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1.
Biochim Biophys Acta Gen Subj ; 1865(1): 129769, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33141061

RESUMO

BACKGROUND: Oxysterols, which are derivatives of cholesterol produced by enzymic or non-enzymic pathways, are potent regulators of cellular lipid homeostasis. Sterol homeostasis in the brain is an important area of interest with regards to neurodegenerative conditions like Alzheimer's disease (AD). Brain cells including neurons and astrocytes express sterol transporters belonging to the ABC transporter family of proteins, including ABCA1, ABCG1 and ABCG4, and these transporters are considered of interest as therapeutic targets. Although regulation of ABCA1 and ABCG1 is well established, regulation of ABCG4 is still controversial, in particular whether the transporter is an Liver X receptor (LXR) target. ABCG4 is thought to transport cholesterol, oxysterols and cholesterol synthesis intermediates, and was recently found on the blood brain barrier (BBB), implicated in amyloid-beta export. In this study, we investigate the regulation of ABCG4 by oxysterols, cholesterol-synthesis intermediates and cholesterol itself. METHODS: ABC transporter expression was measured in neuroblastoma and gliablastoma cell lines and cells overexpressing ABCG4 in response to synthetic LXR ligands, oxysterols and cholesterol-synthesis intermediates. RESULTS: In contrast to previous reports, ABCG4 expression was induced by a synthetic LXR ligand in U87-MG astrocytes but not in neuroblastoma and BBB endothelial cell lines. In addition, ABCG4 protein was stabilized by cholesterol as was previously shown for ABCG1. ABCG4 protein was furthermore stabilized by cholesterol-synthesis intermediates, desmosterol, lathosterol and lanosterol. CONCLUSIONS: These results identify new aspects of the post-translational control of ABCG4 that warrant further exploration into the role of this transporter in the maintenance of sterol homeostasis in the brain.


Assuntos
Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Receptores X do Fígado/metabolismo , Esteróis/metabolismo , Animais , Astrócitos/metabolismo , Células CHO , Linhagem Celular , Colesterol/metabolismo , Cricetulus , Regulação da Expressão Gênica , Humanos , Ligantes , RNA Mensageiro/metabolismo , Regulação para Cima
2.
PLoS One ; 15(8): e0236633, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785249

RESUMO

The induction of general plant defense responses following the perception of external elicitors is now regarded as the first level of the plant immune response. Depending on the involvement or not of these molecules in pathogenicity, this induction of defense is called either Pathogen-Associated Molecular Pattern (PAMP) Triggered Immunity or Pattern Triggered Immunity-both abbreviated to PTI. Because PTI is assumed to be a widespread and stable form of resistance to infection, understanding the mechanisms driving it becomes a major goal for the sustainable management of plant-pathogen interactions. However, the induction of PTI is complex. Our hypotheses are that (i) the recognition by the plant of PAMPs vs non-PAMP elicitors leads to specific defense profiles and (ii) the responses specifically induced by PAMPs target critical life history traits of the pathogen that produced them. We thus analyzed, using a metabolomic approach coupled with transcriptomic and hormonal analyses, the defense profiles induced in potato foliage treated with either a Concentrated Culture Filtrate (CCF) from Phytophthora infestans or two non-PAMP preparations, ß-aminobutyric acid (BABA) and an Ulva spp. Extract, used separately. Each elicitor induced specific defense profiles. CCF up-regulated sesquiterpenes but down-regulated sterols and phenols, notably α-chaconine, caffeoyl quinic acid and rutin, which decreased spore production of P. infestans in vitro. CCF thus induces both defense and counter-defense responses. By contrast, the Ulva extract triggered the synthesis of a large-spectrum of antimicrobial compounds through the phenylpropanoid/flavonoid pathways, while BABA targeted the primary metabolism. Hence, PTI can be regarded as a heterogeneous set of general and pathogen-specific responses triggered by the molecular signatures of each elicitor, rather than as a uniform, non-specific and broad-spectrum set of general defense reactions.


Assuntos
Resistência à Doença/imunologia , Doenças das Plantas/imunologia , Imunidade Vegetal/imunologia , Solanum tuberosum/imunologia , Aminobutiratos/farmacologia , Resistência à Doença/efeitos dos fármacos , Flavonoides/biossíntese , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Fenóis/metabolismo , Phytophthora infestans/imunologia , Phytophthora infestans/patogenicidade , Doenças das Plantas/microbiologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Imunidade Vegetal/efeitos dos fármacos , Sesquiterpenos/metabolismo , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/microbiologia , Esteróis/metabolismo , Ulva/química
3.
PLoS Pathog ; 16(8): e1008810, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817704

RESUMO

Sterol 14-α-demethylase (C14DM) is a key enzyme in the biosynthesis of sterols and the primary target of azoles. In Leishmania major, genetic or chemical inactivation of C14DM leads to accumulation of 14-methylated sterol intermediates and profound plasma membrane abnormalities including increased fluidity and failure to maintain ordered membrane microdomains. These defects likely contribute to the hypersensitivity to heat and severely reduced virulence displayed by the C14DM-null mutants (c14dm‾). In addition to plasma membrane, sterols are present in intracellular organelles. In this study, we investigated the impact of C14DM ablation on mitochondria. Our results demonstrate that c14dm‾ mutants have significantly higher mitochondrial membrane potential than wild type parasites. Such high potential leads to the buildup of reactive oxygen species in the mitochondria, especially under nutrient-limiting conditions. Consistent with these mitochondrial alterations, c14dm‾ mutants show impairment in respiration and are heavily dependent on glucose uptake and glycolysis to generate energy. Consequently, these mutants are extremely sensitive to glucose deprivation and such vulnerability can be rescued through the supplementation of glucose or glycerol. In addition, the accumulation of oxidants may also contribute to the heat sensitivity exhibited by c14dm‾. Finally, genetic or chemical ablation of C14DM causes increased susceptibility to pentamidine, an antimicrobial agent with activity against trypanosomatids. In summary, our investigation reveals that alteration of sterol synthesis can negatively affect multiple cellular processes in Leishmania parasites and make them vulnerable to clinically relevant stress conditions.


Assuntos
Leishmania major/enzimologia , Leishmania major/fisiologia , Leishmaniose Cutânea/patologia , Mitocôndrias/fisiologia , Proteínas de Protozoários/metabolismo , Esterol 14-Desmetilase/metabolismo , Esteróis/metabolismo , Humanos , Leishmaniose Cutânea/metabolismo , Leishmaniose Cutânea/parasitologia , Potencial da Membrana Mitocondrial , Proteínas de Protozoários/genética , Espécies Reativas de Oxigênio/metabolismo , Esterol 14-Desmetilase/genética
4.
Proc Natl Acad Sci U S A ; 117(26): 14948-14957, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541034

RESUMO

Diverting aminoacyl-transfer RNAs (tRNAs) from protein synthesis is a well-known process used by a wide range of bacteria to aminoacylate membrane constituents. By tRNA-dependently adding amino acids to glycerolipids, bacteria change their cell surface properties, which intensifies antimicrobial drug resistance, pathogenicity, and virulence. No equivalent aminoacylated lipids have been uncovered in any eukaryotic species thus far, suggesting that tRNA-dependent lipid remodeling is a process restricted to prokaryotes. We report here the discovery of ergosteryl-3ß-O-l-aspartate (Erg-Asp), a conjugated sterol that is produced by the tRNA-dependent addition of aspartate to the 3ß-OH group of ergosterol, the major sterol found in fungal membranes. In fact, Erg-Asp exists in the majority of "higher" fungi, including species of biotechnological interest, and, more importantly, in human pathogens like Aspergillus fumigatus We show that a bifunctional enzyme, ergosteryl-3ß-O-l-aspartate synthase (ErdS), is responsible for Erg-Asp synthesis. ErdS corresponds to a unique fusion of an aspartyl-tRNA synthetase-that produces aspartyl-tRNAAsp (Asp-tRNAAsp)-and of a Domain of Unknown Function 2156, which actually transfers aspartate from Asp-tRNAAsp onto ergosterol. We also uncovered that removal of the Asp modifier from Erg-Asp is catalyzed by a second enzyme, ErdH, that is a genuine Erg-Asp hydrolase participating in the turnover of the conjugated sterol in vivo. Phylogenomics highlights that the entire Erg-Asp synthesis/degradation pathway is conserved across "higher" fungi. Given the central roles of sterols and conjugated sterols in fungi, we propose that this tRNA-dependent ergosterol modification and homeostasis system might have broader implications in membrane remodeling, trafficking, antimicrobial resistance, or pathogenicity.


Assuntos
Ácido Aspártico/metabolismo , Aspergillus fumigatus/metabolismo , RNA Fúngico/metabolismo , Aminoacil-RNA de Transferência/metabolismo , Esteróis/metabolismo , Aminoacilação , Ácido Aspártico/química , Aspergillus fumigatus/química , Aspergillus fumigatus/genética , RNA Fúngico/química , RNA Fúngico/genética , Aminoacil-RNA de Transferência/química , Aminoacil-RNA de Transferência/genética , Esteróis/química
5.
Appl Environ Microbiol ; 86(16)2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32503912

RESUMO

Vertebrates synthesize a diverse set of steroids and bile acids that undergo bacterial biotransformations. The endocrine literature has principally focused on the biochemistry and molecular biology of host synthesis and tissue-specific metabolism of steroids. Host-associated microbiota possess a coevolved set of steroid and bile acid modifying enzymes that match the majority of host peripheral biotransformations in addition to unique capabilities. The set of host-associated microbial genes encoding enzymes involved in steroid transformations is known as the sterolbiome. This review focuses on the current knowledge of the sterolbiome as well as its importance in medicine and agriculture.


Assuntos
Ácidos e Sais Biliares/metabolismo , Microbioma Gastrointestinal/genética , Esteróis/metabolismo , Vertebrados/microbiologia , Animais , Vertebrados/metabolismo
6.
Appl Environ Microbiol ; 86(17)2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32561581

RESUMO

Biosynthesis of sterols, which are considered essential components of virtually all eukaryotic membranes, requires molecular oxygen. Anaerobic growth of the yeast Saccharomyces cerevisiae therefore strictly depends on sterol supplementation of synthetic growth media. Neocallimastigomycota are a group of strictly anaerobic fungi which, instead of containing sterols, contain the pentacyclic triterpenoid "sterol surrogate" tetrahymanol, which is formed by cyclization of squalene. Here, we demonstrate that expression of the squalene-tetrahymanol cyclase gene TtTHC1 from the ciliate Tetrahymena thermophila enables synthesis of tetrahymanol by S. cerevisiae Moreover, expression of TtTHC1 enabled exponential growth of anaerobic S. cerevisiae cultures in sterol-free synthetic media. After deletion of the ERG1 gene from a TtTHC1-expressing S. cerevisiae strain, native sterol synthesis was abolished and sustained sterol-free growth was demonstrated under anaerobic as well as aerobic conditions. Anaerobic cultures of TtTHC1-expressing S. cerevisiae on sterol-free medium showed lower specific growth rates and biomass yields than ergosterol-supplemented cultures, while their ethanol yield was higher. This study demonstrated that acquisition of a functional squalene-tetrahymanol cyclase gene offers an immediate growth advantage to S. cerevisiae under anaerobic, sterol-limited conditions and provides the basis for a metabolic engineering strategy to eliminate the oxygen requirements associated with sterol synthesis in yeasts.IMPORTANCE The laboratory experiments described in this report simulate a proposed horizontal gene transfer event during the evolution of strictly anaerobic fungi. The demonstration that expression of a single heterologous gene sufficed to eliminate anaerobic sterol requirements in the model eukaryote Saccharomyces cerevisiae therefore contributes to our understanding of how sterol-independent eukaryotes evolved in anoxic environments. This report provides a proof of principle for a metabolic engineering strategy to eliminate sterol requirements in yeast strains that are applied in large-scale anaerobic industrial processes. The sterol-independent yeast strains described in this report provide a valuable platform for further studies on the physiological roles and impacts of sterols and sterol surrogates in eukaryotic cells.


Assuntos
Expressão Gênica , Liases/genética , Proteínas de Protozoários/genética , Saccharomyces cerevisiae/genética , Tetrahymena thermophila/genética , Evolução Biológica , Transferência Genética Horizontal , Liases/metabolismo , Microrganismos Geneticamente Modificados/genética , Microrganismos Geneticamente Modificados/metabolismo , Proteínas de Protozoários/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Esteróis/metabolismo
7.
J Virol ; 94(12)2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32269127

RESUMO

Positive-strand RNA [(+)RNA] viruses assemble numerous membrane-bound viral replicase complexes (VRCs) with the help of viral replication proteins and co-opted host proteins within large viral replication compartments in the cytosol of infected cells. In this study, we found that deletion or depletion of Sac1 phosphatidylinositol 4-phosphate [PI(4)P] phosphatase reduced tomato bushy stunt virus (TBSV) replication in yeast (Saccharomyces cerevisiae) and plants. We demonstrate a critical role for Sac1 in TBSV replicase assembly in a cell-free replicase reconstitution assay. The effect of Sac1 seems to be direct, based on its interaction with the TBSV p33 replication protein, its copurification with the tombusvirus replicase, and its presence in the virus-induced membrane contact sites and within the TBSV replication compartment. The proviral functions of Sac1 include manipulation of lipid composition, sterol enrichment within the VRCs, and recruitment of additional host factors into VRCs. Depletion of Sac1 inhibited the recruitment of Rab5 GTPase-positive endosomes and enrichment of phosphatidylethanolamine in the viral replication compartment. We propose that Sac1 might be a component of the assembly hub for VRCs, likely in collaboration with the co-opted the syntaxin18-like Ufe1 SNARE protein within the TBSV replication compartments. This work also led to demonstration of the enrichment of PI(4)P phosphoinositide within the replication compartment. Reduction in the PI(4)P level due to chemical inhibition in plant protoplasts; depletion of two PI(4)P kinases, Stt4p and Pik1p; or sequestration of free PI(4)P via expression of a PI(4)P-binding protein in yeast strongly inhibited TBSV replication. Altogether, Sac1 and PI(4)P play important proviral roles during TBSV replication.IMPORTANCE Replication of positive-strand RNA viruses depends on recruitment of host components into viral replication compartments or organelles. Using TBSV, we uncovered the critical roles of Sac1 PI(4)P phosphatase and its substrate, PI(4)P phosphoinositide, in promoting viral replication. Both Sac1 and PI(4)P are recruited to the site of viral replication to facilitate the assembly of the viral replicase complexes, which perform viral RNA replication. We found that Sac1 affects the recruitment of other host factors and enrichment of phosphatidylethanolamine and sterol lipids within the subverted host membranes to promote optimal viral replication. In summary, this work demonstrates the novel functions of Sac1 and PI(4)P in TBSV replication in the model host yeast and in plants.


Assuntos
Interações Hospedeiro-Patógeno/genética , Fosfatos de Fosfatidilinositol/metabolismo , Monoéster Fosfórico Hidrolases/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Tombusvirus/genética , Replicação Viral/genética , 1-Fosfatidilinositol 4-Quinase/genética , 1-Fosfatidilinositol 4-Quinase/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/virologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Endossomos/metabolismo , Regulação da Expressão Gênica , Fosfatidiletanolaminas/genética , Fosfatidiletanolaminas/metabolismo , Monoéster Fosfórico Hidrolases/deficiência , Monoéster Fosfórico Hidrolases/metabolismo , Células Vegetais/metabolismo , Células Vegetais/virologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/virologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Protoplastos/metabolismo , Proteínas Qa-SNARE/genética , Proteínas Qa-SNARE/metabolismo , /metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/virologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais , Esteróis/metabolismo , Tabaco/genética , Tabaco/metabolismo , Tabaco/virologia , Tombusvirus/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas rab5 de Ligação ao GTP/genética , Proteínas rab5 de Ligação ao GTP/metabolismo
8.
J Plant Res ; 133(3): 383-392, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32185672

RESUMO

Sterols are important lipid constituents of cellular membranes in plants and other organisms. Sterol homeostasis is under strict regulation in plants because excess sterols negatively impact plant growth. HIGH STEROL ESTER 1 (HISE1) functions as a negative regulator of sterol accumulation. If sterol production exceeds a certain threshold, excess sterols are detoxified via conversion to sterol esters by PHOSPHOLIPID STEROL ACYL TRANSFERASE 1 (PSAT1). We previously reported that the Arabidopsis thaliana double mutant hise1-3 psat1-2 shows 1.5-fold higher sterol content than the wild type and consequently a severe growth defect. However, the specific defects caused by excess sterol accumulation in plants remain unknown. In this study, we investigated the effects of excess sterols on plants by analyzing the phenotypes and transcriptomes of the hise1-3 psat1-2 double mutant. Transcriptomic analysis revealed that 435 genes were up-regulated in hise1-3 psat1-2 leaves compared with wild-type leaves. Gene ontology (GO) enrichment analysis revealed that abiotic and biotic stress-responsive genes including RESPONSIVE TO DESICCATION 29B/LOW-TEMPERATURE-INDUCED 65 (RD29B/LTI65) and COLD-REGULATED 15A (COR15A) were up-regulated in hise1-3 psat1-2 leaves compared with wild-type leaves. Expression levels of senescence-related genes were also much higher in hise1-3 psat1-2 leaves than in wild-type leaves. hise1-3 psat1-2 leaves showed early senescence, suggesting that excess sterols induce senescence of leaves. In the absence of sucrose, hise1-3 psat1-2 exhibited defects in seedling growth and root elongation. Together, our data suggest that excess sterol accumulation disrupts cellular activities of vegetative organs including leaves and roots, resulting in multiple damages to plants.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Esteróis/metabolismo , Arabidopsis/genética , Mutação
9.
Artigo em Inglês | MEDLINE | ID: mdl-32169653

RESUMO

During cold acclimation fruit flies switch their feeding from yeast to plant food, however there are no robust molecular markers to monitor this in the wild. Drosophila melanogaster is a sterol auxotroph and relies on dietary sterols to produce lipid membranes, lipoproteins and molting hormones. We employed shotgun lipidomics to quantify eight major food sterols in total lipid extracts of heads and genital tracts of adult male and female flies. We found that their sterol composition is dynamic and reflective of fly diet in an organ-specific manner. Season-dependent changes observed in the organs of wild-living flies suggested that the molar ratio between yeast (ergosterol, zymosterol) and plant (sitosterol, stigmasterol) sterols is a quantifiable, generic and unequivocal marker of their feeding behavior suitable for ecological and environmental population-based studies. The enrichment of phytosterols over yeast sterols in wild-living flies at low temperatures is consistent with switching from yeast to plant diet and corroborates the concomitantly increased unsaturation of their membrane lipids.


Assuntos
Dieta , Esteróis/metabolismo , Aclimatação , Animais , Drosophila melanogaster , Feminino , Masculino
10.
Sci Rep ; 10(1): 4204, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144288

RESUMO

Diatoms are ubiquitous microalgae that have developed remarkable metabolic plasticity and gene diversification. Here we report the first elucidation of the complete biosynthesis of sterols in the lineage. The study has been carried out on the bloom-forming species Skeletonema marinoi and Cyclotella cryptica that synthesise an ensemble of sterols with chemotypes of animals (cholesterol and desmosterol), plants (dihydrobrassicasterol and 24-methylene cholesterol), algae (fucosterol) and marine invertebrates (clionasterol). In both species, sterols derive from mevalonate through cyclization of squalene to cycloartenol by cycloartenol synthase. The pathway anticipates synthesis of cholesterol by enzymes of the phytosterol route in plants, as recently reported in Solanaceae. Major divergences stem from reduction of Δ24(28) and Δ24(25) double bonds which, in diatoms, are apparently dependent on sterol reductases of fungi, algae and animals. Phylogenetic comparison revealed a good level of similarity between the sterol biosynthetic genes of S. marinoi and C. cryptica with those in the genomes of the other diatoms sequenced so far.


Assuntos
Diatomáceas/metabolismo , Esteróis/metabolismo , Animais , Transferases Intramoleculares/metabolismo , Ácido Mevalônico/metabolismo , Filogenia , Fitosteróis/metabolismo , Transdução de Sinais/fisiologia , Solanaceae/metabolismo , Esqualeno/metabolismo , Triterpenos/metabolismo
11.
Sci Rep ; 10(1): 3309, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32094454

RESUMO

Cannabis research has historically focused on the most prevalent cannabinoids. However, extracts with a broad spectrum of secondary metabolites may have increased efficacy and decreased adverse effects compared to cannabinoids in isolation. Cannabis's complexity contributes to the length and breadth of its historical usage, including the individual application of the leaves, stem barks, and roots, for which modern research has not fully developed its therapeutic potential. This study is the first attempt to profile secondary metabolites groups in individual plant parts comprehensively. We profiled 14 cannabinoids, 47 terpenoids (29 monoterpenoids, 15 sesquiterpenoids, and 3 triterpenoids), 3 sterols, and 7 flavonoids in cannabis flowers, leaves, stem barks, and roots in three chemovars available. Cannabis inflorescence was characterized by cannabinoids (15.77-20.37%), terpenoids (1.28-2.14%), and flavonoids (0.07-0.14%); the leaf by cannabinoids (1.10-2.10%), terpenoids (0.13-0.28%), and flavonoids (0.34-0.44%); stem barks by sterols (0.07-0.08%) and triterpenoids (0.05-0.15%); roots by sterols (0.06-0.09%) and triterpenoids (0.13-0.24%). This comprehensive profile of bioactive compounds can form a baseline of reference values useful for research and clinical studies to understand the "entourage effect" of cannabis as a whole, and also to rediscover therapeutic potential for each part of cannabis from their traditional use by applying modern scientific methodologies.


Assuntos
Cannabis/metabolismo , Inflorescência/metabolismo , Casca de Planta/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Metabolismo Secundário , Vias Biossintéticas , Canabinoides/metabolismo , Flavonoides/metabolismo , Reprodutibilidade dos Testes , Sesquiterpenos/metabolismo , Esteróis/metabolismo
12.
Molecules ; 25(4)2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32070000

RESUMO

Invertebrates are an important source of structurally-diverse and biologically-active halogenated metabolites. The sea hare Aplysia dactylomela Rang has long been known to possess halogenated metabolites of dietary origin that are used as a self-defense mechanism. The compounds from Aplysia dactylomela Rang are comprised mainly of terpenoids and small percentages of C-15 acetogenins, indoles, macrolides, sterols and alkaloids with potent cytotoxic, anti-microbial and anti-inflammatory properties. For decades the metabolites discovered have been investigated for their medical and pharmaceutical applications, so much so that the ecological role of the metabolites has been overlooked. The interaction between Aplysia dactylomela Rang and its diet that is comprised of seaweed can provide information into the distribution and diversity of the seaweed, the application of bioaccumulated secondary metabolites as part of its defense mechanism and the potential roles of these metabolites for adaptation in the marine environment. This paper compiles the diversity of halogenated secondary metabolites documented from Aplysia dactylomela Rang.


Assuntos
Aplysia/metabolismo , Acetogeninas/metabolismo , Alcaloides/metabolismo , Animais , Halogenação , Indóis/metabolismo , Macrolídeos/metabolismo , Alga Marinha , Esteróis/metabolismo
13.
Nat Commun ; 11(1): 984, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-32080181

RESUMO

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of functionally versatile proteins that play critical roles in the biogenesis, cellular localization and transport of RNA. Here, we outline a role for hnRNPs in gene regulatory circuits controlling sterol homeostasis. Specifically, we find that tissue-selective loss of the conserved hnRNP RALY enriches for metabolic pathways. Liver-specific deletion of RALY alters hepatic lipid content and serum cholesterol level. In vivo interrogation of chromatin architecture and genome-wide RALY-binding pattern reveal insights into its cooperative interactions and mode of action in regulating cholesterogenesis. Interestingly, we find that RALY binds the promoter region of the master metabolic regulator Srebp2 and show that it directly interacts with coactivator Nuclear Transcription Factor Y (NFY) to influence cholesterogenic gene expression. Our work offers insights into mechanisms orchestrating selective promoter activation in metabolic control and a model by which hnRNPs can impact health and disease states.


Assuntos
Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Metabolismo dos Lipídeos/genética , Esteróis/metabolismo , Animais , Fator de Ligação a CCAAT/metabolismo , Colesterol/biossíntese , Colesterol/genética , Regulação da Expressão Gênica , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/deficiência , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Humanos , Fígado/metabolismo , Masculino , Redes e Vias Metabólicas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regiões Promotoras Genéticas , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Distribuição Tecidual
14.
Arterioscler Thromb Vasc Biol ; 40(3): 597-610, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31996021

RESUMO

OBJECTIVE: By binding to its high-affinity receptor FcεR1, IgE activates mast cells, macrophages, and other inflammatory and vascular cells. Recent studies support an essential role of IgE in cardiometabolic diseases. Plasma IgE level is an independent predictor of human coronary heart disease. Yet, a direct role of IgE and its mechanisms in cardiometabolic diseases remain incompletely understood. Approach and Results: Using atherosclerosis prone Apoe-/- mice and IgE-deficient Ige-/- mice, we demonstrated that IgE deficiency reduced atherosclerosis lesion burden, lesion lipid deposition, smooth muscle cell and endothelial cell contents, chemokine MCP (monocyte chemoattractant protein)-1 expression and macrophage accumulation. IgE deficiency also reduced bodyweight gain and increased glucose and insulin sensitivities with significantly reduced plasma cholesterol, triglyceride, insulin, and inflammatory cytokines and chemokines, including IL (interleukin)-6, IFN (interferon)-γ, and MCP-1. From atherosclerotic lesions and peritoneal macrophages from Apoe-/-Ige-/- mice that consumed an atherogenic diet, we detected reduced expression of M1 macrophage markers (CD68, MCP-1, TNF [tumor necrosis factor]-α, IL-6, and iNOS [inducible nitric oxide synthase]) but increased expression of M2 macrophage markers (Arg [arginase]-1 and IL-10) and macrophage-sterol-responsive-network molecules (complement C3, lipoprotein lipase, LDLR [low-density lipoprotein receptor]-related protein 1, and TFR [transferrin]) that suppress macrophage foam cell formation. These IgE activities can be reproduced in bone marrow-derived macrophages from wild-type mice, but muted in cells from FcεR1-deficient mice, or blocked by anti-IgE antibody or complement C3 deficiency. CONCLUSIONS: IgE deficiency protects mice from diet-induced atherosclerosis, obesity, glucose tolerance, and insulin resistance by regulating macrophage polarization, macrophage-sterol-responsive-network gene expression, and foam cell formation.


Assuntos
Aorta/metabolismo , Aterosclerose/metabolismo , Células Espumosas/metabolismo , Imunoglobulina E/metabolismo , Inflamação/metabolismo , Ativação de Macrófagos , Macrófagos Peritoneais/metabolismo , Obesidade/metabolismo , Animais , Aorta/imunologia , Aorta/patologia , Aterosclerose/imunologia , Aterosclerose/patologia , Aterosclerose/prevenção & controle , Glicemia/metabolismo , Células Cultivadas , Citocinas/metabolismo , Modelos Animais de Doenças , Células Espumosas/imunologia , Células Espumosas/patologia , Redes Reguladoras de Genes , Imunoglobulina E/deficiência , Imunoglobulina E/genética , Inflamação/imunologia , Inflamação/patologia , Inflamação/prevenção & controle , Mediadores da Inflamação/metabolismo , Resistência à Insulina , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Obesidade/imunologia , Obesidade/patologia , Obesidade/prevenção & controle , Fenótipo , Placa Aterosclerótica , Receptores de IgE/genética , Receptores de IgE/metabolismo , Transdução de Sinais , Esteróis/metabolismo
15.
J Sci Food Agric ; 100(2): 500-508, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31435948

RESUMO

BACKGROUND: In the present study a metabolomics-based approach was used to discriminate among different hazelnut cultivars and to trace their geographical origins. Ultra-high-pressure liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-ESI/QTOF-MS) was used to profile phenolic and sterolic compounds. RESULTS: Compounds were identified against an in-house database using accurate monoisotopic mass and isotopic patterns. The screening approach was designed to discern 15 hazelnut cultivars and to discriminate among the geographical origins of six cultivars from the four main growing regions (Chile, Georgia, Italy, and Turkey). This approach allowed more than 1000 polyphenols and sterols to be annotated. The metabolomics data were elaborated with both unsupervised (hierarchical clustering) and supervised (orthogonal projections to latent structures discriminant analysis, OPLS-DA) statistics. These multivariate statistical tools allowed hazelnut samples to be discriminated, considering both 'cultivar type' and 'geographical origin'. Flavonoids (anthocyanins, flavanols and flavonols - VIP scores 1.34-1.49), phenolic acids (mainly hydroxycinnamics - VIP scores 1.35-1.55) together with cholesterol, ergosterol, and stigmasterol derivatives (VIP scores 1.34-1.49) were the best markers to discriminate samples according to geographical origin. CONCLUSIONS: This work illustrates the potential of untargeted profiling of phenolics and sterols based on UHPLC-ESI/QTOF mass spectrometry to discriminate hazelnut and support authenticity and origin. © 2019 Society of Chemical Industry.


Assuntos
Corylus/química , Nozes/química , Extratos Vegetais/química , Chile , Cromatografia Líquida de Alta Pressão , Corylus/classificação , Corylus/metabolismo , Análise Discriminante , República da Geórgia , Itália , Espectrometria de Massas , Metabolômica , Análise Multivariada , Nozes/classificação , Nozes/metabolismo , Fenóis/química , Fenóis/metabolismo , Extratos Vegetais/metabolismo , Esteróis/química , Esteróis/metabolismo , Turquia
16.
Mol Neurobiol ; 57(2): 860-878, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31506900

RESUMO

Chronic relapsing experimental allergic encephalomyelitis (CR-EAE) exhibits neuropathological and immunological dysfunctions similar to those found in multiple sclerosis (MS) and has been used as an animal model of MS. Inflammatory infiltrates and oxidative stress have been linked to the development of both diseases. Ethanolamine plasmalogen derivates have been shown to be powerful antioxidants and immunomodulators. Therefore, the objective of this study was to analyse inflammatory infiltrates, the state of the oxidative defences and the possible protective effects of calcium, magnesium and phosphate ethanolamine (EAP) in the CR-EAE rat hippocampus. To this aim, we evaluated, by immunohistochemistry, T cell infiltrates, Iba-1+ (a marker of activated microglia) immunoreactivity and TUNEL (+) cells. We also measured the protein levels and activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GP) and glutathione reductase (GR). In addition, reduced (GSH) and oxidized (GSSG) glutathione levels, lipid peroxidation and cholesterol as well as desmosterol content were determined. We found an increase in T cell infiltrates and Iba1+ immunoreactivity, lipid peroxidation, SOD, GP and GR activities as well as enhanced cholesterol levels and a decrease in CAT activity, GSH and desmosterol levels in the first and second attack in the CR-EAE rat hippocampus. Pretreatment of CR-EAE rats with EAP led to a delay in the onset of the clinical signs of the disease as well as a decrease in inflammatory infiltrates and alterations of the antioxidant defences in the hippocampus. Altogether, the present results suggest a protective role of EAP in the CR-EAE rat hippocampus.


Assuntos
Encefalomielite Autoimune Experimental/imunologia , Etanolaminas/uso terapêutico , Hipocampo/patologia , Hipersensibilidade/imunologia , Linfócitos/patologia , Fármacos Neuroprotetores/uso terapêutico , Estresse Oxidativo , Animais , Apoptose/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Complexo CD3/metabolismo , Catalase/metabolismo , Doença Crônica , Encefalomielite Autoimune Experimental/enzimologia , Encefalomielite Autoimune Experimental/patologia , Etanolaminas/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Hipersensibilidade/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Ratos Endogâmicos Lew , Ratos Wistar , Recidiva , Esteróis/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo
17.
Biochimie ; 169: 3-11, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31291593

RESUMO

Diatoms are a phylum of unicellular photosynthetic eukaryotes living in oceans and fresh waters, characterized by the complexity of their plastid, resulting from a secondary endosymbiosis event. In the model diatom Phaeodactylum tricornutum, fatty acids (FAs) are synthesized from acetyl-CoA in the stroma of the plastid, producing palmitic acid. FAs are elongated and desaturated to form very-long chain polyunsaturated fatty acids (VLC-PUFAs) in domains of the endomembrane system that need to be identified. Synthesis of VLC-PUFAs is coupled with their import to the core of the plastid via the so-called "omega" pathway. The biosynthesis of sterols in diatoms is likely to be localized in the endoplasmic reticulum as well as using precursors deriving from the mevalonate pathway, using acetyl-CoA as initial substrate. These metabolic modules can be characterized functionally by genetic analyzes or chemical treatments with appropriate inhibitors. Some 'metabolic modules' are characterized by a very low level of metabolic intermediates. Since some chemical treatments or genetic perturbation of lipid metabolism induce the accumulation of these intermediates, channeling processes are possibly involved, suggesting that protein-protein interactions might occur between enzymes within large size complexes or metabolons. At the junction of these modules, metabolic intermediates might therefore play dramatic roles in directing carbon fluxes from one direction to another. Here, acetyl-CoA seems determinant in the balance between TAGs and sterols. Future lines of research and potential utilization for biotechnological applications are discussed.


Assuntos
Acetilcoenzima A/metabolismo , Diatomáceas/metabolismo , Retículo Endoplasmático/metabolismo , Metabolismo dos Lipídeos/fisiologia , Plastídeos/metabolismo , Esteróis/metabolismo , Proteínas de Algas/metabolismo , Carbono/metabolismo , Ácidos Graxos Insaturados/metabolismo , Ácido Mevalônico/metabolismo , Complexos Multienzimáticos/metabolismo , Ácido Palmítico/metabolismo , Triglicerídeos/metabolismo
19.
Int J Biol Macromol ; 143: 814-824, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31734363

RESUMO

Plant proteins are emerging as an alternative to conventional treatments against candidiasis. The aim of this study was to better understand the mechanism of action of Mo-CBP2 against Candida spp, evaluating redox system activity, lipid peroxidation, DNA degradation, cytochrome c release, medium acidification, and membrane interaction. Anti-candida activity of Mo-CBP2 decreased in the presence of ergosterol, which was not observed with antioxidant agents. C. albicans treated with Mo-CBP2 also had catalase and peroxidase activities inhibited, while superoxide dismutase was increased. Mo-CBP2 increased the lipid peroxidation, but it did not alter the ergosterol profile in live cells. External medium acidification was strongly inhibited, and cytochrome c release and DNA degradation were detected. Mo-CBP2 interacts with cell membrane constituents, changes redox system enzymes in C. albicans and causes lipid peroxidation by ROS overproduction. DNA degradation and cytochrome c release suggest apoptotic or DNAse activity. Lipid peroxidation and H+-ATPases inhibition may induce the process of apoptosis. Finally, Mo-CBP2 did not have a cytotoxic effect in mammalian Vero cells. This study highlights the biotechnological potential of Mo-CBP2 as a promising molecule with low toxicity and potent activity. Further studies should be performed to better understand its mode of action and toxicity.


Assuntos
Candida/efeitos dos fármacos , Membrana Celular/metabolismo , Moringa oleifera/química , Proteínas de Plantas/farmacologia , Sementes/química , Esteróis/metabolismo , Animais , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Citocromos c/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Ergosterol/metabolismo , Glucose/farmacologia , Itraconazol/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Nistatina/farmacologia , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Células Vero
20.
Appl Environ Microbiol ; 86(2)2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31704679

RESUMO

Steryl esters (SEs) are important storage compounds in many eukaryotes and are often prominent components of intracellular lipid droplets. Here, we demonstrate that selected Actino- and Proteobacteria growing on sterols are also able to synthesize SEs and to sequester them in cytoplasmic lipid droplets. We found cholesteryl ester (CE) formation in members of the actinobacterial genera Rhodococcus, Mycobacterium, and Amycolatopsis, as well as several members of the proteobacterial Cellvibrionales order. CEs maximally accumulated under nitrogen-limiting conditions, suggesting that steryl ester formation plays a crucial role for storing excess energy and carbon under adverse conditions. Rhodococcus jostii RHA1 was able to synthesize phytosteryl and cholesteryl esters, the latter reaching up to 7% of its cellular dry weight and 69% of its lipid droplets. Purified lipid droplets from RHA1 contained CEs, free cholesterol, and triacylglycerols. In addition, we found formation of CEs in Mycobacterium tuberculosis when it was grown with cholesterol plus an additional fatty acid substrate. This study provides a basis for the application of bacterial whole-cell systems in the biotechnological production of SEs for use in functional foods and cosmetics.IMPORTANCE Oleaginous bacteria exhibit great potential for the production of high-value neutral lipids, such as triacylglycerols and wax esters. This study describes the formation of steryl esters (SEs) as neutral lipid storage compounds in sterol-degrading oleaginous bacteria, providing a basis for biotechnological production of SEs using bacterial systems with potential applications in the functional food, nutraceutical, and cosmetic industries. We found cholesteryl ester (CE) formation in several sterol-degrading Actino- and Proteobacteria under nitrogen-limiting conditions, suggesting an important role of this process in storing energy and carbon under adverse conditions. In addition, Mycobacterium tuberculosis grown on cholesterol accumulated CEs in the presence of an additional fatty acid substrate.


Assuntos
Bactérias/metabolismo , Ésteres/metabolismo , Esteroides/metabolismo , Esteróis/metabolismo , Gotículas Lipídicas/metabolismo
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