Kinin B2 receptor regulates chemokines CCL2 and CCL5 expression and modulates leukocyte recruitment and pathology in experimental autoimmune encephalomyelitis (EAE) in mice

BACKGROUND: Kinins are important mediators of inflammation and act through stimulation of two receptor subtypes, B1 and B2. Leukocyte infiltration contributes to the pathogenesis of autoimmune inflammation in the central nervous system (CNS), occurring not only in multiple sclerosis (MS) but also in experimental autoimmune encephalomyelitis (EAE). We have previously shown that the chemokines CCL2 and CCL5 play an important role in the adhesion of leukocytes to the brain microcirculation in EAE. The aim of the present study was to evaluate the relevance of B2 receptors to leukocyte-endothelium interactions in the cerebral microcirculation, and its participation in CNS inflammation in the experimental model of myelin-oligodendrocyte-glycoprotein (MOG)35-55-induced EAE in mice. METHODS: In order to evaluate the role of B2 receptor in the cerebral microvasculature we used wild-type (WT) and kinin B2 receptor knockout (B2-/-) mice subjected to MOG35-55-induced EAE. Intravital microscopy was used to investigate leukocyte recruitment on pial matter vessels in B2-/- and WT EAE mice. Histological documentation of inflammatory infiltrates in brain and spinal cords was correlated with intravital findings. The expression of CCL5 and CCL2 in cerebral tissue was assessed by ELISA. RESULTS: Clinical parameters of disease were reduced in B2-/- mice in comparison to wild type EAE mice. At day 14 after EAE induction, there was a significant decrease in the number of adherent leukocytes, a reduction of cerebral CCL5 and CCL2 expressions, and smaller inflammatory and degenerative changes in B2-/- mice when compared to WT. CONCLUSION: Our results suggest that B2 receptors have two major effects in the control of EAE severity: (i) B2 regulates the expression of chemokines, including CCL2 and CCL5, and (ii) B2 modulates leukocyte recruitment and inflammatory lesions in the CNS

Role of bradykinin B2 and B1 receptors in the local, remote, and systemic inflammatory responses that follow intestinal ischemia and reperfusion injury

The administration of bradykinin may attenuate ischemia and reperfusion (I/R) injury by acting on B2Rs. Blockade of B2R has also been shown to ameliorate lesions associated with I/R injury. In an attempt to explain these contradictory results, the objective of the present work was to investigate the role of and interaction between B1 and B2 receptors in a model of intestinal I/R injury in mice. The bradykinin B 2R antagonist (HOE 140) inhibited reperfusion-induced inflammatory tissue injury and delayed lethality. After I/R, there was an increase in the expression of B1R mRNA that was prevented by HOE 140. In mice that were deficient in B1Rs (B1R-/- mice), inflammatory tissue injury was abrogated, and lethality was delayed and partially prevented. Pretreatment with HOE 140 reversed the protective anti-inflammatory and antilethality effects provided by the B1R -/- phenotype. Thus, B2Rs are a major driving force for B1R activation and consequent induction of inflammatory injury and lethality. In contrast, activation of B2Rs may prevent exacerbated tissue injury and lethality, an effect unmasked in B1R-/- mice and likely dependent on the vasodilatory actions of B2Rs. Blockade of B1Rs could be a more effective strategy than B 2 or B1/B2 receptor blockade for the treatment of the inflammatory injuries that follow I/R

Transcriptional regulation of the rat bradykinin B2 receptor gene: Identification of a silencer element

Kinins are involved in a variety of physiological and pathophysiological processes related to cardiovascular homeostasis, inflammation, blood flow, and nociception. Under physiological conditions, the bradykinin B2 (BKB2) receptor is constitutively expressed and mediates most of kinins' actions. However, the mechanisms regulating BKB2 receptor gene expression are still poorly understood. In this study, 4.6 kilobases of the 5′-flanking region from the rat BKB2 receptor gene were sequenced, and computer analysis revealed several sites for transcriptional factors. Nine promoter mutants were cloned in luciferase reporter gene vectors and transfected in NG108-15 cells and rat aorta vascular smooth muscle cells (VSMCs), showing several positive and negative regulatory elements. A classical silencer with 56 base pairs (bp) caused a decrease in reporter gene activity in NG108-15 cells and VSMCs and was able to inhibit the thymidine kinase promoter. Using electrophoretic mobility shift assay and surface plasmon resonance assay, protein-DNA interactions in the silencer region were determined and specific sets of protein-silencer complexes were detected in both cell types. More intense complexes were observed in the central 21 bp of the silencer and mutation in a putative SRE-1 site strongly impaired the protein-DNA binding. Down-regulation of the BKB2 receptor population in NG108-15 cells promoted by N6, 2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate was paralleled by an increase in the amount of nuclear proteins bound to the silencer sequence showing an inverse relationship between protein-silencer complexes and the transcription of the BKB2 receptor gene. In summary, these data highlight the cell-specific regulation of the BKB2 receptor and the importance of a silencer element present in the regulatory region of the gene

Molecular cloning and functional characterization of a mouse bradykinin B1 receptor gene

The gene encoding a putative mouse bradykinin B1 receptor was cloned from a genomic library by low stringency screening. Analysis of two isolated clones revealed a region which contains an open reading frame uninterrupted by introns and encodes a 334 amino acid protein, which exhibits seven potential transmembrane domains and is 68% identical to the human and rabbit bradykinin B1 receptors, Lipopolysaccharide-treatment induces B1 receptor transcripts in the heart, liver and lung, Stable expression of the coding region in COS-7 cells resulted in high levels of binding sites for the specific B1 ligand des-Arg(10) kallidin (K-d = 1.3 nM; B-max = 51 fmol/mg protein). the rank order of affinity of the receptor for the agonists and antagonists was: des Arg(9)BKdes-Arg(9)Leu(8)BKdrs-Arg(10)kallidin much greater than Hoe-140 = bradykinin. Functional coupling of the cloned receptor was demonstrated by the dose-dependent effect of des-Arg(9)BK on the extracellular acidification rate in stably transfected COS-7 cells. This effect was not produced by bradykinin and could be blocked by the B1 antagonist des-Arg(9)Leu(8)BK. (C) 1996 Academic Press, Inc.MAX DELBRUCK CTR MOLEC MED,D-13125 BERLIN,GERMANYESCOLA PAULISTA MED,DEPT BIOPHYS,BR-04032062 São Paulo,BRAZILUNIV FED MINAS GERAIS,ICB,DEPT PHYSIOL & BIOPHYS,BR-31270010 BELO HORIZONT,MG,BRAZILUNIV MUNICH,CHILDRENS HOSP,DEPT CLIN CHEM & BIOCHEM,D-80337 MUNICH,GERMANYCELL CONTROL BIOMED LABS,D-82152 MARTINSRIED,GERMANYESCOLA PAULISTA MED,DEPT BIOPHYS,BR-04032062 São Paulo,BRAZILWeb of Scienc

Oklahoma Neuigkeiten

Weekly German newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising

High expression of human carboxypeptidase M in Pichia pastoris: Purification and partial characterization

Carboxypeptidase M (CPM) is an extracellular glycosylphosphatidyl-inositol-anchored membrane glycoprotein, which removes the C-terminal basic residues, lysine and arginine, from peptides and proteins at neutral pH. CPM plays an important role in the control of peptide hormones and growth factor activity on the cell surface. The present study was carried out to clone and express human CPM in the yeast Pichia pastoris in order to evaluate the importance of this enzyme in physiological and pathological processes. The cDNA for the enzyme was amplified from total placental RNA by RT-PCR and cloned in the vector pPIC9, which uses the methanol oxidase promoter and drives the expression of high levels of heterologous proteins in P. pastoris. The cpm gene, after cloning and transfection, was integrated into the yeast genome, which produced the active protein. The recombinant protein was secreted into the medium and the enzymatic activity was measured using the fluorescent substrate dansyl-Ala-Arg. The enzyme was purified by a two-step protocol including gel filtration and ion-exchange chromatography, resulting in a 1753-fold purified active protein (16474 RFU mg protein-1 min-1). This purification protocol permitted us to obtain 410 mg of the purified protein per liter of fermentation medium. SDS-PAGE showed that recombinant CPM migrated as a single band with a molecular mass similar to that of native placental enzyme (62 kDa), suggesting that the expression of a glycosylated protein had occurred. These results demonstrate for the first time the establishment of a method using P. pastoris to express human CPM necessary to the development of specific antibodies and antagonists, and the analysis of the involvement of this peptidase in different physiological and pathological processe

High expression of human carboxypeptidase M in Pichia pastoris: Purification and partial characterization

Carboxypeptidase M (CPM) is an extracellular glycosylphosphatidyl-inositol-anchored membrane glycoprotein, which removes the C-terminal basic residues, lysine and arginine, from peptides and proteins at neutral pH. CPM plays an important role in the control of peptide hormones and growth factor activity on the cell surface. The present study was carried out to clone and express human CPM in the yeast Pichia pastoris in order to evaluate the importance of this enzyme in physiological and pathological processes. The cDNA for the enzyme was amplified from total placental RNA by RT-PCR and cloned in the vector pPIC9, which uses the methanol oxidase promoter and drives the expression of high levels of heterologous proteins in P. pastoris. The cpm gene, after cloning and transfection, was integrated into the yeast genome, which produced the active protein. The recombinant protein was secreted into the medium and the enzymatic activity was measured using the fluorescent substrate dansyl-Ala-Arg. The enzyme was purified by a two-step protocol including gel filtration and ion-exchange chromatography, resulting in a 1753-fold purified active protein (16474 RFU mg protein-1 min-1). This purification protocol permitted us to obtain 410 mg of the purified protein per liter of fermentation medium. SDS-PAGE showed that recombinant CPM migrated as a single band with a molecular mass similar to that of native placental enzyme (62 kDa), suggesting that the expression of a glycosylated protein had occurred. These results demonstrate for the first time the establishment of a method using P. pastoris to express human CPM necessary to the development of specific antibodies and antagonists, and the analysis of the involvement of this peptidase in different physiological and pathological processe

Feasibility Study of SrRuO3/SrTiO3/SrRuO3 Thin Film Capacitors in DRAM Applications

Tonin is a serine proteinase of the kallikrein family able to produce angiotensin II directly from angiotensinogen. In order to clarify the importance of this enzyme for the central nervous control of the cardiovascular system, we have generated transgenic mice, TGM(rTon), which express rat tonin in astrocytes. These mice present high levels of tonin mRNA and activity specifically in the brain. As a consequence, TGM(rTon) develop increased blood pressure and water intake. Lisinopril, an ACE inhibitor, is less hypotensive for transgenic mice than for control animals. The AT(1) receptor antagonist candesartan equally lowers blood pressure in transgenic and in control mice. Plasma angiotensin II, but not angiotensin I, is increased in TGM(rTon) as compared to the wild type suggesting a release of the peptide from the brain into the circulation. However, AT(1) receptors are desensitized in this transgenic model as shown by a blunted pressor response to intravenous application of angiotensin II. In conclusion, tonin in the brain may represent an alternative pathway to generate angiotensin II with effects on the cardiovascular system