Transient TNF regulates the self-renewing capacity of stem-like label-retaining cells in sphere and skin equivalent models of melanoma.

International audience: BackgroundIt is well established that inflammation promotes cancer, including melanoma, although the exact mechanisms involved are less known. In this study, we tested the hypothesis that inflammatory factors affect the cancer stem cell (CSC) compartment responsible for tumor development and relapse.ResultsUsing an inducible histone 2B-GFP fusion protein as a tracer of cell divisional history, we determined that tumor necrosis factor (TNF), which is a classical pro-inflammatory cytokine, enlarged the CSC pool of GFP-positive label-retaining cells (LRCs) in tumor-like melanospheres. Although these cells acquired melanoma stem cell markers, including ABCB5 and CD271, and self-renewal ability, they lost their capacity to differentiate, as evidenced by the diminished MelanA expression in melanosphere cells and the loss of pigmentation in a skin equivalent model of human melanoma. The undifferentiated cell phenotype could be reversed by LY294002, which is an inhibitor of the PI3K/AKT signaling pathway, and this reversal was accompanied by a significant reduction in CSC phenotypic markers and functional properties. Importantly, the changes induced by a transient exposure to TNF were long-lasting and observed for many generations after TNF withdrawal.ConclusionsWe conclude that pro-inflammatory TNF targets the quiescent/slow-cycling melanoma SC compartment and promotes PI3K/AKT-driven expansion of melanoma SCs most likely by preventing their asymmetrical self-renewal. This TNF effect is maintained and transferred to descendants of LRC CSCs and is manifested in the absence of TNF, suggesting that a transient exposure to inflammatory factors imprints long-lasting molecular and/or cellular changes with functional consequences long after inflammatory signal suppression. Clinically, these results may translate into an inflammation-triggered accumulation of quiescent/slow-cycling CSCs and a post-inflammatory onset of an aggressive tumor

Arginine-Vasopressin regulates intracellular pH via V1 and V2 receptors in renal collecting duct cells

Arginine-vasopressin (AVP) has been proposed to be involved in the modulation of acid-base transporters; however, the nature of the mechanisms underlying AVP direct action on intracellular pH (pH(i)) in the cortical collecting duct (CCD) is not yet clearly defined. The aim of the present study was to elucidate which are the proteins implicated in AVP modulation of pH(i), as well as the receptors involved in these responses using a CCD cell line (RCCD(1)); pH(i) was monitored with the fluorescent dye BCECF in basal conditions and after stimulation with basolateral 10(-8) M AVP. Specific V1- or V2-receptor antagonists were also used. RT-PCR studies demonstrated that RCCD(1) cells express V1a and V2 receptors. Functional studies showed that while V2-receptor activation induced a biphasic response (alkalinization-acidification), V1-receptor activation resulted in an intracellular acidification. The V2-mediated alkalinization phase involves the activation of basolateral NHE-1 isoform of the Na(+)/H(+) exchanger while in the acidification phase CFTR is probably implicated. On the other hand, V1-mediated acidification was due to activation of a Cl(-)/HCO(3)(-) exchanger. We conclude that in RCCD(1) cells AVP selectively activates, via a complex of V1 and V2 receptor-mediated actions, different ion transporters linked to pH(i) regulation which might have physiological implications.Fil: Rivarola, Valeria. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Ford, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Flamenco, María del Pilar. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Galizia, Luciano. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Capurro, Claudia Graciela. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Aquaporin 2-increased renal cell proliferation is associated with cell volume regulation

We have previously demonstrated that in renal cortical collecting duct cells (RCCD1) the expression of the water channel Aquaporin 2 (AQP2) raises the rate of cell proliferation. In this study, we investigated the mechanisms involved in this process, focusing on the putative link between AQP2 expression, cell volume changes, and regulatory volume decrease activity (RVD). Two renal cell lines were used: WT‐RCCD1 (not expressing aquaporins) and AQP2‐RCCD1 (transfected with AQP2). Our results showed that when most RCCD1 cells are in the G1‐phase (unsynchronized), the blockage of barium‐sensitive K+ channels implicated in rapid RVD inhibits cell proliferation only in AQP2‐RCCD1 cells. Though cells in the S‐phase (synchronized) had a remarkable increase in size, this enhancement was higher and was accompanied by a significant down‐regulation in the rapid RVD response only in AQP2‐RCCD1 cells. This decrease in the RVD activity did not correlate with changes in AQP2 function or expression, demonstrating that AQP2—besides increasing water permeability—would play some other role. These observations together with evidence implying a cell‐sizing mechanism that shortens the cell cycle of large cells, let us to propose that during nutrient uptake, in early G1, volume tends to increase but it may be efficiently regulated by an AQP2‐dependent mechanism, inducing the rapid activation of RVD channels. This mechanism would be down‐regulated when volume needs to be increased in order to proceed into the S‐phase. Therefore, during cell cycle, a coordinated modulation of the RVD activity may contribute to accelerate proliferation of cells expressing AQP2.Fil: Di Giusto, Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Flamenco, María del Pilar. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Rivarola, Valeria. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Fernández, Juan. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Melamud, Luciana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Ford, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; ArgentinaFil: Capurro, Claudia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Biomembranas; Argentin

Reunión Internacional de estudios sobre los orígenes del flamenco : 19-06-1969

Empieza mal, José Luque Navajas inicia la conferencia explicando que su estudio está centrado en el fenómeno flamenco partiendo de la realidad presente y de lo que conocemos del pasado. Analiza la materia del cante llegando a la disección, a fin de encontrar en el flamenco de hoy en relación con el de otras etapas una constante que sirva para ver lo que está por venir, ya que el flamenco es un arte en evolución. Continúa realizando un repaso por los diferentes tipos de cantes flamencos como: fandango, tirana, romance, polo, caña, toná, martinete, malagueña… Destaca Luque que existe un denominador común en los cantes flamencos y es un compás dividido en 10 golpes y 2 silencios, en total 12 golpes. Incluye inserciones musicales como ejemplo de su exposición. – Min. 53.47: Aplausos – Min. 54.07: El Conde de Montarco da comienzo al coloquio entre los conferenciantes y el público asistente. – Min. 56.26: Toma la palabra, Pilar López (bailarina) quien explica el compás de la soleá en la pizarra dispuesta en la sala y continúa realizando un zapateado para explicar la seguidilla – 1 Hora Min. 04.10: Continúa el coloquio. – 1 Hora Min. 12.29: Toma la palabra Antonio Mata Gómez, para decir que el cante es libre, aunque depende demasiado del compás, y establece una comparativa entre el cante flamenco y los que se emplean en Oriente, incluye inserciones musicales sobre ritmos de Marruecos, Túnez… -- 1 Hora Min. 18.56: Continúa coloquio. – 1 Hora Min. 48.18: Aplausos.José Luque Navajas. Conde de Montarco. Pilar López. Antonio Mata GómezMadrid, Instituto de Cultura Hispánica. Jueves, 19 de junio, a las diez y media de la mañan

Combined VEGF gene transfer and erythropoietin in ovine reperfused myocardial infarction

BACKGROUND: In reperfused acute myocardial infarction (RAMI), cardioprotective treatments may enhance myocardial salvage and hence reduce the area of necrosis. Based on studies showing that plasmid-mediated vascular endothelial growth factor (pVEGF) gene transfer reduces infarct size by combining angio-arteriogenic and cardiomyogenic effects and that erythropoietin (EPO) exerts anti-apoptotic actions in animal models of AMI, we aimed to assess if their association would reduce infarct size to a larger extent than any of them individually in a large mammalian model of RAMI. METHODS: Adult sheep subjected to 90-minute coronary artery occlusion received upon reperfusion intramyocardial pVEGF 3.8 mg plus intravenous EPO 1000 IU/kg (n=8), pVEGF (n=8), EPO (n=8) or placebo (n=8). RESULTS: Fifteen days after treatment, infarct size was smaller in the 3 treatment groups (pVEGF+EPO: 8 ± 1 %; pVEGF: 16 ± 5 %; EPO: 13 ± 4 %) compared to placebo (25 ± 7 %, p<0.001). However, in the EPO+VEGF group infarct size was significantly smaller than in the groups receiving EPO or VEGF individually (p<0.05). DNA fragmentation, a hallmark of late apoptosis, was significantly lower in sheep receiving EPO. The combined treatment, while not affecting global left ventricular performance, improved regional peri-infarct function and prevented over-time expansion of the post-infarct perfusion defect. CONCLUSIONS: Combined pVEGF and EPO treatment might be clinically useful to enhance the benefits of early revascularization in patients with acute myocardial infarction.Fil: Olea, Fernanda Daniela. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: De Lorenzi, Andrea. Fundación Favaloro; ArgentinaFil: Cortés, Claudia. Fundación Favaloro; ArgentinaFil: Cuniberti, Luis Alberto. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fazzi, Lucía. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Básicas de la Patología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Flamenco, María del Pilar. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Locatelli, Paola. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabeza Meckert, Patricia. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Básicas de la Patología; ArgentinaFil: Bercovich, Andrés. Bio Sidus; ArgentinaFil: Laguens, Rubén. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Básicas de la Patología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crottogini, Alberto José. Universidad Favaloro. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin