Search results for "Cyclase"
showing 10 items of 141 documents
Soluble guanylyl cyclase appears in a specific subset of periglomerular cells in the olfactory bulb
2005
In the brain, nitric oxide acts as an atypical messenger in cellular nonsynaptic transmission. In the olfactory bulb, this gas is produced at the level of the olfactory glomeruli by a subpopulation of periglomerular cells that participates in the first synaptic relay of the olfactory information between the olfactory nerve and the dendritic tufts of principal cells. It has been proposed that nitric oxide modulates intraglomerular synaptic integration of sensory inputs, but its specific role in the glomerular circuitry remains to be understood. In this article, we demonstrate that, in the glomerular circuits, a specific subset of periglomerular cells, most of them expressing the calcium bind…
CD38/CD31, the CCL3 and CCL4 chemokines, and CD49d/vascular cell adhesion molecule-1 are interchained by sequential events sustaining chronic lymphoc…
2009
AbstractCD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Despite evidence that both molecules are involved in interactions occurring between CLL and normal cells in the context of CLL-involved tissues, a functional link is still missing. Using gene expression profiles comparing CD38+CD49d+ versus CD38−CD49d− CLL cells, we showed overexpression of the CCL3 and CCL4 chemokines in cells from the former group. These chemokines were also up-regulated by CD38 signals in CLL; moreover, CCL3 was expressed by CLL cells from bone marrow biopsies (BMB) of CD38+CD49d+ but not CD38−CD49d− cases. High levels of CCR1 and, to a lesser extent, CCR5, the receptors…
Optimization of retroviral-mediated gene transfer to human NOD/SCID mouse repopulating cord blood cells through a systematic analysis of protocol var…
1999
Abstract Retroviral transduction of human hematopoietic stem cells is still limited by lack of information about conditions that will maximize stem cell self-renewal divisions in vitro. To address this, we first compared the kinetics of entry into division of single human CD34 + CD38 − cord blood (CB) cells exposed in vitro to three different flt3-ligand (FL)-containing cytokine combinations. Of the three combinations tested, FL + hyperinterleukin 6 (HIL-6) yielded the least clones and these developed at a slow rate. With either FL + Steel factor (SF) + HIL-6 + thrombopoietin (TPO) or FL + SF + interleukin 3 (IL-3) + IL-6 + granulocyte-colony-stimulating factor (G-CSF), >90% of the cells th…
Mechanisms of Increased Vascular Superoxide Production in an Experimental Model of Idiopathic Dilated Cardiomyopathy
2005
Objective— In the present study, we sought to identify mechanisms underlying increased oxidative stress in vascular tissue in an experimental animal model of chronic congestive heart failure (CHF). Methods and Results— Superoxide and nitric oxide (NO) was measured in vessels from cardiomyopathic hamsters (CHF hamsters) and golden Syrian hamsters. We also determined expression of endothelial nitric oxide synthase (NOSIII), the soluble guanylyl cyclase, the cGMP-dependent kinase, and the NADPH oxidase. To analyze the contribution of the renin-angiotensin system to oxidative stress, CHF hamsters were treated with the angiotensin-converting enzyme inhibitor captopril for 200 days (120 mg · kg …
Current knowledge of pituitary adenylate cyclase activating polypeptide (PACAP) in articular cartilage
2020
Pituitary adenylate cyclase activating polypeptide (PACAP) is an evolutionally well conserved neuropeptide, mainly expressed by neuronal and peripheral cells. It proves to be an interesting object of study both for its trophic functions during the development of several tissues and for its protective effects against oxidative stress, hypoxia, inflammation and apoptosis in different degenerative diseases. This brief review summarises the recent findings concerning the role of PACAP in the articular cartilage. PACAP and its receptors are expressed during chondrogenesis and are shown to activate the pathways involved in regulating cartilage development. Moreover, this neuropeptide proves to be…
Purification and characterization of two exopolyphosphatases from the marine sponge Tethya lyncurium
1995
Abstract Two exopolyphosphatases (exopolyphosphatase I and II; EC 3.6.1.11) which release orthophosphate from inorganic polyphosphates have been detected and purified for the first time from a marine sponge, Tethya lyncurium . Exopolyphosphatase I has a molecular mass of 45 kDa, a pH optimum of 5.0 and does not require divalent cations for activity, while exopolyphosphatase II has a molecular mass of 70 kDa, a pH optimum of 7.5 and displays optimal activity in the presence of Mg 2+ ions. Final purification of the enzymes could be achieved by affinity chromatography on polyphosphate-modified zirconia. The mode of action of both enzymes was found to be processive. Orthophosphate is the sole p…
Regulation of cyclooxygenase-2 expression by cyclic AMP.
2007
Abstract Prostaglandins (PG) regulate many biological processes, among others inflammatory reactions. Cyclooxygenases-1 and -2 (COX-1 and COX-2) catalyse PG synthesis. Since this step is rate limiting, the regulation of COX expression is of critical importance to PG biology. Contrary to COX-1, which is constitutively expressed, COX-2 expression is subject to regulation. For example, COX-2 levels are increased in inflammatory reactions. Many signalling pathways can regulate COX-2 expression, not least those involving receptors for COX products themselves. Analysis of the intracellular signal transducers involved reveals a crucial role for cAMP, albeit as a modulator rather than direct induce…
Hypothalamic S-Nitrosylation Contributes to the Counter-Regulatory Response Impairment following Recurrent Hypoglycemia
2013
http://www.ncbi.nlm.nih.gov/pubmed/23894333; International audience; AIMS: Hypoglycemia is a severe side effect of intensive insulin therapy. Recurrent hypoglycemia (RH) impairs the counter-regulatory response (CRR) which restores euglycemia. During hypoglycemia, ventromedial hypothalamus (VMH) production of nitric oxide (NO) and activation of its receptor soluble guanylyl cyclase (sGC) are critical for the CRR. Hypoglycemia also increases brain reactive oxygen species (ROS) production. NO production in the presence of ROS causes protein S-nitrosylation. S-nitrosylation of sGC impairs its function and induces desensitization to NO. We hypothesized that during hypoglycemia, the interaction b…
Evolutionary analysis of G-proteins in early metazoans: Cloning of α- and β-subunits from the sponge Geodia cydonium1The sequences reported here have…
1998
G-protein-coupled (seven-transmembrane segment)-receptors represent a major group of metazoan receptors, involved in transduction of extracellular signals. The G-proteins, which are made up of Galpha/beta/gamma-subunits, link the receptors to the effector system(s). To analyze the phylogenetic relationships among the metazoan alpha-subunits of G-proteins, cDNAs of alpha-subunits were isolated from Geodia cydonium, a marine sponge belonging to the lowest metazoan phylum, Porifera. One encodes a putative isotype of a stimulator of the adenylyl cyclase (Galpha s), another one a putative inhibitor of the adenylyl cyclase (Galpha i/o) and the third one a putative activator of phospholipase C (Ga…
Coexpression of inducible NO synthase and soluble guanylyl cyclase in colonic enterocytes: a pathophysiologic signaling pathway for the initiation of…
1998
Infectious diarrhea is often caused by the exotoxins of gram-negative bacteria such as Escherichia coli. However, these organisms also contain lipopolysaccharide (LPS) endotoxin. LPS induces nitric oxide synthase II (NOS II, inducible NOS) in various types of cells. We now demonstrate by RNase protection analysis, Western blot, and immunohistochemistry that the expression of NOS II mRNA and protein is markedly induced in colonic enterocytes of mice that ingest LPS with their drinking water. Using the same techniques, significant levels of soluble guanylyl cyclase (GC-S), the effector enzyme of NO, were found constitutively expressed in the mucosa. This creates a pathophysiologic autocrine p…