
• aminokyseliny metabolismus   MeSH
• financování organizované MeSH
• inhibitory proteasomu MeSH
• krysa rodu rattus MeSH
• leupeptiny farmakologie   MeSH
• metabolická clearance účinky léků   MeSH
• orgánová specificita MeSH
• potkani Wistar MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• proteom metabolismus   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH

The Ubiquitin-proteasome system has recently been shown to be involved in the regulation of cytokine expression. We tested the hypothesis of whether the in vivo administration of proteasome inhibitor MG-132 can modulate cytokine response and mortality in sepsis. Sepsis was induced in mice by caecal ligation and puncture (CLP). Animals were divided into four groups: control, CLP, CLP and 1 microg MG-132/g of b.w. intraperitoneally, and CLP and 10 microg MG-132/g of b.w. Plasma levels of interleukin (IL)-1, tumour necrosis factor-alpha (TNF-alpha, IL-6 and IL-10 were determined by ELISA 6 h after the induction of sepsis. CLP induced significant increase in plasma levels of all measured cytokines. MG-132 treatment resulted in lower increase in IL-1, TNF-alpha and IL-10 levels. IL-6 was not significantly affected. A mortality study revealed prolonged survival in MG-132 treated mice. We conclude that MG-132 treatment decreases inflammatory response and prolongs survival in the CLP model of sepsis.

• MeSH
• analýza přežití MeSH
• cytokiny krev   MeSH
• inhibitory cysteinových proteinas * terapeutické užití   MeSH
• inhibitory proteasomu * MeSH
• leupeptiny * terapeutické užití   MeSH
• mediátory zánětu * krev   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• sepse * farmakoterapie   krev   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH