Search results for "Signal Transduction"
showing 10 items of 2020 documents
Tight Junctions as a Key for Pathogens Invasion in Intestinal Epithelial Cells
2021
Tight junctions play a major role in maintaining the integrity and impermeability of the intestinal barrier. As such, they act as an ideal target for pathogens to promote their translocation through the intestinal mucosa and invade their host. Different strategies are used by pathogens, aimed at directly destabilizing the junctional network or modulating the different signaling pathways involved in the modulation of these junctions. After a brief presentation of the organization and modulation of tight junctions, we provide the state of the art of the molecular mechanisms leading to permeability breakdown of the gut barrier as a consequence of tight junctions’ attack by pathogens, including…
Extracellular histones activate autophagy and apoptosis via mTOR signaling in human endothelial cells.
2018
Circulating histones have been proposed as targets for therapy in sepsis and hyperinflammatory symptoms. However, the proposed strategies have failed in clinical trials. Although different mechanisms for histone-related cytotoxicity are being explored, those mediated by circulating histones are not fully understood. Extracellular histones induce endothelial cell death, thereby contributing to the pathogenesis of complex diseases such as sepsis and septic shock. Therefore, the comprehension of cellular responses triggered by histones is capital to design effective therapeutic strategies. Here we report how extracellular histones induce autophagy and apoptosis in a dose-dependent manner in cu…
Chemopreventive Property of Sencha Tea Extracts towards Sensitive and Multidrug-Resistant Leukemia and Multiple Myeloma Cells
2020
The popular beverage green tea possesses chemopreventive activity against various types of tumors. However, the effects of its chemopreventive effect on hematological malignancies have not been defined. In the present study, we evaluated antitumor efficacies of a specific green tea, sencha tea, on sensitive and multidrug-resistant leukemia and a panel of nine multiple myelomas (MM) cell lines. We found that sencha extracts induced cytotoxicity in leukemic cells and MM cells to different extents, yet its effect on normal cells was limited. Furthermore, sencha extracts caused G2/M and G0/G1 phase arrest during cell cycle progression in CCRF/CEM and KMS-12-BM cells, respectively. Specifically,…
Integrated molecular signaling involving mitochondrial dysfunction and alteration of cell metabolism induced by tyrosine kinase inhibitors in cancer.
2020
Cancer cells have unlimited replicative potential, insensitivity to growth-inhibitory signals, evasion of apoptosis, cellular stress, and sustained angiogenesis, invasiveness and metastatic potential. Cancer cells adequately adapt cell metabolism and integrate several intracellular and redox signaling to promote cell survival in an inflammatory and hypoxic microenvironment in order to maintain/expand tumor phenotype. The administration of tyrosine kinase inhibitor (TKI) constitutes the recommended therapeutic strategy in different malignancies at advanced stages. There are important interrelationships between cell stress, redox status, mitochondrial function, metabolism and cellular signali…
The Double-Edged Sword Profile of Redox Signaling: Oxidative Events As Molecular Switches in the Balance between Cell Physiology and Cancer.
2018
The intracellular redox state in the cell depends on the balance between the level of reactive oxygen species (ROS) and the activity of defensive systems including antioxidant enzymes. This balance is a dynamic process that can change in relation to many factors and/or stimuli induced within the cell. ROS production is derived from physiological metabolic events. For instance, mitochondria represent the major ROS sources during oxidative phosphorylation, but other systems, such as NADPH oxidase or specific enzymes in certain metabolisms, may account for ROS production as well. Whereas high levels of ROS perturb the cell environment, causing oxidative damage to biological macromolecules, low…
An actin network dispatches ciliary GPCRs into extracellular vesicles to modulate signaling
2017
Signaling receptors dynamically exit cilia upon activation of signaling pathways such as Hedgehog. Here, we find that when activated G protein-coupled receptors (GPCRs) fail to undergo BBSome-mediated retrieval from cilia back into the cell, these GPCRs concentrate into membranous buds at the tips of cilia before release into extracellular vesicles named ectosomes. Unexpectedly, actin and the actin regulators drebrin and myosin 6 mediate ectosome release from the tip of cilia. Mirroring signal-dependent retrieval, signal-dependent ectocytosis is a selective and effective process that removes activated signaling molecules from cilia. Congruently, ectocytosis compensates for BBSome defects as…
The Stalk Domain of NKp30 Contributes to Ligand Binding and Signaling of a Preassembled NKp30-CD3ζ Complex
2016
The natural cytotoxicity receptor (NCR) NKp30 (CD337) is a key player for NK cell immunosurveillance of infections and cancer. The molecular details of ligand recognition and its connection to CD3ζ signaling remain unsolved. Here, we show that the stalk domain (129KEHPQLGAGTVLLLR143) of NKp30 is very sensitive to sequence alterations, as mutations lead to impaired ligand binding and/or signaling capacity. Surprisingly, the stalk domains of NKp30 and NKp46, another NCR employing CD3ζ for signaling, were not exchangeable without drastic deficiencies in folding, plasma membrane targeting, and/or ligand-induced receptor signaling. Further mutational studies, N-glycosylation mapping, and plasma …
EpCAM duality becomes this molecule in a new Dr. Jekyll and Mr. Hyde tale.
2018
EpCAM, known as an epithelial cell adhesion molecule, plays an essential role in cell adhesion, migration, metastasis and cell signalling. Rather than acting as an apoptosis antagonist, it induces cellular proliferation that impacts the cell cycle, and as a signalling transducer it uses and enhances the Wnt pathway, which is significantly relevant in cell renewal and cancer. EpCAM has become a marker of circulating tumour cells (CTCs) in lung cancer due to its specificity, and its high and stable expression level. Recent findings have allowed us to relearn and discover EpCAM again as a CSCs marker by demonstrating its role in human epithelial cancer progression. In line with this, the focus…
Evaluation of Planar-Cell-Polarity Phenotypes in Ciliopathy Mouse Mutant Cochlea
2016
In recent years, primary cilia have emerged as key regulators in development and disease by influencing numerous signaling pathways. One of the earliest signaling pathways shown to be associated with ciliary function was the non-canonical Wnt signaling pathway, also referred to as planar cell polarity (PCP) signaling. One of the best places in which to study the effects of planar cell polarity (PCP) signaling during vertebrate development is the mammalian cochlea. PCP signaling disruption in the mouse cochlea disrupts cochlear outgrowth, cellular patterning and hair cell orientation, all of which are affected by cilia dysfunction. The goal of this protocol is to describe the analysis of PCP…
Identification of the integrin-binding site on coagulation factor VIIa required for proangiogenic PAR2 signaling.
2018
The tissue factor (TF) pathway serves both hemostasis and cell signaling, but how cells control these divergent functions of TF remains incompletely understood. TF is the receptor and scaffold of coagulation proteases cleaving protease-activated receptor 2 (PAR2) that plays pivotal roles in angiogenesis and tumor development. Here we demonstrate that coagulation factor VIIa (FVIIa) elicits TF cytoplasmic domain-dependent proangiogenic cell signaling independent of the alternative PAR2 activator matriptase. We identify a Lys-Gly-Glu (KGE) integrin-binding motif in the FVIIa protease domain that is required for association of the TF-FVIIa complex with the active conformer of integrin β1. A po…