RESUMO
Crocetin is a natural carotenoid dicarboxylic acid that is found in the fruit of Gardenia jasminoides Ellis (Cape Jasmine) and in the stamen and pistil of Crocus sativus L. (saffron). It is used worldwide as an important spice, food colorant, and herbal medicine. In the current investigation, we have examined the cardiovascular effects of crocetin using stroke-prone spontaneously hypertensive rats (SHRSPs). Male SHRSPs (6 weeks old) were classified into three groups: a control group and two crocetin groups (25 and 50 mg/kg/day). The animals were given crocetin for 3 weeks. Body weights in each group were not significantly different during the treatment period, but the increase in systolic blood pressures observed with age was significantly moderated by crocetin. Thrombogenesis, assessed using a He-Ne laser technique in pial vessels, was significantly decreased. Antioxidant activity, assessed by measuring urinary 8-hydroxy-2'-deoxyguanosine levels, together with urinary nitric oxide (NO) metabolite levels, was increased significantly after treatment. Acetylcholine-induced vasodilation was measured using the aorta and indicated that endothelial function was significantly improved by crocetin. These results strongly suggest that the antihypertensive and antithrombotic effects of crocetin were related to an increase in bioavailable NO, possibly mediated by decreased inactivation of NO by reactive oxygen species.
Assuntos
Anti-Hipertensivos/farmacologia , Carotenoides/farmacologia , Hipertensão/tratamento farmacológico , Trombose Intracraniana/prevenção & controle , Animais , Pressão Sanguínea/efeitos dos fármacos , Crocus/química , Frutas/química , Gardenia/química , Masculino , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos Endogâmicos SHR , Vasodilatação , Vitamina A/análogos & derivadosRESUMO
Mice with a targeted gene disruption of Fut8 (Fut8(-/-)) showed an abnormality in the transition from pro-B cell to pre-B cell, reduced peripheral B cells, and a decreased immunoglobulin production. Alpha 1,6-fucosyltransferase (FUT8) is responsible for the alpha 1,6 core fucosylation of N-glycans, which could modify the functions of glycoproteins. The loss of a core fucose in both very late antigen 4 (VLA-4, alpha4beta1 integrin) and vascular cell adhesion molecule 1 (VCAM-1) led to a decreased binding between pre-B cells and stromal cells, which impaired pre-B cells generation in Fut8(-/-) mice. Moreover, the B lineage genes, such as CD79a, CD79b, Ebf1, and Tcfe2a, were downregulated in Fut8(-/-) pre-B cells. Indeed, the frequency of preBCR(+)CD79b(low) cells in bone marrow pre-B cells in Fut8(-/-) was much lower than that in Fut8(+/+) cells. These results reveal a new role of core fucosylated N-glycans in mediating early B cell development and functions.
Assuntos
Fucosiltransferases/fisiologia , Integrina alfa4beta1/metabolismo , Células Precursoras de Linfócitos B/citologia , Molécula 1 de Adesão de Célula Vascular/metabolismo , Animais , Linhagem Celular Tumoral , Fucose/metabolismo , Fucosiltransferases/genética , Fucosiltransferases/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Células Precursoras de Linfócitos B/enzimologia , Células Precursoras de Linfócitos B/metabolismo , Células EstromaisRESUMO
This study examined whether the chain length of glucose in the diet could affect the selection of foods by Zn-adequate and Zn-deficient rats. Dextrin, maltose and glucose were used as sources of carbohydrate in the diet and the selection patterns of the rats were analyzed for 28 d by a 3-choice selection. Diets provided as a set of three either Zn-adequate or Zn-deficient diets were rotated daily. The Zn-adequate control rats selected widely from the three diets throughout the 28 d. In contrast, rats fed a Zn-deficient diet selected exclusively and continuously the dextrin diet or dextrin and glucose diets from the three diets over the experimental periods. The average daily total food intakes of rats fed a Zn-deficient diet were very significantly decreased. The selections of dextrin, maltose and glucose diets in the 3-choice methods of the control rats were 5.7+/-1.6(b), 5.8+/-2.0(b) and 2.7+/-0.9(a) g/d, respectively (p<0.05), and those of the Zn-deficient rats were 6.4+/-2.5(c), 0.8+/-1.3(a) and 2.6+/-1.4(b) g/d, respectively (p<0.05). The ratios of the selected maltose-diet in the Zn-adequate control and the Zn-deficient rats were 40.8+/-13.8 and 9.0+/-15.6%, respectively (p<0.01) and those of the dextrin-diet were 40.3+/-11.4 and 63.0+/-22.3%, respectively (p<0.05). The decreased preference for the maltose-diet in the Zn-deficient rats may reflect the increased selection of the dextrin-diet.
Assuntos
Dextrinas/administração & dosagem , Dieta/métodos , Preferências Alimentares/fisiologia , Glucose/administração & dosagem , Maltose/administração & dosagem , Zinco/deficiência , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Comportamento de Escolha/efeitos dos fármacos , Comportamento de Escolha/fisiologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Preferências Alimentares/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar , Fatores de Tempo , Zinco/administração & dosagemRESUMO
We recently reported on a brain-specific beta1,6-N-acetylglucosaminyltransferase IX (GnT-IX, also referred to as GnT-VB), a GnT-V homologue, which acts on alpha-linked mannose of N-glycans and O-mannosyl glycans. To distinguish functions of GnT-IX with GnT-V, we examined the distribution of GnT-IX and GnT-V transcripts in mouse tissues by Northern blot analysis. The two enzymes were differentially expressed as has previously been observed in human tissues. GnT-IX transcripts were restricted to the cerebrum, cerebellum, thymus and testis, whereas GnT-V transcripts were expressed ubiquitously in mouse tissues. To investigate the localization of these enzymes in mouse tissues in more detail, a polyclonal antibody against GnT-IX was prepared. The antibody specifically recognized GnT-IX, but not GnT-V, in the Golgi apparatus, as confirmed by the use of GnT-IX and GnT-V transfectants. In agreement with the Northern blot analysis data, an immunohistochemical study showed substantial expression of GnT-IX in the brain, while no expression was observed in the liver. Moreover, to exclude GnT-V contamination, we performed an enzymatic assay for GnT-IX using a Mgat5 (GnT-V)-null mouse brain as an enzyme source and found the enzymatic activities do, in fact, exist in mouse brain. The reaction product was confirmed by high performance liquid chromatography and mass spectrometry. These results demonstrate, for the first time, that GnT-IX protein is actually expressed and may function as a glycosyltransferase in the brain.
Assuntos
Encéfalo/enzimologia , Regulação Enzimológica da Expressão Gênica , N-Acetilglucosaminiltransferases/genética , Proteínas do Tecido Nervoso/genética , Animais , Cromatografia Líquida de Alta Pressão , Humanos , Espectrometria de Massas , Camundongos , Camundongos Knockout , Camundongos Transgênicos , N-Acetilglucosaminiltransferases/análise , N-Acetilglucosaminiltransferases/metabolismo , Proteínas do Tecido Nervoso/análise , Proteínas do Tecido Nervoso/metabolismo , RNA Mensageiro/análise , Distribuição TecidualRESUMO
Fibronectins (FNs) are major cell-adhesive proteins in the extracellular matrix and are essential for embryonic development. FNs are encoded by a single gene, but heterogeneity is introduced by alternative pre-mRNA splicing. One of the alternatively spliced segments, extra domain B (EDB), is prominently expressed during embryonic development and in tumor tissues, although it is mostly eliminated from FN in normal adult tissues. To examine the function of the EDB segment in vivo, we generated mice lacking the EDB exon using the Cre-loxP system. Although EDB-containing FNs are highly expressed throughout early embryogenesis, EDB-deficient mice developed normally and were fertile. Despite the absence of any significant phenotypes observed in vivo, however, fibroblasts obtained from EDB-deficient mice grew slowly in vitro and deposited less FN in the pericellular matrix than fibroblasts from wild-type mice. These results indicate that expression of EDB-containing isoforms is dispensable during embryonic development, yet may play a modulating role in the growth of connective tissue cells via the FN matrix.
Assuntos
Fibronectinas/fisiologia , Sequência de Aminoácidos , Animais , Cartilagem/crescimento & desenvolvimento , Divisão Celular/fisiologia , Quimera , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Matriz Extracelular/fisiologia , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Isoformas de Proteínas , Estrutura Terciária de Proteína/genéticaRESUMO
Glucose and fructose selection patters of rats were analyzed for 28 d by a 2-choice selection in either Zn-adequate or Zn-deficient status. In this paper, we describe the following serial studies: (1) For the first 24 h, rats fed a Zn-deficient diet preferred a fructose-diet compared with a glucose-diet. On and after the third day, rats fed both Zn-adequate and Zn-deficient diets preferred the glucose-diet. (2) Throughout the experimental period, many of the rats fed a Zn-adequate and Zn-deficient diet continuously selected one diet. (3) Some of the rats fed a Zn-adequate and Zn-deficient diet suddenly changed preference for the glucose-diet or the fructose-diet. (4) The sum of daily glucose- and fructose-diet intake in rats fed a Zn-deficient diet showed a characteristic variation with the cyclic period of 3.9 +/- 0.4 d.
Assuntos
Carboidratos da Dieta , Preferências Alimentares/fisiologia , Frutose/administração & dosagem , Glucose/administração & dosagem , Zinco/deficiência , Animais , Dieta , Ingestão de Alimentos , Masculino , Ratos , Ratos Wistar , Aumento de Peso , Zinco/administração & dosagemRESUMO
The effect of fasting on mouse liver methionine adenosyltransferase (MAT I/ III) expression and the regulation of methionine metabolism were investigated. The mRNA level, protein level, and activity of MAT I/III were increased by fasting for 10 or 16 h. In spite of the increase of MAT I/III activity, S-adenosylmethionine, the product of methionine due to MAT I/III, decreased. S-Adenosylhomocysteine, which is made from S-adenosylmethionine by its coupling to methyltransferase, increased as a result of fasting for 16 h. These results suggest that the total methylation reactions using S-adenosylmethionine are stimulated in the fasting mouse liver. However, the DNA methylation level was not changed by fasting for 16 h. Glutathione, which is made by the transsulfuration pathway from homocysteine, decreased due to fasting. Regulation of supplementation of S-adenosylmethionine may occur in the fasting mouse because MAT I/III activity increases and the flow to glutathione is decreased.
Assuntos
Jejum/fisiologia , Expressão Gênica/fisiologia , Fígado/enzimologia , Metionina Adenosiltransferase/genética , Metionina/metabolismo , Animais , Metilação de DNA , Glutationa/metabolismo , Cinética , Fígado/química , Masculino , Metionina Adenosiltransferase/análise , Metionina Adenosiltransferase/metabolismo , Metilação , Camundongos , RNA Mensageiro/análise , S-Adenosilmetionina/análiseRESUMO
Ischemic acute kidney injury (AKI) is the most key pathological event for accelerating progression to chronic kidney disease through vascular endothelial injury or dysfunction. Thus, it is critical to elucidate the molecular mechanism of endothelial protection and regeneration. Emerging evidence indicates that bone marrow-derived cells (BMCs) contribute to tissue reconstitution in several types of organs post-injury, but little is known whether and how BMCs contribute to renal endothelial reconstitution, especially in an early-stage of AKI. Using a mouse model of ischemic AKI, we provide evidence that incorporation of BMCs in vascular components (such as endothelial and smooth muscle cells) becomes evident within four days after renal ischemia and reperfusion, associated with an increase in stromal cell-derived factor-1 (SDF1) in endothelium and that in CXCR4/SDF1-receptor in BMCs. Notably, anti-CXCR4 antibody decreased the numbers of infiltrated BMCs and BMC-derived endothelium-like cells, but not of BMC-derived smooth muscle cell-like cells. These results suggest that reconstitution of renal endothelium post-ischemia partially depends on a paracrine loop of SDF1-CXCR4 between resident endothelium and BMCs. Such a chemokine ligand-receptor system may be attributable for selecting a cellular lineage (s), required for renal vascular protection, repair and homeostasis, even in an earlier phase of AKI.
Assuntos
Injúria Renal Aguda/metabolismo , Quimiocina CXCL12/metabolismo , Células Endoteliais/metabolismo , Animais , Quimiocina CXCL12/genética , Regulação da Expressão Gênica/fisiologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Hipóxia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Comunicação Parácrina/fisiologia , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Traumatismo por ReperfusãoRESUMO
Diabetic nephropathy (DN), a major cause of end-stage chronic renal failure, is histologically characterized by glomerulosclerosis. To investigate the molecular mechanisms of DN, it is important to establish a stable model of glomerulosclerosis in mice, because genomic manipulation techniques (such as gene destruction or transgene insertion) are well established in rodent species. In this study, we found that repeated administrations of streptozotocin led to early onset of glomerular sclerotic lesions in C57BL/6 mice, accompanied with renal dysfunction. During the natural course of DN, glomerular endothelial cells decreased at 10 weeks after the start of streptozotocin-injections, whereas myofibroblastic mesangial cells became evident. Our results provide an animal tool to elucidate the molecular mechanisms of DN, for example to investigate vascular pathology in diabetic glomerular diseases.
Assuntos
Nefropatias Diabéticas/induzido quimicamente , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Estreptozocina/toxicidade , Animais , Feminino , Imuno-Histoquímica , Injeções , Camundongos , Camundongos Endogâmicos C57BL , Fatores de TempoRESUMO
Rats fed a Zn-deficient diet show characteristic variations in feed intake. These variations were followed by means of a personal computer. The specific feed intake patterns in rats fed a zinc-deficient diet before and after supplementation with protein and several essential amino acids were determined. The high-protein diet decreased the amplitude of feed intake under zinc deficiency, probably because of a decrease in sensitivity to the deficiency. Furthermore, the zinc-deficient diet was supplemented with essential amino acids, and of them L-threonine showed the most marked effect on the increased variability of feed intake.
Assuntos
Aminoácidos Essenciais/administração & dosagem , Proteínas Alimentares/administração & dosagem , Comportamento Alimentar , Treonina/administração & dosagem , Zinco/deficiência , Ração Animal , Animais , Suplementos Nutricionais , Ingestão de Alimentos , Masculino , Ratos , Ratos WistarRESUMO
When dextrin, maltose, sucrose, glucose, and fructose were used as a source of carbohydrate in a diet, the food intake of rats fed either a Zn-adequate or Zn-deficient diet was evaluated daily over 28 d. The average food intake of all groups of rats fed the Zn-deficient diet was significantly lower than that of the corresponding groups of Zn-adequate control rats. The food intake of the dextrin group was the highest under both Zn-deficient and Zn-adequate diets, and that of the fructose group was the lowest. All rats of the dextrin, maltose, sucrose, glucose, and fructose groups with the Zn-deficient status showed a characteristic cyclic variation in food intake and fitted well to a Cosinor curve. The values of the mesor, amplitude, and period of the food intake cycles showed significant differences among the groups. The higher intake of the glucose diet than the fructose diet of rats fed a Zn-deficient diet may be related to the different metabolisms of the carbohydrates used, from the comparison of the quantities consumed in the corresponding carbohydrates of Zn-adequate diets.
Assuntos
Peso Corporal , Dieta , Carboidratos da Dieta/administração & dosagem , Ingestão de Alimentos , Zinco/administração & dosagem , Zinco/deficiência , Animais , Peso Corporal/fisiologia , Dextrinas/administração & dosagem , Frutose/administração & dosagem , Glucose/administração & dosagem , Masculino , Maltose/administração & dosagem , Periodicidade , Distribuição Aleatória , Ratos , Ratos Wistar , Sacarose/administração & dosagemRESUMO
This study examined whether protein concentrations in the diet of rats fed adequate Zn or deficient Zn affect their preference for disaccharides of sucrose and maltose. Sucrose and maltose were used as a source of carbohydrate and the selection patterns of rats were analyzed for 28 d by a two-choice selection method. Diets provided as a set of two either Zn-adequate or Zn-deficient diets containing 10, 20 and 40% protein each were changed in position daily. For the first 24 h, both the control Zn-adequate and Zn-deficient rats preferred sucrose to maltose and then gradually selected the maltose diet. Protein in the diet affected the selection of the disaccharides for both the control and Zn-deficient rats. The decrease order of the ratio of consumed sucrose to maltose over 28 d was 10% > 20% > 40% protein diet group, and Zn-deficiency emphasized the decrease. These results suggest that sucrose has a stronger taste effect than maltose in rats, but that the selection of sucrose is decreased by the post-ingestive effect which is stimulated in low-protein and Zn-deficient diets.
Assuntos
Dieta com Restrição de Proteínas , Preferências Alimentares , Sacarose/administração & dosagem , Sacarose/metabolismo , Zinco/deficiência , Animais , Peso Corporal , Proteínas Alimentares , Ingestão de Alimentos , Masculino , Maltose/administração & dosagem , Maltose/metabolismo , RatosRESUMO
Podocytes have a peculiar structure constituting slit diaphragm (SD) and foot process (FP), and play essential roles in the glomerular filtration barrier. There is now ample evidence that SD- and FP-associated molecules, such as podocin and CD2-associated protein (CD2AP), are down-regulated during albuminuria of chronic kidney disease. However, it is still unclear whether these molecules are altered during acute renal failure (ARF) with albuminuria. Using lipopolysaccharide (LPS)-treated mice as a model of septic ARF, we provide evidence that the expression of SD- and FP-associated molecules becomes faint, along with albuminuria. In the LPS-treated mice, urinary albumin levels gradually increased, associated with the elevation of blood urea nitrogen levels, indicating the successful induction of albuminuria during septic ARF. In this pathological process, glomerular podocin expression became faint, especially at 36 hr post-LPS challenge (i.e., a peak of albuminuria). Likewise, LPS treatment led to a significant decrease in CD2AP, an anchorage between podocin and F-actin. With regard to this, tensin2 is a novel molecule that stabilizes F-actin extension. Interestingly, glomerular tensin2 expression levels were also decreased during the albuminuric phase, associated with losses of glomerular F-actin and synaptopodin under septic states. As a result, there were some lesions of podocytic FP effacement, as shown by electron microscopy. Based on these data, we emphasize the importance of concomitant decreases in podocin, CD2AP and tensin2 during septic ARF-associated proteinuria.
Assuntos
Injúria Renal Aguda/etiologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Albuminúria/etiologia , Proteínas do Citoesqueleto/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Sepse/complicações , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas do Citoesqueleto/genética , Feminino , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Lipopolissacarídeos/toxicidade , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Fosfoproteínas Fosfatases/genética , Podócitos/fisiologia , Podócitos/ultraestrutura , TensinasRESUMO
This paper describes a preference for two disaccharides in the diets of Zn-adequate and Zn-deficient rats. Maltose and sucrose were used as a source of carbohydrate in the diet and the selection patterns of rats were analyzed for 28 d by a two-choice selection method. Diets provided as a set of two either Zn-adequate or Zn-deficient diets were changed in position daily. Control Zn-adequate and Zn-deficient rats both exclusively selected the sucrose diet at days 1 and 2, after onset of the feeding experiment, and then gradually selected the maltose-diet. After changing their preference from sucrose to maltose, the Zn-adequate control rats selected widely from both the maltose and sucrose diets, while the Zn-deficient rats exclusively and continuously selected the maltose diet from the two diets over the experimental period. The level of selection of sucrose-diet on day 28 had a correlation with the intestinal sucrase activity in the control rats. The sum of daily maltose and sucrose diet intake in rats fed a Zn-deficient diet showed a characteristic variation with the cyclic period of 3.6+/-0.2 d. The daily body-weight change of rats fed a Zn-deficient diet was well synchronized with their own food intake cycle. The day before changing preference from sucrose to maltose in rats fed a Zn-deficient diet represented a trough in their own food intake and body-weight cycles. These results suggest that one sign of a change in preference from sucrose to maltose in Zn-deficient rats is caused by a stage of negative energy balance.
Assuntos
Carboidratos da Dieta/administração & dosagem , Sacarose Alimentar/administração & dosagem , Metabolismo Energético , Preferências Alimentares , Maltose/administração & dosagem , Sacarose/administração & dosagem , Zinco/deficiência , Animais , Comportamento Animal , Peso Corporal , Dieta , Ingestão de Energia , Intestino Delgado/metabolismo , Ratos , Ratos Wistar , Sacarase/metabolismoRESUMO
Acute renal failure (ARF) occurs in septic patients and is histologically characterized by tubular apical damages, including brush border breakdown. Nevertheless, little information is available to identify the apical injury at a molecular level. Type 2a Na-phosphate (Pi) co-transporter (NaPiT2a) is constitutively expressed by brush borders of proximal tubules under a healthy condition. Therefore, we investigated if NaPiT2a could be used as a negative marker to predict the renal dysfunction, using an animal model of septic ARF. After the treatment of lipopolysaccharide (LPS), mice manifested the tubular apical injury and renal dysfunction, as evidenced by the increase in blood urea nitrogen (BUN) levels. Immunohistochemical examination revealed that the expression of NaPiT2a by renal proximal tubules became faint, being reciprocal to the development of tubular hypoxia during sepsis. Inversely, the loss in apical NaPiT2a was restored in a regenerating stage, associated with the recovery from renal hypoxia. Overall, there was a negative correlation between the NaPiT2a expression and BUN levels or tubular injury scores in septic mice. Our data indicate that the loss of NaPiT2a is a reliable marker for predicting the progression of septic ARF, while local hypoxia might be involved in the decrease of NaPiT2a expression.
Assuntos
Injúria Renal Aguda/metabolismo , Túbulos Renais Proximais/metabolismo , Sepse/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/biossíntese , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/patologia , Animais , Biomarcadores/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hipóxia/induzido quimicamente , Hipóxia/metabolismo , Hipóxia/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Lipopolissacarídeos/toxicidade , Camundongos , Sepse/induzido quimicamente , Sepse/patologiaRESUMO
The alpha1,6-fucosyl residue (core fucose) of glycoproteins is widely distributed in mammalian tissues and is altered under pathological conditions. A probe that specifically detects core fucose is important for understanding the role of this oligosaccharide structure. Aleuria aurantia lectin (AAL) and Lens culimaris agglutinin-A (LCA) have been often used as carbohydrate probes for core fucose in glycoproteins. Here we show, by using surface plasmon resonance (SPR) analysis, that Aspergillus oryzae l-fucose-specific lectin (AOL) has strongest preference for the alpha1,6-fucosylated chain among alpha1,2-, alpha1,3-, alpha1,4-, and alpha1,6-fucosylated pyridylaminated (PA)-sugar chains. These results suggest that AOL is a novel probe for detecting core fucose in glycoproteins on the surface of animal cells. A comparison of the carbohydrate-binding specificity of AOL, AAL, and LCA by SPR showed that the irreversible binding of AOL to the alpha1,2-fucosylated PA-sugar chain (H antigen) relative to the alpha1,6-fucosylated chain was weaker than that of AAL, and that the interactions of AOL and AAL with alpha1,6-fucosylated glycopeptide (FGP), which is considered more similar to in vivo glycoproteins than PA-sugar chains, were similar to their interactions with the alpha1,6-fucosylated PA-sugar chain. Furthermore, positive staining of AOL, but not AAL, was completely abolished in the cultured embryo fibroblast (MEF) cells obtained from alpha1,6-fucosyltransferase (Fut8) knock-out mice, as assessed by cytological staining. Taken together, these results suggest that AOL is more suitable for detecting core fucose than AAL or LCA.
Assuntos
Aspergillus oryzae/química , Fucose/química , Proteínas Fúngicas/química , Glicoproteínas/química , Lectinas/química , Sondas Moleculares/química , Animais , Embrião de Mamíferos/citologia , Embrião de Mamíferos/enzimologia , Fibroblastos/citologia , Fibroblastos/enzimologia , Fucose/metabolismo , Fucosiltransferases/deficiência , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/farmacologia , Glicoproteínas/metabolismo , Lectinas/metabolismo , Lectinas/farmacologia , Camundongos , Camundongos Knockout , Sondas Moleculares/metabolismo , Sondas Moleculares/farmacologia , Ligação Proteica/fisiologia , Especificidade por Substrato/fisiologiaRESUMO
Alpha1,6-fucosyltransferase (Fut8) plays important roles in physiological and pathological conditions. Fut8-deficient (Fut8-/-) mice exhibit growth retardation, earlier postnatal death, and emphysema-like phenotype. To investigate the underlying molecular mechanism by which growth retardation occurs, we examined the mRNA expression levels of Fut8-/- embryos (18.5 days postcoitum [dpc]) using a cDNA microarray. The DNA microarray and real-time polymerase chain reaction (PCR) analysis showed that a group of genes, including trypsinogens 4, 7, 8, 11, 16, and 20, were down-regulated in Fut8-/- embryos. Consistently, the expression of trypsinogen proteins was found to be lower in Fut8-/- mice in the duodenum, small intestine, and pancreas. Trypsin, an active form of trypsinogen, regulates cell growth through a G-protein-coupled receptor, the proteinase-activated receptor 2 (PAR-2). In a cell culture system, a Fut8 knockdown mouse pancreatic acinar cell carcinoma, TGP49-Fut8-KDs, showed decreased growth rate, similar to that seen in Fut8-/- mice, and the decreased growth rate was rescued by the application of the PAR-2-activating peptide (SLIGRL-NH2). Moreover, epidermal growth factor (EGF)-induced receptor phosphorylation was attenuated in TGP49-Fut8-KDs, which was highly associated with a reduction of trypsinogens mRNA levels. The addition of exogenous EGF recovered c-fos, c-jun, and trypsinogen mRNA expression in TGP49-Fut8-KDs. Again, the EGF-induced up-regulation of c-fos and c-jun mRNA expression was significantly blocked by the protein kinase C (PKC) inhibitor. Our findings clearly demonstrate a relationship between Fut8 and the regulation of EGF receptor (EGFR)-trypsin-PAR-2 pathway in controlling cell growth and that the EGFR-trypsin-PAR-2 pathway is suppressed in TGP49-Fut8-KDs as well as in Fut8-/- mice.
Assuntos
Retardo do Crescimento Fetal/metabolismo , Fucosiltransferases/genética , Receptor PAR-2/metabolismo , Tripsinogênio/metabolismo , Animais , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo , Embrião de Mamíferos/metabolismo , Receptores ErbB/metabolismo , Masculino , Camundongos , Camundongos Knockout , Oligopeptídeos/farmacologia , Fosforilação , Receptor PAR-2/agonistas , Células Tumorais CultivadasRESUMO
Fucosylated alpha-fetoprotein (AFP) is a highly specific tumor marker for hepatocellular carcinoma (HCC). However, the molecular mechanism by which serum level of fucosylated AFP increases in patients with HCC remains largely unknown. Here, we report that the fucosylation of glycoproteins could be a possible signal for secretion into bile ducts in the liver. We compared oligosaccharide structures on glycoproteins in human bile with those in serum by several types of lectin blot analyses. Enhanced binding of biliary glycoproteins to lectins that recognize a fucose residue was observed over a wide range of molecular weights compared with serum glycoproteins. A structural analysis of oligosaccharides by two-dimensional mapping high performance liquid chromatography and matrix-assisted laser desorption ionization time-of flight mass spectrometry confirmed the increases in the fucosylation of biliary glycoproteins. Purification followed by structural analysis on alpha1-antitrypsin, alpha1-acid glycoprotein and haptoglobin, which are synthesized in the liver, showed higher fucosylation in bile than in serum. To find direct evidence for fucosylation and sorting signal into bile ducts, we used alpha1-6 fucosyltransferase (Fut8)-deficient mice because fucosylation of glycoproteins produced in mouse liver was mainly an alpha1-6 linkage. Interestingly, the levels of alpha1-antitrypsin and alpha1-acid glycoprotein were quite low in bile of Fut8-deficient mice as compared with wild-type mice. An immunohistochemical study showed dramatic changes in the localization of these glycoproteins in the liver of Fut8-deficient mice. Taken together, these results suggest that fucosylation is a possible signal for the secretion of glycoproteins into bile ducts in the liver. A disruption in this system might involve an increase in fucosylated AFP in the serum of patients with HCC.
Assuntos
Ductos Biliares/metabolismo , Fucose/metabolismo , Glicoproteínas/metabolismo , Fígado/metabolismo , Polissacarídeos/metabolismo , Animais , Sequência de Carboidratos , Fucosiltransferases/deficiência , Fucosiltransferases/genética , Glicoproteínas/sangue , Humanos , Fígado/enzimologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Dados de Sequência Molecular , Polissacarídeos/químicaRESUMO
Rabeprazole achieves more potent acid suppression than other proton pump inhibitors. Therefore it is administered at reduced as well as high dosages in eradication therapy for Helicobacter pylori; however, there is incomplete assessment of the efficacy of a reduced dosage of rabeprazole as might be employed in therapy. In this study, we evaluated acid-suppressive efficacy of a reduced dosage of rabeprazole on day 7 by 24-hr pH-metry in 10 healthy male cytochrome P-450 2C19 extensive metabolizers without Helicobacterpylori infection and compared the results with those of high dosages of rabeprazole, lansoprazole, and omeprazole. Median intragastric pH value, pH >3 holding time ratio (pH>3HT), pH>4HT, pH>5HT, pH>6HT, and pH>7HT for 24 hr with rabeprazole, 10 mg twice daily, were not significantly different from those of rabeprazole, 20 mg twice daily, lansoprazole, 30 mg twice daily, and omeprazole, 20 mg twice daily. In conclusion, for acid-suppressive efficacy, a reduced dosage of rabeprazole is comparable to high dosages of rabeprazole, lansoprazole, and omeprazole.
Assuntos
Benzimidazóis/administração & dosagem , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacologia , Ácido Gástrico/metabolismo , Omeprazol/análogos & derivados , Omeprazol/administração & dosagem , 2-Piridinilmetilsulfinilbenzimidazóis , Adulto , Hidrocarboneto de Aril Hidroxilases/metabolismo , Benzimidazóis/farmacologia , Ritmo Circadiano , Estudos Cross-Over , Citocromo P-450 CYP2C19 , Relação Dose-Resposta a Droga , Esquema de Medicação , Mucosa Gástrica/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Lansoprazol , Masculino , Oxigenases de Função Mista/metabolismo , Monitorização Fisiológica , Omeprazol/farmacologia , RabeprazolRESUMO
BACKGROUND: Follicular gastritis is thought to be caused by Helicobacter pylori infection. However, the pathophysiology of it remains unclear. MATERIALS AND METHODS: We assessed gastric acidity in 15 patients with follicular gastritis, aged 20-37 years, using a 24-hour intragastric pH-metry, as well as by histologic and serologic evaluations; and compared it with that in other age-matched groups: 18 cases of H. pylori-positive antrum-predominant gastritis, 12 of pangastritis, and 24 H. pylori-negative normals. In eight cases with follicular gastritis, it was re-assessed 6 months after the eradication therapy for H. pylori. RESULTS: During nighttime, the percentage of time with intragastric pH above 3.0 in follicular gastritis was significantly higher than that in normals (p<.0001), and in antrum-predominant gastritis (p<.001), but was comparable with that in pangastritis. In the daytime period, this parameter in follicular gastritis was significantly higher than that in normal (p<.001), in antrum-predominant gastritis (p<.001), and in pangastritis (p<.05). Marked mononuclear cell and neutrophil infiltration but no apparent glandular atrophy were observed in both the antrum and corpus. Serum pepsinogen I/II ratio was significantly lower in follicular gastritis than that in normals (p<.0001) and in antrum-predominant gastritis (p<.001), whereas serum gastrin was significantly higher than that in normals (p<.0001), in antrum-predominant gastritis (p<.01) and in pangastritis (p<.05). After eradication for H. pylori, all of the parameters in follicular gastritis were altered to the same ranges as those in normals. CONCLUSIONS: In follicular gastritis, gastric acidity is significantly reduced, but can be normalized by eradication of H. pylori. It can thus be speculated that inflammatory cytokines or H. pylori-infection-induced prostaglandins might strongly inhibit gastric acid secretion in follicular gastritis.