Barrenetxe, J. (Jaione)
- Publications
- item.page.relationships.isContributorAdvisorOfPublication
- item.page.relationships.isContributorOfPublication
7 results
Search Results
Now showing 1 - 7 of 7
- Matrix metalloproteinase-10 effectively reduces infarct size in experimental stroke by enhancing fibrinolysis via a thrombin-activatable fibrinolysis inhibitor-mediated mechanism(Lippincott, Williams & Wilkins, 2011) Parks, W.C. (William C.); Paramo, J.A. (José Antonio); Purroy, A. (A.); Orbe, J. (Josune); Rodriguez, J.A. (José Antonio); Barrenetxe, J. (Jaione); Serrano, R. (Rosario); Martinez-de-Lizarrondo, S. (Sara); Orset, C. (C.); Angles-Cano, E. (Eduardo); Vivien, D. (D.); Birkland, T.P. (T.P.)BACKGROUND: The fibrinolytic and matrix metalloproteinase (MMP) systems cooperate in thrombus dissolution and extracellular matrix proteolysis. The plasminogen/plasmin system activates MMPs, and some MMPs have been involved in the dissolution of fibrin by targeting fibrin(ogen) directly or by collaborating with plasmin. MMP-10 has been implicated in inflammatory/thrombotic processes and vascular integrity, but whether MMP-10 could have a profibrinolytic effect and represent a promising thrombolytic agent is unknown. METHODS AND RESULTS: The effect of MMP-10 on fibrinolysis was studied in vitro and in vivo, in MMP-10-null mice (Mmp10(-/-)), with the use of 2 different murine models of arterial thrombosis: laser-induced carotid injury and ischemic stroke. In vitro, we showed that MMP-10 was capable of enhancing tissue plasminogen activator-induced fibrinolysis via a thrombin-activatable fibrinolysis inhibitor inactivation-mediated mechanism. In vivo, delayed fibrinolysis observed after photochemical carotid injury in Mmp10(-/-) mice was reversed by active recombinant human MMP-10. In a thrombin-induced stroke model, the reperfusion and the infarct size in sham or tissue plasminogen activator-treated animals were severely impaired in Mmp10(-/-) mice. In this model, administration of active MMP-10 to wild-type animals significantly reduced blood reperfusion time and infarct size to the same extent as tissue plasminogen activator and was associated with shorter bleeding time and no intracranial hemorrhage. This effect was not observed in thrombin-activatable fibrinolysis inhibitor-deficient mice, suggesting thrombin-activatable fibrinolysis inhibitor inactivation as one of the mechanisms involved in the MMP-10 profibrinolytic effect. CONCLUSIONS: A novel profibrinolytic role for MMP-10 in experimental ischemic stroke is described, opening new pathways for innovative fibrinolytic strategies in arterial thrombosis.
- The facilitated glucose transporter GLUT12: What do we know and what would we like to know?(Springer, 2013) Lostao, M.P. (María Pilar); Gonzalez-Muniesa, P. (Pedro); Barrenetxe, J. (Jaione); Pujol-Gimenez, J. (Jonai)Human GLUT12 was isolated from the breast cancer cell line MCF-7 by its homology with GLUT4. Glucose has been described as its main substrate, but it also can transport other sugars. In humans, GLUT12 protein is expressed mainly in insulin sensitive tissues. Functional analysis has showed that GLUT12 transports sugars down its concentration gradient, but it can also work as a proton-coupled symporter. Studies from our laboratory, performed in Xenopus laevis oocytes expressing GLUT12, show that glucose uptake increases in the presence of Na+ and induces inward current. These findings suggest a transport mechanism never described for other GLUTs, which would indicate a distinct functional role for GLUT12. In relation with its physiological and pathophysiological function, GLUT12 has been mainly studied due to its role as a secondary insulin-sensitive glucose transporter and its possible implication in impaired insulin signalling pathologies. Its expression in some tumour tissues has been described and recently, it has been proposed as one of the key proteins in the glucose supply to malignant cells. Overall, even though a lot of information about GLUT12 has been released during the last years, its functional characteristics, physiological role or implication in the development of some diseases is still unclear. Therefore, this review of the literature can help to address further investigations needed to elucidate these issues that, in our view, are of great interest mainly due to the direct GLUT12 relation with cancer and probably with diabetes development.
- Matrix metalloproteinase-10 is upregulated by thrombin in endothelial cells and increased in patients with enhanced thrombin generation(American Heart Association, 2009) Paramo, J.A. (José Antonio); Rodriguez-Calvo, R. (Ricardo); Orbe, J. (Josune); Rodriguez, J.A. (José Antonio); Rodriguez, C. (Cristina); Barrenetxe, J. (Jaione); Martinez-Gonzalez, J. (José); Martinez-de-Lizarrondo, S. (Sara); Calvayrac, O. (Olivier); Roncal, C. (Carmen); Reverter, J.C. (Juan C.)OBJECTIVE: Thrombin is a multifunctional serine protease that promotes vascular proinflammatory responses whose effect on endothelial MMP-10 expression has not previously been evaluated. METHODS AND RESULTS: Thrombin induced endothelial MMP-10 mRNA and protein levels, through a protease-activated receptor-1 (PAR-1)-dependent mechanism, in a dose- and time-dependent manner. This effect was mimicked by a PAR-1 agonist peptide (TRAP-1) and antagonized by an anti-PAR-1 blocking antibody. MMP-10 induction was dependent on extracellular regulated kinase1/2 (ERK1/2) and c-jun N-terminal kinase (JNK) pathways. By serial deletion analysis, site-directed mutagenesis and electrophoretic mobility shift assay an AP-1 site in the proximal region of MMP-10 promoter was found to be critical for thrombin-induced MMP-10 transcriptional activity. Thrombin and TRAP-1 upregulated MMP-10 in murine endothelial cells in culture and in vivo in mouse aorta. This effect of thrombin was not observed in PAR-1-deficient mice. Interestingly, circulating MMP-10 levels (P<0.01) were augmented in patients with endothelial activation associated with high (disseminated intravascular coagulation) and moderate (previous acute myocardial infarction) systemic thrombin generation. CONCLUSIONS: Thrombin induces MMP-10 through a PAR-1-dependent mechanism mediated by ERK1/2, JNK, and AP-1 activation. Endothelial MMP-10 upregulation could be regarded as a new proinflammatory effect of thrombin whose pathological consequences in thrombin-related disorders and plaque stability deserve further investigation.
- Leptin regulates sugar and amino acids transport in the human intestinal cell line Caco-2(Wiley, 2012) Sakar, Y. (Yassine); Fanjul, C. (Carmen); Lostao, M.P. (María Pilar); Ducroc, R. (Robert); Barber, A. (Ana); Barrenetxe, J. (Jaione); Iñigo, C. (Carmen)Aim: Studies in rodents have shown that leptin controls sugars and glutamine entry in the enterocytes by regulating membrane transporters. Here, we have examined the effect of leptin on sugar and amino acids absorption in the human model of intestinal cells Caco-2 and investigated the transporters involved. Methods: Substrate uptake experiments were performed in Caco-2 cells, grown on plates, in the presence and the absence of leptin and the expression of the different transporters in brush border membrane vesicles was analysed by Western blot. Results: Leptin inhibited 0.1 mM α-methyl-D-glucoside uptake after 5 or 30 min treatment, and decreased SGLT1 protein abundance in the apical membrane. Uptake of 20 µM glutamine and 0.1 mM phenylalanine was also inhibited by leptin, indicating sensitivity to the hormone of the Na+-dependent neutral amino acid transporters ASCT2 and B0AT1. This inhibition was accompanied by a reduction of the transporters expression at the brush-border membrane. Leptin also inhibited 1 mM proline and β-alanine uptake in Na+ medium at pH 6, conditions for optimal activity of the H+-dependent neutral amino acid transporter PAT1. In this case, abundance of PAT1 in the brush-border membrane after leptin treatment was not modified. Interestingly, leptin inhibitory effect on β-alanine uptake was reversed by the PKA inhibitor H-89 suggesting involvement of PKA pathway in leptin´s regulation of PAT1 activity. Conclusion: These data show in human intestinal cells that leptin can rapidly control the activity of physiologically relevant transporters for rich-energy molecules, i.e D-glucose (SGLT1) and amino acids (ASCT2, B0AT1 and PAT1).
- Distribution of the long leptin receptor isoform in brush border, basolateral membrane, and cytoplasm of enterocytes.(British Society of Gastroenterology, 2002) Pascual, I. (I.); Villaro, A.C. (Ana Cristina); Muñoz-Navas, M. (Miguel); Lostao, M.P. (María Pilar); Barber, A. (Ana); Guembe, L. (L.); Barrenetxe, J. (Jaione)BACKGROUND AND AIM: Leptin, a hormone mainly produced by fat cells, acts primarily on the hypothalamus regulating energy expenditure and food intake. Leptin receptors are expressed in several tissues and the possible physiological role of leptin is being extensively investigated, with the result that important peripheral actions of the hormone in the organism are being discovered. Recent studies have demonstrated leptin and leptin receptor expression in gastric epithelial cells. In the present study, we report the presence of the long leptin receptor isoform (OB-Rb) in human, rat, and mouse small intestine, supporting the hypothesis of leptin as a hormone involved in gastrointestinal function. METHODS: The presence of the leptin receptor was determined by immunocytochemical methods using antibodies against the peptide corresponding to the carboxy terminus of the long isoform of the leptin receptor. Human duodenal biopsies from normal individuals undergoing gastrointestinal endoscopy, and intestinal fragments of Wistar rats and Swiss mice were processed for the study. RESULTS: Immunoreactivity for the long leptin receptor isoform was observed in the three studied species. Staining was located throughout the cytoplasm of the enterocytes, of both villi and crypts, and in the basolateral plasma membrane. Immunolabelling for OB-Rb protein was also found in the brush border of human enterocytes of formol and paraformaldehyde fixed samples. CONCLUSION: This report demonstrates the presence of the long leptin receptor isoform in the absorptive cells of rat, mouse, and human small intestine, suggesting that leptin could have a physiological role in the regulation of nutrient absorption.
- TNFalpha regulates sugar transporters in the human intestinal epithelial cell line Caco-2(W.B. Saunders, 2013) Rodriguez-Yoldi, M.J. (M.J.); Sanchez, O. (O.); Lostao, M.P. (María Pilar); Barber, A. (Ana); Barrenetxe, J. (Jaione); Gascon, S. (S.)PURPOSE: During intestinal inflammation TNFα levels are increased and as a consequence malabsorption of nutrients may occur. We have previously demonstrated that TNFα inhibits galactose, fructose and leucine intestinal absorption in animal models. In continuation with our work, the purpose of the present study was to investigate in the human intestinal epithelial cell line Caco-2, the effect of TNFα on sugar transport and to identify the intracellular mechanisms involved. METHODS: Caco-2 cells were grown on culture plates and pre-incubated during different periods with various TNFα concentrations before measuring the apical uptake of galactose, α-methyl-glucoside (MG) or fructose for 15 min. To elucidate the signaling pathway implicated, cells were pre-incubated for 30min with the PKA inhibitor H-89 or the PKC inhibitor chelerythrine, before measuring the sugar uptake. The expression in the apical membrane of the transporters implicated in the sugars uptake process (SGLT1 and GLUT5) was determined by Western blot. RESULTS: TNFα inhibited 0.1mM MG uptake after pre-incubation of the cells for 6-48h with the cytokine and in the absence of cytokine pre-incubation. In contrast, 5mM fructose uptake was stimulated by TNFα only after long pre-incubation times (24 and 48 h). These effects were mediated by the binding of the cytokine to its specific receptor TNFR1, present in the apical membrane of the Caco-2 cells. Analysis of the expression of the MG and fructose transporters at the brush border membrane of the cells, after 24h pre-incubation with the cytokine, revealed decrease on the amount of SGLT1 and increase on the amount of GLUT5 proteins. Short-term inhibition of MG transport by TNFα was not modified by H-89 but was blocked by chelerythrine. CONCLUSIONS: SGLT1 and GLUT5 expression in the plasma membrane is regulated by TNFα in the human epithelial cell line Caco-2 cells, leading to alteration on sugars transport, suggesting that TNFα could be considered as a physiological local regulator of nutrients absorption in response to an intestinal inflammatory status.
- Basal leptin regulates amino acid uptake in polarized Caco-2 cells(Springer, 2013) Fanjul, C. (Carmen); Lostao, M.P. (María Pilar); Barrenetxe, J. (Jaione)Leptin is secreted by gastric mucosa and is able to reach the intestinal lumen where its receptors are located in the apical membrane of the enterocytes. We have previously demonstrated that apical leptin inhibits sugar and amino acids uptake in vitro and glucose absorption in vivo. Since leptin receptors are also expressed in the basolateral membrane of the enterocytes, the aim of the present work was to investigate whether leptin acting from the basolateral side could also regulate amino acid uptake. Tritiated Gln and β-Ala were used to measure uptake into Caco-2 cells grown on filters, in the presence of basal leptin at short incubation times (5 and 30 min) and after 6 h of preincubation with the hormone. In order to compare apical and basal leptin effect, Gln and β-Ala uptake was measured in the presence of leptin acting from the apical membrane also in cells grown on filters. Basal leptin (8 mM) inhibited by ~15–30 % the uptake of 0.1 mM Gln and 1 mM β-Ala quickly, after 5 min exposure, and the effect was maintained after long preincubation periods. Apical leptin had the same effect. Moreover, the inhibition was rapidly and completely reversed when leptin was removed from the apical or basolateral medium. These results extend our previous findings and contribute to the vision of leptin as an important hormonal signal for the regulation of intestinal absorption of nutrients.