Search results for "signal transduction."
showing 10 items of 1278 documents
Thiol antioxidants block the activation of antigen-presenting cells by contact sensitizers.
2003
Strong contact sensitizers are able to induce signal transduction mechanisms such as tyrosine phosphorylation and activation of MAP kinases in antigen-presenting cells. We studied the capacity of different antioxidants (ascorbic acid, alpha-tocopherol, pyrrolidine dithiocarbamate, N-acetylcysteine, and glutathione) to block the increase in tyrosine phosphorylation in human monocytes seen after stimulation with strong contact sensitizers. Human peripheral blood mononuclear cells were stimulated with 5-chloro-2-methylisothiazolinone plus 2-methylisothiazolinone in the presence or absence of these antioxidants. The total amount of membrane-associated phosphotyrosine in CD14+ cells was quantifi…
Resveratrol modulates the levels of microRNAs targeting genes encoding tumor-suppressors and effectors of TGFbeta signaling pathway in SW480 cells.
2010
International audience; Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural antioxidant with cardiovascular and cancer preventive properties that is currently at the stage of pre-clinical studies for human cancer prevention. Beside its known effects on protein coding genes, one possible mechanism for resveratrol protective activities is by modulating the levels of non-coding RNAs. Here, we analyzed the effects of resveratrol on microRNA populations in human SW480 colon cancer cells. We establish that resveratrol treatment decreases the levels of several oncogenic microRNAs targeting genes encoding Dicer1, a cytoplasmic RNase III producing mature microRNAs from their immediate precurs…
PTEN Mediates the Antioxidant Effect of Resveratrol at Nutritionally Relevant Concentrations
2014
Introduction.Antioxidant properties of resveratrol have been intensively studied for the last years, bothin vivoandin vitro. Its bioavailability after an oral dose is very low and therefore it is very important to make sure that plasma concentrations of free resveratrol are sufficient enough to be active as antioxidant.Aims.In the present study, using nutritionally relevant concentrations of resveratrol, we aim to confirm its antioxidant capacity on reducing peroxide levels and look for the molecular pathway involved in this antioxidant effect.Methods.We used mammary gland tumor cells (MCF-7), which were pretreated with different concentrations of resveratrol for 48 h, and/or a PTEN inhibit…
Apolipoprotein E Regulates Amyloid Formation within Endosomes of Pigment Cells.
2015
International audience; Accumulation of toxic amyloid oligomers is a key feature in the pathogenesis of amyloid-related diseases. Formation of mature amyloid fibrils is one defense mechanism to neutralize toxic prefibrillar oligomers. This mechanism is notably influenced by apolipoprotein E variants. Cells that produce mature amyloid fibrils to serve physiological functions must exploit specific mechanisms to avoid potential accumulation of toxic species. Pigment cells have tuned their endosomes to maximize the formation of functional amyloid from the protein PMEL. Here, we show that ApoE is associated with intraluminal vesicles (ILV) within endosomes and remain associated with ILVs when th…
Superoxide Flux in Endothelial Cells via the Chloride Channel-3 Mediates Intracellular Signaling
2007
Reactive oxygen species (ROS) have been implicated in both cell signaling and pathology. A major source of ROS in endothelial cells is NADPH oxidase, which generates superoxide (O2.−) on the extracellular side of the plasma membrane but can result in intracellular signaling. To study possible transmembrane flux of O2.−, pulmonary microvascular endothelial cells were preloaded with the O2.−-sensitive fluorophore hydroethidine (HE). Application of an extracellular bolus of O2.−resulted in rapid and concentration-dependent transient HE oxidation that was followed by a progressive and nonreversible increase in nuclear HE fluorescence. These fluorescence changes were inhibited by superoxide dism…
Activation of nitric oxide signaling by the rheumatoid arthritis shared epitope
2006
Objective. Susceptibility to rheumatoid arthritis (RA) is closely associated with HLA–DRB1 alleles encoding a shared epitope (SE) in positions 70–74 of the HLA–DR chain. The mechanistic basis for this association is unknown. Given the proposed pathogenic role of nitric oxide (NO) in RA, this study was undertaken to examine whether the SE can trigger NO signaling events. Methods. The intracellular levels of NO were measured with the fluorescent NO probe 4,5diaminofluorescein diacetate and by the 2,3diaminonaphthalene method. NO synthase activity was determined by measuring the rate of conversion of radioactive arginine to citrulline. Levels of cGMP were measured with a commercial enzyme-link…
The rheumatoid arthritis shared epitope increases cellular susceptibility to oxidative stress by antagonizing an adenosine-mediated anti-oxidative pa…
2006
We have recently demonstrated that the rheumatoid arthritis (RA) shared epitope (SE) acts as a ligand that triggers nitric oxide (NO) signaling in opposite cells. Given the known pro-oxidative effect of NO and the proposed role of oxidative stress in the pathogenesis of RA, this study explores whether SE-triggered signaling can increase cellular oxidative stress. cAMP levels, adenylyl cyclase activity, and protein kinase A activity were measured using commercial kits. Generation of reactive oxygen species (ROS) was quantified using the fluorochrome dichlorofluorescein diacetate. Oxidative DNA damage was quantified using the single-cell electrophoresis technique. Here, we report that cells e…
PACAP induces bradycardia in guinea-pig heart by stimulation of atrial cholinergic neurones
1996
Based on previous studies which indicated that pituitary adenylate cyclase activating peptide (PACAP) acts as a positive inotropic and chronotropic substance in different species via the cAMP signal transduction pathway, the objective of the present work was to investigate cAMP-regulated myocardial key proteins in response to PACAP in isolated ventricular cells of the guinea pig. Surprisingly, the two molecular forms of PACAP, PACAP(1-27) and PACAP(1-38), showed no effect on intracellular cAMP-levels, L-type Ca2+ channel current or phosphorylation of troponin inhibitor (TnI) and phospholamban (PLB). Additionally, inotropy of isolated guinea-pig ventricular strips was not affected by the neu…
Arginine vasopressin, via activation of post-junctional V1 receptors, induces contractile effects in mouse distal colon
2013
The aim of this study was to analyze whether arginine vasopressin (AVP) may be considered a modulator of intestinal motility. In this view, we evaluated, in vitro, the effects induced by exogenous administration of AVP on the contractility of mouse distal colon, the subtype(s) of receptor(s) activated and the action mechanism. Isometric recordings were performed on longitudinal and circular muscle strips of mouse distal colon. AVP (0.001 nM-100 nM) caused concentration-dependent contractile effects only on the longitudinal muscle, antagonized by the V1 receptor antagonist, V-1880. AVP-induced effect was not modified by tetrodotoxin, atropine and indomethacin. Contractile response to AVP was…
Transcriptomic metaanalyses of autistic brains reveals shared gene expression and biological pathway abnormalities with cancer
2019
Este es el artículo que se ha publicado de forma definitiva en: https://molecularautism.biomedcentral.com/articles/10.1186/s13229-019-0262-8 En este artículo también participa Joan Climent, Vera Pancaldi, Lourdes Fañanás, Celso Arango, Mara Parellada, Anaïs Baudot, Daniel Vogt, John L. Rubenstein, Alfonso Valencia y Rafael Tabarés-Seisdedos. Background: Epidemiological and clinical evidence points to cancer as a comorbidity in people with autism spectrum disorders (ASD). A significant overlap of genes and biological processes between both diseases has also been reported. Methods: Here, for the first time, we compared the gene expression profiles of ASD frontal cortex tissues and 22 cancer t…