Cell communication systems based on polypeptide ligands use transmembrane receptors to transmit signals across the plasma membrane. In their biogenesis, receptors depend on the endoplasmic reticulum (ER)-Golgi system for folding, maturation, transport and localization to the cell surface. ER stress, caused by protein overproduction and misfolding, is a well-known pathology in neurodegeneration, cancer and numerous other diseases. How ER stress affects cell communication via transmembrane receptors is largely unknown. In disease models of multiple myeloma, chronic lymphocytic leukemia and osteogenesis imperfecta, we show that ER stress leads to loss of the mature transmembrane receptors FGFR3, ROR1, FGFR1, LRP6, FZD5 and PTH1R at the cell surface, resulting in impaired downstream signaling. This is caused by downregulation of receptor production and increased intracellular retention of immature receptor forms. Reduction of ER stress by treatment of cells with the chemical chaperone tauroursodeoxycholic acid or by expression of the chaperone protein BiP resulted in restoration of receptor maturation and signaling. We show a previously unappreciated pathological effect of ER stress; impaired cellular communication due to altered receptor processing. Our findings have implications for disease mechanisms related to ER stress and are particularly important when receptor-based pharmacological approaches are used for treatment.
- MeSH
- chaperon endoplazmatického retikula BiP MeSH
- kyselina taurochenodeoxycholová farmakologie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- receptory buněčného povrchu * metabolismus MeSH
- signální transdukce * účinky léků MeSH
- stres endoplazmatického retikula * účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND & AIMS: Severity of portal hypertension is usually quantified by measuring the hepatic venous pressure gradient (HVPG). However, due to its invasiveness, alternative markers are being sought. Bile acids (BA), being synthesized, metabolized, and transported by the liver, seem to have the potential to serve as endogenous markers. The aim of the present study was to determine whether serum BA reflect the severity of portal hypertension. METHODS: We correlated serum concentrations of individual BA with portal pressure (as HVPG) in an exploratory cohort of 21 cirrhotic patients with portal hypertension. The predictive potential of selected candidates was then confirmed in an independent validation cohort (n = 214). Additionally, nine previously published noninvasive markers were added to the stepwise logistic regression model to identify the most relevant ones, which were eventually used to create a prognostic index of portal hypertension. RESULTS: Serum levels of taurochenodeoxycholic acid (TCDCA) significantly correlated with HVPG and showed a high potential to predict clinically significant portal hypertension (HVPG ≥ 10 mm Hg: AUROC = 0.97 ± 0.06). This was confirmed in the validation cohort (AUROC = 0.96 ± 0.01). The predictive index (constructed based on AST/ALT, spleen diameter, and TCDCA concentration) was able to distinguish clinically significant portal hypertension with 95% sensitivity and 76% specificity. CONCLUSIONS: TCDCA seems to be a promising noninvasive marker of clinically significant portal hypertension. Its predictive potential may be further enhanced when it is combined with both the AST/ALT ratio and spleen diameter.
The novel copper complex [Cu(phen)2(salubrinal)](ClO4)2 (C0SAL) has been synthesised and characterised. Copper(ii) is coordinated by salubrinal through the thionic group, as shown by the UV-Vis, IR, ESI-MS and tandem mass results, together with the theoretical calculations. The formed complex showed a DPPH radical scavenging ability higher than that of salubrinal alone. Studies on lipid oxidation inhibition showed that the C0SAL concentration, required to inhibit the enzyme, was lower than that of salubrinal. The inhibition of the enzyme could take place via allosteric modulation, as suggested by docking calculations. C0SAL showed a good cytotoxic activity on A2780 cells, 82 fold higher than that of the precursor salubrinal and 1.4 fold higher than that of [Cu(phen)2(H2O)](ClO4)2. Treatment with C0SAL in SKOV3 ovarian cancer cells induced expression of GRP-78 and DDIT3 regulators of ER-stress response. The cytotoxic effect of C0SAL was reverted in the presence of TUDCA, suggesting that C0SAL induces cell death through ER-stress. In A2780 cells treated with C0SAL γ-H2AX was accumulated, suggesting that DNA damage was also involved.
- MeSH
- antivirové látky farmakologie MeSH
- cinnamáty farmakologie MeSH
- fenantroliny farmakologie MeSH
- kyselina taurochenodeoxycholová farmakologie MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- měď farmakologie MeSH
- molekulární struktura MeSH
- nádorové buněčné linie MeSH
- peroxidace lipidů účinky léků MeSH
- poškození DNA účinky léků genetika MeSH
- thiomočovina analogy a deriváty farmakologie MeSH
- transkripční faktor CHOP genetika metabolismus MeSH
- transmisní elektronová mikroskopie MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ovarian surface epithelium (OSE) forms a single layer of mostly cuboidal cells on surface of mammalian ovaries that is inherently exposed to cell stress evoked by tissue damage every ovulation and declines morphologically after menopause. Endoplasmic reticulum (ER) is a principal cell organelle involved in proteosynthesis, but also integrating various stress signals. ER stress evokes a conserved signaling pathway, the unfolded protein response (UPR), leading to cell death or adaptation to stress conditions. In this work, we document that mouse OSE suffers from ER stress during replicative senescence in vitro, develops abnormalities in ER and initiates UPR. Attenuation of ER stress in senescent OSE by tauroursodeoxycholic acid (TUDCA) reconditions ER architecture and leads to delayed onset of senescence. In summary, we show for the first time a mutual molecular link between ER stress response and replicative senescence leading to phenotypic changes of non-malignant ovarian surface epithelium.
- MeSH
- down regulace účinky léků MeSH
- epitel účinky léků patologie ultrastruktura MeSH
- kyselina taurochenodeoxycholová farmakologie MeSH
- messenger RNA genetika metabolismus MeSH
- myši MeSH
- ovarium patologie MeSH
- stárnutí buněk účinky léků MeSH
- stres endoplazmatického retikula účinky léků MeSH
- tunikamycin farmakologie MeSH
- upregulace účinky léků MeSH
- zkracování telomer účinky léků MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Stress of endoplasmic reticulum (ERS) is one of the molecular triggers of adipocyte dysfunction and chronic low inflammation accompanying obesity. ERS can be alleviated by chemical chaperones from the family of bile acids (BAs). Thus, two BAs currently used to treat cholestasis, ursodeoxycholic and tauroursodeoxycholic acid (UDCA and TUDCA), could potentially lessen adverse metabolic effects of obesity. Nevertheless, BAs effects on human adipose cells are mostly unknown. They could regulate gene expression through pathways different from their chaperone function, namely through activation of farnesoid X receptor (FXR) and TGR5, G-coupled receptor. Therefore, this study aimed to analyze effects of UDCA and TUDCA on human preadipocytes and differentiated adipocytes derived from paired samples of two distinct subcutaneous adipose tissue depots, abdominal and gluteal. While TUDCA did not alter proliferation of cells from either depot, UDCA exerted strong anti-proliferative effect. In differentiated adipocytes, acute exposition to neither TUDCA nor UDCA was able to reduce effect of ERS stressor tunicamycin. However, exposure of cells to UDCA during whole differentiation process decreased expression of ERS markers. At the same time however, UDCA profoundly inhibited adipogenic conversion of cells. UDCA abolished expression of PPARγ and lipogenic enzymes already in the early phases of adipogenesis. This anti-adipogenic effect of UDCA was not dependent on FXR or TGR5 activation, but could be related to ability of UDCA to sustain the activation of ERK1/2 previously linked with PPARγ inactivation. Finally, neither BAs did lower expression of chemokines inducible by TLR4 pathway, when UDCA enhanced their expression in gluteal adipocytes. Therefore while TUDCA has neutral effect on human preadipocytes and adipocytes, the therapeutic use of UDCA different from treating cholestatic diseases should be considered with caution because UDCA alters functions of human adipose cells.
- MeSH
- adipogeneze účinky léků MeSH
- aktivace enzymů účinky léků MeSH
- buněčná diferenciace účinky léků MeSH
- cytokiny genetika MeSH
- kyselina taurochenodeoxycholová farmakologie MeSH
- kyselina ursodeoxycholová farmakologie MeSH
- lidé MeSH
- mitogenem aktivovaná proteinkinasa 1 metabolismus MeSH
- mitogenem aktivovaná proteinkinasa 3 metabolismus MeSH
- podkožní tuk cytologie MeSH
- proliferace buněk účinky léků MeSH
- regulace genové exprese účinky léků MeSH
- stres endoplazmatického retikula účinky léků MeSH
- tukové buňky cytologie účinky léků metabolismus MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
