Úvod: Varianty rs738409 c.444C>G (p.I148M) v patatin-like phospholipase domain-containing 3 (PNPLA3) a rs58542926 c.499G>A (p.E167K) v TM6SF2 (transmembrane 6 superfamily member 2) jsou významnými genetickými faktory vzniku a progrese nealkoholové tukové nemoci jater (NAFLD). U obou variant byla popsána vyšší mortalita na jaterní onemocnění, vliv na celkovou mortalitu nebyl prokázán. Cílem této studie bylo posoudit význam genotypů PNPLA3 rs738409 a TM6SF2 rs58542926 dárce a příjemce na dlouhodobé přežívání pacientů po LT. Metody: V kohortě 268 dospělých pacientů po LT, u kterých byly k dispozici genotypy PNPLA3 rs738409 a TM6SF2 rs58542926 dárce a příjemce a byl histologicky zhodnocen výskyt steatózy 6–30 měsíců po LT, jsme hodnotili dlouhodobé přežívání pacientů. Medián sledování byl 17,0 let. Odhady funkcí přežití byly vytvořeny pomocí Kaplan-Meierova modelu a pro zkoumání prediktivní hodnoty vybraných proměnných byl použit Coxův model proporcionálního hazardu. Výsledky: Na přežívání pacientů po LT měly negativní vliv vyšší věk příjemce (p < 0,001), mužské pohlaví (p = 0,014), alkoholická (p = 0,021) nebo HCV (p = 0,042) etiologie jaterní cirhózy a přítomnost hepatocelulárního karcinomu v explantátu jater (p = 0,009). Genotypy PNPLA3 rs738409 a TM6SF2 rs58542926 příjemce ani dárce neměly na přežívání pacientů žádný vliv. Závěr: Ačkoli varianty PNPLA3 c.444G a TM6SF2 c.499A dárce zvyšují riziko steatózy jaterního štěpu po LT, nebyl pro tyto genotypy dárce ani příjemce prokázán negativní vliv na dlouhodobé přežívání pacientů po LT.

Introduction: The variants rs738409 c.444C>G (p.I148M) in patatin-like phospholipase domain-containing 3 (PNPLA3) and rs58542926 c.499G>A (p.E167K) in TM6SF2 (transmembrane 6 superfamily member 2) are significant genetic risk factors of development and progression of non-alcoholic fatty liver dis ease (NAFLD). In both variants, increased liver-specific mortality was described, while the impact on all-cause mortality was not proved. The aim of the study was to evaluate the impact of PNPLA3 rs738409 and TM6SF2 rs58542926 genotypes of the donor and recipient respectively on long-term patient survival after LT. Methods: We evaluated long-term patient survival in a cohort of 268 adult LT recipients, in whom PNPLA3 rs738409 and TM6SF2 rs58542926 genotypes of the donor and recipient respectively were available and steatosis was evaluated in liver graft biopsy 6–30 months after LT. The median fol low-up was 17 years. The Kaplan-Meier model was used for the survival estimates and the Cox proportional hazard model was used to assess the predictive value of the chosen variables. Results: Increased recipient age (P < 0.001), male sex (P = 0.014), alcoholic (P = 0.021) or HCV (P = 0.042) etiology of liver cirrhosis, and presence of hepatocellular carcinoma (P = 0.009) negatively influenced long-term patient survival after LT. PNPLA3 rs738409 and TM6SF2 rs58542926 genotypes of the recipient and donor respectively had no effect on patient survival. Conclusion: Although PNPLA3 c.444G and TM6SF2 c.499A variants of the donor increase the risk of steatosis of the liver graft after LT, we did not prove a negative impact of these genotypes of the donor and recipient on long-term patient survival after LT.

• MeSH
• kohortové studie MeSH
• lidé MeSH
• nealkoholová steatóza jater * etiologie   genetika   komplikace   MeSH
• polymorfismus genetický * MeSH
• transplantace jater * metody   mortalita   MeSH
• Check Tag
• lidé MeSH

BACKGROUND AND PURPOSE: More than 30% of currently marketed medications act via GPCRs. Thus, GPCRs represent one of the most important pharmacotherapeutic targets. In contrast to traditional agonists activating multiple signalling pathways, agonists activating a single signalling pathway represent a new generation of drugs with increased specificity and fewer adverse effects. EXPERIMENTAL APPROACH: We have synthesized novel agonists of muscarinic ACh receptors and tested their binding and function (on levels of cAMP and inositol phosphates) in CHO cells expressing individual subtypes of muscarinic receptors, primary cultures of rat aortic smooth muscle cells and suspensions of digested native tissues from rats. Binding of the novel compounds to M2 receptors was modelled in silico. KEY RESULTS: Two of the tested new compounds (1-(thiophen-2-ylmethyl)-3,6-dihydro-2H-pyridinium and 1-methyl-1-(thiophen-2-ylmethyl)-3,6-dihydro-2H-pyridinium) only inhibited cAMP synthesis in CHO cells, primary cultures, and native tissues, with selectivity for M2 muscarinic receptors and displaying bias towards the Gi signalling pathway at all subtypes of muscarinic receptors. Molecular modelling revealed interactions with the orthosteric binding site in a way specific for a given agonist followed by agonist-specific changes in the conformation of the receptor. CONCLUSIONS AND IMPLICATIONS: The identified compounds may serve as lead structures in the search for novel non-steroidal and non-opioid analgesics acting via M2 and M4 muscarinic receptors with reduced side effects associated with activation of the phospholipase C signalling pathway.

• MeSH
• agonisté muskarinových receptorů * farmakologie   MeSH
• antagonisté muskarinových receptorů farmakologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• křečci praví MeSH
• krysa rodu rattus MeSH
• receptor muskarinový M2 MeSH
• receptory muskarinové * MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

C-terminal Src kinase (CSK) is a major negative regulator of Src family tyrosine kinases (SFKs) that play critical roles in immunoreceptor signaling. CSK is brought in contiguity to the plasma membrane-bound SFKs via binding to transmembrane adaptor PAG, also known as CSK-binding protein. The recent finding that PAG can function as a positive regulator of the high-affinity IgE receptor (FcεRI)-mediated mast cell signaling suggested that PAG and CSK have some non-overlapping regulatory functions in mast cell activation. To determine the regulatory roles of CSK in FcεRI signaling, we derived bone marrow-derived mast cells (BMMCs) with reduced or enhanced expression of CSK from wild-type (WT) or PAG knockout (KO) mice and analyzed their FcεRI-mediated activation events. We found that in contrast to PAG-KO cells, antigen-activated BMMCs with CSK knockdown (KD) exhibited significantly higher degranulation, calcium response, and tyrosine phosphorylation of FcεRI, SYK, and phospholipase C. Interestingly, FcεRI-mediated events in BMMCs with PAG-KO were restored upon CSK silencing. BMMCs with CSK-KD/PAG-KO resembled BMMCs with CSK-KD alone. Unexpectedly, cells with CSK-KD showed reduced kinase activity of LYN and decreased phosphorylation of transcription factor STAT5. This was accompanied by impaired production of proinflammatory cytokines and chemokines in antigen-activated cells. In line with this, BMMCs with CSK-KD exhibited enhanced phosphorylation of protein phosphatase SHP-1, which provides a negative feedback loop for regulating phosphorylation of STAT5 and LYN kinase activity. Furthermore, we found that in WT BMMCs SHP-1 forms complexes containing LYN, CSK, and STAT5. Altogether, our data demonstrate that in FcεRI-activated mast cells CSK is a negative regulator of degranulation and chemotaxis, but a positive regulator of adhesion to fibronectin and production of proinflammatory cytokines. Some of these pathways are not dependent on the presence of PAG.

• MeSH
• analýza rozptylu MeSH
• buňky kostní dřeně fyziologie   MeSH
• C-terminální Src kinasa MeSH
• cytokiny metabolismus   MeSH
• degranulace buněk MeSH
• fibronektiny metabolismus   MeSH
• fosfoproteiny metabolismus   MeSH
• fosforylace MeSH
• genetické vektory MeSH
• HEK293 buňky MeSH
• lidé MeSH
• mastocyty fyziologie   MeSH
• membránové proteiny metabolismus   MeSH
• mezibuněčné signální peptidy a proteiny MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• receptory IgE metabolismus   MeSH
• signální transdukce imunologie   MeSH
• skupina kinas odvozených od src-genu metabolismus   fyziologie   MeSH
• transkripční faktor STAT5 metabolismus   MeSH
• tyrosin metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 6 metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Background and Aims: The non-specific phospholipase C (NPC) is a new member of the plant phospholipase family that reacts to abiotic environmental stresses, such as phosphate deficiency, high salinity, heat and aluminium toxicity, and is involved in root development, silicon distribution and brassinolide signalling. Six NPC genes (NPC1-NPC6) are found in the Arabidopsis genome. The NPC2 isoform has not been experimentally characterized so far. Methods: The Arabidopsis NPC2 isoform was cloned and heterologously expressed in Escherichia coli. NPC2 enzyme activity was determined using fluorescent phosphatidylcholine as a substrate. Tissue expression and subcellular localization were analysed using GUS- and GFP-tagged NPC2. The expression patterns of NPC2 were analysed via quantitative real-time PCR. Independent homozygous transgenic plant lines overexpressing NPC2 under the control of a 35S promoter were generated, and reactive oxygen species were measured using a luminol-based assay. Key Results: The heterologously expressed protein possessed phospholipase C activity, being able to hydrolyse phosphatidylcholine to diacylglycerol. NPC2 tagged with GFP was predominantly localized to the Golgi apparatus in Arabidopsis roots. The level of NPC2 transcript is rapidly altered during plant immune responses and correlates with the activation of multiple layers of the plant defence system. Transcription of NPC2 decreased substantially after plant infiltration with Pseudomonas syringae, flagellin peptide flg22 and salicylic acid treatments and expression of the effector molecule AvrRpm1. The decrease in NPC2 transcript levels correlated with a decrease in NPC2 enzyme activity. NPC2-overexpressing mutants showed higher reactive oxygen species production triggered by flg22. Conclusions: This first experimental characterization of NPC2 provides new insights into the role of the non-specific phospholipase C protein family. The results suggest that NPC2 is involved in the response of Arabidopsis to P. syringae attack.

• MeSH
• Arabidopsis enzymologie   imunologie   mikrobiologie   MeSH
• fosfatidylcholiny metabolismus   MeSH
• fosfolipasy typu C fyziologie   MeSH
• Golgiho aparát enzymologie   MeSH
• imunita rostlin fyziologie   MeSH
• klonování DNA MeSH
• konfokální mikroskopie MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• nemoci rostlin imunologie   mikrobiologie   MeSH
• proteiny huseníčku fyziologie   MeSH
• protoplasty enzymologie   MeSH
• Pseudomonas syringae * MeSH
• reaktivní formy kyslíku MeSH
• regulace genové exprese u rostlin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

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.

• 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

Isolated supraoptic neurones generate spontaneous [Ca(2+)]i oscillations in isolated conditions. Here we report in depth analysis of the contribution of plasmalemmal ion channels (Ca(2+), Na(+)), Na(+)/Ca(2+) exchanger (NCX), intracellular Ca(2+) release channels (InsP3Rs and RyRs), Ca(2+) storage organelles, plasma membrane Ca(2+) pump and intracellular signal transduction cascades into spontaneous Ca(2+) activity. While removal of extracellular Ca(2+) or incubation with non-specific voltage-gated Ca(2+) channel (VGCC) blocker Cd(2+) suppressed the oscillations, neither Ni(2+) nor TTA-P2, the T-type VGCC blockers, had an effect. Inhibitors of VGCC nicardipine, ω-conotoxin GVIA, ω-conotoxin MVIIC, ω-agatoxin IVA (for L-, N-, P and P/Q-type channels, respectively) did not affect [Ca(2+)]i oscillations. In contrast, a specific R-type VGCC blocker SNX-482 attenuated [Ca(2+)]i oscillations. Incubation with TTX had no effect, whereas removal of the extracellular Na(+) or application of an inhibitor of the reverse operation mode of Na(+)/Ca(2+) exchanger KB-R7943 blocked the oscillations. The mitochondrial uncoupler CCCP irreversibly blocked spontaneous [Ca(2+)]i activity. Exposure of neurones to Ca(2+) mobilisers (thapsigargin, cyclopiazonic acid, caffeine and ryanodine); 4-aminopyridine (A-type K(+) current blocker); phospholipase C and adenylyl cyclase pathways blockers U-73122, Rp-cAMP, SQ-22536 and H-89 had no effect. Oscillations were blocked by GABA, but not by glutamate, apamin or dynorphin. In conclusion, spontaneous oscillations in magnocellular neurones are mediated by a concerted action of R-type Ca(2+) channels and the NCX fluctuating between forward and reverse modes.

• MeSH
• adenylátcyklasy metabolismus   MeSH
• biologický transport MeSH
• draslíkové kanály metabolismus   MeSH
• fosfolipasy typu C metabolismus   MeSH
• gating iontového kanálu MeSH
• intracelulární prostor metabolismus   MeSH
• neurony metabolismus   MeSH
• neurotransmiterové látky metabolismus   MeSH
• nucleus supraopticus metabolismus   MeSH
• potkani Wistar MeSH
• pumpa pro výměnu sodíku a vápníku metabolismus   MeSH
• sodík metabolismus   MeSH
• sodíkové kanály metabolismus   MeSH
• systémy druhého messengeru MeSH
• vápník metabolismus   MeSH
• vápníková signalizace * MeSH
• vápníkové kanály - typ R metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The first indication of the aluminum (Al) toxicity in plants growing in acidic soils is the cessation of root growth, but the detailed mechanism of Al effect is unknown. Here we examined the impact of Al stress on the activity of non-specific phospholipase C (NPC) in the connection with the processes related to the plasma membrane using fluorescently labeled phosphatidylcholine. We observed a rapid and significant decrease of labeled diacylglycerol (DAG), product of NPC activity, in Arabidopsis seedlings treated with AlCl₃. Interestingly, an application of the membrane fluidizer, benzyl alcohol, restored the level of DAG during Al treatment. Our observations suggest that the activity of NPC is affected by Al-induced changes in plasma membrane physical properties.

• MeSH
• Arabidopsis účinky léků   enzymologie   MeSH
• benzylalkohol farmakologie   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• diglyceridy metabolismus   MeSH
• fosfolipasy typu C metabolismus   MeSH
• hliník farmakologie   MeSH
• ionty MeSH
• kořeny rostlin účinky léků   metabolismus   MeSH
• semenáček účinky léků   metabolismus   MeSH
• sloučeniny boru metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• imunita MeSH
• imunitní systém MeSH
• imunoterapie MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie
• biologie

Mutations of the TMPRSS6 gene, encoding the serine protease matriptase-2, lead to iron-refractory iron deficiency anemia. Matriptase-2 is a potent negative regulator of hepcidin. Based on in vitro data, it has recently been proposed that matriptase-2 decreases hepcidin synthesis by cleaving membrane hemojuvelin, a key protein of the hepcidin-regulatory pathway. However, in vivo evidence for this mechanism of action of matriptase-2 is lacking. To investigate the hemojuvelin-matriptase-2 interaction in vivo, an immunoblot assay for liver membrane hemojuvelin was optimized using hemojuvelin-mutant mice as a negative control. In wild-type mice, two hemojuvelin-specific bands of 35kDa and 20kDa were detected in mouse liver membrane fraction under reducing conditions; under non-reducing conditions, a single band of approximately 50kDa was seen. Phosphatidylinositol-specific phospholipase C treatment confirmed binding of the detected protein to the cell membrane by a glycosylphosphatidylinositol anchor, indicating that the major form of mouse liver membrane hemojuvelin is a glycosylphosphatidylinositol-bound heterodimer. Unexpectedly, comparison of liver homogenates from Tmprss6+/+ and Tmprss6-/- mice revealed significantly decreased, rather than increased, hemojuvelin heterodimer content in Tmprss6-/- mice. These data do not provide direct support for the concept that matriptase-2 cleaves membrane hemojuvelin and may indicate that, in vivo, the role of matriptase-2 in the regulation of hepcidin gene expression is more complex.

• MeSH
• anemie z nedostatku železa genetika   metabolismus   MeSH
• buněčná membrána genetika   metabolismus   MeSH
• dimerizace MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• fosfolipasa C fosfoinositidové signalizace metabolismus   MeSH
• glykosylfosfatidylinositoly chemie   metabolismus   MeSH
• játra metabolismus   patologie   MeSH
• kationické antimikrobiální peptidy genetika   metabolismus   MeSH
• membránové proteiny nedostatek   genetika   metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• polymerázová řetězová reakce MeSH
• regulace genové exprese MeSH
• serinové endopeptidasy nedostatek   genetika   MeSH
• signální transdukce genetika   MeSH
• tkáňové extrakty chemie   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

CD148 is a receptor-like protein-tyrosine phosphatase known to inhibit transduction of mitogenic signals in non-hematopoietic cells. Similarly, in the hematopoietic lineage, CD148 inhibited signal transduction downstream of T cell receptor. However, it also augmented immunoreceptor signaling in B cells and macrophages via dephosphorylating C-terminal tyrosine of Src family kinases (SFK). Accordingly, endogenous CD148 compensated for the loss of the main SFK activator CD45 in murine B cells and macrophages but not in T cells. Hypothetical explanations for the difference between T cells and other leukocyte lineages include the inability of CD148 to dephosphorylate a specific set of SFKs involved in T cell activation or the lack of CD148 expression during critical stages of T cell development. Here we describe striking differences in CD148 expression between human and murine thymocyte subsets, the only unifying feature being the absence of CD148 during the positive selection when the major developmental block occurs under CD45 deficiency. Moreover, we demonstrate that similar to CD45, CD148 has both activating and inhibitory effects on the SFKs involved in TCR signaling. However, in the absence of CD45, activating effects prevail, resulting in functional complementation of CD45 deficiency in human T cell lines. Importantly, this is independent of the tyrosines in the CD148 C-terminal tail, contradicting the recently proposed phosphotyrosine displacement model as a mechanism of SFK activation by CD148. Collectively, our data suggest that differential effects of CD148 in T cells and other leukocyte subsets cannot be explained by the CD148 inability to activate T cell SFKs but rather by its dual inhibitory/activatory function and specific expression pattern.

• MeSH
• adaptorové proteiny signální transdukční metabolismus   MeSH
• aktivace enzymů MeSH
• antigeny CD45 nedostatek   MeSH
• fosfolipasa C gama metabolismus   MeSH
• fosforylace MeSH
• hematopoetické kmenové buňky cytologie   enzymologie   metabolismus   MeSH
• Jurkat buňky MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• myši MeSH
• receptory antigenů T-buněk imunologie   metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu chemie   metabolismus   MeSH
• T-lymfocyty cytologie   enzymologie   metabolismus   MeSH
• terciární struktura proteinů MeSH
• thymus cytologie   MeSH
• tyrosin metabolismus   MeSH
• tyrosinfosfatasy receptorového typu, třída 3 chemie   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH