Mechanisms and regulation of monosaccharide transport in suspension cultured cells of Vitis Vinifera

Apresentação efectuada no "14th Congress of the Federation of European Societies of Plant Biology", em Cracow, Polland em 2004.Fundação para a Ciência e a Tecnologia (FCT) - grant SFRH/BD/10689/2002

N,N′-Dimethyl­ethylenediammonium dioxalatocuprate(II)

The asymmetric unit of the title salt, (C4H14N2)[Cu(C2O4)2], consists of one complex anion and two cationic half-mol­ecules, the other halves being generated by inversion symmetry. The CuII atom in the anion is coordinated by two bidentate oxalate ligands in a distorted square-planar geometry. Inter­molecular hydrogen bonds, involving the NH groups as donors and O atoms as acceptors, are observed, which lead to the formation of a three-dimensional network structure

Utilization and transport of mannitol in Olea europaea and their implications on salt stress tolerance

Comunicação em painel no congresso "14th Congress of the Federation of European Societies of Plant Biology". August 23-27. 2004. Cracow. Poland.Fundação para a Ciência e a Tecnologia (FCT

Tumor necrosis factor-alpha modulates survival, proliferation, and neuronal differentiation in neonatal subventricular zone cell cultures

Tumor necrosis factor (TNF)- has been reported to modulate brain injury, but remarkably, little is known about its effects on neurogenesis. We report that TNF- strongly influences survival, proliferation, and neuronal differentiation in cultured subventricular zone (SVZ) neural stem/progenitor cells derived from the neonatal P1-3 C57BL/6 mice. By using single-cell calcium imaging, we developed a method, based on cellular response to KCl and/or histamine, that allows the functional evaluation of neuronal differentiation. Exposure of SVZ cultures to 1 and 10 ng/ml mouse or 1 ng/ml human recombinant TNF- resulted in increased differentiation of cells displaying a neuronal-like profile of [Ca2+]i responses, compared with the predominant profile of immature cells observed in control, nontreated cultures. Moreover, by using neutralizing antibodies for each TNF- receptor, we found that the proneurogenic effect of 1 ng/ml TNF- is mediated via tumor necrosis factor receptor 1 activation. Accordingly, the percentage of neuronal nuclear protein-positive neurons was increased following exposure to mouse TNF-. Interestingly, exposure of SVZ cultures to 1 ng/ml TNF- induced cell proliferation, whereas 10 and 100 ng/ml TNF- induced apoptotic cell death. Moreover, we found that exposure of SVZ cells to TNF- for 15 minutes or 6 hours caused an increase in the phospho-stress-activated protein kinase/c-Jun N-terminal kinase immunoreactivity initially in the nucleus and then in growing axons, colocalizing with tau, consistent with axonogenesis. Taken together, these results show that TNF- induces neurogenesis in neonatal SVZ cell cultures of mice. TNF-, a proinflammatory cytokine and a proneurogenic factor, may play a central role in promoting neurogenesis and brain repair in response to brain injury and infectio

Methamphetamine decreases dentate gyrus stem cell self-renewal and shifts the differentiation towards neuronal fate

Methamphetamine (METH) is a highly addictive psychostimulant drug of abuse that negatively interferes with neurogenesis. In fact, we have previously shown that METH triggers stem/progenitor cell death and decreases neuronal differentiation in the dentate gyrus (DG). Still, little is known regarding its effect on DG stem cell properties. Herein, we investigate the impact of METH on mice DG stem/progenitor cell self-renewal functions. METH (10 nM) decreased DG stem cell self-renewal, while 1 nM delayed cell cycle in the G0/G1-to-S phase transition and increased the number of quiescent cells (G0 phase), which correlated with a decrease in cyclin E, pEGFR and pERK1/2 protein levels. Importantly, both drug concentrations (1 or 10 nM) did not induce cell death. In accordance with the impairment of self-renewal capacity, METH (10 nM) decreased Sox2+/Sox2+ while increased Sox2−/Sox2− pairs of daughter cells. This effect relied on N-methyl-d-aspartate (NMDA) signaling, which was prevented by the NMDA receptor antagonist, MK-801 (10 μM). Moreover, METH (10 nM) increased doublecortin (DCX) protein levels consistent with neuronal differentiation. In conclusion, METH alters DG stem cell properties by delaying cell cycle and decreasing self-renewal capacities, mechanisms that may contribute to DG neurogenesis impairment followed by cognitive deficits verified in METH consumers

Activation of Type 1 Cannabinoid Receptor (CB1R) promotes neurogenesis in murine subventricular zone cell cultures

The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+](i)) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.Fundacao para a Ciencia e a Tecnologia - Portugal [POCTI/SAU-NEU/68465/2006, PTDC/SAU-NEU/104415/2008, PTDC/SAU-NEU/101783/2008, POCTI/SAU-NEU/110838/2009]; Fundacao Calouste Gulbenkian [96542]; Fundacao para a Ciencia e Tecnologiainfo:eu-repo/semantics/publishedVersio

Heterocellular Contacts with Mouse Brain Endothelial Cells Via Laminin and alpha 6 beta 1 Integrin Sustain Subventricular Zone (SVZ) Stem/Progenitor Cells Properties

Neurogenesis in the subventricular zone (SVZ) is regulated by diffusible factors and cell-cell contacts. In vivo, SVZ stem cells are associated with the abluminal surface of blood vessels and such interactions are thought to regulate their neurogenic capacity. SVZ neural stem cells (NSCs) have been described to contact endothelial-derived laminin via (01 integrin. To elucidate whether heterocellular contacts with brain endothelial cells (BEG) regulate SVZ cells neurogenic capacities, cocultures of SVZ neurospheres and primary BEG, both obtained from C57BL/6 mice, were performed. The involvement of laminin integrin interactions in SVZ homeostasis was tested in three ways. Firstly, SVZ cells were analyzed following incubation of BEC with the protein synthesis inhibitor cycloheximide (GHX) prior to coculture, a treatment expected to decrease membrane proteins. Secondly, SVZ cells were cocultured with BEG in the presence of an anti-alpha 6 integrin neutralizing antibody. Thirdly, BEC were cultured with beta 1(-/-) SVZ cells. We showed that contact with BEC supports, at least in part, proliferation and stemness of SVZ cells, as evaluated by the number of BrdU positive (+) and Sox2+ cells in contact with BEG. These effects are dependent on BEG-derived laminin binding to alpha 6 beta 1 integrin and are decreased in cocultures incubated with anti-alpha 6 integrin neutralizing antibody and in cocultures with SVZ beta 1(-/-) cells. Moreover, BEG-derived laminin sustains sternness in SVZ cell cultures via activation of the Notch and mTOR signaling pathways. Our results show that BEC/SVZ interactions involving alpha 6 beta 1 integrin binding to laminin, contribute to SVZ cell proliferation and stemness