Prostaglandin D synthase (beta-trace) in meningeal hemangiopericytoma.

The level of prostaglandin D synthase (PGDS), a major protein constituent of cerebrospinal fluid (CSF), is altered in various brain diseases, including meningitis. However, its role in the brain remains unclear. PGDS is mainly synthesized in the arachnoid cells, the choroid plexus and oligodendrocytes in the central nervous system. Among brain tumors, meningiomas showed intense immunoreactivity to PGDS in the perinuclear region. Thus, PGDS has been considered a specific cell marker of meningioma. In this study, we examined 25 meningeal hemangiopericytomas (HPCs) and found that 16 of the tumors (64%) showed immunoreactivity for PGDS in the perinuclear region. For comparison, 15 meningiomas, 14 soft-tissue HPCs, 1 mesenchymal chondrosarcoma, 3 choroid plexus papillomas, and 7 oligodendrogliomas were also examined. Meningiomas showed positive immunoreactivity for PGDS in 13 cases (80%). Except for one case located at the sacrum, none of the other soft-tissue HPCs showed immunostaining for PGDS. Mesenchymal chondrosarcoma arises in the bones of the skull, and its histological pattern resembles that of HPC; however, it showed no immunoreactivity for PGDS. Neither choroid plexus papillomas nor oligodendrogliomas were immunopositive for PGDS. These findings suggest that meningeal HPCs may have a unique molecular phenotype that is distinct from that of the soft-tissue HPCs. The origin of meningeal HPCs may be more closely related to the arachnoid cells.     

Pharmacokinetics of recombinant human lipocalin-type prostaglandin D synthase/beta-trace in canine

Lipocalin-type prostaglandin (PG) D synthase (L-PGDS) is identical to beta-trace, a major protein in human cerebrospinal fluid (CSF), and acts as both a PGD(2)-producing enzyme and as an extracellular transporter for lipophilic ligands. In this study, we investigated the pharmacokinetics of recombinant human L-PGDS (rh-L-PGDS) in canines. After an intravenous bolus injection of rh-L-PGDS, the serum concentration decreased bi-exponentially with a half-life of the terminal line phase of 0.77h, which was markedly shorter than that of other proteins with the same molecular weight as that of rh-L-PGDS. The distribution volume was 55.4ml/kg, which was close to the volume of canine circulation plasma, indicating that the administrated rh-L-PGDS was distributed mainly in the blood. Only 10.3% of the administered rh-L-PGDS was excreted to the urine, suggesting that rh-L-PGDS was actively degraded within the body. After an intrathecal injection, the peak serum concentration of rh-L-PGDS was observed at 4-5h. The area under the plasma concentration-time curve obtained for 12h after the intrathecal injection was one third of the value for 3h after the intravenous injection, suggesting that at least one third of the intrathecally injected rh-L-PGDS shifted to the blood.     

Lipocalin-type prostaglandin D synthase (beta-trace) in cerebrospinal fluid: a useful marker for the diagnosis of normal pressure hydrocephalus

Lipocalin-type prostaglandin D synthase (PGDS) is considered to be mainly produced in the leptomeninges and secreted into cerebrospinal fluid (CSF). We found PGDS levels in CSF of patients with normal pressure hydrocephalus (NPH) (8.99+/-2.59 microg/ml, mean+/-S.D., n=14) to be significantly lower than levels in a control (15.29+/-5.17, n=14, P<0.0001) and other dementia group (19.14+/-4.34, n=7, P=0.0003). Thus, PGDS level in CSF is a useful marker for the differential diagnosis of NPH from other diseases with dementia.     

Prostaglandin D synthase isoforms from cerebrospinal fluid vary with brain pathology

Glutathione independent prostaglandin D synthase (Swissprot P41222, PTGDS) has been identified in human cerebrospinal fluid and some changes in PTGDS in relation to disease have been reported. However, little is known of the extent that PTGDS isoforms fluctuate across a large range of congenital and acquired diseases. The purpose of this study was to examine changes in PTGDS isoforms in such a population. Spinal fluid from 22 healthy study participants (normal controls) with no classifiable neurological or psychiatric diagnosis was obtained and PTGDS isoforms were identified by specific immunostaining and mass spectrometry after denaturing 2D gel electrophoresis. The PTGDS isoforms in controls consisted of five charge isoforms that were always present and a small number of occasional, low abundance isoforms. A qualitative survey of 98 different people with a wide range of congenital and acquired diseases revealed striking changes. Loss of the control isoforms occurred in congenital malformations of the nervous system. Gain of additional isoforms occurred in some degenerative, most demyelinating and vasculitic diseases, as well as in Creutzfeldt-Jakob disease. A retrospective analysis of published data that quantified relative amounts of PTGDS in multiple sclerosis, schizophrenia and Parkinson's disease compared to controls revealed significant dysregulation. It is concluded that qualitative and quantitative fluctuations of cerebrospinal fluid PTGDS isoforms reflect both major and subtle brain pathophysiology.     

Diurnal preference, sleep habits, circadian sleep propensity and melatonin rhythm in healthy human subjects

We studied the in vitro effects of ethanol (25, 50 and 100 mM) on pyroglutamyl aminopeptidase activity (pGluAP), which has been reported as thyrotrophin-releasing-hormone-degrading activity. pGluAP was measured in presence or absence of calcium, under basal and K(+)-stimulated conditions, in synaptosomes and their incubation supernatant, using pyroglutamyl-beta-naphthylamide as substrate. In basal conditions, in synaptosomes, pGluAP was inhibited by ethanol in a calcium-independent way. In the supernatant, the response differed depending on the concentration of ethanol. Depolarization with K(+) modified pGluAP in synaptosomes and supernatant depending on the presence or not of calcium. In synaptosomes, in absence of calcium, the activity was inhibited at the highest concentrations of ethanol. In contrast, in the supernatant, under depolarizing conditions, ethanol increases pGluAP in absence of calcium. These changes may be in part responsible of the behavioural changes associated to alcohol intake.     

Diurnal preference, sleep habits, circadian sleep propensity and melatonin rhythm in healthy human subjects

After 24-h sleep deprivation, 33 healthy young subjects entered the 10/20 min ultra-short sleep–wake schedule for 26 h. Melatonin rhythm was hourly assessed simultaneously. Results indicated that morning preference was significantly correlated with habitual sleep onset (r=−0.41, P=0.04), habitual sleep offset (r=−0.52, P=0.002), melatonin peak time (r=−0.36, P=0.04), and sleep propensity onset time (r=−0.36, P=0.04). The intervals between habitual sleep mid-point and melatonin peak time and between habitual sleep mid-point and sleep propensity onset time were significantly longer in morning-preference subjects than in evening-preference subjects (P<0.05). These findings suggest that the variance of diurnal preference may be related to differences in phase relations between habitual sleep timing and the circadian pacemaker.     

前列腺素D2受体调节PGD2诱导的人气道黏液高分泌

目的研究前列腺素D2(PGD2)通过D类前列腺素受体2(DP2)对人气道上皮细胞黏液分泌的效应及其作用机制。方法用PGD2刺激人气道上皮16HBE细胞,以DP2拮抗剂AZD6430、DP1拮抗剂BWA868C及三磷酸肌醇蛋白激酶(PI3K)抑制剂LY294002为干预因素,将细胞分为对照组、PGD2刺激组、PGD2刺激+AZD6430组、PGD2刺激+BWA868C组、PGD2刺激+LY294002组。ELISA检测细胞中肿瘤坏死因子(TNF)-α、白介素(IL)-4和IL-13的蛋白含量,激光共聚焦技术检测细胞内黏蛋白(MUC)5AC含量;Western blot检测DP2、DP1、PI3K和磷酸化AKT(p-AKT)表达水平;实时荧光定量PCR检测TNF-α、IL-4、IL-13和MUC5AC mRNA表达水平。结果 PGD2刺激后MUC5AC、TNF-α、IL-4、IL-13、DP2、PI3K和p-AKT表达显著高于对照组(P0.05);AZD6430拮抗组中MUC5AC、TNF-α、IL-4、IL-13、PI3K及p-AKT表达较PGD2刺激组明显减弱(P0.05);LY294002组TNF-α、IL-4、IL-13和MUC5AC表达较PGD2组亦显著减弱(P0.05)。结论 PGD2激活人气道上皮细胞的DP2受体,活化PI3K/AKT引起黏液高分泌。     

Mutations and polymorphisms in the human N-acetylglutamate synthase (NAGS) gene

N-acetylglutamate synthase (NAGS) deficiency, an autosomal recessive disorder, is the last urea cycle disorder for which molecular testing became available. This is the first comprehensive report of 21 mutations that cause NAGS deficiency and of commonly found polymorphisms in the NAGS gene. Five mutations are reported here for the first time. A total of 10 disease-causing mutations are associated with acute neonatal hyperammonemia; the remaining mutations were found in patients with late onset disease. Residual enzymatic activities are included in this report and the deleterious effects of eight mutations were confirmed by expression studies. Mutations in the NAGS gene are distributed throughout its reading frame. No mutations have been found in exon 1, which encodes for the putative mitochondrial targeting signal and variable segment of NAGS. Three polymorphisms have been found. Early, accurate, and specific diagnosis of NAGS deficiency is critical since this condition can be successfully treated with N-carbamylglutamate (NCG, Carbaglu; Orphan Europe). Treatment with NCG should be initiated as soon as a patient is suspected of having NAGS deficiency. Molecular testing represents the most reliable method of diagnosis.     

Endothelial nitric oxide synthase (eNOS) expression and localization in healthy and diabetic rat hearts

Several studies suggest that nitric oxide (NO) production is reduced in diabetes and that the decrease of NO may be related to the pathogenesis of diabetic endothelial damage. NO synthase (NOS) catalyses the conversion of L-arginine to L-citrulline in the presence of oxygen and NADPH-diaphorase (NADPH-d). In this study, we evaluated the expression of endothelial NOS (eNOS) enzyme and its co-enzyme in diabetic rat hearts. Male Wistar rats (n = 20, 4 mo old) and 20 male Bio Breeding Wistar (BB/W) rats of the same age were used; the Wistar rats represent the control non-diabetic rats while the BB/W rats represent the diabetic group. After the hearts were excised, the NADPH-d co-enzyme was visualized by a histochemical method and the endothelial isoform of NOS was localized by immunohistochemistry. In addition, eNOS gene expression was estimated by rt-PCR, and eNOS protein level was detected by Western blot analysis. The eNOS visualization, which involved immunoprecipitation, and the NADPH-d visualization, which involved histochemical staining, were both diminished in endothelial cells of the vascular wall of diabetic hearts, compared to non-diabetic hearts. The eNOS protein level, evaluated by Western blotting, was evident as an intense band in cardiac homogenates of non-diabetic and diabetic rats. The expression of mRNA for eNOS did not differ significantly between the two groups. These findings indicate that, in this rat heart model, diabetes does not influence the overall eNOS protein level or its mRNA level. However, there a diminution in the deposition of eNOS in cardiac endothelial cells of diabetic rats, versus non-diabetic controls, suggesting a relation between eNOS and the loss of vasodilatory response that is observed in diabetes.     

Inflammation and sleep in healthy individuals

STUDY OBJECTIVES: Inflammation is relatively common in individuals with a sleep disorder and is associated with quality of sleep. The purpose of this study was to examine whether inflammation is associated with quality of sleep in healthy individuals. DESIGN & SETTING: Observational study in a General Clinical Research Center. PARTICIPANTS: This study characterized inflammation and polysomno-graphically verified sleep in 124 African American and Caucasian American women and men without a sleep disorder. MEASUREMENTS AND RESULTS: Circulating levels of 3 markers and/or mediators of inflammation known to be elevated in sleep disorders and in cardiovascular disease were determined (interleukin-6 [IL-6] endothelin-1 [ET-1], soluble intercellular adhesion molecule-1 [sICAM-1]). Sleep was characterized by polysomnography. Multiple linear regression analyses showed that increasing age, male sex, and African American ethnicity were independently associated with poorer sleep. After controlling for these variables, higher levels of ET-1 were independently associated with greater sleep latency (P < or = 0.01), greater rapid eye movement (REM) latency (P < or = 0.01), more slow wave sleep (P < or = 0.05), and less stage 1 sleep (P < or = 0.01). Higher IL-6 levels were independently associated with greater REM latency (P < or = 0.05). CONCLUSIONS: The findings suggest that, in individuals without a known sleep disorder, ET-1, a potent vasoconstrictor and mediator of inflammation, is associated with more deep sleep, whereas both ET-1 and IL-6 are associated with increased latency of sleep and of REM. The findings underscore the complex relationships between peripheral markers of inflammation and sleep.     

Stability of EEG sleep and sleep quality in healthy seniors

When the electroencephalogram-recorded (EEG) sleep of 19 healthy seniors (9 men, 10 women) aged 60-82 years was restudied after an average interval of 2.2 years, most measures of EEG sleep and sleep quality were stable over time. Both elderly men and women showed more awakenings during the second recording series, but no change in visual or computer-scored delta activity. Furthermore, gender-dependent sleep changes were noted only in phasic rapid eye movement (REM) measures (increasing in men, decreasing in women). Reports of sleep quality were also stable over time despite the increase in awakenings, with women reporting a lower sleep quality than men.     

Inducible nitric oxide synthase (NOS II) is constitutive in human neutrophils

The objective was to study the expression of inducible nitric oxide synthase (NOS II) in and NO production by human blood neutrophils and in in vivo exudated neutrophils. Cellular expression of NOS II was evaluated by flow cytometry in whole blood, in isolated blood neutrophils, and in neutrophils obtained by exudation in vivo into skin chambers. Neutrophil NOS II was also demonstrated by Western blotting. Uptake of 3H-labelled L-arginine was studied in vitro and NOS activity measured in a whole cell assay by the conversion of 3H-arginine to 3H-citrulline. In contrast to unseparated blood cells, NOS II was demonstrable both in isolated blood neutrophils and exudated cells. The failure to detect NOS II by flow cytometry in whole blood cells thus proved to be due to the quenching effect of hemoglobin. Western blotting revealed a 130 kD band corresponding to NOS II in isolated blood neutrophils, but detection was dependent on diisopropylfluorophosphate for proteinase inhibition. L-arginine was taken up by neutrophils, but enzymatic activity could not be demonstrated. We conclude that human neutrophils constitutively express NOS II, but that its demonstration by FITC-labelling is inhibited by hemoglobin-mediated quenching in whole blood samples.     

Dendritic Cells Express Hematopoietic Prostaglandin D Synthase and Function as a Source of Prostaglandin D2 in the Skin

Prostaglandin D2 (PGD2), an arachidonic acid metabolite, has been implicated in allergic responses. A major source of PGD2 in the skin is mast cells that express hematopoietic PGD synthase (H-PGDS). In this study, we show the expression of H-PGDS in human dendritic cells (DCs) and the regulatory mechanisms by which DCs produce PGD2. We detected H-PGDS in epidermal Langerhans cells, dermal DCs, plasmacytoid DCs, and myeloid DCs. Monocyte-derived DCs rapidly secreted PGD2 when stimulated with the calcium ionophore A23187. More importantly, pretreatment of monocyte-derived DCs with PMA (phorbol 12-myrisate 13-acetate) synergistically enhanced the rapid PGD2 secretion induced by {"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187, whereas PMA alone did not induce PGD2 secretion. Lipopolysaccharide (LPS) reduced H-PGDS expression, but interferon-γ followed by LPS induced significant PGD2 production in a delayed time course at 6 hours. This effect was associated with inhibition of LPS-induced H-PGDS reduction. Interestingly, an irritant compound, SDS, also induced a rapid PGD2 release. PGD2 synergistically enhanced CCL22/macrophage-derived chemokine synthesis in interferon-γ-treated human keratinocytes. In addition, bone marrow-derived DCs from wild-type mice stimulated lymph node cells to produce higher amounts of interleukin-17 than did DCs from mice lacking the H-PGDS gene. Thus, DCs could be an important source of skin PGD2 and may mediate or regulate skin inflammation by releasing PGD2 in response to various stimuli, contributing to the innate and/or acquired immune responses.Prostaglandin D2 (PGD2) is one of the arachidonic acid metabolites and exerts a range of biological activities, including vasodilatation, bronchoconstriction, and inhibition of platelet aggregation.^1–4 PGD2 is also implicated in allergic diseases. PGD2 production is observed in bronchoalveolar lavage fluid from asthmatic patients.⁵ Mice that overproduce PGD2 exhibit an enhanced allergic lung response, eosinophilia, and increased Th2-type cytokine production.⁶ We have demonstrated that PGD2 plays an essential role in IgE-mediated skin responses in mice.⁷ A possible anti-pruritic potential of PGD2 in the scratching behavior of mice was recently proposed.^8,9PGD2 exerts its effect through D prostanoid (DP) and CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells) receptors. DP and CRTH2 are members of the G protein-coupled, seven transmembrane receptor family. DP is coupled with Gs protein, whereas Gi protein is associated with CRTH2.¹⁰ DP-mediated signals inhibit dendritic cell (DC) migration.^11–13 Effects of PGD2 on DC maturation and interleukin-12 production are also mediated by the DP receptor.¹⁴ On the other hand, CRTH2 signals induce calcium mobilization and chemotaxis in eosinophils and basophils.¹⁰ In addition, CRTH2 signals enhance interleukin-4, -5, and -13 production from Th2 cells.¹⁵PGD2 synthesis is mediated by the isomerization of prostaglandin H2 (PGH2) into PGD2 through the enzymatic activity of PGD synthase (PGDS).¹⁶ Two types of PGDS have been identified: lipocalin-type PGDS and hematopoietic PGDS (H-PGDS).^16,17 Lipocalin-type PGDS is present in meningeal cells, epithelial cells of the choroids plexus, and oligodendrocytes in the brain and is involved in the sleep-wake cycle.¹⁸ H-PGDS was originally isolated from rat spleen as a cytosolic glutathione (GSH)-requiring enzyme.^19,20 Mast cells express H-PGDS and rapidly secrete PGD2 in response to antigen stimulation.^21,22 Thus, mast cells are a major source of PGD2 in the skin and contribute to inflammation,^23,24 although a small population of Th2-type cells contains H-PGDS.²⁵H-PGDS is also detected in antigen-presenting cells, such as histiocytes and/or DCs in rat spleen, thymus, and skin.^26,27 We have revealed that epidermal Langerhans cells in mouse skin express H-PGDS.⁷ Thus, it can be postulated that DCs could be a source of PGD2 in skin tissues and may affect various immune cells and effector cells, including DCs themselves, through DP and/or CRTH2 receptors. However, H-PGDS in human DCs and their capability for PGD2 secretion have not been fully characterized. In the present study, we analyzed H-PGDS expression in human DCs and identified regulatory mechanisms of PGD2 production with a variety of stimuli. Moreover, the biological significance of DC-derived PGD2 in terms of chemokine synthesis from keratinocytes and cytokine production from lymphocytes were also assessed.     

The effect of total sleep deprivation on plasma melatonin and cortisol in healthy human volunteers

Twelve healthy volunteers were included in this study. Baseline curves for melatonin and cortisol were obtained after one night of adaptation to laboratory conditions. From 10:00 p.m. to 6:00 a.m., blood samples were drawn every hour. On the third night, the subjects were kept awake at the sleep unit. Curves for the two hormones were then obtained after 36 h of total sleep deprivation (SD). The levels of these hormones were evaluated by calculating the area under the curve at each hour in both situations (basal and after sleep deprivation). It was found that the melatonin levels were increased after sleep deprivation, whereas the cortisol levels remained the same. These results suggest a mechanism by which a reset of abnormal rhythms can occur in depression.     

Prostaglandin endoperoxide H synthase mRNA expression in the human amnion and decidua during pregnancy and in the amnion at preterm labour

We have examined the expression of prostaglandin endoperoxide H synthase (PGHS) isoenzymes in the amnion and the decidua during gestation, and the abundance of PGHS mRNA in the amnion at idiopathic preterm labour. PGHS-1 and -2 mRNA abundance in the amnion, determined with ribonuclease protection assays, was significantly (P< 0.05) higher at term than earlier during pregnancy. In contrast, neither PGHS-1 and -2 mRNA values, nor PGHS-specific activity, measured with a cell-free assay, was different in the decidua at term as compared to earlier gestational ages. In individual term patients, PGHS-2 mRNA values in the amnion were positively correlated with PGHS-2 mRNA values in the chorion laeve. PGHS-1 and -2 mRNA abundance was higher (P < 0.05) in the amnion after idiopathic preterm labour than in the absence of labour at the same gestational age (28-35 weeks). Thus, PGHS-1 and -2 are induced in the amnion at term. Furthermore, amniotic PGHS-2 changes in co-ordination with PGHS-2 concentrations in the chorion laeve. PGHS is not induced in the decidua at term. Increased amniotic PGHS expression may contribute to the enhanced intrauterine prostaglandin synthesis before term labour. Both PGHS isoenzymes may participate in the increase of PGHS activity in the amnion at preterm birth.     

Low-frequency (<1 Hz) oscillations in the human sleep electroencephalogram

Low-frequency (<1 Hz) oscillations in intracellular recordings from cortical neurons were first reported in the anaesthetized cat and then also during natural sleep. The slow sequences of hyperpolarization and depolarization were reflected by slow oscillations in the electroencephalogram. The aim of the present study was to examine whether comparable low-frequency components are present in the human sleep electroencephalogram. All-night sleep recordings from eight healthy young men were subjected to spectral analysis in which the low-frequency attenuation of the amplifier was compensated. During sleep stages with a predominance of slow waves and in the first two episodes of non-rapid-eye-movement sleep, the mean power spectrum showed a peak at 0.7–0.8 Hz (range 0.55–0.95 Hz). The typical decline in delta activity from the first to the second non-rapid-eye-movement sleep episode was not present at frequencies below 2 Hz. To detect very low frequency components in the pattern of slow waves and sleep spindles, a new time series was computed from the mean voltage of successive 0.5 s epochs of the low-pass (<4.5 Hz) or band-pass (12–15 Hz) filtered electroencephalogram. Spectral analysis revealed a periodicity of 20–30 s in the prevalence of slow waves and a periodicity of 4 s in the occurrence of activity in the spindle frequency range.The results demonstrate that distinct components below 1 Hz are also present in the human sleep electroencephalogram spectrum. The differences in the dynamics between the component with a mean peak value at 0.7–0.8 Hz and delta waves above 2 Hz is in accordance with results from animal experiments.     

Prostaglandin E(2)-dependent production of latent matrix metalloproteinase-9 in cultures of human fetal membranes

Studies in our laboratory have shown that structural changes in cervical biopsied fetal membranes, prior to labour, coincide with differences in the expression of the gelatinase enzyme, latent matrix metalloproteinase-9 (MMP-9). Concurrently, in vivo, there is an increase in the expression of prostaglandins, notably prostaglandin E(2) (PGE(2)), which has been shown to regulate the expression of MMPs in other systems. The aim of this study was to test the hypothesis (using an in-vitro culture model) that endogenously produced PGE(2) has a role in the elevation of MMP-9 described in vivo. Non-infected fetal membranes sampled from women undergoing elective Caesarean section were stimulated with 10% (v/v) fetal bovine serum (FBS), a known inducer of prostaglandins. This activation resulted in a time-dependent increase in the secretion of PGE(2) into the media, as determined by enzyme-linked immunosorbent assay (day 1: 19 +/- 9 pg/ml/24 h to 358 +/- 54 pg/ml/24 h by day 4). A similar pattern of secretion of latent MMP-9 was observed in parallel with the increase in PGE(2) in the same culture media (day 1: 1.63 +/- 0.17 ng/ml/24 h to 4.2 +/- 1.4 ng/ml/24 h by day 4). When both molecules were compared, a significant (P: < 0.01) positive correlation (r = 0.623) was observed. Secretion of the tissue inhibitor of MMPs-9 (TIMP-1) was not significantly different between untreated (3.07 +/- 0.266 microg/ml/24 h) and FBS-treated (3. 85 +/- 0.24 microg/ml/24 h) cultures during the first 4 days in culture. Prostaglandin synthesis inhibition studies using indomethacin (100 micromol/l) resulted in a 70-80% reduction in the activated secretion of latent MMP-9. Direct PGE(2) stimulation of cultures resulted in the bell shaped dose-response curve with concentrations of 1-100 nmol/l (which are within the range secreted in culture in response to FBS), stimulating significant latent MMP-9 secretion. These results suggest a link between endogenous PGE(2) and latent MMP-9 production in human fetal membranes, raising the possibility that PGE(2) has a role in the mechanism of fetal membrane structural changes and, hence, in parturition-associated membrane rupture.