Search results for "messenger"
showing 10 items of 1493 documents
Liver X Receptor Regulates Arachidonic Acid Distribution and Eicosanoid Release in Human Macrophages
2013
Objective— Liver X receptors (LXRs) are oxysterol-activated nuclear receptors that are highly expressed in macrophages and regulate lipid homeostasis and inflammation. Among putative LXR target genes, lysophosphatidylcholine acyltransferase 3 (LPCAT3) involved in the Lands cycle controls the fatty acid composition at the sn-2 position of glycerophospholipids and, therefore, the availability of fatty acids, such as arachidonic acid (AA), used for eicosanoid synthesis. The aim of our study was to determine whether LXRs could regulate the Lands cycle in human macrophages, to assess the consequences in terms of lipid composition and inflammatory response, and to work out the relative contribut…
Mechanical ventilation and Streptococcus pneumoniae pneumonia alter mitochondrial homeostasis.
2018
Abstract Required mechanical ventilation (MV) may contribute to bacterial dissemination in patients with Streptococcus pneumoniae pneumonia. Significant variations in plasma mitochondrial DNA (mtDNA) have been reported in sepsis according to the outcome. The impact of lung stretch during MV was addressed in a model of pneumonia. Healthy or S. pneumoniae infected rabbits were submitted to MV or kept spontaneously breathing (SB). Bacterial burden, cytokines release, mitochondrial DNA levels, integrity and transcription were assessed along with 48-hour mortality. Compared with infected SB rabbits, MV rabbits developed more severe pneumonia with greater concentrations of bacteria in the lungs, …
A novel putative insect chitinase with multiple catalytic domains: hormonal regulation during metamorphosis
2002
0264-6021 (Print) Journal Article Research Support, Non-U.S. Gov't; We have used differential display to identify genes that are regulated by juvenile hormone in the epidermis of the beetle Tenebrio molitor. One of the genes encodes T. molitor chitinase 5 (TmChit5), a chitinase possessing an unusual structure. Sequence analysis of TmChit5 identified five 'chitinase units' of approx. 480 amino acids with similarity to chitinase family 18. These units are separated by less conserved regions containing putative PEST (rich in proline, glutamic acid, serine and threonine) sequences, putative chitin-binding domains and mucin domains. Northern-blot analysis identified a single transcript of approx…
Na+ dependent glutamate transporters (EAAT1, EAAT2, and EAAT3) in primary astrocyte cultures: effect of oxidative stress.
2001
Abstract The Na + -dependent l -glutamate transporters EAAT1(GLAST), EAAT2 (GLT-1) and EAAT3 (EAAC1) are expressed in primary astrocyte cultures, showing that the EAAT3 transporter is not neuron-specific. The presence of these three transporters was evaluated by RT–PCR, immunoblotting, immunocytochemical techniques, and transport activity. When primary astrocyte cultures were incubated with l -buthionine-( S , R )-sulfoximine (BSO), a selective inhibitor of γ-glutamylcysteine synthetase, the GSH concentration was significantly lower than in control cultures, but the expression and amount of protein of EAAT1, EAAT2 and EAAT3 and transport of l -glutamate was unchanged. Oxidative stress was c…
The Fibril-associated Collagen IX Provides a Novel Mechanism for Cell Adhesion to Cartilaginous Matrix
2004
Collagen IX is the prototype fibril-associated collagen with interruptions in triple helix. In human cartilage it covers collagen fibrils, but its putative cellular receptors have been unknown. The reverse transcription-PCR analysis of human fetal tissues suggested that based on their distribution all four collagen receptor integrins, namely alpha1beta1, alpha2beta1, alpha10beta1, and alpha11beta1, are possible receptors for collagen IX. Furthermore primary chondrocytes and chondrosarcoma cells express the four integrins simultaneously. Chondrosarcoma cells, as well as Chinese hamster ovary cells transfected to express alpha1beta1, alpha2beta1, or alpha10beta1 integrin as their only collage…
Transcription of α2 Integrin Gene in Osteosarcoma Cells Is Enhanced by Tumor Promoters
1998
Integrin alpha2beta1 is a heterodimeric transmembrane receptor for collagens. In osteogenic cells the expression of alpha2beta1 integrin is induced by both Kirsten sarcoma virus and chemical transformation. The association of alpha2 integrin with transformed cell phenotype was studied further by testing the effects of two tumor promoters, 12-O-tetradecanoylphorbol 13-acetate (TPA) and okadaic acid (OA), on human MG-63 osteosarcoma cells. TPA, an activator of protein kinase C, increased the cell surface expression of alpha2 integrin and the corresponding mRNA levels. Nuclear run-on assays indicated that TPA activated the transcription of alpha2 integrin gene. TPA also slightly increased the …
Induction of interferon regulatory factors, 2′‐5′ oligoadenylate synthetase, P68 kinase and RNase L in chronic myelogenous leukaemia cells and its re…
1996
The genes crucially determining the therapeutic response of chronic myelogenous leukaemia (CML) to interferon-alpha (IFN-alpha) are unknown. Recently, two independent IFN-alpha signalling pathways were identified: the classic pathway mediates induction of 2'-5' oligoadenylate synthetase (2-5 OAS), p68 kinase and IFN regulatory factor-2 (IRF-2), whereas the alternate pathway leads to activation of IFN regulatory factor-1 (IRF-1). We investigated whether deficient or imbalanced expression of components of these two pathways is associated with resistance of CML cells to antiproliferative action of IFN alpha/beta. Constitutive and IFN-induced transcript levels of IFN-dependent genes in mononucl…
Cyclic adenosine monophosphate is a key component of regulatory T cell–mediated suppression
2007
Naturally occurring regulatory T cells (T reg cells) are a thymus-derived subset of T cells, which are crucial for the maintenance of peripheral tolerance by controlling potentially autoreactive T cells. However, the underlying molecular mechanisms of this strictly cell contact–dependent process are still elusive. Here we show that naturally occurring T reg cells harbor high levels of cyclic adenosine monophosphate (cAMP). This second messenger is known to be a potent inhibitor of proliferation and interleukin 2 synthesis in T cells. Upon coactivation with naturally occurring T reg cells the cAMP content of responder T cells is also strongly increased. Furthermore, we demonstrate that natur…
Distribution and kinetics of superantigen-induced cytokine gene expression in mouse spleen.
1993
The polyclonal stimulation of T cells by bacterial superantigens is involved in the pathogenesis of the toxic shock syndrome in certain staphylococcal and streptococcal infections. Here we describe the onset and kinetics of superantigen-induced cytokine production in situ in spleens of normal BALB/c mice monitored at the level of cytokine mRNA expression by in situ hybridization. Messenger RNAs for interleukin 2 (IL-2), interferon gamma, and tumor necrosis factors (TNF) alpha and beta were not expressed at detectable levels in spleens of unstimulated animals but became visible already 30 min after intraperitoneal application of 50 micrograms staphylococcal enterotoxin B. All mRNA levels sho…
IL-13 receptor α 2: A regulator of IL-13 and IL-4 signal transduction in primary human fibroblasts
2005
Background IL-13 and IL-4 share many functional properties as a result of their use of a common receptor complex comprising IL-13 receptor α 1 (IL-13Rα1) and IL-4 receptor α (IL-4Rα). The nonsignaling receptor IL-13 receptor α 2 (IL-13Rα2) binds IL-13 with high affinity and specificity and is believed to be a decoy receptor for IL-13. Objective We sought to examine the inhibitory effects of soluble and membrane-bound IL-13Rα2 on IL-13– and IL-4–mediated effects. Methods Primary human fibroblasts were grown from endobronchial biopsy specimens obtained from volunteers. Upregulation of IL-13Rα2 mRNA was measured by means of RT-PCR, and the level of surface expression was measured by means of F…