RESUMEN
We attempted to clarify the reason why folate fortification ameliorates hyperhomocysteinemia induced by vitamin B(6) deficiency. Hyperhomocysteinemia caused by vitamin B(6) deficiency significantly decreased the rat liver 5-methyltetrahydrofolate level which was significantly improved by folate fortification. This result suggests that the amelioration of hyperhomocysteinemia in response to folate supplementation had enhanced the removal of homocysteine via methionine synthase.
Asunto(s)
5-Metiltetrahidrofolato-Homocisteína S-Metiltransferasa/metabolismo , Suplementos Dietéticos , Hiperhomocisteinemia/metabolismo , Metionina/metabolismo , Tetrahidrofolatos/metabolismo , Deficiencia de Vitamina B 6/metabolismo , Animales , Homocisteína/metabolismo , Hiperhomocisteinemia/dietoterapia , Hiperhomocisteinemia/etiología , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Metionina/administración & dosificación , Ratas , Ratas Wistar , Tetrahidrofolatos/administración & dosificación , Vitamina B 6/metabolismo , Deficiencia de Vitamina B 6/complicaciones , Deficiencia de Vitamina B 6/dietoterapiaRESUMEN
Vitamin B6 (B6) deficiency affects homocysteine metabolism, and this leads to hyperhomocysteinemia. In this study, we examined i) the effects of B6-deficiency and graduated levels of dietary methionine on homocysteine metabolism, and ii) the effects of fortified folate on homocysteine metabolism. In experiment 1, Wistar male rats were fed a control or a B6-deficient diet supplemented with L-methionine at a level of 3, 6, or 9 g/kg of diet for 5 weeks. The resulting plasma homocysteine levels in the B6-deficient groups increased in relation to the increase in dietary methionine level. Next, in experiment 2, rats were fed a control, B6-deficient, or folate enriched (10 mg pteroylmonoglutamic acid/kg) B6-deficient diet containing L-methionine at 9 g/kg for 5 weeks. Although the B6-deficient diet induced hyperhomocysteinemia, folate fortification ameliorated the plasma homocysteine concentration. Overall, our results indicate that folate fortification ameliorates the hyperhomocysteinemia induced by B6 deficiency and supplemental methionine intake.
Asunto(s)
Suplementos Dietéticos/efectos adversos , Ácido Fólico/farmacología , Hiperhomocisteinemia/complicaciones , Hiperhomocisteinemia/tratamiento farmacológico , Metionina/metabolismo , Deficiencia de Vitamina B 6/complicaciones , Deficiencia de Vitamina B 6/etiología , Animales , Peso Corporal/efectos de los fármacos , Ingestión de Alimentos/efectos de los fármacos , Ácido Fólico/uso terapéutico , Hiperhomocisteinemia/fisiopatología , Masculino , Metionina/sangre , Proyectos Piloto , Ratas , Ratas WistarRESUMEN
We recently showed that p120 catenin (p120ctn), which is an armadillo family protein member that binds to E-cadherin (E-cad), is also localized to desmosomes by directly or indirectly binding to desmogleins (Dsg). We examined whether p120ctn is associated with Dsg1 and Dsg3, as compared with E-cad and plakoglobin (PG), in keratinocytes grown in high or low Ca2+, using a human squamous cell carcinoma cell line, DJM-1 cells. The cell lysate of DJM-1 cells grown in high- or low-Ca2+ media was immunoprecipitated with anti-Dsg1/2 and Dsg3 antibodies, and we examined whether p120ctn is associated with Dsg1 and Dsg3. Then, we observed the co-localization between Dsg3 and p120ctn in cells grown in high- or low-Ca2+ medium on double-staining immunofluorescence microscopy using anti-p120ctn and anti-Dsg3 antibodies. Immunoprecipitates with anti-Dsg1/2 and Dsg3 antibodies in cells grown in high-Ca2+ medium contained p120ctn. In contrast, in low-Ca2+ medium, p120ctn was co-immunoprecipitated with neither Dsg1 nor Dsg3, but was co-immunoprecipitated with E-cad in cells grown in both high- and low-Ca2+ media. Dsg3 was associated with PG in cells grown in both low- and high-Ca2+ media. On immunofluorescence microscopy, p120ctn and Dsg3 were independently observed in cells grown in low-Ca2+ medium; p120ctn, but not Dsg3, was observed in a linear pattern at the cell-cell boundary. However, they were co-localized at cell-cell contacts in cells grown in high-Ca2+ medium. Thus, these proteins are not co-localized in low Ca2+ medium. These results suggest that p120ctn plays an important role in Ca2+-induced desmosome formation.
Asunto(s)
Cadherinas/metabolismo , Calcio/metabolismo , Moléculas de Adhesión Celular/metabolismo , Desmogleína 1/metabolismo , Desmogleína 3/metabolismo , Desmosomas/metabolismo , Queratinocitos/metabolismo , Fosfoproteínas/metabolismo , Anticuerpos Monoclonales , Western Blotting , Cateninas , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/fisiología , Línea Celular Tumoral , Células Cultivadas , Medios de Cultivo/química , Humanos , Inmunoprecipitación , Queratinocitos/fisiología , Microscopía Fluorescente , Fosfoproteínas/química , Fosfoproteínas/fisiología , Isoformas de Proteínas/metabolismo , gamma Catenina/metabolismo , Catenina deltaRESUMEN
In this study, we demonstrated that the two ginger-derived components have a potent and unique pharmacological function in 3T3-L1 adipocytes via different mechanisms. Both pretreatment of 6-shogaol (6S) and 6-gingerol (6G) significantly inhibited the tumor necrosis factor-alpha (TNF-alpha) mediated downregulation of the adiponectin expression in 3T3-L1 adipocytes. Our study demonstrate that (1) 6S functions as a PPARgamma agonist with its inhibitory mechanism due to the PPARgamma transactivation, and (2) 6G is not a PPARgamma agonist, but it is an effective inhibitor of TNF-alpha induced c-Jun-NH(2)-terminal kinase signaling activation and thus, its inhibitory mechanism is due to this inhibitory effect.
Asunto(s)
Adipocitos/efectos de los fármacos , Adiponectina/biosíntesis , Catecoles/farmacología , Alcoholes Grasos/farmacología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Células 3T3-L1 , Adipocitos/metabolismo , Animales , Regulación hacia Abajo/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Zingiber officinale/química , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Ratones , PPAR gamma/agonistas , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
P120-catenin (p120ctn) is an armadillo-repeat protein that directly binds to the intracytoplasmic domains of classical cadherins. p120ctn binding promotes the stabilization of cadherin complexes on the plasma membrane and thus positively regulates the adhesive activity of cadherins. Using co-immunoprecipitation, we show here that p120ctn associates to desmogleins (Dsg) 1 and 3. To determine which region is involved in the association between Dsg3 and p120ctn, we constructed mutant Dsg3 proteins, in which various cytoplasmic subdomains were removed. The tailless Dsg3 constructs Delta IA:AA1-641Dsg3 and Delta 641-714Dsg3, which do not contain the intracellular anchor (IA) region, did not coprecipitate with p120cn, nor did they colocalize at the plasma membrane. Immunocytochemical analysis revealed that p120ctn does not localize to desmosomes, but colocalizes with Dsg3 at the cell surface. A biotinylation assay for Dsg3 showed that biotinylated Delta 641-714Dsg3 was turned over more rapidly than wild-type Dsg3. These results indicate that the membrane proximal region (corresponding to residues 641-714) in the IA region of Dsg3 is necessary for complex formation with p120ctn, and to maintain free Dsg3 at the cell surface before it is integrated into desmosomes. In summary, we show that p120ctn is a novel interactor of the Dsg proteins, and may play a role in desmosome remodeling.
Asunto(s)
Moléculas de Adhesión Celular/metabolismo , Desmogleína 3/química , Desmogleína 3/metabolismo , Fosfoproteínas/metabolismo , Animales , Sitios de Unión , Cateninas , Moléculas de Adhesión Celular/análisis , Línea Celular , Membrana Celular/química , Desmogleína 1/análisis , Desmogleína 1/metabolismo , Desmogleína 3/análisis , Humanos , Inmunoprecipitación , Queratinocitos/química , Ratones , Mutación , Fosfoproteínas/análisis , Estructura Terciaria de Proteína , Catenina deltaRESUMEN
Adipocyte dysfunction is strongly associated with the development of obesity and insulin resistance. It is accepted that the regulation of adipocytokine expression is one of the most important targets for the prevention of obesity and improvement of insulin sensitivity. In this study, we have demonstrated that anthocyanin (cyanidin 3-glucoside; C3G) which is a pigment widespread in the plant kingdom, ameliorates hyperglycemia and insulin sensitivity due to the reduction of retinol binding protein 4 (RBP4) expression in type 2 diabetic mice. KK-A(y) mice were fed control or control +0.2% of a C3G diet for 5 weeks. Dietary C3G significantly reduced blood glucose concentration and enhanced insulin sensitivity. The adiponectin and its receptors expression were not responsible for this amelioration. C3G significantly upregulated the glucose transporter 4 (Glut4) and downregulated RBP4 in the white adipose tissue, which is accompanied by downregulation of the inflammatory adipocytokines (monocyte chemoattractant protein-1 and tumor necrosis factor-alpha) in the white adipose tissue of the C3G group. These findings indicate that C3G has significant potency in an anti-diabetic effect through the regulation of Glut4-RBP4 system and the related inflammatory adipocytokines.
Asunto(s)
Antocianinas/farmacología , Diabetes Mellitus Experimental/tratamiento farmacológico , Glucósidos/farmacología , Hiperglucemia/tratamiento farmacológico , Resistencia a la Insulina/fisiología , Adipoquinas/genética , Adipoquinas/metabolismo , Adiponectina/genética , Adiponectina/metabolismo , Tejido Adiposo Blanco/efectos de los fármacos , Tejido Adiposo Blanco/metabolismo , Animales , Antocianinas/química , Antocianinas/uso terapéutico , Glucemia/metabolismo , Western Blotting , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/genética , Prueba de Tolerancia a la Glucosa , Transportador de Glucosa de Tipo 4/genética , Transportador de Glucosa de Tipo 4/metabolismo , Glucosa-6-Fosfatasa/metabolismo , Glucósidos/química , Glucósidos/uso terapéutico , Hiperglucemia/sangre , Mediadores de Inflamación/antagonistas & inhibidores , Mediadores de Inflamación/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos , Estructura Molecular , Receptores de Adiponectina/genética , Receptores de Adiponectina/metabolismo , Proteínas Plasmáticas de Unión al Retinol/genética , Proteínas Plasmáticas de Unión al Retinol/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
The objective of this study was to clarify the relationship between the accumulation of S-adenosylhomocysteine (SAH) and the change in the SAH hydrolase activity in vitamin B6 (B6). Male Wistar rats were fed a control diet (control and pair-fed groups) or B6-free diet (B6-deficient group) for 5 wk. Although the SAH-synthetic activity of SAH hydrolase significantly increased in the B6-deficient group, SAH-hydrolytic activity of SAH hydrolase showed no significant difference in the liver among the three groups. On the other hand, SAH hydrolase mRNA in the liver did not show any significant change. Thus, the accumulation of SAH would be due to the increased SAH-synthetic activity of SAH hydrolase. The disturbed methionine metabolism by B6-deficiency, such as a significant increase of plasma homocysteine, might induce the activation of SAH hydrolase in the direction of SAH synthesis.
Asunto(s)
Adenosilhomocisteinasa/metabolismo , Metionina/metabolismo , S-Adenosilhomocisteína/metabolismo , Deficiencia de Vitamina B/metabolismo , Análisis de Varianza , Animales , Peso Corporal/fisiología , Homocisteína/sangre , Hígado/enzimología , Hígado/metabolismo , Masculino , Distribución Aleatoria , Ratas , Ratas Wistar , Deficiencia de Vitamina B/sangre , Deficiencia de Vitamina B/enzimologíaRESUMEN
The objective of this study was to examine how transient high plasma homocysteine (Hcy) levels affect the metabolism of Hcy, the activity and expression of S-adenosylhomocysteine (SAH) hydrolase which catalyzes both SAH hydrolysis and SAH synthesis. Wistar ST rats (males) were cannulated in the right jugular vein for intravenous infusion of physiological saline or DL-Hcy solutions (15 and 30 mg/mL) for 1 h at 1.1 mL/h/rat. The content of S-adenosylmethionine (SAM), SAH-synthetic activity of SAH hydrolase and the expression of SAH hydrolase mRNA in liver extracts showed no significant difference in the Hcy infused groups as compared to the Control group. On the other hand, the contents of hepatic SAH in the Hcy infused groups were dose-dependent and significantly higher than that of the Control group. Thus, this study showed that hepatic SAH increased without any increase in the SAH-synthetic activity and the expression of SAH hydrolase mRNA under transient high plasma Hcy levels after intravenous infusion of Hcy.