Search results for "Cysteine"
showing 10 items of 550 documents
Oxidative stress and innate immunity responses in cigarette smoke stimulated nasal epithelial cells
2013
Cigarette smoke extracts (CSE) may play a significant role in diseases of the upper airway including chronic rhinosinusitis. Even short term exposure of cigarette smoke has adverse effects on mitochondrial functions and redox homeostasis in tissues which may progress to further complications associated with chronic smoking. Cigarette smoke alters toll-like receptor 4 (TLR4) expression and activation in bronchial epithelial cells. Carbocysteine is an anti-oxidant and mucolytic agent. The effects of carbocysteine on CSE induced oxidative stress and on associated innate immune and inflammatory responses in nasal epithelial cells are largely unknown. The present study was aimed to assess in CSE…
Distribution of homocysteine and cysteine in plasma lipoprotein fractions
2008
S-thiolation of plasma proteins have been detected in healthy humans, in patients with cardiovascular diseases and it is a recurrent phenomenon in oxidative stress elicited by reactive oxygen species. The low-molecular-weight aminothiols homocysteine (Hcy) and cysteine (Cys) can exist in the plasma either free or bound to thiol-combining groups, many of which are present in proteins (Pb), particularly albumin. Recent studies have demonstrated that also plasma lipoproteins (LP) are susceptible to form disulfide-linked products with Hcy and Cys and that the N-homocysteinylation is accompanied by structural and functional alteration and could increase the atherogenicity of LDL. However, the me…
Identification of a putative membrane-inserted segment in the alpha-toxin of Staphylococcus aureus.
1994
To gain a fuller understanding of the regions of the Staphylococcus aureus alpha-toxin important in pore formation, we have used Forster dipole-dipole energy transfer to demonstrate that a central glycine-rich region of alpha-toxin (the so-called "hinge" region) inserts deeply into the bilayer on association of toxin with liposomes. Mutant alpha-toxins with unique cysteine (C) residues at positions 69 and 130 [Palmer, M., et al. (1993) J. Biol. Chem. 268, 11959) were reacted with the C-specific fluorophore acrylodan, which acted as an energy donor. The chosen acceptor was N-(7-nitrobenz-2-oxa-13- diazol-4-yl)-1,2-bis(hexadecanoyl)-sn-glycero-3-phosphoethanolamin e (NBD-PE). Measurement of t…
Reduced mRNA abundance of the main enzymes involved in methionine metabolism in human liver cirrhosis and hepatocellular carcinoma
2000
Abstract Background/Aims: It has been known for at least 50 years that alterations in methionine metabolism occur in human liver cirrhosis. However, the molecular basis of this alteration is not completely understood. In order to gain more insight into the mechanisms behind this condition, mRNA levels of methionine adenosyltransferase ( MAT1A ), glycine methyltransferase ( GNMT ), methionine synthase ( MS ), betaine homocysteine methyltransferase ( BHMT ) and cystathionine β-synthase ( CBS ) were examined in 26 cirrhotic livers, five hepatocellular carcinoma (HCC) tissues and ten control livers. Methods: The expression of the above-mentioned genes was determined by quantitative RT-PCR analy…
Can PBDEs affect the pathophysiologic complex of epithelium in lung diseases?
2020
Brominated flame-retardant (BFRs) exposure promotes multiple adverse health outcomes involved in oxidative stress, inflammation, and tissues damage. We investigated BFR effects, known as polybrominated diphenyl ethers (PBDEs) (47, 99 and 209) in an air-liquid-interface (ALI) airway tissue derived from A549 cell line, and compared with ALI culture of primary human bronchial epithelial cells (pHBEC). The cells, exposed to PBDEs (47, 99 and 209) (0.01-1 mu M) for 24 h, were studied for IL-8, Muc5AC and Muc5B (mRNAs and proteins) production, as well as NOX-4 (mRNA) expression. Furthermore, we evaluated tight junction (TJ) integrity by Trans-Epithelial Electrical Resistance (TEER) measurements, …
Acute pancreatitis and cystinosis as experimental models of disulfide stress characterized by protein cysteinylation
2017
Disulfide stress is a specific type of oxidative stress that is associated with protein cysteinylation. The aim of this research was to characterize experimental models of disulphide stress. Thus, the redox status of free thiols and protein cysteinylation was studied in acute pancreatitis as an in vivo model of inflammation and in cystinosis an in vitro model of cystine accumulation due to its dysfunctional lysosomal transport. Cystine and homocystine levels, and protein cysteinylation rose after taurocholate-induced acute pancreatitis. Oxidation of cysteines in mitochondrial sulfide quinone oxidoreductase and 60S ribosomal protein L7a was observed. Cysteinylated albumin was also detected. …
Coupling of Contact Sensitizers to Thiol Groups is a Key Event for the Activation of Monocytes and Monocyte-Derived Dendritic Cells
2003
Strong contact sensitizers are able to induce distinct signal transduction mechanisms in antigen-presenting cells by coupling to cell proteins. The predominant target structures of haptens are thought to be thiol and amino groups in cysteine and lysine residues. We studied whether coupling of small reactive chemicals to thiol or amino groups might be responsible for the activation of monocytes and mature monocyte-derived dendritic cells. Human peripheral blood mononuclear cells were stimulated in vitro with subtoxic concentrations of the strong haptens 5-chloro-2-methylisothiazolinone plus 2-methylisothiazolinone and 2, 4, 6-trinitrochlorobenzene, the thiol-reactive reagents N-hydroxymaleim…
Caspartin and calprismin, two proteins of the shell calcitic prisms of the Mediterranean fan mussel Pinna nobilis.
2005
We used the combination of preparative electrophoresis and immunological detection to isolate two new proteins from the shell calcitic prisms of Pinna nobilis, the Mediterranean fan mussel. The amino acid composition of these proteins was determined. Both proteins are soluble, intracrystalline, and acidic. The 38-kDa protein is glycosylated; the 17-kDa one is not. Ala, Asx, Thr, and Pro represent the dominant residues of the 38-kDa protein, named calprismin. An N-terminal sequence was obtained from calprismin. This sequence, which comprises a pattern of 4 cysteine residues, is not related to any known protein. The second protein, named caspartin, exhibits an unusual amino acid composition, …
S-nitrosylation of the death receptor fas promotes fas ligand-mediated apoptosis in cancer cells.
2011
International audience; BACKGROUND & AIMS: Fas belongs to the family of tumor necrosis factor receptors which induce apoptosis. Many cancer cells express Fas but do not undergo Fas-mediated apoptosis. Nitric oxide reverses this resistance by increasing levels of Fas at the plasma membrane. We studied the mechanisms by which NO affects Fas function. METHODS: Colon and mammary cancer cell lines were incubated with the NO donor glyceryl trinitrate or lipid A; S-nitrosylation of Fas was monitored using the biotin switch assay. Fas constructs that contained mutations at cysteine residues that prevent S-nitrosylation were used to investigate the involvement of S-nitrosylation in Fas-mediated cell…
Novel combination of celecoxib and proteasome inhibitor MG132 provides synergistic antiproliferative and proapoptotic effects in human liver tumor ce…
2010
Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Celecoxib (Celebrex®) exhibits antitumor effects in human HCC cells, and its mechanism of action is mediated either by its ability to inhibit cyclooxygenase 2 (COX-2) or by a number of various other COX-2 independent effects. Proteasome inhibitors (PIs) can exert cell growth inhibitory and apoptotic effects in different tumor cell types, including HCC cells. The present study examined the interaction between celecoxib and the PI MG132 in two human liver tumor cell lines HepG2 and HA22T/VGH. Our data showed that each inhibitor reduced proliferation and induced apoptosis in a dose-dependen…