Murine and human autotaxin alpha, beta, and gamma isoforms: gene organization, tissue distribution, and biochemical characterization.

Autotaxin is a type II ectonucleotide pyrophosphate phosphodiesterase enzyme. It has been recently discovered that it also has a lysophospholipase D activity. This enzyme probably provides most of the extracellular lysophosphatidic acid from lysophosphatidylcholine.

Cellular knock-down of quinone reductase 2: a laborious road to successful inhibition by RNA interference.

NRH:quinone oxidoreductase 2 (QR2) is a long forgotten oxidoreductive enzyme that metabolizes quinones and binds melatonin. We used the potency of the RNA interference (RNAi)-mediated gene silencing to build a cellular model in which the role of QR2 could be studied. Because standard approaches were poorly successful, we successively used: (1) two chemically synthesized fluorescent small interfering RNA (siRNA) duplexes designed and tested for their gene silencing capacity leading to a maximal 40% QR2 gene silencing 48h post-transfection; (2) double transfection and cell-sorting of high fluorescent siRNA-transfected HT22 cells further enhancing QR2 RNAi silencing to 88%; (3) stable QR2 knock-down HT22 cell lines established with H1and U6 promoter driven QR2 short hairpin RNA (shRNA) encoding vectors, resulting in a 71-80% reduction of QR2 enzymatic activity in both QR2 shRNA HT22 cells.

Comment on "Obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's effects on food intake".

Zhang et al. (Research Articles, 11 November 2005, p. 996) reported that obestatin, a peptide derived from the ghrelin precursor, activated the orphan G protein-coupled receptor GPR39.

Use-dependent inhibition of hHCN4 by ivabradine and relationship with reduction in pacemaker activity.

Background And Purpose: Ivabradine, a specific and use-dependent I(f) inhibitor, exerts anti-ischaemic activity purely by reducing heart rate. The aim of this work was to characterize its effect on the predominant HCN channel isoform expressed in human sino-atrial nodes (hSAN), to determine its kinetics in HCN channels from multicellular preparations and rate-dependency of its action.

Experimental Approach: RT-PCR analysis of the four HCN channel isoforms was carried out on RNAs from hSAN.

Novel 1,3-dicarbonyl compounds having 2(3H)-benzazolonic heterocycles as PPARgamma agonists.

A series of 1,3-dicarbonyl compounds having 2(3H)-benzazolonic heterocycles has been synthesized and tested for PPARgamma agonist activity. SAR were developed and revealed that 6-acyl-2(3H)-benzothiazolone derivatives with 1,3-dicarbonyl group were the most potent. IP administration of compound 22 exhibited comparable levels of glucose and triglyceride correction to PO administration of rosiglitazone in the ob/ob mouse studies.

The use of IRES-based bicistronic vectors allows the stable expression of recombinant G-protein coupled receptors such as NPY5 and histamine 4.

Stable expression of G protein coupled receptors in cell lines is a crucial tool for the characterization of the molecular pharmacology of receptors and the screening for new antagonists. However, in some instances, many difficulties have been encountered to obtain stable cell lines expressing functional receptors. Here, we addressed the question of vector optimization to establish cell lines expressing the human neuropeptide Y receptor 5 (NPY5-R) or histamine receptor 4 (HH4R).

Characterization of the melatoninergic MT3 binding site on the NRH:quinone oxidoreductase 2 enzyme.

Melatonin acts through a series of molecular targets: the G-protein coupled receptors, MT1 and MT2, and a third binding site, MT3, recently identified as the enzyme NRH:quinone oxydoreductase 2 (QR2). The relationship between the multiple physiological functions of melatonin and this enzyme remains unclear. Because of the relationship of QR2 with the redox status of cells, these studies could bring the first tools for a molecular rationale of the antioxidant effects of melatonin.

Molecular evidence that melatonin is enzymatically oxidized in a different manner than tryptophan: investigations with both indoleamine 2,3-dioxygenase and myeloperoxidase.

The catabolism of melatonin, whether naturally occurring or ingested, takes place via two pathways: approximately 70% can be accounted for by conjugation (sulpho- and glucurono-conjugation), and approximately 30% by oxidation. It is commonly thought that the interferon-induced enzyme indoleamine 2,3-dioxygenase (EC 1.13.

Functional characterization of human neuropeptide Y receptor subtype five specific antagonists using a luciferase reporter gene assay.

Neuropeptide Y (NPY) has several receptors; one of them, the neuropeptide Y5 receptor (NPY5) seems involved in feeding behavior in mammals. Although this particular receptor has been extensively studied in the literature, the difficulties encountered to obtain a stable cell line expressing this recombinant receptor have impaired the development of tools necessary to establish its molecular pharmacology. We thus established a method for the functional study of new ligands.

TNF skews monocyte differentiation from macrophages to dendritic cells.

Monocytes represent a large pool of circulating precursors of APCs, both macrophages and dendritic cells (DCs). It is thus important to identify the mechanisms by which microenvironment regulates monocyte differentiation. We have previously shown that, upon contact with resting stromal cells such as fibroblasts, monocytes differentiate into macrophages in an IL-6/M-CSF-dependent fashion.

Autotaxin is released from adipocytes, catalyzes lysophosphatidic acid synthesis, and activates preadipocyte proliferation. Up-regulated expression with adipocyte differentiation and obesity.

Our group has recently demonstrated (Gesta, S., Simon, M., Rey, A.

IL-6 switches the differentiation of monocytes from dendritic cells to macrophages.

Monocytes can give rise to either antigen presenting dendritic cells (DCs) or scavenging macrophages. This differentiation is initiated when monocytes cross the endothelium. But the regulation of DC and macrophage differentiation in tissues remains elusive.

In breast carcinoma tissue, immature dendritic cells reside within the tumor, whereas mature dendritic cells are located in peritumoral areas.

We have analyzed the presence of immature and mature dendritic cells (DCs) within adenocarcinoma of the breast using immunohistochemistry. Immature DCs were defined by expression of CD1a-, Langerin-, and intracellular major histocompatibility complex class II-rich vesicles. Mature DCs were defined by expression of CD83 and DC-Lamp.

Hepatitis B virus-induced liver injury and altered expression of carcinogen metabolising enzymes: the role of the HBx protein.

Hepatitis B virus (HBV) and aflatoxins are major risk factors for hepatocellular carcinoma (HCC) exhibiting a synergistic interaction in the development of this disease. The molecular mechanisms of this interaction remain to be elucidated but an altered carcinogen metabolism in the presence of hepatitis-induced liver injury is one hypothesis. The availability of biomarkers of aflatoxin exposure and metabolism permits this hypothesis to be examined in human populations whilst animal models, such as HBV transgenic mice permit parallel studies in an experimental setting.

Interleukin-4 and interleukin-13: their similarities and discrepancies.

Interleukin-4 (IL-4) and the closely related cytokine, interleukin-13 (IL-13) share many biological and immunoregulatory functions on B lymphocytes, monocytes, dendritic cells and fibroblasts. Both IL-4 and IL-13 genes are located in the same vicinity on chromosome 5 and display identical major regulatory sequences in their respective promoters, thus explaining their restricted secretion pattern to activated T cells and mast cells. The IL-4 and IL-13 receptors are multimeric and share at least one common chain called IL-4R alpha.

An update on interleukin-4 and its receptor.

Interleukin-4 (IL-4) exhibits many biological and immunoregulatory functions on B lymphocytes, monocytes, dendritic cells and fibroblasts. The IL-4 gene is located on chromosome 5 and displays several cell-specific regulatory sequences in its promoter, which explain its restricted secretion pattern to activated T cells and mast cells. The IL-4 receptor is multimeric and is constituted by at least IL-4Ralpha, a chain common to other cytokine receptors.

Distinct time courses of increase in cytochromes P450 1A2, 2A5 and glutathione S-transferases during the progressive hepatitis associated with Helicobacter hepaticus.

Mice naturally infected by Helicobacter hepaticus develop a chronic active hepatitis leading to hepatocellular carcinoma. This mouse model of liver cancer was used to examine the impact of bacterial infection on the hepatic expression and activity of enzymes involved in carcinogen bioactivation (phase I enzymes) and detoxification (phase II enzymes). No major differences in total cytochrome P450 (CYP) content were found between control and infected mice during the course of the study.

Increased oxidative DNA damage and hepatocyte overexpression of specific cytochrome P450 isoforms in hepatitis of mice infected with Helicobacter hepaticus.

A recently discovered bacterium, Helicobacter hepaticus, infects the intrahepatic bile canaliculi of mice, causing a severe chronic hepatitis culminating in liver cancer. Thus, it affords an animal model for study of bacteria-associated tumorigenesis including H. pylori-related gastric cancer.

The functional CD40 antigen of fibroblasts may contribute to the proliferation of rheumatoid synovium.

This paper demonstrates that CD40 is expressed on rheumatoid synovial pannus and primary fibroblast cell lines established from rheumatoid and osteoarthritic synovium as well as normal skin. Among various tested cytokines, interferon-gamma (IFN-gamma) and to a lower extent, tumour necrosis factor-alpha (TNF-alpha) were found to upregulate CD40 expression on fibroblasts. Synovial and skin fibroblasts cultured over CD40 Ligand transfected L cells (L-CD40 L) demonstrate a CD40 specific increase of DNA synthesis as measured by tritiated thymidine incorporation.

T cell interleukin-17 induces stromal cells to produce proinflammatory and hematopoietic cytokines.

Analysis of the cDNA encoding murine interleukin (IL) 17 (cytotoxic T lymphocyte associated antigen 8) predicted a secreted protein sharing 57% amino acid identity with the protein predicted from ORF13, an open reading frame of Herpesvirus saimiri. Here we report on the cloning of human IL-17 (hIL-17), the human counterpart of murine IL-17. hIL-17 is a glycoprotein of 155 amino acids secreted as an homodimer by activated memory CD4+ T cells.

Contribution of IL-1, CD14, and CD13 in the increased IL-6 production induced by in vitro monocyte-synoviocyte interactions.

Rheumatoid synovitis is characterized by an infiltration of mononuclear cells and by the proliferation of synoviocytes. Monocytes and synoviocytes are major producers of cytokines, growth factors, and enzymes that contribute to the rheumatoid arthritis (RA) process. Since they are in close contact in vivo, we engaged in an in vitro study of the functional consequences of their interactions.

Differential effects of interleukins 10 and 4 on the production of interleukin-6 by blood and synovium monocytes in rheumatoid arthritis.

Objective: To determine how the antiinflammatory cytokines interleukin-10 (IL-10) and IL-4 affect the production of IL-6 in rheumatoid arthritis (RA) and to assess the contribution of IL-10 production.

Methods: IL-6 production was measured by enzyme-linked immunosorbent assay (ELISA) in the supernatants of cultured RA synovium pieces (from 23 patients), purified RA synovial tissue monocyte/macrophages, and RA blood monocytes, in the presence of IL-10 and IL-4. IL-10 was also detected by ELISA in culture supernatants and in RA sera.

The primary binding subunit of the human interleukin-4 receptor is also a component of the interleukin-13 receptor.

Interleukin (IL)-13 elicits a subset of the biological activities of the related IL-4. The basis of this functional similarity is that their specific cell-surface receptors (called IL-13R and IL-4R) are distinct, yet are complex and share a common subunit(s). The IL-4R primary binding subunit (called IL-4R alpha) does not by itself bind IL-13.

Balance of IL-1 receptor antagonist/IL-1 beta in rheumatoid synovium and its regulation by IL-4 and IL-10.

The spontaneous production of IL-1 beta (IL-1 beta) and IL-1 receptor antagonist (IL-1Ra) by rheumatoid arthritis (RA) synovium, and the regulation of their production by IL-4 and IL-10, were studied. Supernatants from cultured synovium pieces from 19 RA patients were assayed for IL-1 beta and IL-1Ra production using ELISA and RIA, respectively. After 10 days of culture, spontaneous production of IL-1Ra was 1.