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1.
J Endocrinol Invest ; 42(12): 1497-1507, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31359403

RESUMO

PURPOSE: The effect of combined lifestyle interventions (LSI) including dietary and physical activity on metabolic health, energy metabolism and VO2max in diabetic patients has provided mixed results. We evaluated the impact of 1-year caloric restriction (CR), and 12-week supervised structured exercise training (SSET) on metabolic health, RMR and VO2max in obese adults with type 2 diabetes. METHODS: After 1-month education for LSI, 33 participants had anthropometric, biochemical and metabolic assessments. They then started CR based on RMR, and 3-month SSET during the months 1-3 (Early-SSET) or 4-6 (Late-SSET). Reassessments were planned after 3, 6 and 12 months. Using a per-protocol analysis, we evaluated parameter changes from baseline and their associations for the 23 participants (11 Early-SSET, 12 Late-SSET) who completed the study. RMR was adjusted (adjRMR) for age, sex, fat-free mass (FFM) and fat mass (FM). RESULTS: Compared with baseline, after 6 months we found significant increases in VO2max (+ 14%) and HDL-cholesterol (+ 13%), and reduction in body mass index (- 3%), FM (- 8%) and glycated hemoglobin (HbA1c, - 7%). Training-related caloric expenditure negatively correlated with changes in body weight (p < 0.001), FM (p < 0.001) and HbA1c (p = 0.006). These results were confirmed at the 12-month follow-up. Pooling together all follow-up data, adjRMR changes correlated with changes in glycemia (r = 0.29, p = 0.02), total-cholesterol (r = 0.29, p = 0.02) and VO2max (r = - 0.26,p = 0.02). No significant differences emerged between the Early- and Late-SSET groups. CONCLUSIONS: Combined intervention with SSET and CR improved metabolic control. Changes in metabolic health and fitness correlated with changes of adjRMR, which was reduced improving fitness, glycemia and cholesterolemia. CLINICAL TRIAL REGISTRY: Trial registration number: NCT03785379. URL of registration: http://clinicaltrials.gov .


Assuntos
Metabolismo Basal/fisiologia , Restrição Calórica , Diabetes Mellitus Tipo 2/terapia , Metabolismo Energético/fisiologia , Terapia por Exercício , Obesidade/terapia , Peso Corporal , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/metabolismo , Dieta Redutora , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Obesidade/dietoterapia , Obesidade/metabolismo
2.
Glycobiology ; 25(11): 1142-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26224786

RESUMO

Chagas' disease is a potentially life-threatening disease caused by the protozoan parasite Trypanosoma cruzi. Since the description of Chagas'disease in 1909 extensive research has identified important events in the disease in order to understand the biochemical mechanism that modulates T. cruzi-host cell interactions and the ability of the parasite to ensure its survival in the infected host. Exactly 30 years ago, we presented evidence for the first time of a trans-sialidase activity in T. cruzi (T. cruzi-TS). This enzyme transfers sialic acid from the host glycoconjugates to the terminal ß-galactopyranosyl residues of mucin-like molecules on the parasite's cell surface. Thenceforth, many articles have provided convincing data showing that T. cruzi-TS is able to govern relevant mechanisms involved in the parasite's survival in the mammalian host, such as invasion, escape from the phagolysosomal vacuole, differentiation, down-modulation of host immune responses, among others. The aim of this review is to cover the history of the discovery of T. cruzi-TS, as well as some well-documented biological effects encompassed by this parasite's virulence factor, an enzyme with potential attributes to become a drug target against Chagas disease.


Assuntos
Doença de Chagas/parasitologia , Glicoproteínas/toxicidade , Neuraminidase/toxicidade , Proteínas de Protozoários/toxicidade , Trypanosoma cruzi/patogenicidade , Fatores de Virulência/toxicidade , Animais , Doença de Chagas/imunologia , Glicoproteínas/imunologia , Humanos , Neuraminidase/imunologia , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/imunologia , Fatores de Virulência/imunologia
3.
J Lipid Res ; 42(10): 1552-61, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11590210

RESUMO

We report the clinical phenotype in three kindreds with familial heterozygous hypobetalipoproteinemia (FHBL) carrying novel truncated apolipoprotein Bs (apoBs) of different sizes (apoB-8.15, apoB-33.4 and apoB-75.7). In D.A. kindred, we found three carriers of a C-deletion in exon 10 leading to the synthesis of apoB-8.15 not detectable in plasma. They showed steatorrhea and fatty liver. In N.L. kindred, the proband is heterozygous for a nonsense mutation in exon 26, leading to the formation of apoB-33.4. He had premature cerebrovascular disease and fatty liver; two apoB-33.4 carriers in this kindred showed only fatty liver. In B.E. kindred, the proband is heterozygous for a T-deletion in exon 26, which converts tyrosine at codon 3435 into a stop codon, resulting in apoB-75.7. The proband, a heavy alcohol drinker, had steatohepatitis, whereas his teetotaller daughter, an apoB-75.7 carrier, had no detectable fatty liver. This study suggests that: i) fatty liver invariably develops in FHBL carriers of short and medium-size truncated apoBs (< apoB-48), but its occurrence needs additional environmental factors in carriers of longer apoB forms; ii) intestinal lipid malabsorption develops only in carriers of short truncated apoBs, which are not secreted into the plasma; and iii) cerebrovascular disease due to premature atherosclerosis may occur even in FHBL subjects.


Assuntos
Apolipoproteínas B/genética , Mutação/genética , Doença de Tangier/genética , Adulto , Idoso , Sequência de Aminoácidos , Sequência de Bases , Centrifugação com Gradiente de Concentração , Análise Mutacional de DNA , Éxons/genética , Feminino , Humanos , Lipídeos/sangue , Lipoproteínas/sangue , Fígado/patologia , Masculino , Linhagem , Fenótipo , Doença de Tangier/sangue , Doença de Tangier/metabolismo , Doença de Tangier/patologia
4.
Infect Immun ; 69(11): 6874-80, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11598061

RESUMO

Systemic sporotrichosis is an emerging infection potentially fatal for immunocompromised patients. Adhesion to extracellular matrix proteins is thought to play a crucial role in invasive fungal diseases. Here we report studies of the adhesion of Sporothrix schenckii to the extracellular protein fibronectin (Fn). Both yeast cells and conidia of S. schenckii were able to adhere to Fn as detected by enzyme-linked immunosorbent binding assays. Adhesion of yeast cells to Fn is dose dependent and saturable. S. schenckii adheres equally well to 40-kDa and 120-kDa Fn proteolytic fragments. While adhesion to Fn was increased by Ca(2+), inhibition assays demonstrated that it was not RGD dependent. A carbohydrate-containing cell wall neutral fraction blocked up to 30% of the observed adherence for the yeast cells. The biochemical nature of this fraction suggests the participation of cell surface glycoconjugates in binding by their carbohydrate or peptide moieties. These results provide new data concerning S. schenckii adhesion mechanisms, which could be important in host-fungus interactions and the establishment of sporotrichosis.


Assuntos
Fibronectinas/metabolismo , Sporothrix/metabolismo , Animais , Cátions Bivalentes , Parede Celular/metabolismo , Humanos , Monossacarídeos/metabolismo , Oligopeptídeos/metabolismo , Coelhos
5.
Eur J Biochem ; 268(15): 4243-50, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11488918

RESUMO

Novel structures of glycoinositolphosphorylceramide (GIPC) from the infective yeast form of Sporothrix schenckii were determined by methylation analysis, mass spectrometry and NMR spectroscopy. The lipid portion was characterized as a ceramide composed of C-18 phytosphingosine N-acylated by either 2-hydroxylignoceric acid (80%), lignoceric (15%) or 2,3-dihydroxylignoceric acids (5%). The ceramide was linked through a phosphodiester to myo-inositol (Ins) which is substituted on position O-6 by an oligomannose chain. GIPC-derived Ins oligomannosides were liberated by ammonolysis and characterized as: Manpalpha1-->6Ins; Manpalpha1-->3Manpalpha1-->6Ins; Manpalpha1-->6Manpalpha1-->3Manpalpha1-->3Manpalpha1-->6Ins; Manpalpha1-->2Manpalpha1-->6Manpalpha1-->3Manpalpha1-->3Manpalpha1-->6Ins. These structures comprise a novel family of fungal GIPC, as they contain the Manpalpha1-->6Ins substructure, which has not previously been characterized unambigously, and may be acylated with a 2,3 dihydroxylignoceric fatty acid, a feature hitherto undescribed in fungal lipids.


Assuntos
Glicoesfingolipídeos/química , Sporothrix/química , Sequência de Carboidratos , Carboidratos/química , Ceramidas/química , Ácidos Graxos/química , Inositol/química , Lipídeos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Metilação , Dados de Sequência Molecular , Oligossacarídeos/química , Polissacarídeos/química , Conformação Proteica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Esfingosina/análogos & derivados , Esfingosina/química
6.
Parasitology ; 123(Pt 1): 33-43, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11467781

RESUMO

In this study the Golgi complex of the epimastigote forms of Trypanosoma cruzi were isolated and characterized. Using well-controlled sonication to rupture the cells and centrifugation on a discontinuous sucrose density gradient, a highly enriched Golgi fraction was obtained. The Golgi fraction contained most of the beta-galactosyltransferase (beta-Gal transferase) and UDP-N-acetyl-glucosamine: polypeptide-alpha-N-acetyl-glucosaminyltransferase (O-alpha-GlcNAc transferase) activities with minimal contamination of other organelles, as observed by enzymatic assays and electron microscopy analysis. To characterize the Golgi from T. cruzi cells further, it was incubated with a monoclonal antibody against a 58 kDa protein involved in the association of the Golgi complex with microtubules in mammalian cells. Immunofluorescence microscopy showed that the 58 kDa protein is localized in the T. cruzi Golgi region, a result confirmed by high resolution scanning electron microscopy immunocytochemistry. Thus, our results show, for the first time, that the beta-Gal transferase, the O-alpha-GlcNAc transferase and the 58 kDa protein are present in the Golgi complex of T. cruzi and are novel biochemical markers which can be used in the characterization of this organelle in T. cruzi.


Assuntos
Complexo de Golgi/fisiologia , Trypanosoma cruzi/ultraestrutura , Fosfatase Ácida/metabolismo , Animais , Western Blotting , Centrifugação com Gradiente de Concentração , Eletroforese em Gel de Poliacrilamida , Complexo de Golgi/enzimologia , Complexo de Golgi/ultraestrutura , Hexoquinase/metabolismo , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , N-Acetilglucosaminiltransferases/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/fisiologia , beta-N-Acetilglucosaminilglicopeptídeo beta-1,4-Galactosiltransferase/metabolismo
7.
Eur J Biochem ; 268(11): 3174-9, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11389718

RESUMO

The structure of an exopolysaccharide (EPS) produced by Burkholderia brasiliensis, a diazotrophic endophytic organism originally isolated from rice roots, has been determined. The bacterium was grown in a synthetic medium, containing mannitol and glutamate, which favours the expression of two anionic EPSs, which were separated by anion-exchange chromatography. The structure of the repeat unit of EPS A, eluted at higher ionic strength, was determined by a combination of methylation analysis, partial hydrolysis, chemical degradations, and NMR spectroscopic studies, and shown to be the linear O-acetylated pentasaccharide: -->4)-alpha-D-Glcp-(1-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GlcpA-(1-->3)-beta-L-Rhap[2OAc]-(1-->4)-beta-D-Glcp-(1-->.


Assuntos
Burkholderia/metabolismo , Polissacarídeos Bacterianos/química , Burkholderia/genética , Sequência de Carboidratos , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Metilação , Dados de Sequência Molecular , Estrutura Molecular , Polissacarídeos Bacterianos/isolamento & purificação
8.
Glycobiology ; 11(1): 47-55, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11181561

RESUMO

Glycoproteins on the cell surface of Trypanosoma cruzi are known to play important roles in the interaction of the parasite with the host cells. We previously determined the structures of the O-glycan chains from the sialoglycoproteins (mucin-like molecules) of the G- and Y-strains and observed significant differences between them. We now report the structures of the sialylated and nonsialylated O-linked oligosaccharides isolated from the cell surface glycoproteins of the myotropic CL-Brener strain grown in the presence of fetal calf serum. The structures of the O-linked oligosaccharide alditols obtained by reductive beta-elimination of the sialoglycoprotein were determined by a combination of methylation analysis, fast atom bombardment-mass spectrometry and nuclear magnetic resonance spectroscopy. The presence of a beta-galactopyranose substituent on the N-acetylglucosamine O-4 position shows that these O-linked oligosaccharides from CL-Brener strain belong to the same family as those isolated from mucins expressed by T. cruzi Y strain, a reticulotropic strain. In addition, novel O-glycans, including alpha2-3 mono-sialylated species are described.


Assuntos
Glicoproteínas/química , Ácido N-Acetilneuramínico/química , Oligossacarídeos/química , Trypanosoma cruzi/química , Animais , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Metilação , Dados de Sequência Molecular , Espectrometria de Massas de Bombardeamento Rápido de Átomos
9.
Carbohydr Res ; 328(3): 321-30, 2000 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-11072839

RESUMO

We report full 1H and 13C NMR assignments for 13 gluco- or galacto-pyranosylated derivatives of GlcNAc-ol, GalNAc-ol or ManNAc-ol, many of which have been prepared by enzymatic methods. These spectra are reference data to aid the structural analysis by NMR spectroscopy of glycosylated alditols derived from the mucin of the protozoan parasite Trypanosoma cruzi. A series of structural reporter groups for the derivatives from this unusual series of O-glycans are described.


Assuntos
Espectroscopia de Ressonância Magnética , Oligossacarídeos/química , Álcoois Açúcares/química , Trypanosoma cruzi/química , Animais , Sequência de Carboidratos , Galactose/química , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Glicosilação , Dados de Sequência Molecular , Mucinas/química
10.
Eur J Biochem ; 267(17): 5387-96, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10951196

RESUMO

The structure of a glycosylphosphatidyl inositol-anchored glucoxylan (GPI-glucoxylan) synthesized by the monogenetic trypanosomatid Leptomonas samueli has been determined. The glucoxylan is anchored to the membrane by phytoceramide and an oligosaccharide core, the structure of which is identical to glycoinositolphospholipids (GIPLs) expressed by this protozoan. The glucoxylan chain is linear, containing -->4Glcalpha1-->, -->4Xylbeta1--> and -->3Xylbeta1--> residues. A well defined sequence heterogeneity was analysed in terms of a series of overlapping trisaccharide substructures. A proportion of the chains are capped with a GlcAalpha1-->3Glcalpha1--> sequence. While an average GlcA-capped chain contained 10 Glc and 16 Xyl residues, uncapped chains have a higher molecular mass with an average of 30 Glc and 50 Xyl per chain. We propose a mode of biosynthesis based on the observed structural heterogeneity.


Assuntos
Glucanos , Glicosilfosfatidilinositóis/química , Polissacarídeos/química , Trypanosomatina/química , Xilanos , Animais , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular
11.
Glycobiology ; 10(2): 213-21, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10642613

RESUMO

The trans -sialidase from Trypanosoma cruzi is a member of the sialidase superfamily that functions as a sialidase in the absence of a carbohydrate acceptor. We have used(1)H nuclear magnetic resonance (NMR) spectroscopy to investigate the stereospecificity of the hydrolysis of two substrates, namely, 4-methyl-umbelliferyl- N -acetylneur-aminic acid and alpha(2-3)-sialyllactose, catalyzed by a recombinant T.cruzi trans -sialidase. We demonstrate that, in aqueous solution, the thermodynamically less stable alpha-form of N -acetylneuraminic acid is the initial product of the hydrolysis; subsequent mutarotation leads eventually to an equilibrium mixture of the alpha and beta forms, in molar ratio 8:92. In a mixed water/methanol solution, the hydrolysis reaction produces also the alpha-methyl sialoside but not its beta-methyl counterpart. We also show that 4-methyl-umbelliferyl- N -acetylneuraminic acid is a significantly better substrate for the sialidase than alpha(2-3)-sialyllactose. Prolonged incubation of alpha(2-3)-sialyllactose with an excess of trans -sialidase produced a trace of 2-deoxy-2,3-didehydro- N -acetylneuraminic acid, as identified by NMR spectroscopy and by gas liquid chromatography/mass spectro-metry. In conclusion, this study shows that the stereo-selectivity of the sialidase activity of T.cruzi trans -sialidase is identical to that of bacterial, viral, and mammalian sialidases, suggesting a similar active-site architecture.


Assuntos
Glicoproteínas/metabolismo , Neuraminidase/metabolismo , Oligossacarídeos/metabolismo , Ácidos Siálicos/metabolismo , Animais , Antígenos de Protozoários/metabolismo , Configuração de Carboidratos , Cromatografia Gasosa-Espectrometria de Massas , Hidrólise , Espectroscopia de Ressonância Magnética , Oligossacarídeos/química , Proteínas Recombinantes/metabolismo , Ácidos Siálicos/química , Especificidade por Substrato , Termodinâmica , Trypanosoma cruzi/enzimologia
12.
Glycoconj J ; 17(10): 727-34, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11425193

RESUMO

The surface of the protozoan Trypanosoma cruzi, the etiologic agent of Chagas' disease, is covered by a dense glycolipid layer, composed mainly by a structurally related family of glycoinositolphospholipids (GIPLs). In the present study we evaluated the in vivo effects of the GIPL on B cell function and immunoglobulin (Ig) secretion. We observed that GIPL injection led to a sustained increase in circulating IgM levels. B cells from GIPL injected mice showed higher response when activated in vitro with either LPS or dextran-conjugated anti-IgD antibodies or purified cytokines. GIPL purified from T. cruzi also showed an adjuvant effect, since this glycophospholipid boosted a polysaccharide-(TNP-Ficoll) induced IgG response. Taken together, our data indicate that T. cruzi-derived GIPL could be at least partially responsible for the remarkable B cell activation observed during T. cruzi acute infection in vivo.


Assuntos
Linfócitos B/efeitos dos fármacos , Glicolipídeos/farmacologia , Fosfolipídeos/farmacologia , Trypanosoma cruzi/química , Animais , Linfócitos B/metabolismo , Feminino , Glicolipídeos/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/efeitos dos fármacos , Lipopolissacarídeos , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fosfolipídeos/imunologia
13.
Infect Immun ; 67(11): 6177-80, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10531285

RESUMO

Glycoinositolphospholipids (GIPLs) are some of the major glycolipids of the Trypanosoma cruzi surface that were previously shown to activate B cells. In the present study, we investigated whether (i) T. cruzi GIPLs could induce immunoglobulin secretion from B cells in the absence of T cells and NK cells and whether (ii) NK cells are also stimulated by the GIPLs. B cells purified from mice deficient in both T and NK cells (CD3epsilon transgenic mice) secreted immunoglobulin in response to the GIPL. This response was increased by coculture with a murine NK cell line. The T. cruzi GIPL also increased the NK cell (interleukin-2 induced) proliferative response. Our data indicate that the T. cruzi GIPL has a direct stimulatory effect on NK cells and induces immunoglobulin secretion in the absence of T lymphocytes and NK cells. These findings suggest that this T. cruzi-derived molecule may be one of the stimulators that lead to NK cell activation during T. cruzi infection.


Assuntos
Linfócitos B/efeitos dos fármacos , Glicoconjugados/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Fosfatidilinositóis/farmacologia , Trypanosoma cruzi/imunologia , Animais , Linfócitos B/imunologia , Linhagem Celular , Imunoglobulina M/biossíntese , Interleucina-2/farmacologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária , Camundongos , Camundongos Transgênicos
14.
FASEB J ; 13(12): 1627-36, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10463955

RESUMO

The effects of the glycoinositolphospholipids (GIPLs) fromTrypanosoma cruzi on T lymphocyte activation were investigated in a mouse T cell hybridoma (DO-11.10). Purified GIPLs from T. cruzi strains Y and G markedly increased IL-2 mRNA transcripts and IL-2 secretion induced by mitogenic anti-CD3 and anti-Thy1 mAbs. This costimulatory function was also revealed by the induction of IL-2 secretion after the simultaneous addition of the T. cruzi GIPLs and either the calcium ionophore A23187 or phorbol ester. The capacity of the GIPL molecule to induce an increase in cytoplasmic calcium levels was also demonstrated. After exposure of T cell hybridoma to GIPL, the nuclear transcription factor NFAT1 became partially dephosphorylated, and its nuclear localization was demonstrated both in the T cell hybridoma and in Balb/c CD3(+) cells. These results demonstrate that T. cruzi GIPL molecules are capable of signaling to T cells and therefore could be valuable tools for the study of T cell activation, besides playing a potential role in subverting the T lymphocyte immune response during T. cruzi infection.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Glicolipídeos/imunologia , Interleucina-2/genética , Ativação Linfocitária , Proteínas Nucleares , Fosfolipídeos/imunologia , Linfócitos T/fisiologia , Fatores de Transcrição/metabolismo , Transcrição Gênica/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/farmacologia , Complexo CD3/imunologia , Calcimicina/farmacologia , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Glicolipídeos/isolamento & purificação , Glicolipídeos/farmacologia , Hibridomas/efeitos dos fármacos , Hibridomas/imunologia , Hibridomas/fisiologia , Interleucina-2/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fatores de Transcrição NFATC , Fosfolipídeos/isolamento & purificação , Fosfolipídeos/farmacologia , Fosforilação , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Células Th1/imunologia , Transcrição Gênica/efeitos dos fármacos
15.
J Immunol ; 161(9): 4909-16, 1998 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-9794425

RESUMO

The effects of glycoinositolphospholipid (GIPL), from the pathogenic protozoan Trypanosoma cruzi, and its isolated glycan and lipid (dihydroceramide) components, were investigated in J774 cells and primary macrophages. Isolated GIPL ceramide, but not intact GIPL or its glycan, induced intense fluid phase endocytosis when added exogenously. In the presence of the cytokine IFN-gamma, GIPL ceramide induced marked apoptosis in J774 cells and macrophages, independent of nitric oxide secretion. When cells were preincubated with the GIPL-derived glycan chain, addition of intact GIPL induced macrophage apoptosis in the presence of IFN-gamma. Synthetic C2-dihydroceramide also induced apoptosis in the presence of IFN-gamma. Induction of apoptosis in T. cruzi-infected macrophages by GIPL ceramide plus IFN-gamma led to increased parasite release compared with IFN-gamma treatment alone. Viable parasites released comprised both infective trypomastigote and spheromastigote forms. These results identify a novel pathway by which T. cruzi glycosylphosphatidylinositol family molecules affect host macrophages, with implications for the infectious process.


Assuntos
Apoptose/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glicolipídeos/farmacologia , Interferon gama/fisiologia , Macrófagos Peritoneais/parasitologia , Fosfolipídeos/farmacologia , Trypanosoma cruzi/química , Animais , Ceramidas/farmacologia , Sinergismo Farmacológico , Endocitose/efeitos dos fármacos , Feminino , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Polissacarídeos/farmacologia , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/patogenicidade , Células Tumorais Cultivadas , Virulência , ômega-N-Metilarginina/farmacologia
16.
Am J Physiol ; 274(5): L737-49, 1998 05.
Artigo em Inglês | MEDLINE | ID: mdl-9612289

RESUMO

Serum lipoproteins may enter the airways and appear in sputum (chyloptysis) when the lymphatic circulation is impaired by inflammation, neoplasia, or an abnormal proliferation of smooth muscle cells. While analyzing the bronchoalveolar lavage fluid of a patient with chyloptysis, we noticed that surfactant could not be separated from contaminating serum lipoproteins and speculated that lipoproteins might interact with surfactant components. To clarify this point we immobilized surfactant protein (SP) A on microtiter wells and incubated it with 125I-labeled very low density lipoproteins (VLDLs), low-density lipoproteins, and high-density lipoproteins. We found that SP-A binds lipoproteins. Studying in greater detail the interaction of SP-A with VLDLs, we found that the binding is time and concentration dependent; is inhibited by unlabeled lipoproteins, phospholipids, and antibodies to SP-A; is increased by Ca2+; and is unaffected by methyl alpha-D-mannopyranoside. Whole surfactant is a potent inhibitor of binding. Furthermore, we found that SP-A increases the degradation of VLDLs by alveolar macrophages and favors the association of VLDLs with alveolar surfactant. We conclude that SP-A influences the disposal of serum lipoproteins entering the airways and speculate that binding to alveolar surfactant might represent an important step in the interaction between exogenous substances and the lung.


Assuntos
Quilotórax/fisiopatologia , Lipoproteínas/sangue , Lipoproteínas/metabolismo , Pulmão/metabolismo , Proteolipídeos/fisiologia , Surfactantes Pulmonares/fisiologia , Líquido da Lavagem Broncoalveolar/química , Feminino , Humanos , Lipoproteínas VLDL/metabolismo , Macrófagos Alveolares/metabolismo , Microscopia Eletrônica , Pessoa de Meia-Idade , Proteína A Associada a Surfactante Pulmonar , Proteínas Associadas a Surfactantes Pulmonares
17.
J Biol Chem ; 273(24): 14982-8, 1998 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-9614105

RESUMO

In this study, we have characterized the activity of a uridine diphospho-N-acetylglucosamine:polypeptide-alpha-N-acetylglucosaminylt ransferase (O-alpha-GlcNAc-transferase) from Trypanosoma cruzi. The activity is present in microsomal membranes and is responsible for the addition of O-linked alpha-N-acetylglucosamine to cell surface proteins. This preparation adds N-acetylglucosamine to a synthetic peptide KPPTTTTTTTTKPP containing the consensus threonine-rich dodecapeptide encoded by T. cruzi MUC gene (Di Noia, J. M., Sánchez D. O., and Frasch, A. C. C. (1995) J. Biol. Chem. 270, 24146-24149). Incorporation of N-[3H]acetylglucosamine is linearly dependent on incubation time and concentration of enzyme and substrate. The transferase activity has an optimal pH of 7.5- 8.5, requires Mn2+, is unaffected by tunicamycin or amphomycin, and is strongly inhibited by UDP. The optimized synthetic peptide acceptor for the cytosolic O-GlcNAc-transferase (YSDSPSTST) (Haltiwanger, R. S., Holt, G. D., and Hart, G. W. (1990) J. Biol. Chem. 265, 2563-2568) is not a substrate for this enzyme. The glycosylated KPPTTTTTTTTKPP product is susceptible to base-catalyzed beta-elimination, and the presence of N-acetylglucosamine alpha-linked to threonine is supported by enzymatic digestion and nuclear magnetic resonance data. These results describe a unique biosynthetic pathway for T. cruzi surface mucin-like molecules, with potential chemotherapeutic implications.


Assuntos
Acetilglucosamina/química , N-Acetilglucosaminiltransferases/química , Polissacarídeos/biossíntese , Trypanosoma cruzi/enzimologia , Animais , Cátions/farmacologia , Citosol/enzimologia , Inibidores Enzimáticos/farmacologia , Glicopeptídeos/análise , Glicosilação , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Glicoproteínas de Membrana/biossíntese , Microssomos/enzimologia , Peptídeos/metabolismo , Proteínas de Protozoários/química , Difosfato de Uridina/farmacologia
18.
FASEB J ; 12(6): 433-7, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9535215

RESUMO

In this study we assessed whether widely accepted risk factors for atherosclerotic vascular diseases such as lipoprotein(a) [Lp(a)], a cholesterol-rich lipoprotein under strict genetical control, and other lipid parameters change with age. The variations of blood levels and the pathophysiological role of Lp(a) in old people, and particularly in the oldest old, are unknown. Accordingly, we measured Lp(a) levels as well as total, LDL, and HDL cholesterol (CT), and triglycerides (TG) in sera from 75 healthy centenarians, 114 randomly selected subjects under 65 years, 73 randomly selected elderly people, and 30 healthy selected elderly people. The results showed that Lp(a) serum levels did not vary by age group, including centenarians. Remarkably, one-quarter of the centenarians had high Lp(a) serum levels even though they never suffered from atherosclerosis-related diseases. At variance with young and aged people, centenarians with high Lp(a) serum levels also had high plasma concentrations of the proinflammatory cytokine IL-6, suggesting that genetic control of the Lp(a) serum level may attenuate with age and that environmental factors such as chronic subclinical inflammatory processes may play a role. We also showed that most centenarians are paradoxically characterized by low HDL-CT and relatively high TG levels, which together are considered to be strong risk factors for coronary heart disease. On the whole, these data support the hypothesis that a continuous and complex reshaping of lipid metabolism occurs in physiological aging, likely contributing to successful aging.


Assuntos
HDL-Colesterol/sangue , LDL-Colesterol/sangue , Lipoproteína(a)/sangue , Triglicerídeos/sangue , Doenças Vasculares/sangue , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Interleucina-6/sangue , Masculino , Valores de Referência , Fatores de Risco , Fator de Necrose Tumoral alfa/metabolismo , Doenças Vasculares/epidemiologia
19.
Biochem J ; 329 ( Pt 3): 665-73, 1998 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-9445397

RESUMO

We have characterized glycoinositol phospholipids (GIPLs) from three strains of the trypanosomatid parasites Endotrypanum schaudinni and Endotrypanum monterogeii. Methanolysis of the intact GIPLs liberated methyl esters of tetracosanoic acid, docosanoic acid, octadecanoic acid and hexadecanoic acid and C20 and C21 phytosphingosines. Phosphoinositol oligosaccharides were released from the GIPLs by mild base treatment, and their structures were determined by compositional analysis, fast-atom-bombardment MS and NMR spectroscopy. Similar compounds were detected in all three strains, although their relative proportions varied. The predominant components in E. schaudinni strain LV59 and E. monterogeii LV88 were Galpbeta1-3Galpbeta1-3Manalpha1-3Manalpha1-4G lcNalpha1-6Ins-1-P and Arapbeta1-2Ga lpbeta1-3Galpbeta1-3Manalpha1-3Manalpha1-4Glc Nalpha1-6Ins-1-P, and the major phosphoinositol oligosaccharide in E. schaudinni LV58 was the hybrid-type GIPL Manalpha1-2(EtNP-6)Manalpha1-6(Galpbeta1-3Man alpha1-3)Manalpha1-4GlcN alpha1-6Ins-1-P (where EtNP is ethanolamine phosphate). Several minor oligosaccharides containing additional galactose and/or arabinose residues were also detected.


Assuntos
Antígenos de Protozoários/química , Epitopos/biossíntese , Glicoesfingolipídeos/química , Glicosilfosfatidilinositóis/química , Leishmania major/química , Oligossacarídeos/química , Trypanosomatina/química , Animais , Antígenos de Protozoários/biossíntese , Sequência de Carboidratos , Epitopos/química , Técnica Indireta de Fluorescência para Anticorpo , Glicoesfingolipídeos/imunologia , Glicosilfosfatidilinositóis/imunologia , Glicosilfosfatidilinositóis/isolamento & purificação , Leishmania major/imunologia , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Oligossacarídeos/imunologia , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Trypanosomatina/imunologia
20.
Glycobiology ; 7(5): 687-95, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9254050

RESUMO

Glycoinositolphospholipids (GIPLs) were isolated from promastigotes of the lizard parasites Leishmania adleri by phenol/water extraction. Phosphoinositol oligosaccharides were liberated by mild alkaline hydrolysis, purified by gel filtration and high pH anion exchange chromatography, and characterized by methylation analysis, fast atom bombardment mass spectrometry, and nuclear magnetic resonance spectroscopy. The four major compounds (I-IV) from L. adleri were linked to alkylacyl glycerol, and their glycan moieties had the following structures: Man alpha(1-2)Man alpha(1-6)[Man alpha(1-3)] Man alpha(1-4)GlcN alpha(1-6)Ins-1-PO4 (I), Galp alpha(1-6) Galp alpha(1-3)Galf beta(1-3)Man alpha(1-3)Man alpha(1-4)GlcN alpha(1-6)Ins-1-PO4 (II), Galp alpha(1-3)Galf beta(1-3)Man alpha(1-3) Man alpha(1-4)GlcN alpha(1-6)Ins-1-PO4 (III), Man alpha(1-2)[EtNP(-6)]Man alpha(1-6)[Man alpha(1-3)] Man alpha(1-4)GlcN alpha(1-6)Ins-1-PO4 (IV). These compounds are analogous to the previously characterized GIPLs from New and Old World leishmanial parasites of mammals designated iM4 (identical to compound I), GIPLs 3 and 2 (identical to compounds II and III, respectively), and EPiM4 (identical to compound IV), which is consistent with a close phylogenetic relationship between lizard and mammalian Leishmania. However, in contrast to the mammalian parasites, the abundant surface glycoconjugate known as lipophosphoglycan was either absent or confined to the flagellar pocket region in L. adleri.


Assuntos
Glucanos/química , Glicosilfosfatidilinositóis/química , Leishmania/metabolismo , Lagartos/parasitologia , Animais , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia em Gel , Cromatografia por Troca Iônica , Glucanos/isolamento & purificação , Glicosilfosfatidilinositóis/biossíntese , Glicosilfosfatidilinositóis/isolamento & purificação , Leishmania/química , Leishmania/classificação , Espectroscopia de Ressonância Magnética , Mamíferos , Metilação , Dados de Sequência Molecular , Filogenia , Espectrometria de Massas de Bombardeamento Rápido de Átomos
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