Search results for "phospholipases"
showing 10 items of 106 documents
Effects of naturally occurring dihydroflavonols from Inula viscosa on inflammation and enzymes involved in the arachidonic acid metabolism
2007
Abstract The anti-inflammatory properties of three flavanones isolated from Inula viscosa , sakuranetin, 7- O -methylaromadendrin, and 3-acetyl-7- O -methylaromadendrin, have been tested both in vitro and in vivo. Acute inflammation in vivo was induced by means of topical application of 12- O -tetradecanoylphorbol 13-acetate (TPA) to mouse ears or by subcutaneous injection of phospholipase A 2 (PLA 2 ) into mouse paws. The test compounds were evaluated in vitro for their effect on both the metabolism of arachidonic acid and on the release and/or activity of enzymes involved in the inflammatory response such as elastase, myeloperoxidase (MPO), and protein kinase C (PKC). The most active comp…
Linkage studies of bipolar disorder in the region of the Darier's disease gene on chromosome 12q23-24.1.
1995
We have recently described a family in which there is cosegregation of major affective disorder with Darier's disease and have mapped this autosomal dominant skin disorder to 12q23-q24.1. This has provided an interesting candidate region for genetic studies of bipolar disorder. We have studied the segregation of seven markers spanning the Darier's disease locus in 45 bipolar disorder pedigrees and found modest evidence in support of linkage under heterogeneity for 5 of these markers. Nonparametric analyses were suggestive of linkage with a marker at the gene encoding a secretory form of phospholipase A2. Our sample has relatively low power to detect linkage under heterogeneity and independe…
A lytic mechanism based on soluble phospholypases A2 (sPLA2) and b-galactoside specific lectins is exerted by Ciona intestinalis (ascidian) unilocula…
2011
Abstract Hemocytes from the ascidian Ciona intestinalis exert in vitro Ca 2+ -dependent cytotoxic activity toward mammalian erythrocytes and K562 cells. To examine the lytic mechanism, hemocyte populations were separated (B1–B6 bands) through a Percoll discontinuous density gradient, the hemocyte cytotoxic activity (HCA) and the lytic activity of the hemocyte lysate supernatant (HLS) were assayed. In addition the separated hemocytes were cultured and the cell-free culture medium (CFM) assayed after 3 h culture. Results support that unilocular refractile hemocytes (URGs), enriched in B5, are cytotoxic. The B5-HLS contains lysins and the activity of B5-CFM shows that lysins can be released in…
Peroxisome proliferator-activated receptors as regulators of lipid metabolism; tissue differential expression in adipose tissues during cold acclimat…
2004
Brown (BAT) and white (WAT) adipose tissues play a key role in the body energy balance orchestrated by the central nervous system. Hibernators have developed a seasonal obesity to respond to inhospitable environment. Jerboa is one of the deep hibernator originated from sub-desert highlands. Thus, this animal represents an excellent model to study cold adaptation mechanism. We report that the adipogenic factor PPARgamma exhibits a differential expression between BAT and WAT at mRNA level. A specific induction was only seen in WAT of pre-hibernating jerboa. Interestingly, PPAR beta/delta is specifically induced in BAT and brain of pre-hibernating jerboa, highlighting for the first time the po…
Characterization of Acylating and Deacylating Activities of an Extracellular Phospholipase A2 in a Water-Restricted Environment
1994
The behavior of porcine pancreatic phospholipase A2 (ppPLA2) in monophasic low-water media has been explored, for the first time, in a systematic manner. It has been investigated how a number of variables can modulate both acylating and deacylating activities of the enzyme, and several interesting, unexpected results are presented. Among the most relevant, when placing ppPLA2 in the water-restricted environment, are the following: (i) it displays a remarkable alteration of its specificity toward the substrate polar head relative to all-water medium; (ii) it is quite severely inhibited by lysophosphatidylcholine (LPC), which has important implications, particularly concerning its acylation a…
Modulation of acute and chronic inflammatory processes by cacospongionolide B, a novel inhibitor of human synovial phospholipase A2.
1999
1. Cacospongionolide B is a novel marine metabolite isolated from the sponge Fasciospongia cavernosa. In in vitro studies, this compound inhibited phospholipase A2 (PLA2), showing selectivity for secretory PLA2 (sPLA2) versus cytosolic PLA2 (cPLA2), and its potency on the human synovial enzyme (group II) was similar to that of manoalide. 2. This activity was confirmed in vivo in the 8 h zymosan-injected rat air pouch, on the secretory enzyme accumulating in the pouch exudate. Cacospongionolide B, that is bioavailable when is given orally, reduced the elevated levels of sPLA2 present in paw homogenates of rats with adjuvant arthritis. 3. This marine metabolite showed topical anti-inflammator…
Inhibitory effect of nonviable preparations from human immunodeficiency virus 1 on inositol phospholipid metabolism
1989
Previously it was established [Pahwa, S., Pahwa, R., Saxinger, C., Gallo, R. C. & Good, R. A. (1985) Proc. Natl Acad. Sci. USA 82, 8198] that nonviable preparations of human immunodeficiency virus 1 (HIV-1) abolish the proliferative response of human lymphocytes to phytohemagglutinin A. Now we describe that this effect might be, at least partially, due to an impairment of the function of phospholipase C. It was found that addition of HIV-1 preparation to lymphocytes diminished the stimulation of phosphatidylinositol phosphorylation caused by phytohemagglutinin A. Moreover, this preparation completely abolished the phytohemagglutinin-A-stimulated release of inositol trisphosphate and prevent…
Signal transduction pathways involved in the mechanical responses to protease-activated receptors in rat colon.
2002
Recording simultaneously in vitro the changes of endoluminal pressure (index of circular muscle activity) and isometric tension (index of longitudinal muscle activity), we examined the mechanisms responsible for the apamin-sensitive relaxant and contractile responses induced by protease-activated receptor (PAR)-1 and PAR-2 activating peptides, SFLLRN-NH2 and SLIGRL-NH2, respectively, in rat colon. In the circular muscle, the inhibitory effects of SFLLRN-NH2 and SLIGRL-NH2 were significantly reduced by ryanodine, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, but unaffected by 1-[6-[[17beta-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122), a phosph…
Potassium regulates IL-1 beta processing via calcium-independent phospholipase A2.
2000
Abstract We report that potassium leakage from cells leads to activation of the Ca2+-independent phospholipase A2 (iPLA2), and the latter plays a pivotal role in regulating the cleavage of pro-IL-1β by the IL-converting enzyme caspase-1 in human monocytes. K+ efflux led to increases of cellular levels of glycerophosphocholine, an unambiguous indicator of phospholipase A2 activation. Both maturation of IL-1β and formation of glycerophosphocholine were blocked by bromoenol lactone, the specific iPLA2 inhibitor. Bromoenol lactone-dependent inhibition of IL-1β processing was not due to perturbation of the export machinery for pro-IL-1β and IL-1β or to caspase-1 suppression. Conspicuously, activ…
Release of choline in the isolated heart, an indicator of ischemic phospholipid degradation and its protection by ischemic preconditioning: No eviden…
2003
Abstract The release of choline as a water-soluble product of phospholipid hydrolysis was measured in the perfusate of rat hearts to monitor ischemic membrane degradation and its protection by ischemic preconditioning (IPC). Hearts were subjected to global ischemia (GI; 30 min of no-flow) followed by 60 min of reperfusion. To induce IPC, GI was preceded by four no-flow episodes of 5 min each. Deleterious consequences of GI and reperfusion, namely coronary flow reduction, incidence of arrhythmias and release of cardiac troponin T, were significantly attenuated by IPC. The release of choline increased during reperfusion in a biphasic manner: a first phase peaked immediately after GI and was f…