Search results for "Jurkat Cell"
showing 10 items of 89 documents
Soluble interleukin-6 receptor (sIL-6R) makes IL-6R negative T cell line respond to IL-6: it inhibits TNF production
2000
The receptor for interleukin-6 (IL-6) consists of two subunits: a ligand specific IL-6Ralpha and gp130 that is responsible for signal-transduction. A soluble form of the ligand specific chain was described that when complexed to IL-6 is capable of binding to the membrane-bound gp130 subunit and thus can elicit signal-transduction. This soluble receptor can act on cells that express only the gp130 but not the ligand-specific subunit of the IL-6R. This phenomenon, called trans-signaling, introduced a novel aspect of cytokine action. In this study we examined the response of Jurkat cells, that are known not to express IL-6Ralpha, to IL-6, the soluble IL-6 receptor (sIL-6R) and a covalent compl…
The ubiquitin-specific protease USP8 is critical for the development and homeostasis of T cells
2015
The modification of proteins by ubiquitin has a major role in cells of the immune system and is counteracted by various deubiquitinating enzymes (DUBs) with poorly defined functions. Here we identified the ubiquitin-specific protease USP8 as a regulatory component of the T cell antigen receptor (TCR) signalosome that interacted with the adaptor Gads and the regulatory molecule 14-3-3β. Caspase-dependent processing of USP8 occurred after stimulation of the TCR. T cell-specific deletion of USP8 in mice revealed that USP8 was essential for thymocyte maturation and upregulation of the gene encoding the cytokine receptor IL-7Rα mediated by the transcription factor Foxo1. Mice with T cell-specifi…
Polyethyleneimine-based immunopolyplex for targeted gene transfer in human lymphoma celllines
2002
Background Specific and efficient delivery of genes into targeted cells is a priority objective in non-viral gene therapy. Polyethyleneimine-based polyplexes have been reported to be good non-viral transfection reagents. However, polyplex-mediated DNA delivery occurs through a non-specific mechanism. This article reports the construction of an immunopolyplex, a targeted non-viral vector based on a polyplex backbone, and its application in gene transfer over human lymphoma cell lines. Methods Targeting elements (biotin-labeled antibodies), which should recognize a specific element of the target cell membrane and promote nucleic acid entry into the cell, were attached to the polyplex backbone…
Tristetraprolin regulation of interleukin-22 production
2015
AbstractInterleukin (IL)-22 is a STAT3-activating cytokine displaying characteristic AU-rich elements (ARE) in the 3′-untranslated region (3′-UTR) of its mRNA. This architecture suggests gene regulation by modulation of mRNA stability. Since related cytokines undergo post-transcriptional regulation by ARE-binding tristetraprolin (TTP), the role of this destabilizing protein in IL-22 production was investigated. Herein, we demonstrate that TTP-deficient mice display augmented serum IL-22. Likewise, IL-22 mRNA was enhanced in TTP-deficient splenocytes and isolated primary T cells. A pivotal role for TTP is underscored by an extended IL-22 mRNA half-life detectable in TTP-deficient T cells. Lu…
New Acylated Triterpene Saponins from Silene fortunei that Modulate Lymphocyte Proliferation
2002
Three new acylated triterpene saponins 1-3, with a quillaic acid as aglycon, were isolated from the roots of Silene fortunei together with a known phytoecdysteroid (20-hydroxyecdysone). The compounds were characterized mainly by a combination of 2D NMR techniques, mass spectrometry, and chemical methods. Saponins 1-3, jenisseensosides C and D (4, 5), and 6 (deacylated form of 2/3 and 4/5) were found to stimulate the proliferation of the Jurkat tumor cell lines at low concentration. At high concentration, 2/3 and 4/5 inhibited the proliferation of the cells and suggested the induction of apoptosis.
A halocin acting on Na+/H+ exchanger of Haloarchaea as a new type of inhibitor in NHE of mammals
2006
10 páginas, 3 figuras.
Flow cytometric kinetic assay of the activity of Na+/H+ antiporter in mammalian cells.
2004
Background The Na+/H+ exchanger (NHE) of mammalian cells is an integral membrane protein that extrudes H+ ion in exchange for extracellular Na+ and plays a crucial role in the regulation of intracellular pH (pHi). Thus, when pHi is lowered, NHE extrudes protons at a rate depending of pHi that can be expressed as pH units/s. Methods To abolish the activity of other cellular pH-restoring systems, cells were incubated in bicarbonate-free Dulbecco's modified Eagle's medium buffered with HEPES. Flow cytometry was used to determine pHi with 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester or 5-(and-6)-carboxy SNARF-1 acetoxymethyl ester acetate, and the appropriate fluo…
11H‑Pyrido[3′,2′:4,5]pyrrolo[3,2‑c]cinnoline and Pyrido[3′,2′:4,5]pyrrolo[1,2‑c][1,2,3]benzotriazine: Two New Ring Systems with Antitumor Activity
2014
Derivatives of new ring systems 11H-pyrido[3',2':4,5]pyrrolo[3,2-c]cinnoline and pyrido[3',2':4,5]pyrrolo[1,2-c][1,2,3]benzotriazine have been prepared from the key intermediates 2-(1H-pyrrolo[2,3-b]pyridin-2-yl)anilines in excellent yields (94-99%) and screened by the National Cancer Institute (Bethesda, MD) on about 60 human tumor cell lines derived from nine cancer cell types. The tested compounds exhibited antiproliferative activity against all the human cell lines, showing comparable MG_MID (mean graph midpoint) values in the range of 0.74-1.15 μM. A particular efficacy was observed against the leukemia subpanel (GI50 = 0.73-0.0090 μM). Flow cytometric analysis of the cell cycle demons…
Induction of apoptosis in a leukemia cell line by triterpene saponins from Albizia adianthifolia
2004
Abstract Triterpenoid saponins, which are present in plants and some marine animals, exert various important pharmacological effects. The present study examines the effects of adianthifoliosides A, B, and D (AdA, AdB, and AdD) together with two prosapogenins (Pro1 and Pro2) obtained from Albizia adianthifolia (Mimosaceae) on human leukemia T-cells (Jurkat cells) and on splenocytes. AdA, AdB, and AdD were found to exhibit a cytotoxic effect on Jurkat cells, whereas the prosapogenins were found to exert a lymphoproliferative effect on this cell type. Furthermore, all tested compounds were found to exert a synergistic lymphoproliferative activity with concanavalin A (ConA) on splenocytes. The …
Diacylglycerol-containing oleic acid induces increases in [Ca(2+)](i) via TRPC3/6 channels in human T-cells.
2011
Though most of the studies have focused on the effects of free fatty acids on T-cell activation, fatty acids incorporated into plasma membrane phospholipids may also affect cell signaling via diacylglycerol (DAG), generally produced by phospholipid hydrolysis. In the present study, we have synthesized a DAG-containing oleic acid and studied its implication in the modulation of calcium signaling in human Jurkat T-cells. 1-palmitoyl-2-oleoyl-sn-glycerol (POG) induced a dose-dependent increase in [Ca(2+)](i). This effect was due to the presence of oleic acid at the sn-2 position as no differences were observed between POG and 1-stearoly-2-oleoyl-sn-glycerol (SOG). However, the substitution of …