Group IVC Research Articles

Pengaruh Model Project Based Learning Berbantuan Wordwall terhadap Kemampuan Berpikir Kritis Siswa Materi Gaya Gravitasi pada Kelas IV SDN Ciracas 10 Pagi

Critical thinking skills can be pursued in various ways, one of which is by applying innovative learning models. The purpose of this study was to examine how the Wordwall-assisted Project-Based Learning Model was applied to the gravity material for Class IV SDN Ciracas 10. There were 64 participants in this study: 32 from the experimental group IV-C and 32 from the control group IV-B. The data passed the normality test which was carried out using the Shapiro-Wilk Liliefors distribution before being analyzed and the homogeneous test with Fisher's test with homogeneous results. Statistical results in this study the control class obtained 70.13 and the experimental class 79.78, which means that there was an influence on the research

To evaluate and compare surface characteristics of different aesthetic nickel-titanium archwires using surface profilometry, sem and stereomicroscopy: A multi-arm split-mouth randomized controlled trial

This multi-arm split-mouth randomized controlled trial aimed to compare the surface characteristics, coating thickness and coating stability of four different aesthetic coated Nickel-Titanium Orthodontic rectangular archwires before and after oral exposure. To evaluate and compare the surface characteristics of four as-received (Control group) aesthetic nickel-titanium orthodontic rectangular archwires (0.016 x 0.022ʺ NiTi) from different manufacturers that are BioForce (Group I), Rabbit force (Group II), Libral (Group III), and ORMCO (Group IV) and after oral exposure (Experimental group) of four weeks, 15 patients meeting the inclusion criteria were recruited for this prospective study. Scanning electron microscopy, stereomicroscopy, and 3D profilometry were done for evaluating the surface characteristics of each group of wires.Four quadrants of every patient were randomized in a 1:1:1:1 ratio to the wires of either BioForce (Group I), Rabbit force (Group II), Libral (Group III), or ORMCO (Group IV). On examination of as-received wires (control group), the maximum coating thickness was seen in Group III c (Teflon coated, Libral), followed by Group IIc (Epoxy coated, Rabbit Force), then Group Ic (Teflon coated, BioForce), and least in Group IVc (Epoxy coated, ORMCO). After 4 weeks of oral exposure, the maximum coating loss was seen in Group II (Rabbit Force) wire, and the least amount of coating loss was seen in Group IV (ORMCO).The results of this study indicated a low aesthetic value of each of the manufacturer’s coated archwires because they presented a non-durable coating after oral exposure.

Expression of cPLA2γ mRNA and protein differs the response of PBMC from severe and non-severe asthmatics to bacterial lipopolysaccharide and house dust mite allergen

Chronic inflammation in asthmatics is initiated/exacerbated by many environmental factors, such as bacterial lipopolysaccharide and allergens. Phospholipase A2 and histone acetyltransferase/deacetylases are enzymes involved in inflammatory process, particularly in lipid inflammatory mediators production and control of transcription of many inflammatory genes, respectively. The aim of the study was to identify differences in the inflammatory process in patients with severe and non-severe asthma, taking as a criterion expression of two groups of enzymes: phospholipases A2 and histone acetyltransferases/deacetylases. Thirty-two patients with severe, non-severe atopic to house dust mite asthmatics and 14 healthy volunteers were recruited. Peripheral blood mononuclear cells were stimulated with Dermatophagoides pteronyssinus allergen (nDer p1) and bacterial lipopolysaccharide (LPS). The expression of phospholipases A2 and histone acetyltransferases and deacetylases were assessed using TaqMan Low Density Array Cards. The protein expression was analyzed with immunoblot. Increased expression of phospholipase A2 Group IVC (PLA2G4C) and cytosolic phospholipase A2 gamma (cPLA2γ) protein was observed in peripheral blood mononuclear cells (PBMC) from severe asthmatics in response to LPS and nDer p1, compared to non-severe asthmatics. nDer p1-stimulated PBMC from severe asthmatics exhibit induced expression of HDAC1 and similar trend was observed in protein concentration. Decreased expression of EP300 occurred in PBMC of severe asthmatics. PBMC from non-severe asthmatics showed decreased expression of HDAC2 and PLA2G15 after LPS treatment. In conclusion, in response to LPS and dust mite allergen, PBMC from severe and non-severe asthmatics modulate expression of selected phospholipase A2, histone acetyltransferases and deacetylases, while increased expression of cPLA2γ characterizes PBMC response from severe asthmatics.

Effect of Cisplatin on the Kidney of the Albino Rat and Possible Protective Role of Vitamin C

AbstractBackground: Cisplatin has a major nephrotoxic effect.Aim of Study: To evaluate the protective effect of vitamin C against cisplatin-induced nephrotoxicity.Material and Methods: Sixty adult albino rats divided into 5 groups; group I (10 rats; control), group II (10 rats); received single dose of cisplatin 6mg/kg IP. Group III (10 rats); received single dose of cisplatin 6mg/kg IP 6 hours after single dose of oral vitamin C 350mg/kg. Group IV (15 rats); received single dose of cisplatin 2mg/kg/week for 4 weeks IP and subdivided into three subgroups (5 rats each). Group V (15 rats); received single dose of cisplatin 2mg/kg/week for 4 weeks IP 6 hours after single dose of oral vitamin C 350mg/kg and subdivided into three subgroups (5 rats each). Kidneys were dissected and stained by (H&E), Masson's trichrome (MT) and Periodic acid Schiff (PAS) and examined by light microscopy, and fresh tissue taken from group I, IV-B and V-C examined by electron microscopy.Results: Our results showed toxic effect of cisplatin on renal glomeruli and proximal tubular lining in group II with improvement in group III, chronic toxicity effect in group IV-C in the form of hyaline casts and thickened BM with apparent improvement in group V.Conclusion: We conclude that the vitamin C has a protec-tive effect against cisplatin- induced nephrotoxicity.

Alternatively spliced variants in Atlantic cod (Gadus morhua) support response to variable salinity environment

Analysis of gill transcriptome of the Atlantic cod from the Baltic Sea demonstrated that alternatively spliced (AS) variants may be actively involved in the process of adaptation to altered salinity. Some AS variants of different genes, like phospholipase A2 group IVC (PLA2G4C), appeared only in fish exposed to altered salinity, while other isoforms of the same genes were present in all experimental groups. Novel sequence arrangements represent 89% of all AS in the Baltic cod compared to the Atlantic population. Profiles of modified pathways suggest that regulation by AS can afford specific changes of genes expressed in response to the environment. The AS variants appear to be involved in the response to stress by modifications of signalling in apoptosis pathways, an innate immunological response and pro-inflammatory process. Present results support the hypothesis that developing new AS variants could support genome complexity and reinforce the ability to fast adapt to local environments.

Pengaruh Model Discovery Learning Berbantuan Media Audio Visual dalam Setting Lesson Study Terhadap Hasil Belajar IPA Mahasiswa PGSD Undiksha UPP Denpasar Tahun 2017

This research is intended to know the influence of NHT model by audio visual media toward the mastery of science competence of fourth grade students of SD Gugus Yos Sudarso in academic year 2016/2017. Type of research conducted in this research is quantitative research with experimental design that is quasi experiment (Experimental Semu). The experimental design used is "Nonequivalent control group design". In the two samples that have been drawn are one group of expreiments and one control group. Class IVB SDN 12 Sanur as experimental group and grade IVC SDN 10 Sanur as control group. The learning in the experimental and control class is equally given 6 times, and is given the last postet to know the improvement of the knowledge competence of science knowledge. To collect data in this research is done by test method. The data obtained were analyzed using the t-test. The results of data analysis obtained thitnung = 6,536 while at the level of significance 5% and dk = 68 obtained t table = 2,000 so thitung = 6,536 > t table = 2,000. Based on the test criteria, Ho is rejected and Ha accepted. The average value of science knowledge competence in the group that was taught with NHT model with audio visual aid was 80.17, while in the group taught by conventional learning was 68,66. So it can be concluded that Model Type NHT Assisted Audio Visual Media influence on the mastery of knowledge competence of science class IV elementary school Gugus Yos Sudarso District South Denpasar Lesson 2016/2017.

Association of Peripheral Monocyte Count with Soluble P-Selectin and Advanced Stages in Nasopharyngeal Carcinoma.

Introduction Inflammation is widely recognized to play an important role in cancer progression and is related to thrombosis. Soluble P-selectin (sP-selectin) is one of several biomarkers that may be predictive of thrombosis in cancer. This study aimed to investigate the correlation between monocyte count and sP-selectin in various stages of nasopharyngeal carcinoma. Methods Fifty-five patients with nasopharyngeal carcinoma were divided into three groups according to nodal and distant metastasis (group of stages I-IVA, IVB, and IVC). Monocyte count was calculated from routine peripheral blood examination, while sP-selectin level was measured using commercial ELISA kit. Results The monocyte count of subjects in groups IVB and IVC was significantly higher compared to group I-IVA (707/μL versus 528/μL, p = 0.022; 841/μL versus 528/μL, p = 0.005). Plasma levels of sP-selectin in group IVC were higher than group I-IVA (59.5 ng/mL versus 41.97 ng/mL, p = 0.001) and group IVB (59.5 ng/mL versus 45.53 ng/mL, p = 0.007). In subjects with high monocyte count (>665/μL), there was moderate correlation between monocyte count and sP-selectin (r = 0.436, p = 0.022). Conclusion Advanced stages of nasopharyngeal carcinoma had higher levels of monocyte count and sP-selectin compared to earlier stages. Monocyte count was correlated with sP-selectin especially in high monocyte count subgroup.

The rs251684 Variant of PLA2G4C Is Associated with Autism Spectrum Disorder in the Northeast Han Chinese Population.

To investigate the association between autism spectrum disorder (ASD) and the phospholipase A2 group IVC (PLA2G4C) and phospholipase A2 group XIIA (PLA2G12A) polymorphisms in the Northeast Han Chinese population. A total of 68 family trios (children diagnosed with ASD and their unaffected parents) were enrolled. Five single-nucleotide polymorphisms (SNPs) (rs9226, rs1045376, rs251684, rs2307279, and rs156631) in PLA2G4C and four SNPs (rs6533451, rs2285714, rs2285713, and rs11728699) in PLA2G12A were selected and genotyped. The association between the SNPs and ASD was analyzed using the transmission disequilibrium test. Our results showed a significant association between ASD and the rs251684 variant of PLA2G4C (transmitted/nontransmitted = 36/21, χ2 = 3.947, p = 0.047), but no association between ASD and the other eight SNPs investigated (all p > 0.05). Moreover, we found no preference in the transmission of haplotypes constructed for either PLA2G4C or PLA2G12A. The rs251684 polymorphism of PLA2G4C may be associated with ASD risk.

Deletion of phospholipase A2 group IVc induces apoptosis in rat mammary tumour cells by the nuclear factor-κB/lipocalin 2 pathway.

Although some forms of phospholipase A2, the initiator of the arachidonic acid cascade, contribute to carcinogenesis in many organs, the contribution of phospholipase A2 group IVc (Pla2g4c) remains to be clarified and the function of the enzyme in cancer development is unknown. The Hirosaki hairless rat (HHR), a mutant rat strain with autosomal recessive inheritance, derived spontaneously from the Sprague-Dawley rat (SDR). The HHRs showed a lower incidence and much smaller volume of mammary tumours induced by 7,12-dimethylbenz[a]anthracene, and a markedly increased number of TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling)-positive apoptotic cells was detected. Array comparative genomic hybridization and PCR analyses revealed the deletion of 50-kb genomic DNA on 1q21, including Pla2g4c, in HHRs. The Pla2g4c gene was expressed in the ductal carcinoma cells and myoepithelial cells in SDRs, but not in HHRs. The direct involvement of Pla2g4c in the prevention of cell death was demonstrated through the inhibition of its expression in rat mammary tumour RMT-1 cells using siRNA. This treatment also induced expression of lipocalin 2 (Lcn2) and other NF-κB (nuclear factor κB)-related genes. siRNA-induced apoptosis was inhibited by Lcn2 repression or NF-κB inhibitors. This is the first report on Pla2g4c gene-deficient rats and their low susceptibility to mammary carcinogenesis by enhancing NF-κB/Lcn2-induced apoptosis.

Induction of group IVC phospholipase A2 in allergic asthma: transcriptional regulation by TNFα in bronchoepithelial cells

Airway inflammation in allergen-induced asthma is associated with eicosanoid release. These bioactive lipids exhibit anti- and pro-inflammatory activities with relevance to pulmonary pathophysiology. We hypothesized that sensitization/challenge using an extract from the ubiquitous fungus Aspergillus fumigatus in a mouse model of allergic asthma would result in altered phospholipase gene expression, thus modulating the downstream eicosanoid pathway. We observed the most significant induction in the group IVC PLA2 (phospholipase A2) [also known as cPLA2γ (cytosolic PLA2γ) or PLA2G4C]. Our results infer that A. fumigatus extract can induce cPLA2γ levels directly in eosinophils, whereas induction in lung epithelial cells is most likely to be a consequence of TNFα (tumour necrosis factor α) secretion by A. fumigatus-activated macrophages. The mechanism of TNFα-dependent induction of cPLA2γ gene expression was elucidated through a combination of promoter deletions, ChIP (chromatin immunoprecipitation) and overexpression studies in human bronchoepithelial cells, leading to the identification of functionally relevant CRE (cAMP-response element), NF-κB (nuclear factor κB) and E-box promoter elements. ChIP analysis demonstrated that RNA polymerase II, ATF-2 (activating transcription factor 2)-c-Jun, p65-p65 and USF (upstream stimulating factor) 1-USF2 complexes are recruited to the cPLA2γ enhancer/promoter in response to TNFα, with overexpression and dominant-negative studies implying a strong level of co-operation and interplay between these factors. Overall, our results link cytokine-mediated alterations in cPLA2γ gene expression with allergic asthma and outline a complex regulatory mechanism.

Regulation of macrophage differentiation and polarization by group IVC phospholipase A2

Although the cellular function of group IVC phospholipase A2 (IVC-PLA2) remains to be understood, the expression of IVC-PLA2 in human monocytic THP-1 cells was increased during phorbol ester-induced macrophage differentiation. We therefore examined the role of IVC-PLA2 in macrophage differentiation using THP-1 cells. Two THP-1 cell lines stably expressing IVC-PLA2-specific shRNA were established. Differentiation and maturation into macrophages on treatment with phorbol ester were facilitated by knockdown of IVC-PLA2 without the compensatory induction of mRNA expression for other group IV and VI PLA2s. Furthermore, the enhancement of macrophage differentiation by IVC-PLA2-knockdown were abolished by treatment with lysophosphatidylcholine, a metabolite of phospholipids generated by PLA2-mediated hydrolysis, indicating that PLA2 activity is necessary for the inhibition of macrophage differentiation by IVC-PLA2. Additionally, we found that the differentiation into classically activated M1 macrophage was superior in IVC-PLA2-knockdown cells, whereas the differentiation into alternatively activated M2 macrophage was suppressed by IVC-PLA2-knockdown. These findings suggest that IVC-PLA2 is involved in regulations of macrophage differentiation and macrophage polarization.

Triacylglycerol Deposition with Group IVC Phospholipase A2 Expression in Oleate- and Linoleate-Stimulated Huh-7 Hepatocytes

The accumulation of hepatocellular triacylglycerol (TG), a major symptom of fatty liver, is associated with the excessive incorporation of exogenous free fatty acids into hepatocytes, the free fatty acids inducing an increase in TG bearing acyl chains derived from not only themselves but also endogenous fatty acids. However, the mechanisms responsible for the supply of endogenous fatty acids, which are mainly esterified into phospholipids, remain unclear. In the present study, we examined the possible involvement of intracellular phospholipase A(2) (PLA(2))s including group IVA, IVC, VIA, and VIB PLA(2)s, which catalyze the release of endogenous fatty acids, in the deposition of TG in hepatocytes. Stimulation of human hepatoma Huh-7 cells with oleate or linoleate for 48 h increased TG contents time-dependently. Under the conditions, increased expression of group IVC PLA(2) mRNA and protein was observed at 6-12 h and 24-48 h after the stimulation, respectively. However, mRNA levels of group IVA, VIA, or VIB PLA(2) did not change. When cells were treated with methyl arachidonyl fluorophosphonate used as an inhibitor of group IVC PLA(2), the fatty acid-induced deposition of TG was partially but significantly suppressed at 48 h, although no significant inhibition was observed at 24 h. Overexpression of wild-type group IVC PLA(2) but not a catalytically inactive mutant of group IVC PLA(2) tended to increase cellular TG levels. The present findings suggest that stimulation of Huh-7 hepatocytes with free fatty acids induces the expression of group IVC PLA(2), which is involved in the fatty acid-induced deposition of TG.

Activation of group IVC phospholipase A2 by polycyclic aromatic hydrocarbons induces apoptosis of human coronary artery endothelial cells

Exposure to environmental pollutants, such as polycyclic aromatic hydrocarbons (PAHs) found in coal tar mixtures and tobacco sources, is considered a significant risk factor for the development of heart disease in humans. The goal of this study was to determine the influence of PAHs present at a Superfund site on human coronary artery endothelial cell (HCAEC) phospholipase A(2) (PLA(2)) activity and apoptosis. Extremely high levels of 12 out of 15 EPA high-priority PAHs were present in both the streambed and floodplain sediments at a site where an urban creek and its adjacent floodplain were extensively contaminated by PAHs and other coal tar compounds. Nine of the 12 compounds and a coal tar mixture (SRM 1597A) activated group IVC PLA(2) in HCAECs, and activation of this enzyme was associated with histone fragmentation and poly (ADP) ribose polymerase (PARP) cleavage. Genetic silencing of group IVC PLA(2) inhibited both (3)H-fatty acid release and histone fragmentation by PAHs and SRM 1597A, indicating that individual PAHs and a coal tar mixture induce apoptosis of HCAECs via a mechanism that involves group IVC PLA(2). Western blot analysis of aortas isolated from feral mice (Peromyscus leucopus) inhabiting the Superfund site showed increased PARP and caspase-3 cleavage when compared to reference mice. These data suggest that PAHs induce apoptosis of HCAECs via activation of group IVC PLA(2).

Subcellular localization and lysophospholipase/transacylation activities of human group IVC phospholipase A2 (cPLA2γ)

cPLA2γ was identified as an ortholog of cPLA2α, which is a key enzyme in eicosanoid production. cPLA2γ was reported to be located in endoplasmic reticulum (ER) and mitochondria and to have lysophospholipase activity beside phospholipase A2 (PLA2) activity. However, subcellular localization, mechanism of membrane binding, regulation and physiological function have not been fully established. In the present study, we examined the subcellular localization and enzymatic properties of cPLA2γ with C-terminal FLAG-tag. We found that cPLA2γ was located not only in ER but also mitochondria even in the absence of the prenylation. Purified recombinant cPLA2γ catalyzed an acyltransferase reaction from one molecule of lysophosphatidylcholine (LPC) to another, forming phosphatidylcholine (PC). LPC or lysophosphatidylethanolamine acted as acyl donor and acceptor, but lysophosphatidylserine, lysophosphatidylinositol and lysophosphatidic acid (LPA) did not. PC and phosphatidylethanolamine (PE) also acted as weak acyl donors. Reaction conditions changed the balance of lysophospholipase and transacylation activities, with addition of LPA/PA, pH > 8, and elevated temperature markedly increasing transacylation activity; this suggests that lysophospholipase/transacylation activities of cPLA2γ may be regulated by various factors. As lysophospholipids are known to accumulate in ischemia heart and to induce arryhthmia, the cPLA2γ that is abundant in heart may have a protective role through clearance of lysophospholipids by its transacylation activity.

Morphological properties of chick retinal ganglion cells in relation to their central projections

Morphological properties of chick retinal ganglion cells (RGCs) were studied in relation to their central projections in 23 chicks. A total of 217 RGCs were retrogradely labeled by applying a carbocyanine dye (DiI) to the thalamus and optic tectum. The labeled RGCs were classified into six groups on the basis of their somal areas, dendritic fields, and branching patterns. The dendrites of these RGCs extended horizontally in the inner plexiform layer (IPL) forming eight dendritic strata. The RGCs in each group showed certain specificities in their central projections. Group Ic predominantly projected to the tectum. Groups IIs and IIIs showed a high thalamic dominance. Groups Is and IIc were nonspecific with regard to their tectal and thalamic projections. Group IVc showed tectal-specific projections. Occurrence rates of the dendritic strata increased progressively toward the inner part of the IPL, i.e., DSs (dendritic strata) 1-4 were scantily distributed, DSs 5 and 6 were moderately distributed, and DSs 7 and 8 were the most frequently distributed. A total of 42 dendritic stratification patterns were identified, and of these, 18 patterns were common to the tectal RGCs (tec-RGCs) and thalamic RGCs (tha-RGCs). The common patterns were detected very frequently in the tec- and tha-RGCs (approximately 85%), and the dendritic strata were largely distributed in the inner part of the IPL (DSs 5-8). In contrast, the remaining 24 noncommon stratification patterns showed low occurrence rates (approximately 15%); however, these dendritic strata were widely distributed in both the outer (DSs 1-4) and inner (DSs 5-8) IPL.

Trichinella spiralis induces de novo expression of group IVC phospholipase A 2 in the intestinal epithelium

Phospholipase A 2 (PLA 2) enzymes play a central role in the initiation, propagation and resolution of inflammation. Here, we describe de novo expression of group IVC PLA 2 (PLA2g4c) within the intestinal epithelium of Trichinella spiralis parasitised mice. This mouse mast cell protease-1 sensitive, calcium-independent PLA 2 is not detectable in the jejunal epithelium of uninfected mice but becomes highly expressed within the epithelial compartment within days of nematode establishment. We propose that epithelial PLA2g4c accounts for the increased lysophospholipase activity observed during intestinal nematodiasis and that it plays a major role in the inflammatory response to nematodes.

Alternative splicing of CTP:phosphoethanolamine cytidylyltransferase produces two isoforms that differ in catalytic properties

CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) catalyzes the rate-controlling reaction of the CDP-ethanolamine (Kennedy) pathway. We have previously established that Pcyt2 is encoded by a single gene that can be alternatively spliced from an internal exon into two transcripts, designated Pcyt2alpha and Pcyt2beta. Little is currently known about the regulation of Pcyt2. Here, we functionally express both murine Pcyt2 (mPcyt2) transcripts and investigate the roles of the two proteins in the regulation of mPcyt2 activity. We demonstrate that the tagged and purified alpha and beta proteins differ significantly in their kinetic properties. The K(m) of mPcyt2alpha for phosphoethanolamine was 318.4 microM, compared with 140.3 microM for mPcyt2beta. The maximal velocities of the alpha and beta isoforms at saturating conditions for both substrates were 138.0 and 114.4 nmol/min/mumol enzyme, respectively. When phosphoethanolamine was used at a fixed concentration of 1 mM, the K(m) of mPcyt2alpha for CTP was 102.0 microM and that of mPcyt2beta was 84.09 microM. Using a combination of nondenaturing PAGE, gel filtration chromatography, and immunoprecipitation, we provide evidence that mPcyt2alpha and mPcyt2beta proteins can form both homodimeric and heterodimeric complexes. We show that alternative splicing of the mPcyt2 transcript is ubiquitous but could also be regulated in a tissue-specific manner, producing a variable ratio of mPcyt2alpha/mPcyt2beta mRNAs. The expression of two distinct protein isoforms maybe an important mechanism by which Pcyt2 activity is regulated.

Distinct phospholipase A2 enzymes regulate prostaglandin E2 and F2alpha production by bovine endometrial epithelial cells

BackgroundThe rate-limiting step in prostaglandin (PG) biosynthesis is catalyzed by phospholipase A2 (PLA2) enzymes which hydrolyze arachidonic acid from membrane phospholipids. Despite their importance in uterine PG production, little is known concerning the specific PLA2 enzymes that regulate arachidonic acid liberation in the uterine endometrium. The objectives of this study were to evaluate the expression and activities of calcium-independent Group VI and Group IVC PLA2 (PLA2G6 and PLA2G4C) and calcium-dependent Group IVA PLA2 (PLA2G4A) enzymes in the regulation of bovine uterine endometrial epithelial cell PG production.MethodsBovine endometrial epithelial cells in culture were treated with oxytocin, interferon-tau and the PLA2G6 inhibitor bromoenol lactone, alone and in combination. Concentrations of PGF2alpha and PGE2 released into the medium were analyzed. Western blot analysis was performed on cellular protein to determine the effects of treatments on expression of PLA2G4A, PLA2G6 and PLA2G4C. Group-specific PLA2 activity assays were performed on cell lysates following treatment with oxytocin, interferon-tau or vehicle (control), alone and in combination. To further evaluate the role of specific PLA2 enzymes in uterine cell PG biosynthesis, cells were transfected with cDNAs encoding human PLA2G6 and PLA24C, treated as described above and PG assays performed.ResultsConstitutive cell production of PGF2alpha was about two-fold higher than PGE2. Oxytocin stimulated production of both PGs but the increase of PGF2alpha was significantly greater. Interferon-tau diminished oxytocin stimulation of both PGs. The PLA2G6 inhibitor, bromoenol lactone, abolished oxytocin-stimulated production of PGF2alpha. Treatments had little effect on PLA2G4A protein expression. In contrast, oxytocin enhanced expression of PLA2G6 and this effect was diminished in the presence of interferon-tau. Expression of PLA2G4C was barely detectable in control and oxytocin treated cells but it was enhanced in cells treated with interferon-tau. Oxytocin stimulated PLA2 activity in assays designed to evaluate PLA2G6 activity and interferon-tau inhibited this response. In assays designed to measure PLA2G4C activity, only interferon-tau was stimulatory. Cells overexpressing PLA2G6 produced similar quantities of the two PGs and these values were significantly higher than PG production by non-transfected cells. Oxytocin stimulated production of both PGs and this response was inhibited by interferon-tau. Bromoenol lactone inhibited oxtocin stimulation of PGF2alpha production but stimulated PGE2 production, both in the absence and presence of oxytocin. Cells over-expressing PLA2G4C produced more PGE2 than PGF2alpha and interferon-tau stimulated PGE2 production.ConclusionResults from these studies indicate that oxytocin stimulation of uterine PGF2alpha production is mediated, at least in part, by up-regulation of PLA2G6 expression and activity. In addition to its known inhibitory effect on oxytocin receptor expression, interferon-tau represses oxytocin-stimulated PLA2G6 expression and activity and this contributes to diminished PGF2alpha production. Furthermore, endometrial cell PGE2 biosynthesis was associated with PLA2G4C expression and activity and interferon-tau was stimulatory to this process.

Tu-P7:200 Group IVC phospholipase A2 supplies fatty acids utilized for the formation of cholesteryl ester and triacylglycerol in macrophages

Tu-P7:200 Group IVC phospholipase A2 supplies fatty acids utilized for the formation of cholesteryl ester and triacylglycerol in macrophages

Group IVC cytosolic phospholipase A2γ is farnesylated and palmitoylated in mammalian cells

Cytosolic phospholipase A(2)gamma (cPLA(2)gamma) is a member of the group IV family of intracellular phospholipase A(2) enzymes, but unlike the well-studied cPLA(2)alpha, it is constitutively bound to membrane and is calcium independent. cPLA(2)gamma contains a C-terminal CaaX sequence and is radiolabeled by mevalonic acid when expressed in cPLA(2)alpha-deficient immortalized lung fibroblasts (IMLF(-/-)). The radiolabel associated with cPLA(2)gamma was identified as the farnesyl group. The protein farnesyltransferase inhibitor BMS-214662 prevented the incorporation of [(3)H]mevalonic acid into cPLA(2)gamma and partially suppressed serum-stimulated arachidonic acid release from IMLF(-/-) and undifferentiated human skeletal muscle (SkMc) cells overexpressing cPLA(2)gamma, but not from cells overexpressing cPLA(2)alpha. However, BMS-214662 did not alter the amount of cPLA(2)gamma associated with membrane. These results were consistent in COS cells expressing the C538S cPLA(2)gamma prenylation mutant. cPLA(2)gamma also contains a classic myristoylation site and several potential palmitoylation sites and was found to be acylated with oleic and palmitic acids but not myristoylated. Immunofluorescence microscopy revealed that cPLA(2)gamma is associated with mitochondria in IMLF(-/-), SkMc cells, and COS cells.