RESUMEN

The deregulation of fatty acid metabolism plays a pivotal role in cancer. Our objective is to construct a prognostic model for patients with endometrial carcinoma (EC) based on genes related to fatty acid metabolism-related genes (FAMGs). RNA sequencing and clinical data for EC were obtained from The Cancer Genome Atlas (TCGA). Lasso-Penalized Cox regression was employed to derive the risk formula for the model, the score = esum(corresponding coefficient × each gene's expression). Gene set enrichment analysis (GSEA) was utilized to examine the enrichment of KEGG and GO pathways within this model. Correlation analysis of immune function was conducted using Single-sample GSEA (ssGSEA). The "ESTIMATE" package in R was utilized to evaluate the tumor microenvironment. The support vector machine recursive feature elimination (SVM-RFE) and randomforest maps were employed to identify key genes. The effects of PTGIS on the malignant biological behavior of EC were assessed through CCK-8 assay, transwell invasion assay, cell cycle analysis, apoptosis assay, and tumor xenografts in nude mice. A novel prognostic signature comprising 10 FAMGs (INMT, ACACB, ACOT4, ACOXL, CYP4F3, FAAH, GPX1, HPGDS, PON3, PTGIS) was developed. This risk score serves as an independent prognostic marker validated for EC. According to ssGSEA analysis, the low- and high-risk groups exhibited distinct immune enrichments. The key gene PTGIS was screened by SVM-RFE and randomforest method. Furthermore, we validated the expression of PTGIS through qRT-PCR. In vitro and in vivo experiments also confirmed the effect of PTGIS on the malignant biological behavior of EC.

Asunto(s)

Neoplasias Endometriales , Animales , Ratones , Femenino , Humanos , Ratones Desnudos , Neoplasias Endometriales/genética , Oxidorreductasas Intramoleculares , Ácidos Grasos , Microambiente Tumoral , Sistema Enzimático del Citocromo P-450

RESUMEN

Prostacyclin (PGI2) synthase (PGIS) and microsomal prostaglandin (PG) E synthase-1 (PGES-1) are PG terminal synthases which functionally couple with inducible cyclooxygenase-2 (COX-2) as their upstream enzymes to produce PGI2 and PGE2, respectively. Non-steroidal anti-inflammatory drugs exert their pharmacological effects by the inhibition of COX-2 and thereby suppression of the biosynthesis of these PGs. PGIS is abundantly expressed in vascular endothelial and smooth muscle cells and has been shown to be critical for regulation of platelet aggregation and vascular tone. In addition to its role in vascular regulation, PGIS has been shown to be expressed in inflammatory cells including macrophages, and the proinflammatory roles of PGIS has been demonstrated. On the other hand, several investigators have recently reported that PGIS functions as an anti-inflammatory mediator by macrophage polarization and have indicated that PGIS is an ambivalent regulator of inflammatory reactions. In this review, we summarize the current understanding of proinflammatory and anti-inflammatory functions of PGIS and discuss its potential as a novel anti-inflammatory therapeutic target.

Asunto(s)

Epoprostenol , Oxidorreductasas Intramoleculares , Ciclooxigenasa 2 , Sistema Enzimático del Citocromo P-450 , Prostaglandina-E Sintasas

RESUMEN

Aim: This study investigated our Enzymelinks, COX-2-10aa-mPGES-1 and COX-2-10aa-PGIS, as cellular cross-screening targets for quick identification of lead compounds to inhibit inflammatory PGE2 biosynthesis while maintaining prostacyclin synthesis. Methods: We integrated virtual and wet cross-screening using Enzymelinks to rapidly identify lead compounds from a large compound library. Results: From 380,000 compounds virtually cross-screened with the Enzymelinks, 1576 compounds were identified and used for wet cross-screening using HEK293 cells that overexpressed individual Enzymelinks as targets. The top 15 lead compounds that inhibited mPGES-1 activity were identified. The top compound that specifically inhibited inflammatory PGE2 biosynthesis alone without affecting COX-2 coupled to PGI2 synthase (PGIS) for PGI2 biosynthesis was obtained. Conclusion: Enzymelink technology could advance cyclooxygenase pathway-targeted drug discovery to a significant degree.

Asunto(s)

Derivados del Benceno/farmacología , Ciclooxigenasa 1/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Oxidorreductasas Intramoleculares/metabolismo , Ingeniería de Proteínas , Derivados del Benceno/química , Evaluación Preclínica de Medicamentos , Células HEK293 , Humanos , Microsomas/efectos de los fármacos , Microsomas/enzimología

RESUMEN

The current article aims to summarize all possible spectrum of protein-protein interactions for thromboxane A synthase (CYP5A1) and prostacyclin synthase (CYP8A1). These enzymes metabolize the same substrate (prostaglandin H2 ) and can participate in cardiovascular, inflammatory, immune processes, and apoptosis modulation, as well as significantly influence the risk of cancers. Binary protein-protein and multiprotein complexes are of great importance in enzyme-regulating and signal-transduction pathways. However, protein partners of CYP5A1 and CYP8A1 are not yet fully identified, although both synthases are considered as prospective drug targets. At least 36 novel protein partners of CYP5A1 and CYP8A1 were revealed from different tissue types using an approach based on affinity isolation and mass spectrometry. Enrichment analysis showed that these proteins have different molecular functions: folding (refolding), unfolded protein and chaperon binding, protein transport (export/import), posttranslational modification, protein domain-specific binding, antioxidant activity, and glutathione homeostasis. A significant part of them, belonging to molecular chaperones, were common partners for CYP5A1 and CYP8A1, while other proteins were unique with the tissue-dependent distribution. New aspects of CYP5A1 and CYP8A1 interactomics and hetero-complex formation with different protein partners, including cytochrome P450s are discussed.

Asunto(s)

Sistema Enzimático del Citocromo P-450/metabolismo , Tromboxano-A Sintasa/metabolismo , Humanos , Ligandos , Complejos Multiproteicos , Unión Proteica

RESUMEN

Pulmonary hypertension (PH) is a progressive and life-threating lung disorder characterized by elevated pulmonary artery pressure and vascular remodeling. PH is classified into five groups, and one of the most common and lethal forms, PH Group-III is defined as PH due to lung diseases and/or hypoxia. Due to the lack of studies in this group, PH-specific drug therapies including prostacyclin (PGI2) analogues have not been approved or recommended for use in these patients. PGI2 is synthesized by the PGI2 synthase (PGIS) enzyme, and its production is determined by measuring its stable metabolite, 6-keto-PGF1α. An impaired PGI2 pathway has been observed in PH animal models and in PH Group-I patients; however, there are contradictory results. The aim of this study is to determine whether PH Group-III is associated with altered expression of PGIS and production of PGI2 in humans. To explore this hypothesis, we measured PGIS expression (by western blot) and PGI2 production (by ELISA) in a large variety of preparations from the pulmonary circulation including human pulmonary artery, pulmonary vein, distal lung tissue, pulmonary artery smooth muscle cells (hPASMC), and bronchi in PH Group-III (n = 35) and control patients (n = 32). Our results showed decreased PGIS expression and/or 6-keto-PGF1α levels in human pulmonary artery, hPASMC, and distal lung tissue derived from PH Group-III patients. Moreover, the production of 6-keto-PGF1α from hPASMC positively correlated with PGIS expression and was inversely correlated with mean pulmonary artery pressure. On the other hand, PH Group-III pulmonary veins and bronchi did not show altered PGI2 production compared to controls. The deficit in PGIS expression and/or PGI2 production observed in pulmonary artery and distal lung tissue in PH Group-III patients may have important implications in the pathogenesis and treatment of PH Group-III.

Asunto(s)

Sistema Enzimático del Citocromo P-450/metabolismo , Epoprostenol/metabolismo , Hipertensión Pulmonar/metabolismo , Oxidorreductasas Intramoleculares/metabolismo , Arteria Pulmonar/metabolismo , Bronquios/enzimología , Bronquios/metabolismo , Hipoxia de la Célula/fisiología , Células Cultivadas , Dinoprost/metabolismo , Regulación hacia Abajo , Femenino , Humanos , Hipertensión Pulmonar/enzimología , Hipertensión Pulmonar/fisiopatología , Pulmón/enzimología , Pulmón/metabolismo , Masculino , Músculo Liso Vascular/enzimología , Músculo Liso Vascular/metabolismo , Arteria Pulmonar/enzimología , Venas Pulmonares/enzimología , Venas Pulmonares/metabolismo

RESUMEN

Prostacyclin synthase (PTGIS; EC 5.3.99.4) catalyzes isomerization of prostaglandin H2 to prostacyclin, a potent vasodilator and inhibitor of platelet aggregation. At present, limited data exist on functional coupling and possible ways of regulating PTGIS due to insufficient information about protein-protein interactions in which this crucial enzyme is involved. The aim of this study is to isolate protein partners for PTGIS from rat tissue lysates. Using CNBr-activated Sepharose 4B with covalently immobilized PTGIS as an affinity sorbent, we confidently identified 58 unique proteins by mass spectrometry (LC-MS/MS). The participation of these proteins in lysate complex formation was characterized by SEC lysate profiling. Several potential members of the PTGIS subinteractome have been validated by surface plasmon resonance (SPR) analysis. SPR revealed that PTGIS interacted with full-length cytochrome P450 2J2 and glutathione S-transferase (GST). In addition, PTGIS was shown to bind synthetic peptides corresponding to sequences of for GSTA1, GSTM1, aldo-keto reductase (AKR1A1), glutaredoxin 3 (GLRX3) and histidine triad nucleotide binding protein 2 (HINT2). Prostacyclin synthase could potentially be involved in functional interactions with identified novel protein partners participating in iron and heme metabolism, oxidative stress, xenobiotic and drugs metabolism, glutathione and prostaglandin metabolism. The possible biological role of the recognized interaction is discussed in the context of PTGIS functioning.

RESUMEN

Biosensor experiments on investigation of interaction between prostacyclin synthase (PGIS) and different proteins of the cytochrome P450 monooxygenase systems were perfomed. Interaction of PGIS with microsomal (CYP21A2, CYP2E1) and mitochondrial (CYP27A1, CYP11B1, CYP11B2, CYP11A1) cytochrome P450s was detected. Kinetic and equilibrium parameters of protein complexes formation were determined. Data obtained suggest an essential role of these hemoproteins interaction in regulation of prostacyclin and thromboxane A2 biosynthesis.

Asunto(s)

Sistema Enzimático del Citocromo P-450/metabolismo , Oxidorreductasas Intramoleculares/metabolismo , Humanos , Microsomas/enzimología , Mitocondrias/enzimología , Prostaglandinas I/biosíntesis , Tromboxano A2/biosíntesis

RESUMEN

Prostacyclin (PGI2) synthase (PGIS) and microsomal prostaglandin (PG) E synthase-1 (PGES-1) functionally couple with inducible cyclooxygenase-2 (COX-2) as their upstream enzymes to produce PGI2 and PGE2, respectively. Non-steroidal anti-inflammatory drugs exert their pharmacological effects including antitumor effects by the inhibition of COX-2 and thereby suppress this PG biosynthesis. PGIS is abundantly expressed in vascular endothelial and smooth muscle cells and was shown to be critical for the regulation of platelet aggregation and vascular tone. In addition to its role in vascular regulation, PGIS was shown to be frequently down-regulated in several types of cancers, and the involvement of PGIS in carcinogenesis has been suggested. In this review, we summarize the current understanding of the roles of PGIS and PGIS-derived PGI2 in carcinogenesis.

Asunto(s)

Carcinogénesis , Sistema Enzimático del Citocromo P-450/metabolismo , Oxidorreductasas Intramoleculares/metabolismo , Neoplasias/enzimología , Neoplasias/patología , Animales , Sistema Enzimático del Citocromo P-450/deficiencia , Sistema Enzimático del Citocromo P-450/genética , Eliminación de Gen , Regulación Enzimológica de la Expresión Génica , Humanos , Oxidorreductasas Intramoleculares/deficiencia , Oxidorreductasas Intramoleculares/genética , Neoplasias/genética

RESUMEN

Oxymatrine (OMT) is an active constituent of traditional Chinese herb Sophora japonica Ait which has been shown to exert potent anti-inflammatory,anti-oxidant and anti-fibrosis properties. Our previous studies have demonstrated that OMT has protective effects on isoproterenol-induced heart failure in rats through regulation of DDAH/ADMA metabolism pathway.In this study,we further investigated whether OMT could attenuate isoproterenol-induced heart failure through the regulation of COX-2/PGI2 pathway. Heart failure was induced in Sprague-Dawley rats by 5mg/kg isoproterenol subcutaneous injection for 7days. The rats were maintained on normal diet and randomly divided into five groups: control, isoproterenol, isoproterenol with OMT (50, 100mg/kg), and OMT alone groups (n=12 in each group). Serum brain natruretic peptide (BNP, a heart failure biomarker), histopathological variables, expression of Cytosolic phospholipase A2 (cPLA2), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and Prostacyclin synthase (PGIS) were analysed. Administration of OMT significantly reduced the increased BNP in plasm of isoproterenol-induced rats, attenuated cardiac fibrosis,suppressed overexpression of myocardial COX-1 expression, up-regulated COX-2 and PGIS expression, but had no effects on isoproterenol-induced elevated protein cPLA2. And compared with control group, any indexes in sham rats treated with OMT (100mg/kg) alone were unaltered. These results demonstrated that OMT has cardioprotective effects on isoproterenol-induced heart failure in rats by regulating COX-2/PGI2 pathway.

Asunto(s)

Alcaloides/uso terapéutico , Antiarrítmicos/uso terapéutico , Ciclooxigenasa 2/fisiología , Epoprostenol/fisiología , Insuficiencia Cardíaca/prevención & control , Isoproterenol/toxicidad , Quinolizinas/uso terapéutico , Agonistas Adrenérgicos beta/toxicidad , Alcaloides/farmacología , Animales , Antiarrítmicos/farmacología , Relación Dosis-Respuesta a Droga , Insuficiencia Cardíaca/inducido químicamente , Insuficiencia Cardíaca/metabolismo , Masculino , Quinolizinas/farmacología , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos

RESUMEN

Acrylamide is known to produce follicular cell tumors of the thyroid in rats. RccHan Wistar rats were exposed in utero to a carcinogenic dose of acrylamide (3 mg/Kg bw/day) from gestation day 6 to delivery and then through their drinking water to postnatal day 35. In order to identify potential mechanisms of carcinogenesis in the thyroid glands, we used a transcriptomics approach. Thyroid glands were collected from male pups at 10 PM and female pups at 10 AM or 10 PM in order to establish whether active exposure to acrylamide influenced gene expression patterns or pathways that could be related to carcinogenesis. While all animals exposed to acrylamide showed changes in expected target pathways related to carcinogenesis such as DNA repair, DNA replication, chromosome segregation, among others; animals that were sacrificed while actively drinking acrylamide-laced water during their active period at night showed increased changes in pathways related to oxidative stress, detoxification pathways, metabolism, and activation of checkpoint pathways, among others. In addition, thyroid hormones, triiodothyronine (T3) and thyroxine (T4), were increased in acrylamide-treated rats sampled at night, but not in quiescent animals when compared to controls. The data clearly indicate that time of day for sample collection is critical to identifying molecular pathways that are altered by the exposures. These results suggest that carcinogenesis in the thyroids of acrylamide treated rats may ensue from several different mechanisms such as hormonal changes and oxidative stress and not only from direct genotoxicity, as has been assumed to date.

RESUMEN

OBJECTIVE: The pathogenic events responsible for accelerated atherosclerosis in patients with chronic renal failure (CRF) are poorly understood. Here we investigate the hypothesis that concentrations of urea associated with CRF and increased ROS production in adipocytes might also increase ROS production directly in arterial endothelial cells, causing the same pathophysiologic changes seen with hyperglycemia. METHODS: Primary cultures of human aortic endothelial cells (HAEC) were exposed to 20mM urea for 48 h. C57BL/6J wild-type mice underwent 5/6 nephrectomy or a sham operation. Randomized groups of 5/6 nephrectomized mice and their controls were also injected i.p. with a SOD/catalase mimetic (MnTBAP) for 15 days starting immediately after the final surgical procedure. RESULTS: Urea at concentrations seen in CRF induced mitochondrial ROS production in cultured HAEC. Urea-induced ROS caused the activation of endothelial pro-inflammatory pathways through the inhibition of GAPDH, including increased protein kinase C isoforms activity, increased hexosamine pathway activity, and accumulation of intracellular AGEs (advanced glycation end products). Urea-induced ROS directly inactivated the anti-atherosclerosis enzyme PGI2 synthase and also caused ER stress. Normalization of mitochondrial ROS production prevented each of these effects of urea. In uremic mice, treatment with MnTBAP prevented aortic oxidative stress, PGI2 synthase activity reduction and increased expression of the pro-inflammatory proteins TNFα, IL-6, VCAM1, Endoglin, and MCP-1. CONCLUSIONS: Taken together, these data show that urea itself, at levels common in patients with CRF, causes endothelial dysfunction and activation of proatherogenic pathways.

Asunto(s)

Endotelio Vascular/patología , Fallo Renal Crónico/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Urea/química , Animales , Antígenos CD/metabolismo , Aorta/metabolismo , Aterosclerosis/enzimología , Aterosclerosis/metabolismo , Aterosclerosis/fisiopatología , Catalasa/metabolismo , Quimiocina CCL2/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Endoglina , Células Endoteliales/metabolismo , Endotelio/enzimología , Endotelio Vascular/efectos de los fármacos , Gliceraldehído-3-Fosfato Deshidrogenasa (Fosforilante)/metabolismo , Humanos , Interleucina-6/metabolismo , Oxidorreductasas Intramoleculares/metabolismo , Fallo Renal Crónico/inducido químicamente , Ratones , Ratones Endogámicos C57BL , Estrés Oxidativo , Distribución Aleatoria , Receptores de Superficie Celular/metabolismo , Superóxido Dismutasa/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismo

RESUMEN

Prostacyclin (PGI2 ) plays a role in cancer progression but the mechanism is currently poorly understood. Additionally, no data are available about the prognostic value of the PGI2 pathway in head and neck squamous cell carcinoma (HNSCC) therapy. We evaluated the expression of the PGI2 pathway in HNSCC patients. PGI2 production and PGI synthase (PGIS) expression, in terms of mRNA (RT-PCR) and protein (immunoblotting), were lower in tumour samples than in non-tumoural mucosa, whereas, as expected, COX-2 expression was increased in HNSCC tumour samples. Using local control of the tumour after radiotherapy or chemoradiotherapy as a dependent variable, patients were classified into two categories of PGIS transcript levels. The high-PGIS group had a significantly lower frequency of local and distant failure than the low-PGIS group, and the 5-year cancer-specific survival was higher [90.2% (95% CI 81.0-99.4%) versus 60.5% (95% CI 44.4-76.6%)]. None of the four HNSCC cell lines analysed expressed PGIS and therefore they did not produce PGI2 . However, HNSCC-conditioned media enhanced PGI2 production in endothelial cells (ECs). The stable analogue of PGI2 , carbaprostacyclin (cPGI2 ), exerted little effect on HNSCC cell line migration, and no effect on cell cycle distribution or proliferation rate after radiation injury was observed. Nevertheless, cPGI2 promoted EP-4-dependent in vitro angiogenesis. Von Willebrand factor expression (EC marker) and capillary density were significantly higher in the group of patients with high expression of PGIS. Our results indicate that PGIS expression was associated with radiotherapy efficiency. Although we do not provide direct evidence of a relationship between tumour vascularization and radiotherapy efficiency, our results suggest that the effect of PGI2 is related to its ability to promote vascularization. These results also support the concept that co-adjuvant therapy with PGIS enhancers, such as retinoids, could have therapeutic value for HNSCC treatment.

Asunto(s)

Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/radioterapia , Sistema Enzimático del Citocromo P-450/metabolismo , Endotelio Vascular/metabolismo , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/radioterapia , Oxidorreductasas Intramoleculares/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/mortalidad , Células Cultivadas , Ciclooxigenasa 2/metabolismo , Femenino , Neoplasias de Cabeza y Cuello/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Carcinoma de Células Escamosas de Cabeza y Cuello

RESUMEN

Aim To investigate the protective effects of beraprost sodium on cerebral cortical neuron injury in chronic aluminum-overload rats and its effects on PGIS-IP signaling pathway. Methods 75 SD rats were randomized into five groups: normal control group, chronic aluminum-overload group ( model group) and beraprost sodium groups-low dose (6 μg· kg-1 ), medium dose ( 12 μg · kg-1 ) and high dose (24 μg·kg-1). Aluminum gluconate (Al3+ 200 mg ·kg-1 d-1, once a day, 5d a week, for 20 weeks, p. o. ) was administered to rats of cerebral damage model. The rats of experimental groups were concomi-tantly treated with beraprost sodium ( p. o. ) daily for 20 weeks. After the model was built successfully, the spatial learning and memory( SLM) function was done by Morris water maze. The cortical neurons damage was detected by HE staining, SOD activities and MDA contents. The 6-k-PGF1α levels in cortex were meas-ured by ELISA. The expressions of PGIS, IP mRNA and IP protein were also studied. Results Compared with the rats of normal control group, the SLM function was significantly impaired ( P<0. 01 ) and considera-ble karyopycnosis was observed in model group rats. The SOD activities were weakened ( P <0. 01 ), the MDA contents increased ( P<0. 05 ) and the levels of 6-k-PGF1α raised significantly ( P <0. 01). The ex-pressions of PGIS and IP mRNA in the rats cortex obvi-ously increased ( P<0. 01 ), so did the expression of IP protein(P<0. 05). Compared with the rats of mod-el group, the SLM function of rats in experimental groups decreased significantly ( P<0. 01 ) and damage of cortical neurons reduced remarkably. The SOD ac-tivities increased ( P <0. 01 ) and the MDA contents decreased ( P <0. 01). Besides, the content of 6-k-PGF1α, the expressions of PGIS mRNA and IP protein in the rats cortex decreased significantly ( P<0. 05 ) as well as IP mRNA ( P<0. 01). Conclusion Our re-sults demonstrate that in cerebral cortical neuron of chronic aluminum-overload rats, beraprost sodium has notably protective effects and the mechanism might be related to PGIS-IP signaling pathway.

RESUMEN

Linoleate diol synthases (LDS) are fungal dioxygenase-cytochrome P450 fusion enzymes. They oxidize 18:2n-6 sequentially to 8R-hydroperoxylinoleic acid (8R-HPODE) and 7S,8S- or 5S,8R-dihydroxylinoleic acids (DiHODE) by intramolecular oxygen transfer. The P450 domains contain a conserved sequence, Ala-Asn-Gln-Xaa-Gln, presumably located in the I-helices. The Asn938Leu replacement of 7,8-LDS of Gaeumannomyces graminis virtually abolished and the Asn938Asp and Asn938Gln replacements reduced the hydroperoxide isomerase activity. Gln941Leu and Gln941Glu substitutions had little effects. Replacements of the homologous Asn(887) and Gln(890) residues of 5,8-LDS of Aspergillus fumigatus yielded the opposite results. Asn887Leu and Asn887Gln of 5,8-LDS retained 5,8-DiHODE as the main metabolite with an increased formation of 6,8- and 8,11-DiHODE, whereas Gln890Leu almost abolished the 5,8-LDS activity. Replacement of Gln(890) with Glu also retained 5,8-DiHODE as the main product, but shifted oxygenation from C-5 to C-7 and C-11 and to formation of epoxyalcohols by homolytic scission of 8R-HPODE. P450 hydroxylases usually contain an "acid-alcohol" pair in the I-helices for the heterolytic scission of O2 and formation of compound I (Por(+) Fe(IV)=O) and water. The function of the acid-alcohol pair appears to be replaced by two different amide residues, Asn(938) of 7,8-LDS and Gln(890) of 5,8-LDS, for heterolysis of 8R-HPODE to generate compound I.

Asunto(s)

Amidas/química , Oxígeno/química , Oxigenasas/química , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Ascomicetos/enzimología , Aspergillus fumigatus/enzimología , Biología Computacional , Secuencia Conservada , Modelos Moleculares , Oxigenasas/genética , Oxigenasas/metabolismo , Estructura Secundaria de Proteína

RESUMEN

In plants and mammals, oxylipins may be synthesized via multi step processes that consist of dioxygenation and isomerization of the intermediately formed hydroperoxy fatty acid. These processes are typically catalyzed by two distinct enzyme classes: dioxygenases and cytochrome P450 enzymes. In ascomycetes biosynthesis of oxylipins may proceed by a similar two-step pathway. An important difference, however, is that both enzymatic activities may be combined in a single bifunctional enzyme. These types of enzymes are named Psi-factor producing oxygenases (Ppo). Here, the spatial organization of the two domains of PpoA from Aspergillus nidulans was analyzed by small-angle X-ray scattering and the obtained data show that the enzyme exhibits a relatively flat trimeric shape. Atomic structures of the single domains were obtained by template-based structure prediction and docked into the enzyme envelope of the low resolution structure obtained by SAXS. EPR-based distance measurements between the tyrosyl radicals formed in the activated dioxygenase domain of the enzyme supported the trimeric structure obtained from SAXS and the previous assignment of Tyr374 as radical-site in PpoA. Furthermore, two phenylalanine residues in the cytochrome P450 domain were shown to modulate the specificity of hydroperoxy fatty acid rearrangement.

Asunto(s)

Aspergillus nidulans/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Dioxigenasas/química , Dioxigenasas/metabolismo , Dispersión del Ángulo Pequeño , Catálisis , Electrones , Mutagénesis Sitio-Dirigida , Unión Proteica , Estructura Cuaternaria de Proteína , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Especificidad por Sustrato , Espectrometría de Masas en Tándem

RESUMEN

Prostacyclin (PGI2) is a member of the prostaglandins family and the main product of arachidonic acid metabolism by cyclooxygenase and prostaglandin synthase. PGI2 mediates cellular activity through binding to G-protein coupled receptor, prostacyclin receptor, therefore leading to activation of adenylyl cyclase, accumulation of cAMP and activation of PKA. PGI2 plays an important role in vascular biology such as regulating vasodilation, platelet aggregation, vascular permeability, and vascular smooth muscle cell proliferation. At high concentrations, PGI2 is able to interact with peroxisomal proliferator-activated receptor, a class of nuclear receptors, and modulate specific cellular functions such as angiogenesis. This paper reviews the research advances in PGI2 synthesis and signal pathway.

RESUMEN

BACKGROUND AND OBJECTIVES: Platelets play an important role in the pathogenesis of acute coronary syndrome. Prostacyclin inhibits platelet aggregation, smooth muscle cell proliferation and vasoconstriction, and it counteracts thromboxane A2 activity. The purpose of this study is to evaluate the association between a single nucleotide polymorphism in the prostacyclin synthase gene and myocardial infarction in Koreans. SUBJECTS AND METHODS: We studied total 119 patients (M: F=72: 47, mean ages=57.9). We compared 60 acute coronary syndrome patients who underwent coronary angiography with the diagnosis of acute myocardial infarction (MI), with 59 normal control group patients who had normal coronary angiograms. With the use of polymerase chain reaction-restriction fragment length polymorphism analysis, we identified a single nucleotide polymorphism, C1117A, in exon 8. RESULTS: The genotype distribution and allele frequencies were significantly different between the control group and MI group. Frequency of the genotype C1117A was: AA: AC: CC=3.4%: 30.5%: 66.1% in control group, respectively, and AA: AC: CC=1.7%: 10.0%: 88.3% in MI group, respectively. Prostacyclin synthase polymorphism was observed in the MI group and the control group, but the frequency of the CC genotype was high in MI group (odds ratio, 3.88; 95% CI 1.49-10.88, p=0.003). Compared to control group, being male, having diabetes, hypertension or obesity, and the smoking rate were high in MI group. There were not significantly differences between genotypes for clinical characteristics. CONCLUSION: We conclude that the C1117A polymorphism in exon 8 of the prostacyclin synthase gene is associated with MI, and it may be a genetic marker of MI in Koreans.

Asunto(s)

Humanos , Masculino , Síndrome Coronario Agudo , Angiografía Coronaria , Diagnóstico , Epoprostenol , Exones , Frecuencia de los Genes , Marcadores Genéticos , Genotipo , Hipertensión , Infarto del Miocardio , Miocitos del Músculo Liso , Obesidad , Agregación Plaquetaria , Polimorfismo de Nucleótido Simple , Humo , Fumar , Tromboxano A2 , Vasoconstricción

RESUMEN

AIM: To study the effect of chronic hypoxic hypercapnia on gene expression of thromboxane synthase and prostacyclin synthase in pulmonary arterioles. METHODS: Sprague-Dawley rats were randomly divided into two groups: control group and hypoxic hypercapnic group. TXS mRNA and PGI 2-S mRNA were observed in pulmonary arterioles by in situ hybridization. RESULTS:mPAP, weight ratio of right ventricle (RV) to left ventricle plus septum(LV+S), contents of TXB 2 and 6-keto-PGF1 ? in plasma and lung and TXS mRNA in pulmonary arterioles were much higher in rats of hypoxic hypercapnic group than those of control group. Differences of PGI 2-S mRNA in pulmonary arterioles were not significant in two groups. Light microscopy showed hypertrophy of vessel smooth muscle cells and vessel cavity straitness were found in hypoxic hypercapnic group. CONCLUSION: Changes of gene expressions of thromboxane synthase and prostacyclin synthase and imbalance of TXA 2/PGI 2 may play an important role in hypoxic hypercapnic pulmonary hypertension.