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Results for “Prostaglandin D2 synthase”

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PubMed2025

iTRAQ-based quantitative proteomics reveals reduced expression of KRT19, KRT7, and PSTDG in cutaneous specimens after kidney transplantation.

Clinical improvement in pigmentation is frequently observed after kidney transplantation. However, the underlying molecular and histological mechanisms remain unclear. We conducted a study to quantify the skin color change using a handheld reflected light colorimeter and to investigate protein expression changes in the skin before and after kidney transplantation. Paired skin biopsies were obtained from three patients who underwent kidney transplantation before and one month after transplantation. Protein expression was analyzed using iTRAQ-based quantitative proteomics. Differentially expressed proteins were identified and visualized using hierarchical clustering and volcano plots. Histopathological evaluation included hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemical (IHC) staining for keratin (KRT) 7, KRT19, and MelanA. Skin pigmentation of the arms, ankles, and abdomen had significant L-value improvement after kidney transplantation. Proteomic profiling identified 2148 proteins, with six proteins showing significant differential expression after transplantation. Among them, KRT7, KRT19, and prostaglandin D2 synthase (PTGDS) were significantly downregulated, potentially reflecting reduced epithelial stress and systemic inflammation. H&E and Masson's trichrome staining revealed a post-transplantation reduction in dermal pigmentation and collagen content. IHC showed decreased KRT7, KRT19, and MelanA expression after transplantation. Our results suggest that targeting KRT or prostaglandin pathways may offer new treatments for ESRD-related skin symptoms.

Humans↗
PubMed1976

Biosynthesis of prostaglandins in rabbit kidney medulla. Properties of prostaglandin synthase.

A simple radioactive-substrate assay for prostaglandin synthase (EC 1.14.99.1), which uses t.l.c. to measure simultaneously different prostaglandins synthesized from one precursor substrate, was developed. Rabbit kidney-medulla prostaglandin synthase catalyses the formation of prostaglandin E2, prostaglandin F2alpha and prostaglandin D2 from arachidonic acid. Fractionation of crude homogenates indicated that the microsomal fraction possessed the highest specific activity of prostaglandin synthase, whereas the soluble fraction exhibited little enzyme activity but rather contained a heat-labile inhibitory macromolecular factor(s), which might be attributed to the serum albumin present in this fraction. The microsomal fraction possessed low intrinsic enzyme activity, but the actvity could be fully stimulated by the presence of both GSH (reduced glutathione) and a phenolic cofactor. Only cysteine could partially replace GSH, whereas other thiols were inactive and some were even inhibitory. A variety of phenolic compounds, including catecholamines, dopamine (3,4-dihydroxyphenethylamine), 5-hydroxytryptamine and quinol, were active in stimulating prostaglandin synthase. In all cases, the stimulation was reflected in the synthesis of all three prostaglandins with ratios not significantly altered by different phenolic cofactors. The synthesis of each of the different prostaglandins appeared to have similar pH optima. The enzyme system was not inhibited by thiol-group inhibitors or a variety of metal chelators except for cyanide and 8-hydroxyquinoline. Characterization of the kidney-medulla prostaglandin synthase system indicated that it exhibited properties similar to those of the enzyme system present in seminal vesicles.

Animals↗
PubMed1978

Further studies on the enzymatic conversion of prostaglandin endoperoxide into prostacyclin by porcine aorta microsomes.

A simple, rapid radiochemical assay for prostacyclin synthesis has been used to characterize the enzyme in arterial walls which converts prostaglandin endoperoxides to prostacyclin. The enzyme displays a broad pH optimum, and catalyses a rapid conversion of saturating concentrations of the endoperoxide at 37 degrees C. Hydroperoxides of several unsaturated fatty acids are potent inhibitors of the enzyme, and act in a time dependent manner. The isomerase which converts prostaglandin endoperoxides to prostaglandin E2 or D2 was not detected in the arterial wall.

Animals↗
PubMed1979

Synthesis and biological properties of pinane-thromboxane A2, a selective inhibitor of coronary artery constriction, platelet aggregation, and thromboxane formation.

Pinane-thromboxane A2 (PTA2, [1alpha,2 beta(Z),-3 alpha (1E,3R*),5 alpha]-7-(3-(3-hydroxy-1-octenyl)-6,6-dimethylbicyclo[3.1.1]hept-2-yl)-5-heptenoic acid) has been synthesized and tested for biological activity in systems responsive to thromboxane A2, stable prostaglandin endoperoxide (PGH2) analogs, and prostatacyclin (PGI2). At low concentrations, PTA2 inhibited cat coronary artery constriction induced by stable prostaglandin endoperoxide analogs, and it stabilized liver lysosomes. At slightly higher concentrations, it inhibited platelet aggregation. At still higher concentrations, PTA2 inhibited thromboxane synthetase, but it had no effect on prostacyclin synthetase. The analog also had no effect on the inhibition of platelet aggregation by PGI2 or prostaglandin D2. It is suggested that PTA2 has a suitable biochemical profile for use as an antithrombotic agent.

Animals↗
PubMed1979

Purification and properties of prostaglandin D synthetase from rat brain.

The prostaglandin D synthetase system was isolated from rat brain. Prostaglandin endoperoxide synthetase solubilized from a microsomal fraction catalyzed the conversion of arachidonic acid to prostaglandin H2 in the presence of heme and tryptophan. Prostaglandin D synthetase (prostaglandin endoperoxidase-D isomerase) catalyzing the isomerization of prostaglandin H2 to prostaglandin D2 was found predominantly in a cytosol fraction and was purified to apparent homogeneity with a specific activity of 1.7 mumol/min/mg of protein at 24 degrees C. The enzyme also acted upon prostaglandin G2 and produced a compound presumed to be 15-hydroperoxy-prostaglandin D2. Glutathione was not required for the enzyme reaction, but the enzyme was stabilized by thiol compounds including glutathione. The enzyme was inhibited by p-chloromercuribenzoic acid in a reversible manner. The purified enzyme was essentially free of the glutathione S-transferase activity which was found in the cytosol of brain.

Animals↗
PubMed1975

Some characteristics of the prostaglandin synthesizing system in rabbit kidney microsomes.

The prostaglandin synthesizing system in rabbit kidney microsomes was characterised using a radiometric assay. Three prostaglandins (F2alpha, E2 and D2) were formed form (1-14C)arachidonic acid, a small amount of prostaglandin A2 was also detected but this was formed non-enzymatically. Biosynthesis was stimulated by reduced-glutathione and 1-adrenaline and was inhibited by aspirin-like drugs. The enzyme system was sensitive to small changes in pH. There were substantial differences in drug sensitivity and optimal reaction conditions between this prostaglandin synthesizing system and the one from bovine seminal vesicles.

Aldosterone↗
PubMed1976

Evidence for enhanced venous smooth muscle turnover of prostaglandin-like substance in portal veins from spontaneously hypertensive rats.

The sensitivity of portal veins from 14 to 18 week-old Okamoto-Aoki spontaneously hypertensive rats to prostaglandins A2, B2, D2 and F2alpha were enhanced whereas the sensitivity to prostaglandin E2 was diminished when compared with responses of veins from normotensive Wistar-Kyoto rats. Inhibition of prostaglandin synthesis with both eicosotetraynoic acid (ETYA) and indomethacin (INDO) abolished the observed differences in sensitivity to prostaglandins. Synthesis of prostaglandin-like substance (with arachidonic acid as precursor) was significantly enhanced in portal veins from spontaneously hypertensive rats. Metabolism of prostaglandins E2 and F2alpha, employing the oil-immersion technique of Kalsner and Nickerson, appeared to be similar in veins from normotensive and hypertensive rats. These findings suggest that prostaglandin synthesis is enhanced in venous smooth muscle from hypertensive rats. The increased concentration of endogenous prostaglandin at the venous smooth muscle cell may modify the responses to exogenously administered prostaglandins thus accounting, in part, for the altered sensitivity to these fatty acids.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1979

Arachidonic acid metabolism by cells in culture: analyses of culture fluids for cyclooxygenase products by radioimmunoassay before and after separation by high pressure liquid chromatography.

Biosynthesis of PGI2, measured as 6-keto-PGF1 alpha, thromboxane A2, measured as thromboxine B2, and prostaglandins E2, F2 alpha and D2 by lymphocytes (WEHI-5), endothelial cells, normal human lung cells (WI-38), normal human fibroblasts (D-550), rat adult Type II alveolar cells (L-2) and canine kidney cells (MDCK) was measured by radioimmunoassay of culture fluids before and after their separation by high pressure liquid chromatography. The metabolic profiles and the levels of each metabolite obtained by both procedures were comparable. The profile of arachidonic biosynthesis was unique to each cell. Endothelial cells synthesized primarily prostacyclin; the lymphocytes synthesized principally thromboxane. The dog kidney cells synthesized relatively large amounts of prostaglandin F2 alpha, I2 and E2, while the normal human lung cells produced predominantly prostaglandins E2, F2 alpha, and thromboxane. The rat adult alveolar cell (L-2) and the normal human fibroblasts (D-550) biosynthesized primarily prostaglandins E2 and F2 alpha.

Animals↗
PubMed1976

Properties of prostaglandin synthetase of rabbit kidney medulla.

The formation in vitro of prostaglandins E2, D2, and F2alpha from arachidonic acid by rabbit kidney medulla homogenate or microsomal fraction is markedly affected by the composition of the incubation medium employed. Optimal biosynthesis is obtained in 0.1 M potassium phosphate buffer, with the optimum pH being 8.0--8.8. Under these conditions prostaglandin formation is linear up to arachidonic acid concentration of 30 muM. The initial rate of formation of prostaglandin E2 + prostaglandin D2 is 3--4 times higher than that of prostaglandin F2alpha. Reduced glutathione (1 mM) did not affect the biosynthesis by medulla homogenate and produced only small stimulation of the biosynthesis by microsomal powder. Hydroquinone produced a small stimulation at a low concentration of 0.005 mM, and a strong inhibition at concentrations of 0.1 mM or higher. Addition of bovine serum albumin (0.1%) reduced the microsomal biosynthesis of prostaglandins by approximately 80%. Addition of boiled homogenate or boiled 140 000 X g supernatant produced small stimulation of microsomal biosynthesis while 140 000 X g supernatant (not boiled) caused small inhibition which was not dose-related. It appears that rabbit kidney prostaglandin-synthetase converts arachidonic acid to prostaglandins E2 and F2alpha in comparable amounts, without apparent need for a cytoplasmic soluble cofactor or specific reducing agents.

Animals↗