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1.
Adv Exp Med Biol ; 1272: 93-116, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845504

RESUMO

The tumor microenvironment (TME) plays a key role in enhancing the growth of malignant tumors and thus contributing to "aggressive phenotypes," supporting sustained tumor growth and metastasis. The precise interplay between the numerous components of the TME that contribute to the emergence of these aggressive phenotypes is yet to be elucidated and currently under intense investigation. The purpose of this article is to identify specific role(s) for lipoproteins as part of these processes that facilitate (or oppose) malignant growth as they interact with specific components of the TME during tumor development and treatment. Because of the scarcity of literature reports regarding the interaction of lipoproteins with the components of the tumor microenvironment, we were compelled to explore topics that were only tangentially related to this topic, to ensure that we have not missed any important concepts.


Assuntos
Lipoproteínas , Neoplasias , Microambiente Tumoral , Humanos , Lipoproteínas/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias/terapia
2.
PLoS Pathog ; 16(8): e1008639, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32790743

RESUMO

Leptospirosis is a worldwide re-emerging zoonosis caused by pathogenic Leptospira spp. All vertebrate species can be infected; humans are sensitive hosts whereas other species, such as rodents, may become long-term renal carrier reservoirs. Upon infection, innate immune responses are initiated by recognition of Microbial Associated Molecular Patterns (MAMPs) by Pattern Recognition Receptors (PRRs). Among MAMPs, the lipopolysaccharide (LPS) is recognized by the Toll-Like-Receptor 4 (TLR4) and activates both the MyD88-dependent pathway at the plasma membrane and the TRIF-dependent pathway after TLR4 internalization. We previously showed that leptospiral LPS is not recognized by the human-TLR4, whereas it signals through mouse-TLR4 (mTLR4), which mediates mouse resistance to acute leptospirosis. However, although resistant, mice are known to be chronically infected by leptospires. Interestingly, the leptospiral LPS has low endotoxicity in mouse cells and is an agonist of TLR2, the sensor for bacterial lipoproteins. Here, we investigated the signaling properties of the leptospiral LPS in mouse macrophages. Using confocal microscopy and flow cytometry, we showed that the LPS of L. interrogans did not induce internalization of mTLR4, unlike the LPS of Escherichia coli. Consequently, the LPS failed to induce the production of the TRIF-dependent nitric oxide and RANTES, both important antimicrobial responses. Using shorter LPS and LPS devoid of TLR2 activity, we further found this mTLR4-TRIF escape to be dependent on both the co-purifying lipoproteins and the full-length O antigen. Furthermore, our data suggest that the O antigen could alter the binding of the leptospiral LPS to the co-receptor CD14 that is essential for TLR4-TRIF activation. Overall, we describe here a novel leptospiral immune escape mechanism from mouse macrophages and hypothesize that the LPS altered signaling could contribute to the stealthiness and chronicity of the leptospires in mice.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Leptospira/imunologia , Leptospirose/imunologia , Lipopolissacarídeos/metabolismo , Lipoproteínas/metabolismo , Antígenos O/metabolismo , Receptor 4 Toll-Like/fisiologia , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Citocinas/metabolismo , Feminino , Leptospirose/metabolismo , Leptospirose/microbiologia , Leptospirose/patologia , Receptores de Lipopolissacarídeos/genética , Receptores de Lipopolissacarídeos/metabolismo , Lipoproteínas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator 88 de Diferenciação Mieloide/fisiologia , Antígenos O/genética , Transdução de Sinais , Receptor 2 Toll-Like/fisiologia
3.
PLoS Genet ; 16(8): e1008941, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760060

RESUMO

Apolipoprotein B-containing lipoproteins (B-lps) are essential for the transport of hydrophobic dietary and endogenous lipids through the circulation in vertebrates. Zebrafish embryos produce large numbers of B-lps in the yolk syncytial layer (YSL) to move lipids from yolk to growing tissues. Disruptions in B-lp production perturb yolk morphology, readily allowing for visual identification of mutants with altered B-lp metabolism. Here we report the discovery of a missense mutation in microsomal triglyceride transfer protein (Mtp), a protein that is essential for B-lp production. This mutation of a conserved glycine residue to valine (zebrafish G863V, human G865V) reduces B-lp production and results in yolk opacity due to aberrant accumulation of cytoplasmic lipid droplets in the YSL. However, this phenotype is milder than that of the previously reported L475P stalactite (stl) mutation. MTP transfers lipids, including triglycerides and phospholipids, to apolipoprotein B in the ER for B-lp assembly. In vitro lipid transfer assays reveal that while both MTP mutations eliminate triglyceride transfer activity, the G863V mutant protein unexpectedly retains ~80% of phospholipid transfer activity. This residual phospholipid transfer activity of the G863V mttp mutant protein is sufficient to support the secretion of small B-lps, which prevents intestinal fat malabsorption and growth defects observed in the mttpstl/stl mutant zebrafish. Modeling based on the recent crystal structure of the heterodimeric human MTP complex suggests the G865V mutation may block triglyceride entry into the lipid-binding cavity. Together, these data argue that selective inhibition of MTP triglyceride transfer activity may be a feasible therapeutic approach to treat dyslipidemia and provide structural insight for drug design. These data also highlight the power of yolk transport studies to identify proteins critical for B-lp biology.


Assuntos
Proteínas de Transporte/genética , Lipídeos/genética , Lipoproteínas/genética , Triglicerídeos/genética , Animais , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Trato Gastrointestinal/metabolismo , Humanos , Imunoprecipitação , Gotículas Lipídicas/metabolismo , Lipoproteínas/metabolismo , Mutação de Sentido Incorreto/genética , Mutação Puntual/genética , Transporte Proteico/genética , Triglicerídeos/metabolismo , Peixe-Zebra/genética
4.
Ecotoxicol Environ Saf ; 204: 111036, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32784013

RESUMO

Human exposure to methylmercury (MeHg) due to contaminated fish intake as part of a high-fat (HFD), high-carbohydrate diets is a reality today for many populations. HFD is associated with hypertension and hyperlipidemia, primary cardiovascular disease (CVD) risk factors. Some studies suggest that MeHg induces those risk factors. We evaluated the effect of MeHg exposure in mice fed with HFD or control diet for eight weeks. In the last experimental 15 days, the half group received a MeHg solution (20 mg/L) replacing water. Blood pressure (BP), heart rate, lipoprotein concentrations, and paraoxonase activity were evaluated. Liver cholesterol, triacylglycerol, and IBA-1+ cells, as well as transcriptional levels of genes related to lipid metabolism and inflammatory response, were also assessed. HFD and both MeHg groups presented increased BP and total cholesterol (TC). In the liver, HFD but not MeHg was related to an increase in TC. Also, MeHg intoxication reduced paraoxonase activity regardless of diet. MeHg intoxication and HFD increased steatosis and the number of IBA-1+ cells and modified some gene transcripts associated with lipid metabolism. In conclusion, we demonstrated that MeHg effects on CVD risk factors resemble those caused by HFD.


Assuntos
Pressão Arterial/efeitos dos fármacos , Aterosclerose/epidemiologia , Dieta Hiperlipídica/efeitos adversos , Poluentes Ambientais/efeitos adversos , Fígado/efeitos dos fármacos , Compostos de Metilmercúrio/efeitos adversos , Estado Nutricional , Animais , Aterosclerose/induzido quimicamente , Fígado Gorduroso/metabolismo , Feminino , Inflamação/induzido quimicamente , Inflamação/fisiopatologia , Lipoproteínas/metabolismo , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Risco
5.
Proc Natl Acad Sci U S A ; 117(29): 17381-17388, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32632018

RESUMO

Adiponectin (Acrp30) is an adipokine associated with protection from cardiovascular disease, insulin resistance, and inflammation. Although its effects are conventionally attributed to binding Adipor1/2 and T-cadherin, its abundance in circulation, role in ceramide metabolism, and homology to C1q suggest an overlooked role as a lipid-binding protein, possibly generalizable to other C1q/TNF-related proteins (CTRPs) and C1q family members. To investigate this, adiponectin, representative family members, and variants were expressed in Expi293 cells and tested for binding to lipids in liposomes using density centrifugation. Binding to physiological lipids were also analyzed using gradient ultracentrifugation, liquid chromatography-mass spectrometry, and shotgun lipidomics. Interestingly, adiponectin selectively bound several anionic phospholipids and sphingolipids, including phosphatidylserine, ceramide-1-phosphate, glucosylceramide, and sulfatide, via the C1q domain in an oligomerization-dependent fashion. Binding to lipids was observed in liposomes, low-density lipoproteins, cell membranes, and plasma. Other CTRPs and C1q family members (Cbln1, CTRP1, CTRP5, and CTRP13) also bound similar lipids. These findings suggest that adiponectin and CTRPs function not only as hormones, but also as lipid opsonins, as may other C1q family proteins.


Assuntos
Adiponectina/metabolismo , Complemento C1q/metabolismo , Fosfolipídeos/metabolismo , Esfingolipídeos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Adipocinas/metabolismo , Adiponectina/genética , Animais , Ânions , Membrana Celular , LDL-Colesterol , Humanos , Metabolismo dos Lipídeos , Lipidômica , Lipoproteínas/metabolismo , Lipossomos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Opsonizantes/metabolismo , Plasma
6.
Expert Rev Cardiovasc Ther ; 18(6): 355-361, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32511037

RESUMO

INTRODUCTION: The prevalence of hypertriglyceridemia (HTG) is increasing. Elevated triglyceride (TG) levels are associated with an increased cardiovascular disease (CVD) risk. Moreover, severe HTG results in an elevated risk of pancreatitis, especially in severe HTG with an up to 350-fold increased risk. Both problems emphasize the clinical need for effective TG lowering. AREAS COVERED: The purpose of this review is to discuss the currently available therapies and to elaborate the most promising novel therapeutics for TG lowering. EXPERT OPINION: Conventional lipid lowering strategies do not efficiently lower plasma TG levels, leaving a residual CVD and pancreatitis risk. Both apolipoprotein C-III (apoC-III) and angiopoietin-like 3 (ANGPTL3) are important regulators in TG-rich lipoprotein (TRL) metabolism. Several novel agents targeting these linchpins have ended phase II/III trials. Volanesorsen targeting apoC-III has shown reductions in plasma TG levels up to 90%. Multiple ANGPLT3 inhibitors (evinacumab, IONIS-ANGPTL3-LRx, ARO-ANG3) effectuate TG reductions up to 70% with concomitant potent reduction in all other apoB containing lipoprotein fractions. We expect these therapeutics to become players in the treatment for (especially) severe HTG in the near future.


Assuntos
Proteínas Semelhantes a Angiopoietina/antagonistas & inibidores , Apolipoproteína C-III/efeitos dos fármacos , Hipertrigliceridemia/tratamento farmacológico , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Ensaios Clínicos como Assunto , Humanos , Hipertrigliceridemia/complicações , Hipertrigliceridemia/metabolismo , Lipoproteínas/metabolismo , Oligonucleotídeos/farmacologia , Oligonucleotídeos/uso terapêutico , Pancreatite/etiologia , Pancreatite/prevenção & controle
7.
PLoS Pathog ; 16(6): e1008597, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32511265

RESUMO

During infection of neurons by alphaherpesviruses including Pseudorabies virus (PRV) and Herpes simplex virus type 1 (HSV-1) viral nucleocapsids assemble in the cell nucleus, become enveloped in the cell body then traffic into and down axons to nerve termini for spread to adjacent epithelia. The viral membrane protein US9p and the membrane glycoprotein heterodimer gE/gI play critical roles in anterograde spread of both HSV-1 and PRV, and several models exist to explain their function. Biochemical studies suggest that PRV US9p associates with the kinesin-3 motor KIF1A in a gE/gI-stimulated manner, and the gE/gI-US9p complex has been proposed to recruit KIF1A to PRV for microtubule-mediated anterograde trafficking into or along the axon. However, as loss of gE/gI-US9p essentially abolishes delivery of alphaherpesviruses to the axon it is difficult to determine the microtubule-dependent trafficking properties and motor-composition of Δ(gE/gI-US9p) particles. Alternatively, studies in HSV-1 have suggested that gE/gI and US9p are required for the appearance of virions in the axon because they act upstream, to help assemble enveloped virions in the cell body. We prepared Δ(gE/gI-US9p) mutant, and control parental PRV particles from differentiated cultured neuronal or porcine kidney epithelial cells and quantitated the efficiency of virion assembly, the properties of microtubule-dependent transport and the ability of viral particles to recruit kinesin motors. We find that loss of gE/gI-US9p has no significant effect upon PRV particle assembly but leads to greatly diminished plus end-directed traffic, and enhanced minus end-directed and bidirectional movement along microtubules. PRV particles prepared from infected differentiated mouse CAD neurons were found to be associated with either kinesin KIF1A or kinesin KIF5C, but not both. Loss of gE/gI-US9p resulted in failure to recruit KIF1A and KF5C, but did not affect dynein binding. Unexpectedly, while KIF5C was expressed in undifferentiated and differentiated CAD neurons it was only found associated with PRV particles prepared from differentiated cells.


Assuntos
Herpesvirus Suídeo 1 , Peptídeos e Proteínas de Sinalização Intracelular , Cinesina/metabolismo , Lipoproteínas , Microtúbulos/metabolismo , Pseudorraiva , Proteínas do Envelope Viral , Proteínas Virais , Liberação de Vírus , Animais , Transporte Biológico Ativo , Linhagem Celular , Deleção de Genes , Herpesvirus Suídeo 1/genética , Herpesvirus Suídeo 1/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Cinesina/genética , Lipoproteínas/genética , Lipoproteínas/metabolismo , Microtúbulos/genética , Microtúbulos/virologia , Pseudorraiva/genética , Pseudorraiva/metabolismo , Pseudorraiva/patologia , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo
8.
J Vis Exp ; (159)2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32478756

RESUMO

Lipoproteins from proteobacteria are posttranslationally modified by fatty acids derived from membrane phospholipids by the action of three integral membrane enzymes, resulting in triacylated proteins. The first step in the lipoprotein modification pathway involves the transfer of a diacylglyceryl group from phosphatidylglycerol onto the prolipoprotein, resulting in diacylglyceryl prolipoprotein. In the second step, the signal peptide of prolipoprotein is cleaved, forming an apolipoprotein, which in turn is modified by a third fatty acid derived from a phospholipid. This last step is catalyzed by apolipoprotein N-acyltransferase (Lnt). The lipoprotein modification pathway is essential in most γ-proteobacteria, making it a potential target for the development of novel antibacterial agents. Described here is a sensitive assay for Lnt that is compatible with high-throughput screening of small inhibitory molecules. The enzyme and substrates are membrane-embedded molecules; therefore, the development of an in vitro test is not straightforward. This includes the purification of the active enzyme in the presence of detergent, the availability of alkyne-phospholipids and diacylglyceryl peptide substrates, and the reaction conditions in mixed micelles. Furthermore, in order to use the activity test in a high-throughput screening (HTS) setup, direct readout of the reaction product is preferred over coupled enzymatic reactions. In this fluorometric enzyme assay, the alkyne-triacylated peptide product is rendered fluorescent through a click-chemistry reaction and detected in a multiwell plate format. This method is applicable to other acyltransferases that use fatty acid-containing substrates, including phospholipids and acyl-CoA.


Assuntos
Aciltransferases/metabolismo , Química Click/métodos , Ensaios Enzimáticos/métodos , Fluorometria/métodos , Ensaios de Triagem em Larga Escala/métodos , Animais , Ácidos Graxos , Fibroblastos/metabolismo , Fluorescência , Humanos , Lipoproteínas/metabolismo , Processamento de Proteína Pós-Traducional , Proteobactérias/metabolismo , Especificidade por Substrato
9.
Gene ; 749: 144720, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32360840

RESUMO

AIMS: The purpose of present study was to examine the correlations of LDL (LDLR) and HDL (SR-B1) receptors with lipoproteins, miR-199a-5p, miR-199b-5p, miR-455-5p in the malignant and benign breast tumors. METHODS: Total cholesterol-rich-lipoproteins and the receptors were determined using enzymatic-homogeneous and ELISA methods. The expression levels of miRNAs were detected by qRT-PCR. RESULTS: Receptor expressions and lipoproteins concentration were significantly higher in the malignant tumors (p < 0.05). Positive correlation was found for LDLR with Ki67% and Her2+. HDL-C content of TNBC tumors was higher than those of Non-TNBC (p < 0.05). The expression level of miR-199a-5p was found to be downregulated significantly in the malignant tumors of <2 cm, TNBC, HER2- or stage3. The expression of miR-199b-5p was downregulated in the malignant tumors and was negatively associated with TNBC, stage and Her2+. The expression of miR-455-5p was significantly correlated with Her2- (p < 0.05). A positive correlation was observed for SR-B1 or LDLR with HDL-C or LDL-C and also for SR-B1 with LDLR, although a reverse association was detected for the expression of miR-199b-5p with LDLR in the malignant tumors (p < 0.05). No significant correlations were found for miR-199a-5p or miR-455-5p with LDLR or SR-B1 expressions and also for LDL-C and SR-B1 with clinicopathological features (p ≥ 0.05). CONCLUSIONS: Mechanisms potentially involved in the present findings may be due to the lipid internalization and lipoprotein consumption through LDLR and SR-B1 over expression. It is noteworthy that the expression of miR-199b-5p is negatively correlated with LDLR which may suggest it as a suppressor for LDLR expression in the breast cancer.


Assuntos
Neoplasias da Mama/metabolismo , MicroRNAs/metabolismo , Receptores de LDL/metabolismo , Receptores Depuradores Classe B/metabolismo , Adulto , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Colesterol/metabolismo , Feminino , Humanos , Lipoproteínas/metabolismo , Pessoa de Meia-Idade
10.
Proc Natl Acad Sci U S A ; 117(23): 13094-13104, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32434914

RESUMO

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. While the histopathology of the different disease stages is well characterized, the cause underlying the progression, from the early drusen stage to the advanced macular degeneration stage that leads to blindness, remains unknown. Here, we show that photoreceptors (PRs) of diseased individuals display increased expression of two key glycolytic genes, suggestive of a glucose shortage during disease. Mimicking aspects of this metabolic profile in PRs of wild-type mice by activation of the mammalian target of rapamycin complex 1 (mTORC1) caused early drusen-like pathologies, as well as advanced AMD-like pathologies. Mice with activated mTORC1 in PRs also displayed other early disease features, such as a delay in photoreceptor outer segment (POS) clearance and accumulation of lipofuscin in the retinal-pigmented epithelium (RPE) and of lipoproteins at the Bruch's membrane (BrM), as well as changes in complement accumulation. Interestingly, formation of drusen-like deposits was dependent on activation of mTORC1 in cones. Both major types of advanced AMD pathologies, including geographic atrophy (GA) and neovascular pathologies, were also seen. Finally, activated mTORC1 in PRs resulted in a threefold reduction in di-docosahexaenoic acid (DHA)-containing phospholipid species. Feeding mice a DHA-enriched diet alleviated most pathologies. The data recapitulate many aspects of the human disease, suggesting that metabolic adaptations in photoreceptors could contribute to disease progression in AMD. Identifying the changes downstream of mTORC1 that lead to advanced pathologies in mouse might present new opportunities to study the role of PRs in AMD pathogenesis.


Assuntos
Envelhecimento/patologia , Macula Lutea/patologia , Degeneração Macular/patologia , Células Fotorreceptoras Retinianas Cones/patologia , Idoso , Idoso de 80 Anos ou mais , Animais , Lâmina Basilar da Corioide/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Lipofuscina/metabolismo , Lipoproteínas/metabolismo , Macula Lutea/citologia , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Células Fotorreceptoras Retinianas Cones/metabolismo , Epitélio Pigmentado da Retina/metabolismo
11.
Arch Biochem Biophys ; 688: 108431, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32461102

RESUMO

Phenylketonuria (PKU) is the most prevalent inborn error of amino acid metabolism. The disease is due to the deficiency of phenylalanine (Phe) hydroxylase activity, which causes the accumulation of Phe. Early diagnosis through neonatal screening is essential for early treatment implementation, avoiding cognitive impairment and other irreversible sequelae. Treatment is based on Phe restriction in the diet that should be maintained throughout life. High dietary restrictions can lead to imbalances in specific nutrients, notably lipids. Previous studies in PKU patients revealed changes in levels of plasma/serum lipoprotein lipids, as well as in fatty acid profile of plasma and red blood cells. Most studies showed a decrease in important polyunsaturated fatty acids, namely DHA (22:6n-3), AA (20:4n-6) and EPA (20:5n-6). Increased oxidative stress and subsequent lipid peroxidation have also been observed in PKU. Despite the evidences that the lipid profile is changed in PKU patients, more studies are needed to understand in detail how lipidome is affected. As highlighted in this review, mass spectrometry-based lipidomics is a promising approach to evaluate the effect of the diet restrictions on lipid metabolism in PKU patients, monitor their outcome, namely concerning the risk for other chronic diseases, and find possible prognosis biomarkers.


Assuntos
Ácidos Graxos/metabolismo , Lipidômica , Lipoproteínas/metabolismo , Fenilcetonúrias/fisiopatologia , Ácidos Graxos/análise , Humanos , Inflamação/complicações , Inflamação/fisiopatologia , Peroxidação de Lipídeos/fisiologia , Lipidômica/métodos , Lipoproteínas/análise , Estresse Oxidativo/fisiologia , Fenilcetonúrias/complicações , Fenilcetonúrias/dietoterapia , Triglicerídeos/análise , Triglicerídeos/metabolismo
12.
Gene ; 753: 144805, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32445923

RESUMO

Genomic variants in both ADTRP and TFPI genes are associated with risk of coronary artery disease (CAD). ADTRP regulates TFPI expression and endothelial cell functions involved in the initiation of atherosclerotic CAD. ADTRP also specifies primitive myelopoiesis and definitive hematopoiesis by upregulating TFPI expression. However, the underlying molecular mechanism is unknown. Here we show that transcription factor POU1F1 is the key by which ADTRP regulates TFPI expression. Luciferase reporter assays, chromatin-immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA) in combination with analysis of large and small deletions of the TFPI promoter/regulatory region were used to identify the molecular mechanism by which ADTRP regulates TFPI expression. Genetic association was assessed using case-control association analysis and phenome-wide association analysis (PhenGWA). ADTRP regulates TFPI expression at the transcription level in a dose-dependent manner. The ADTRP-response element was localized to a 50 bp region between -806 bp and -756 bp upstream of TFPI transcription start site, which contains a binding site for POU1F1. Deletion of POU1F1-binding site or knockdown of POU1F1 expression abolished ADTRP-mediated transcription of TFPI. ChIP and EMSA demonstrated that POU1F1 binds to the ADTRP response element. Genetic analysis identified significant association between POU1F1 variants and risk of CAD. PhenGWA identified other phenotypic traits associated with the ADTRP-POU1F1-TFPI axis such as lymphocyte count (ADTRP), waist circumference (TFPI), and standing height (POU1F1). These data identify POU1F1 as a transcription factor that regulates TFPI transcription in response to ADTRP, and link POU1F1 variants to risk of CAD for the first time.


Assuntos
Doença da Artéria Coronariana/metabolismo , Lipoproteínas/biossíntese , Proteínas de Membrana/metabolismo , Fator de Transcrição Pit-1/metabolismo , Aterosclerose/genética , Estudos de Casos e Controles , Linhagem Celular , Imunoprecipitação da Cromatina/métodos , Doença da Artéria Coronariana/genética , Bases de Dados Genéticas , Células Endoteliais/metabolismo , Genes Homeobox , Células HeLa , Humanos , Lipoproteínas/genética , Lipoproteínas/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Regiões Promotoras Genéticas , Elementos de Resposta , Sítio de Iniciação de Transcrição , Transcrição Genética
13.
Nat Commun ; 11(1): 1789, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286264

RESUMO

The mechanical properties of the cell envelope in Gram-negative bacteria are controlled by the peptidoglycan, the outer membrane, and the proteins interacting with both layers. In Escherichia coli, the lipoprotein Lpp provides the only covalent crosslink between the outer membrane and the peptidoglycan. Here, we use single-cell atomic force microscopy and genetically engineered strains to study the contribution of Lpp to cell envelope mechanics. We show that Lpp contributes to cell envelope stiffness in two ways: by covalently connecting the outer membrane to the peptidoglycan, and by controlling the width of the periplasmic space. Furthermore, mutations affecting Lpp function substantially increase bacterial susceptibility to the antibiotic vancomycin, indicating that Lpp-dependent effects can affect antibacterial drug efficacy.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Celular/metabolismo , Proteínas de Escherichia coli/metabolismo , Lipoproteínas/metabolismo , Antibacterianos/farmacologia , Bacteriologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Microscopia de Força Atômica , Peptidoglicano/metabolismo , Vancomicina/farmacologia
14.
Comput Methods Biomech Biomed Engin ; 23(10): 571-584, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32309993

RESUMO

The purpose of this study is to compare the effects of the different physical factors on lipoproteins accumulation in the aorta artery. Results revealed that hemodynamic parameters (WSS, OSI, RRT) together affect spatial distributions of lipoproteins concentration in the human aorta. Moreover, decreasing the frequency of pulsatile flow and particle size leads to more lipoproteins accumulated on the luminal surface. In addition, given the same flow rate, the pulsatile flow could reduce lipoproteins concentration in the luminal surface of aorta relative to a steady flow condition. The present computer strategy may have great potential in predicting the local atherosclerosis lesion.


Assuntos
Aorta/metabolismo , Lipoproteínas/química , Lipoproteínas/metabolismo , Tamanho da Partícula , Aorta/patologia , Aorta/fisiologia , Hemodinâmica , Humanos , Modelos Cardiovasculares , Rádio (Anatomia) , Estresse Mecânico , Fatores de Tempo
15.
Subcell Biochem ; 94: 35-62, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32189295

RESUMO

Lipoproteins mediate the transport of apolar lipids in the hydrophilic environment of physiological fluids such as the vertebrate blood and the arthropod hemolymph. In this overview, we will focus on the hemolymph lipoproteins in Crustacea that have received most attention during the last years: the high density lipoprotein/ß-glucan binding proteins (HDL-BGBPs), the vitellogenins (VGs), the clotting proteins (CPs) and the more recently discovered large discoidal lipoproteins (dLPs). VGs are female specific lipoproteins which supply both proteins and lipids as storage material for the oocyte for later use by the developing embryo. Unusual within the invertebrates, the crustacean yolk proteins-formerly designated VGs-are more related to the ApoB type lipoproteins of vertebrates and are now termed apolipocrustaceins. The CPs on the other hand, which are present in both sexes, are related to the (sex specific) VGs of insects and vertebrates. CPs serve in hemostasis and wound closure but also as storage proteins in the oocyte. The HDL-BGBPs are the main lipid transporters, but are also involved in immune defense. Most crustacean lipoproteins belong to the family of the large lipid transfer proteins (LLTPs) such as the intracellular microsomal triglyceride transfer protein, the VGs, CPs and the dLPs. In contrast, the HDL-BGBPs do not belong to the LLTPs and their relationship with other lipoproteins is unknown. However, they originate from a common precursor with the dLPs, whose functions are as yet unknown. The majority of lipoprotein studies have focused on decapod crustaceans, especially shrimps, due to their economic importance. However, we will present evidence that the HDL-BGBPs are restricted to the decapod crustaceans which raises the question as to the main lipid transporting proteins of the other crustacean groups. The diversity of crustaceans lipoproteins thus appears to be more complex than reflected by the present state of knowledge.


Assuntos
Crustáceos , Hemolinfa , Lipoproteínas , Animais , Crustáceos/química , Crustáceos/imunologia , Crustáceos/metabolismo , Hemolinfa/química , Hemolinfa/imunologia , Hemolinfa/metabolismo , Lipoproteínas/biossíntese , Lipoproteínas/química , Lipoproteínas/imunologia , Lipoproteínas/metabolismo
16.
Arterioscler Thromb Vasc Biol ; 40(4): 885-900, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32160774

RESUMO

Aortic valve stenosis is the most prevalent heart valve disease worldwide. Although interventional treatment options have rapidly improved in recent years, symptomatic aortic valve stenosis is still associated with high morbidity and mortality. Calcific aortic valve stenosis is characterized by a progressive fibro-calcific remodeling and thickening of the aortic valve cusps, which subsequently leads to valve obstruction. The underlying pathophysiology is complex and involves endothelial dysfunction, immune cell infiltration, myofibroblastic and osteoblastic differentiation, and, subsequently, calcification. To date, no pharmacotherapy has been established to prevent aortic valve calcification. However, novel promising therapeutic targets have been recently identified. This review summarizes the current knowledge of pathomechanisms involved in aortic valve calcification and points out novel treatment strategies.


Assuntos
Estenose da Valva Aórtica/tratamento farmacológico , Estenose da Valva Aórtica/fisiopatologia , Animais , Estenose da Valva Aórtica/patologia , Comunicação Celular , Diferenciação Celular , Células Cultivadas , Modelos Animais de Doenças , Endotélio Vascular/fisiopatologia , Humanos , Inflamação/fisiopatologia , Lipoproteínas/metabolismo , Miofibroblastos/fisiologia , Osteoblastos/fisiologia , Osteoclastos/fisiologia , RNA não Traduzido/metabolismo , Calcificação Vascular/fisiopatologia
17.
Nat Commun ; 11(1): 1305, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32161270

RESUMO

Coordination of outer membrane constriction with septation is critical to faithful division in Gram-negative bacteria and vital to the barrier function of the membrane. This coordination requires the recruitment of the peptidoglycan-binding outer-membrane lipoprotein Pal at division sites by the Tol system. Here, we show that Pal accumulation at Escherichia coli division sites is a consequence of three key functions of the Tol system. First, Tol mobilises Pal molecules in dividing cells, which otherwise diffuse very slowly due to their binding of the cell wall. Second, Tol actively captures mobilised Pal molecules and deposits them at the division septum. Third, the active capture mechanism is analogous to that used by the inner membrane protein TonB to dislodge the plug domains of outer membrane TonB-dependent nutrient transporters. We conclude that outer membrane constriction is coordinated with cell division by active mobilisation-and-capture of Pal at division septa by the Tol system.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Externa Bacteriana/metabolismo , Divisão Celular , Proteínas de Escherichia coli/metabolismo , Escherichia coli/citologia , Lipoproteínas/metabolismo , Peptidoglicano/metabolismo , Escherichia coli/metabolismo , Proteínas de Membrana , Proteínas Periplásmicas/metabolismo
18.
Diabetes ; 69(4): 508-516, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32198194

RESUMO

Diabetes is now a pandemic disease. Moreover, a large number of people with prediabetes are at risk for developing frank diabetes worldwide. Both type 1 and type 2 diabetes increase the risk of atherosclerotic cardiovascular disease (CVD). Even with statin treatment to lower LDL cholesterol, patients with diabetes have a high residual CVD risk. Factors mediating the residual risk are incompletely characterized. An attractive hypothesis is that remnant lipoprotein particles (RLPs), derived by lipolysis from VLDL and chylomicrons, contribute to this residual risk. RLPs constitute a heterogeneous population of lipoprotein particles, varying markedly in size and composition. Although a universally accepted definition is lacking, for the purpose of this review we define RLPs as postlipolytic partially triglyceride-depleted particles derived from chylomicrons and VLDL that are relatively enriched in cholesteryl esters and apolipoprotein (apo)E. RLPs derived from chylomicrons contain apoB48, while those derived from VLDL contain apoB100. Clarity as to the role of RLPs in CVD risk is hampered by lack of a widely accepted definition and a paucity of adequate methods for their accurate and precise quantification. New specific methods for RLP quantification would greatly improve our understanding of their biology and role in promoting atherosclerosis in diabetes and other disorders.


Assuntos
Doenças Cardiovasculares/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Lipoproteínas/metabolismo , Triglicerídeos/metabolismo , Animais , Doenças Cardiovasculares/etiologia , Quilomícrons/metabolismo , Diabetes Mellitus Tipo 2/complicações , Humanos , Lipoproteínas VLDL/metabolismo
19.
PLoS One ; 15(3): e0229322, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32176696

RESUMO

Tetradecylthioacetic acid (TTA) is a synthetic fatty acid with a sulfur substitution in the ß-position. This modification renders TTA unable to undergo complete ß-oxidation and increases its biological activity, including activation of peroxisome proliferator activated receptors (PPARs) with preference for PPARα. This study investigated the effects of TTA on lipid and lipoprotein metabolism in the intestine and liver of mice fed a high fat diet (HFD). Mice receiving HFD supplemented with 0.75% (w/w) TTA had significantly lower body weights compared to mice fed the diet without TTA. Plasma triacylglycerol (TAG) was reduced 3-fold with TTA treatment, concurrent with increase in liver TAG. Total cholesterol was unchanged in plasma and liver. However, TTA promoted a shift in the plasma lipoprotein fractions with an increase in larger HDL particles. Histological analysis of the small intestine revealed a reduced size of lipid droplets in enterocytes of TTA treated mice, accompanied by increased mRNA expression of fatty acid transporter genes. Expression of the cholesterol efflux pump Abca1 was induced in the small intestine, but not in the liver. Scd1 displayed markedly increased mRNA and protein expression in the intestine of the TTA group. It is concluded that TTA treatment of HFD fed mice leads to increased expression of genes involved in uptake and transport of fatty acids and HDL cholesterol in the small intestine with concomitant changes in the plasma profile of smaller lipoproteins.


Assuntos
HDL-Colesterol/sangue , Dieta Hiperlipídica/efeitos adversos , Lipoproteínas/metabolismo , PPAR alfa/agonistas , Sulfetos/administração & dosagem , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Estearoil-CoA Dessaturase/genética , Estearoil-CoA Dessaturase/metabolismo , Sulfetos/farmacologia , Triglicerídeos/sangue
20.
Proc Natl Acad Sci U S A ; 117(12): 6777-6783, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32152098

RESUMO

Tol-Pal is a multiprotein system present in the envelope of Gram-negative bacteria. Inactivation of this widely conserved machinery compromises the outer membrane (OM) layer of these organisms, resulting in hypersensitivity to many antibiotics. Mutants in the tol-pal locus fail to complete division and form cell chains. This phenotype along with the localization of Tol-Pal components to the cytokinetic ring in Escherichia coli has led to the proposal that the primary function of the system is to promote OM constriction during division. Accordingly, a poorly constricted OM is believed to link the cell chains formed upon Tol-Pal inactivation. However, we show here that cell chains of E. coli tol-pal mutants are connected by an incompletely processed peptidoglycan (PG) layer. Genetic suppressors of this defect were isolated and found to overproduce OM lipoproteins capable of cleaving the glycan strands of PG. Among the factors promoting cell separation in mutant cells was a protein of previously unknown function (YddW), which we have identified as a divisome-localized glycosyl hydrolase that cleaves peptide-free PG glycans. Overall, our results indicate that the cell chaining defect of Tol-Pal mutants cannot simply be interpreted as a defect in OM constriction. Rather, the complex also appears to be required for the activity of several OM-localized enzymes with cell wall remodeling activity. Thus, the Tol-Pal system may play a more general role in coordinating OM invagination with PG remodeling at the division site than previously appreciated.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Divisão Celular , Parede Celular/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Lipoproteínas/metabolismo , Peptidoglicano/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Membrana Celular/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Proteínas de Escherichia coli/genética , Lipoproteínas/genética , Ligação Proteica
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