RESUMEN
We hypothesised that different endocrine profiles associated with pre-ovulatory follicle (POF) size would impact on uterine prostanoid pathways and thereby modulate the histotroph composition. Beef cows (n=15 per group) were hormonally manipulated to have small (SF-SCL group) or large (LF-LCL group) pre-ovulatory follicles (POF) and corpora lutea (CL). Seven days after induction of ovulation, animals were slaughtered and uterine tissues and flushings were collected for quantification of prostanoids. The POF and CL size and the circulating progesterone concentrations at Day 7 were greater (P<0.05) in the LF-LCL cows than in the SF-SCL group, as expected. The abundance of 5 out of 19 genes involved in prostanoid regulation was different between groups. Transcript abundance of prostaglandin F2α, E2 and I2 synthases was upregulated (P<0.05) and phospholipase A2 was downregulated (P<0.05) in endometrium of the LF-LCL group. No difference (P>0.1) in prostanoid concentrations in the endometrium or in uterine flushings was detected between groups. However, prostaglandin F2α and E2 concentrations in the uterine flushings were positively correlated with the abundance of transcripts for prostaglandin endoperoxide synthase 2 (0.779 and 0.865, respectively; P<0.002). We conclude that endometrial gene expression related to prostanoid synthesis is modulated by the peri-ovulatory endocrine profile associated with POF size, but at early dioestrus differences in transcript abundance were not reflected in changes in prostanoid concentrations in the uterine tissue and fluid.
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Diestro/metabolismo , Dinoprost/metabolismo , Dinoprostona/metabolismo , Útero/metabolismo , Animales , Bovinos , Regulación hacia Abajo , Endometrio/metabolismo , Femenino , Inducción de la Ovulación , Transducción de Señal/fisiología , Regulación hacia ArribaRESUMEN
Phospholipid metabolism and signaling influences on early pregnancy events in cattle are unknown. This study aimed to characterize global phospholipid composition of oviduct and uterus during early diestrus in a model of contrasting embryo receptivity. Beef cows were treated to ovulate a larger (LF-LCL group, associated with greater receptivity) or smaller (SF-SCL group) follicle and, consequently, to present greater or smaller plasma concentrations of estradiol during proestrus-estrus, as well as progesterone during early diestrus. Oviduct and uterus (4 days after gonadotropin-releasing hormone-induced ovulation; D4) as well as the uterus (D7) were collected, and lipid profiles were monitored by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). This technique allowed the identification and tissue localization of sphingomyelins (SM), phosphatidylcholines (PC), ceramides (Cer), and phosphatidylethanolamines (PE). Multivariate statistics were used to separate samples into groups with distinctly different phospholipid profiles in the uterus at D4 and D7. Different abundance of ions corresponding to specific lipids were detected on D4 (Cer [42:1], PC [31:0], PC [32:1], PC [34:4], and PC [36:4] greater for LF-LCL group; and PC [38:7], PC [38:5], PC [38:4], PC [40:7], and PC [40:6] greater for SF-SCL group) and D7 (SM [34:2], SM [34:1], PC [32:1], and PC [35:2] greater for LF-LCL group). The MALDI-MS imaging showed the spatial distributions of major phospholipids. In conclusion, distinct phospholipid profiles were associated with animals treated to show contrasting receptivity to the embryo. Functional roles of the identified phospholipids on uterine function and preimplantation embryo development deserve further studies.
Asunto(s)
Ceramidas/metabolismo , Diestro/metabolismo , Oviductos/metabolismo , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Esfingomielinas/metabolismo , Útero/metabolismo , Animales , Bovinos , Estradiol/sangre , Femenino , Progesterona/sangre , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Distribución TisularRESUMEN
The timing and magnitude of exposure to preovulatory estradiol followed by post-ovulatory progesterone (periovulatory endocrine milieu) in cattle modulate endometrial gene expression, histotroph composition, and conceptus development, but the mechanisms underlying this regulation remain unknown. Using an experimental model based on the modulation of follicle growth, this work aimed to evaluate if the polyamine metabolic pathway is regulated by the periovulatory endocrine milieu. Nelore cows were manipulated to ovulate small (n = 15) or large (n = 15) follicles, then the profiles of polyamines and their synthetic enzymes were compared between groups. Transcripts for the enzymes of this pathway, ornithine decarboxylase 1 (ODC1; the rate-limiting enzyme in polyamine biosynthesis) protein quantification, adenosylmethionine decarboxylase 1 (AMD1) protein immunolocalization, and concentrations of the different polyamines (putrescine, spermidine, and spermine) were respectively quantified by quantitative reverse-transcriptase PCR, immunoblotting, immunohistochemistry, and gas chromatography-mass spectrometry in both the endometrium and uterine flushing. No differences in gene and protein expression or concentration of polyamines were observed between groups. There were significant correlations between the relative abundance of ODC1 and spermidine/spermine N1-acetyltransferase 1 (SAT1) transcripts as well as between antizyme inhibitor 1 (AZIN1) and adenosylmethionine decarboxylase 1 (AMD1) transcripts. In conclusion, our results show that the polyamine metabolic pathway is present and functional, but not regulated by the periovulatory endocrine milieu in the bovine endometrium.
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Diestro/metabolismo , Endometrio/metabolismo , Redes y Vías Metabólicas/fisiología , Poliaminas/metabolismo , Adenosilmetionina Descarboxilasa/metabolismo , Animales , Bovinos , Endometrio/química , Endometrio/enzimología , Femenino , Ornitina Descarboxilasa/metabolismo , Poliaminas/análisis , Progesterona/análisis , Progesterona/metabolismoRESUMEN
INTRODUCTION: The development of research for diagnosis, prevention and treatment of atherosclerotic cardiovascular disease is of utmost importance due to the fact that it is the main cause of morbidity and mortality in Brazil. OBJECTIVE: To demonstrate the phases of the selection process for candidates with the aim to develop a clinical-laboratorial database of hyper alpha lipoproteinemic patients (hyper A) - high density lipoprotein cholesterol (HDL-C) ≥ 68 mg/dl) and hypo alpha lipoproteinemic patients (hypo A) - HDL-C < 39 mg/dl. MATERIAL AND METHODS: The volunteers were contacted after selection of lipid profiles from individuals treated at the Sistema Único de Saúde (SUS), Campinas-SP and neighboring area. Afterwards, the selected patients went through blood collection, clinical examinations and answered questionnaires on dietary frequency and physical activity. After this preliminary evaluation, some individuals were convened to another blood collection and, subsequently, were submitted to an ultrasonographic exam of the carotid arteries. RESULTS: Only 0.6% and 0.3% from 598,288 lipid profiles were selected for hyper A and hypo A groups, respectively, including gender disparity. Lack of effective questionnaires (75%), missing calls (60%) and non-inclusion were the major hindrances in the construction of this database. DISCUSSION: The difficulties to obtain eligible candidates were also due to the low prevalence of both groups hypo A and hyper A and the high prevalence of pathologies that contribute to non-genetic variations of HDL-C. CONCLUSION: In spite of the obstacles in the development of this database, this study brought about several scientific publications. Furthermore, the development of molecular analyzes and functionality will shortly generate other findings, contributing to the diagnosis and follow-up of HDL dyslipidemias.
INTRODUÇÃO: O desenvolvimento de pesquisa para diagnóstico e prevenção da doença aterosclerótica cardiovascular no Brasil é de grande importância por esta ser a principal causa de morbimortalidade no país. OBJETIVO: Demonstrar as etapas do processo de seleção de voluntários para a construção de um banco de dados clínico-laboratorial de indivíduos hiperalfalipoproteinêmicos (hiper A) - colesterol da lipoproteína de alta densidade (HDL-C) ≥ 68 mg/dl - e hipoalfalipoproteinêmicos (hipo A) - HDL-C < 39 mg/dl. MATERIAL E MÉTODOS: Os voluntários são contatados a partir de resultados de perfis lipídicos de indivíduos atendidos pelo Sistema Único de Saúde (SUS) de Campinas-SP e região e, se selecionados, são convidados para coleta de sangue, exames clínicos e responder a questionários de atividade física e de frequência alimentar. Após essa avaliação, os indivíduos podem ser convocados para nova coleta de sangue e, posteriormente, para a ultrassonografia de carótidas. RESULTADOS: Entre 598.288 perfis lipídicos recebidos das redes públicas, apenas 0,6% e 0,3% compuseram os nossos grupos hiper A e hipo A, com disparidade entre os gêneros. A falta de questionários efetivos (75%), das chamadas não atendidas (60%) e a não inclusão foram os pontos mais difíceis na construção do banco de dados. DISCUSSÃO: A dificuldade de obtenção de voluntários elegíveis também se deve à baixa prevalência de hipo A e hiper A e à alta prevalência de patologias que contribuem para variações não genéticas do HDL-C. CONCLUSÃO: Apesar das dificuldades na criação da base de dados, este estudo gerou várias publicações e, com o desenvolvimento das análises moleculares e da funcionalidade, muitas outras seguirão em curto período, fatos contribuintes para o diagnóstico e o acompanhamento das dislipidemias envolvendo a HDL.
RESUMEN
BACKGROUND: Metabolic predictors and the atherogenicity of oxidized LDL (oxLDL) and the specific antibodies against oxLDL (oxLDL Ab) are unclear and controversial. METHODS: In 107 adults without atherosclerotic manifestations, we measured oxLDL and oxLDL Ab, and also the activities of CETP, PLTP, lipases and the carotid intima-media thickness (cIMT). Comparisons were performed for the studied parameters between the lowest and the highest tertile of oxLDL and oxLDL Ab, and the relationships between studied variables were evaluated. RESULTS: Subjects with higher oxLDL Ab present reduced hepatic lipase activity and borderline increased cIMT. In the highest oxLDL tertile, besides the higher levels of total cholesterol, LDL-C and apoB100, we found reduced CETP activity and higher cIMT. A significant correlation between oxLDL Ab and cIMT, independent of oxLDL, and a borderline correlation between oxLDL and cIMT independent of oxLDL Ab were found. In the multivariate analysis, apoAI was a significant predictor of oxLDL Ab, in contrast to regulation of oxLDL by apoB100, PLTP and inverse of CETP. CONCLUSIONS: In adults without atherosclerotic disease, the metabolic regulation and carotid atherosclerosis of oxLDL Ab and oxLDL groups, characterized a dual trait in oxLDL Ab, as a contributor to carotid atherosclerosis, much less so than oxidized LDL, and with a modest atheroprotective role.
Asunto(s)
Anticuerpos/sangre , Arterias Carótidas/metabolismo , Enfermedades de las Arterias Carótidas/sangre , Colesterol/sangre , Lipoproteínas LDL/sangre , Adulto , Anciano , Análisis de Varianza , Apolipoproteína B-100/sangre , Transporte Biológico , Enfermedades de las Arterias Carótidas/fisiopatología , Grosor Intima-Media Carotídeo , Proteínas de Transferencia de Ésteres de Colesterol/metabolismo , LDL-Colesterol/sangre , Femenino , Humanos , Lipasa/metabolismo , Lipoproteínas LDL/inmunología , Hígado/metabolismo , Persona de Mediana Edad , Proteínas de Transferencia de Fosfolípidos/metabolismo , Factores de RiesgoRESUMEN
Herein, we show that intraerythrocytic stages of Plasmodium falciparum have an active pathway for biosynthesis of menaquinone. Kinetic assays confirmed that plasmodial menaquinone acts at least in the electron transport. Similarly to Escherichia coli, we observed increased levels of menaquinone in parasites kept under anaerobic conditions. Additionally, the mycobacterial inhibitor of menaquinone synthesis Ro 48-8071 also suppressed menaquinone biosynthesis and growth of parasites, although off-targets may play a role in this growth-inhibitory effect. Due to its absence in humans, the menaquinone biosynthesis can be considered an important drug target for malaria.
Asunto(s)
Eritrocitos/parasitología , Estadios del Ciclo de Vida , Plasmodium falciparum/crecimiento & desarrollo , Plasmodium falciparum/metabolismo , Vitamina K 2/análogos & derivados , Anaerobiosis , Animales , Benzofenonas/farmacología , Electrones , Malaria/tratamiento farmacológico , Malaria/metabolismo , Terapia Molecular Dirigida , Plasmodium falciparum/efectos de los fármacos , Vitamina K 2/metabolismoRESUMEN
Background : A broader view of living systems complexity is bringing important contributions to biological sciences, since the genome expression is affected by other classes of molecules, which in their turn interact themselves in cellular metabolic pathways and biochemical networks. This level of information has been made possible by the emergence of the omic strategies, such as proteomics, metabolomics and lipidomics, that are mainly based on mass spectrometry (MS) platforms. MS has presented an incredible development over the last years, evolving to a powerful and universal analytical technique. Its ability to analyze proteins and small molecules such as lipids, sugars and metabolites at the structural level, with sensitivity and speed inconceivable a few years ago, is the major driving force in the omic fields. The development of electrospray and matrix-assisted laser desorption/ionization (MALDI) ionization techniques has decisively contributed to the many applications of this technology nowadays. Herein, we present and discuss omic concepts and strategies, as well as detail basic principles of MS. Applications and future perspectives of these approaches are focused in the reproductive medicine area. Review: The omic technologies propose global characterization of specific classes of target biomolecules of cellular systems as a strategy to achieve comprehensive understanding of biological functions. The genomics, aimed at performing the entire genetic sequencing of organisms, represented the seminal step towards the understanding of the complex logic that orchestrates the function of all organisms or the defects leading to diseases. But to express the phenotype, information needs to flow from DNA via carrier biomolecules through processes that are being addressed by new omic sciences such as the transcriptomics, proteomics, metabolomics, glycomics, lipidomics, and fluxomics. Mass spectrometry (MS) is nowadays the most powerful technique for the structural characterization of biomolecules, and has therefore become the central technique for the omic sciences. Using revolutionary ionization techniques such as electrospray (ESI) and matrix-assisted laser desorption ionization (MALDI), a wide range of biomolecules such as peptides, proteins, lipids and sugars are efficiently transferred in intact ionized forms to the gas phase for MS analysis. The development of ESI-MS and MALDI-MS has been awarded the Nobel Prize for Chemistry in 2002, rocketing the application of MS in the omic sciences. More recently, ambient ionization MS techniques, such as desorption electrospray ionization (DESI) and easy ambient sonic-spray ionization (EASI), have been developed for ionization in the open atmosphere, in a workup free and high throughput fashion directly from sample in their original environments. For the more complex samples, the coupling with separation techniques such as liquid chromatrography (LC) as well as the use of tandem MS (LC-MS/MS) has allowed comprehensive mixture characterization of major biomolecules. Conclusion: This manuscript describes recent advances of MS in the proteomics, metabolomics and lipidomics for biological sciences, and points out the relevant contributions that MS is likely to bring to fundamental and applied research in human and animal embryo biotechnologies.
Asunto(s)
Humanos , Animales , Espectrometría de Masas , Proteómica/tendencias , Embrión de Mamíferos , Metabolómica/tendencias , Lipidómica/tendenciasRESUMEN
Carotenoids are widespread lipophilic pigments synthesized by all photosynthetic organisms and some nonphotosynthetic fungi and bacteria. All carotenoids are derived from the C40 isoprenoid precursor geranylgeranyl pyrophosphate, and their chemical and physical properties are associated with light absorption, free radical scavenging, and antioxidant activity. Carotenoids are generally synthesized in well defined subcellular organelles, the plastids, which are also present in the phylum Apicomplexa, which comprises a number of important human parasites, such as Plasmodium and Toxoplasma. Recently, it was demonstrated that Toxoplasma gondii synthesizes abscisic acid. We therefore asked if Plasmodium falciparum is also capable of synthesizing carotenoids. Herein, biochemical findings demonstrated the presence of carotenoid biosynthesis in the intraerythrocytic stages of the apicomplexan parasite P. falciparum. Using metabolic labeling with radioisotopes, in vitro inhibition tests with norflurazon, a specific inhibitor of plant carotenoid biosynthesis, the results showed that intraerythrocytic stages of P. falciparum synthesize carotenoid compounds. A plasmodial enzyme that presented phytoene synthase activity was also identified and characterized. These findings not only contribute to the current understanding of P. falciparum evolution but shed light on a pathway that could serve as a chemotherapeutic target.
Asunto(s)
Carotenoides/metabolismo , Eritrocitos/parasitología , Plasmodium falciparum/metabolismo , Animales , Clonación Molecular , Herbicidas/farmacología , Humanos , Cinética , Malaria/terapia , Espectrometría de Masas/métodos , Modelos Químicos , Piridazinas/farmacología , Terpenos/química , Toxoplasma/metabolismoRESUMEN
The isoprenoid metabolic pathway in protozoa of the Leishmania genus exhibits distinctive characteristics. These parasites, as well as other members of the Trypanosomatidae family, synthesize ergosterol, instead of cholesterol, as the main membrane sterol lipid. Leishmania has been shown to utilize leucine, instead of acetate as the main precursor for sterol biosynthesis. While mammalian dolichols are molecules containing 15-23 isoprene units, Leishmania amazonensis promastigotes synthesize dolichol of 11 and 12 units. In this paper, we show that the intracellular stages of L. amazonensis, amastigotes, synthesize mainly polyprenols of 9 isoprene units, instead of dolichol.
Asunto(s)
Leishmania mexicana/metabolismo , Terpenos/química , Animales , Butadienos/química , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Dolicoles/biosíntesis , Dolicoles/química , Hemiterpenos/química , Pentanos/química , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
We performed reverse-phase thin-layer chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC) analysis of polyisoprenoids released by sulfonium-salt cleavage with methyl iodide from Plasmodium falciparum proteins labeled with [3H]FPP or [3H]GGPP and showed that a dolichol of 11 isoprene units is bound to 21-28-kDa protein clusters from trophozoite and schizont stages. The dolichol structure was confirmed by electrospray-ionization mass spectrometry analysis. Treatment with protein synthesis inhibitors and RP-HPLC analysis of the proteolytic digestion products from parasite proteins labeled with [35S]cysteine and [3H]FPP showed that the attachment of dolichol to protein is a post-translational event and probably occurs via a covalent bond to cysteine residues.
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Dolicoles/metabolismo , Plasmodium falciparum/metabolismo , Procesamiento Proteico-Postraduccional/fisiología , Proteínas Protozoarias/metabolismo , Animales , Cromatografía Líquida de Alta Presión/métodos , Cromatografía en Capa Delgada/métodos , Cisteína/química , Cisteína/metabolismo , Dolicoles/química , Plasmodium falciparum/química , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Inhibidores de la Síntesis de la Proteína/farmacología , Proteínas Protozoarias/química , Espectrometría de Masa por Ionización de Electrospray/métodosRESUMEN
Direct analysis of polyisoprenoids by electrospray ionization mass spectrometry (ESI-MS) often produces poor results requiring off-line time and sample-consuming derivatization techniques. We describe a simple ESI-MS approach for the direct analysis of polyisoprenoids using several dolichols and polyprenols with different chain sizes as proof-of-principle cases. Lithium iodide is used to promote cationization by intense formation of [M+Li]+ adducts. Thus, detection of polyisoprenoids with mass determination can be performed with high sensitivity (limit of detection [LOD] approximately 100 rhoM), whereas characteristic collision-induced dissociations observed for both dolichols and polyprenols permit investigation of their structure. Using ESI(Li+)-MS and ESI(Li+)-MS/MS analysis, we screened for polyprenol products of an octaprenyl pyrophosphate synthase of Plasmodium falciparum and dolichols in a complex mixture of compounds produced by Leishmania amazonensis and P. falciparum.
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Alcoholes/análisis , Yoduros/química , Litio/química , Polímeros/análisis , Terpenos/análisis , Alcoholes/química , Transferasas Alquil y Aril/metabolismo , Animales , Cationes/química , Cromatografía Líquida de Alta Presión/métodos , Dolicoles/química , Dolicoles/metabolismo , Leishmania/química , Leishmania/metabolismo , Plasmodium falciparum/química , Plasmodium falciparum/metabolismo , Polímeros/química , Sensibilidad y Especificidad , Espectrometría de Masa por Ionización de Electrospray/métodos , Terpenos/químicaRESUMEN
Isoprenoids play important roles in all living organisms as components of structural cholesterol, steroid hormones in mammals, carotenoids in plants, and ubiquinones. Significant differences occur in the length of the isoprenic side chains of ubiquinone between different organisms, suggesting that different enzymes are involved in the synthesis of these side chains. Whereas in Plasmodium falciparum the isoprenic side chains of ubiquinone contain 7-9 isoprenic units, 10-unit side chains are found in humans. In a search for the P. falciparum enzyme responsible for the biosynthesis of isoprenic side chains attached to the benzoquinone ring of ubiquinones, we cloned and expressed a putative polyprenyl synthase. Polyclonal antibodies raised against the corresponding recombinant protein confirmed the presence of the native protein in trophozoite and schizont stages of P. falciparum. The recombinant protein, as well as P. falciparum extracts, showed an octaprenyl pyrophosphate synthase activity, with the formation of a polyisoprenoid with eight isoprenic units, as detected by reverse-phase HPLC and reverse-phase TLC, and confirmed by electrospray ionization and tandem MS analysis. The recombinant and native versions of the enzyme had similar Michaelis constants with the substrates isopentenyl pyrophosphate and farnesyl pyrophosphate. The recombinant enzyme could be competitively inhibited in the presence of the terpene nerolidol. This is the first report that directly demonstrates an octaprenyl pyrophosphate synthase activity in parasitic protozoa. Given the rather low similarity of the P. falciparum enzyme to its human counterpart, decaprenyl pyrophosphate synthase, we suggest that the identified enzyme and its recombinant version could be exploited in the screening of novel drugs.
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Transferasas Alquil y Aril/genética , Transferasas Alquil y Aril/metabolismo , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Plasmodium falciparum/enzimología , Plasmodium falciparum/crecimiento & desarrollo , Transferasas Alquil y Aril/antagonistas & inhibidores , Secuencia de Aminoácidos , Animales , Clonación Molecular , Datos de Secuencia Molecular , Plasmodium falciparum/efectos de los fármacos , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Sesquiterpenos/farmacología , Especificidad por SustratoRESUMEN
The activity of nerolidol, a sesquiterpene used as a food-flavoring agent and currently under testing as a skin penetration enhancer for the transdermal delivery of therapeutic drugs, was evaluated against Leishmania species. Nerolidol inhibited the growth of Leishmania amazonensis, L. braziliensis, and L. chagasi promastigotes and L. amazonensis amastigotes with in vitro 50% inhibitory concentrations of 85, 74, 75, and 67 microM, respectively. The treatment of L. amazonensis-infected macrophages with 100 microM nerolidol resulted in 95% reduction in infection rates. Inhibition of isoprenoid biosynthesis, as shown by reduced incorporation of [2-(14)C]mevalonic acid (MVA) or [1-(14)C]acetic acid precursors into dolichol, ergosterol, and ubiquinone, was observed in nerolidol-treated promastigotes. This drug effect can be attributed to the blockage of an early step in the mevalonate pathway, since incorporation of the precursor [1(n)-(3)H]farnesyl pyrophosphate in polyisoprenoids is not inhibited by nerolidol. L. amazonensis-infected BALB/c mice were treated with intraperitoneal doses of 100 mg/kg/day for 12 days or topically with 5 or 10% ointments for 4 weeks. Significant reduction of lesion sizes in nerolidol treated mice was observed for both treatment routes. However, long-term follow up indicated that the disease was not cured in this highly susceptible animal model. Nonetheless, the in vitro activity of nerolidol against these parasites may prove a useful tool for the development of new drugs for the treatment of leishmaniasis. In addition, biosynthesis of dolichols with 11 and 12 isoprene units was identified in Leishmania, as described for other trypanosomatids and Apicomplexa.
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Antiprotozoarios , Leishmania mexicana/efectos de los fármacos , Sesquiterpenos/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cromatografía en Capa Delgada , Dolicoles/biosíntesis , Dolicoles/química , Ergosterol/biosíntesis , Femenino , Humanos , Leishmania mexicana/crecimiento & desarrollo , Leishmania mexicana/metabolismo , Leishmaniasis/tratamiento farmacológico , Leishmaniasis/parasitología , Leishmaniasis/patología , Metabolismo de los Lípidos , Ratones , Ratones Endogámicos BALB C , Espectrometría de Masa por Ionización de Electrospray , Cola (estructura animal)/patología , Ubiquinona/biosíntesisRESUMEN
Two genes encoding the enzymes 1-deoxy-D-xylulose-5-phosphate synthase and 1-deoxy-D-xylulose-5-phosphate reductoisomerase have been recently identified, suggesting that isoprenoid biosynthesis in Plasmodium falciparum depends on the methylerythritol phosphate (MEP) pathway, and that fosmidomycin could inhibit the activity of 1-deoxy-D-xylulose-5-phosphate reductoisomerase. The metabolite 1-deoxy-D-xylulose-5-phosphate is not only an intermediate of the MEP pathway for the biosynthesis of isopentenyl diphosphate but is also involved in the biosynthesis of thiamin (vitamin B1) and pyridoxal (vitamin B6) in plants and many microorganisms. Herein we report the first isolation and characterization of most downstream intermediates of the MEP pathway in the three intraerythrocytic stages of P. falciparum. These include, 1-deoxy-D-xylulose-5-phosphate, 2-C-methyl-D-erythritol-4-phosphate, 4-(cytidine-5-diphospho)-2-C-methyl-D-erythritol, 4-(cytidine-5-diphospho)-2-C-methyl-D-erythritol-2-phosphate, and 2-C-methyl-D-erythritol-2,4-cyclodiphosphate. These intermediates were purified by HPLC and structurally characterized via biochemical and electrospray mass spectrometric analyses. We have also investigated the effect of fosmidomycin on the biosynthesis of each intermediate of this pathway and isoprenoid biosynthesis (dolichols and ubiquinones). For the first time, therefore, it is demonstrated that the MEP pathway is functionally active in all intraerythrocytic forms of P. falciparum, and de novo biosynthesis of pyridoxal in a protozoan is reported. Its absence in the human host makes both pathways very attractive as potential new targets for antimalarial drug development.