The H+-ATP synthase: A gate to ROS-mediated cell death or cell survival

This article is part of a Special Issue entitled: 18th European Bioenergetic ConferenceCellular oxidative stress results from the increased generation of reactive oxygen species and/or the dysfunction of the antioxidant systems. Most intracellular reactive oxygen species derive from superoxide radical although the majority of the biological effects of reactive oxygen species are mediated by hydrogen peroxide. In this contribution we overview the major cellular sites of reactive oxygen species production, with special emphasis in the mitochondrial pathways. Reactive oxygen species regulate signaling pathways involved in promoting survival and cell death, proliferation, metabolic regulation, the activation of the antioxidant response, the control of iron metabolism and Ca2 + signaling. The reversible oxidation of cysteines in transducers of reactive oxygen species is the primary mechanism of regulation of the activity of these proteins. Next, we present the mitochondrial H+-ATP synthase as a core hub in energy and cell death regulation, defining both the rate of energy metabolism and the reactive oxygen species-mediated cell death in response to chemotherapy. Two main mechanisms that affect the expression and activity of the H+-ATP synthase down-regulate oxidative phosphorylation in prevalent human carcinomas. In this context, we emphasize the prominent role played by the ATPase Inhibitory Factor 1 in human carcinogenesis as an inhibitor of the H+-ATP synthase activity and a mediator of cell survival. The ATPase Inhibitory Factor 1 promotes metabolic rewiring to an enhanced aerobic glycolysis and the subsequent production of mitochondrial reactive oxygen species. The generated reactive oxygen species are able to reprogram the nucleus to support tumor development by arresting cell death. Overall, we discuss the cross-talk between reactive oxygen species signaling and mitochondrial function that is crucial in determining the cellular fateWork in the authors’ laboratory was supported by grants from the Ministerio de Educación y Ciencia (BFU2010-18903), by the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII and by Comunidad de Madrid (S/2011-BMD-2402), Spain. The CBMSO receives an institutional grant from Fundación Ramón Arece

Mecanismos y vías de señalización implicados en la reprogramación metabólica en cáncer de colon

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 04-12-201

AMPK and GCN2-ATF4 signal the repression of mitochondria in colon cancer cells

Reprogramming of energetic metabolism is a phenotypic trait of cancer in which mitochondrial dysfunction represents a key event in tumour progression. In the present study, we show that the acquisition of the tumour-promoting phenotype in colon cancer HCT116 cells treated with oligomycin to inhibit ATP synthase is exerted by repression of the synthesis of nuclear-encoded mitochondrial proteins in a process that is regulated at the level of translation. Remarkably, the synthesis of glycolytic proteins is not affected in this situation. Changes in translational control of mitochondrial proteins are signalled by the activation of AMPK (AMP-activated protein kinase) and the GCN2 (general control non-derepressible 2) kinase, leading also to the activation of autophagy. Changes in the bioenergetic function of mitochondria are mimicked by the activation of AMPK and the silencing of ATF4 (activating transcription factor 4). These findings emphasize the relevance of translational control for normal mitochondrial function and for the progression of cancer. Moreover, they demonstrate that glycolysis and oxidative phosphorylation are controlled at different levels of gene expression, offering the cell a mechanistic safeguard strategy for metabolic adaptation under stressful conditions.</jats:p

miR-127-5p targets the 3'UTR of human β-F1-ATPase mRNA and inhibits its translation

IMW and IMR are the recipients of pre-doctoral fellowships from the Plan de Formación de Profesorado Universitario (AP2007-03035) from the Ministerio de Educación and JAE-CSIC, respectively. The work was supported by grants from the Ministerio de Educación y Ciencia (BFU2010- 18903), by the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII and by Comunidad de Madrid (S2011/BMD-2402), Spain. The CBMSO receives an institutional grant from Fundación Ramón Arece

Polyfluorene-Based Multicolor Fluorescent Nanoparticles Activated by Temperature for Bioimaging and Drug Delivery

Multifunctional nanoparticles have been attracting growing attention in recent years because of their capability to integrate materials with di erent features in one entity, which leads them to be considered as the next generation of nanomedicine. In this work, we have taken advantage of the interesting properties of conjugated polyelectrolytes to develop multicolor fluorescent nanoparticles with integrating imaging and therapeutic functionalities. With this end, thermosensitive liposomes were coated with three recently synthesized polyfluorenes: copoly-((9,9-bis(60-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-1,4-(phenylene)) bromide (HTMA-PFP), copoly-((9,9-bis(60-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-4,7-(2- (phenyl)benzo(d) (1,2,3) triazole)) bromide (HTMA-PFBT) and copoly-((9,9-bis(60-N,N,Ntrimethylammonium) hexyl)-2,7-(fluorene)-alt-1,4-(naphtho(2,3c)-1,2,5-thiadiazole)) bromide (HTMA-PFNT), in order to obtain blue, green and red fluorescent drug carriers, respectively. The stability, size and morphology of the nanoparticles, as well as their thermotropic behavior and photophysical properties, have been characterized by Dynamic Light Scattering (DLS), Zeta Potential, transmission electron microscope (TEM) analysis and fluorescence spectroscopy. In addition, the suitability of the nanostructures to carry and release their contents when triggered by hyperthermia has been explored by using carboxyfluorescein as a hydrophilic drug model. Finally, preliminary experiments with mammalian cells demonstrate the capability of the nanoparticles to mark and visualize cells with di erent colors, evidencing their potential use for imaging and therapeutic applications

Degradation of IF1 controls energy metabolism during osteogenic differentiation of stem cells

Differentiation of human mesenchymal stem cells (hMSCs) requires the rewiring of energy metabolism. Herein, we demonstrate that the ATPase inhibitory factor 1 (IF1) is expressed in hMSCs and in prostate and colon stem cells but is not expressed in the differentiated cells. IF1 inhibits oxidative phosphorylation and regulates the activity of aerobic glycolysis in hMSCs. Silencing of IF1 in hMSCs mimics the metabolic changes observed in osteocytes and accelerates cellular differentiation. Activation of IF1 degradation acts as the switch that regulates energy metabolism during differentiation. We conclude that IF1 is a stemness marker important for maintaining the quiescence stateThis work was supported by grants from the Ministerio de Educación y Ciencia (BFU2010-18903), the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, and Comunidad de Madrid (S2011/BMD-2402), Spai

Overexpression of the ATPase Inhibitory Factor 1 Favors a Non-metastatic Phenotype in Breast Cancer

Partial suppression of mitochondrial oxidative phosphorylation and the concurrent activation of aerobic glycolysis is a hallmark of proliferating cancer cells. Overexpression of the ATPase inhibitory factor 1 (IF1), an in vivo inhibitor of the mitochondrial ATP synthase, is observed in most prevalent human carcinomas favoring metabolic rewiring to an enhanced glycolysis and cancer progression. Consistently, a high expression of IF1 in hepatocarcinomas and in carcinomas of the lung, bladder, and stomach and in gliomas is a biomarker of bad patient prognosis. In contrast to these findings, we have previously reported that a high expression level of IF1 in breast carcinomas is indicative of less chance to develop metastatic disease. This finding is especially relevant in the bad prognosis group of patients bearing triple-negative breast carcinomas. To investigate the molecular mechanisms that underlie the differential behavior of IF1 in breast cancer progression, we have developed the triple-negative BT549 breast cancer cell line that overexpresses IF1 stably. When compared to controls, IF1-cells partially shut down respiration and enhance aerobic glycolysis. Transcriptomic analysis suggested that migration and invasion were specifically inhibited in IF1-overexpressing breast cancer cells. Analysis of gene expression by qPCR and western blotting indicate that IF1 overexpression supports the maintenance of components of the extracellular matrix (ECM) and E-cadherin concurrently with the downregulation of components and signaling pathways involved in epithelial to mesenchymal transition. The overexpression of IF1 in breast cancer cells has no effect in the rates of cellular proliferation and in the cell death response to staurosporine and hydrogen peroxide. However, the overexpression of IF1 significantly diminishes the ability of the cells to grow in soft agar and to migrate and invade when compared to control cells. Overall, the results indicate that IF1 overexpression despite favoring a metabolic phenotype prone to cancer progression in the specific case of breast cancer cells also promotes the maintenance of the ECM impeding metastatic disease. These findings hence provide a mechanistic explanation to the better prognosis of breast cancer patients bearing tumors with high expression level of IF1.CN-T and IM-R were supported by pre-doctoral FPI-MEC and JAE-CSIC fellowships, respectively. This work was supported by grants from the Ministerio de Economía y Competitividad (SAF2013-41945-R; SAF2016-75916-R), Comunidad Madrid (S2011/BMD-2402), and Fundación Ramón Areces 2015, Spain.Peer reviewedPeer Reviewe

Assessment of non-physical user violence and burnout in primary health Care professionals. The modulating role of job satisfaction

Introduction: Growing concern about workplace violence shows the need for an evaluation in specific contexts in order to identify the particularities of each professional group. The health sector consists of a group of professionals with high exposure to violence, specially from users. There are differences depending on the professional category or unit in which the professional works. In this regard, Primary Health Care (PHC) is characterized by a personalized and continuous patient treatment over time, which is not exempt from cases of violence. Among the commonly studied consequences of these situations are decreases in job satisfaction and burnout. Objective: The main objective of this study is to analyze the modulating role of job satisfaction in the relationship between non-physical user violence and the onset of burnout. Methods: Cross-sectional comparative descriptive design. The sample consisted of 574 professionals from 39 PHC centers of the Murcian Health Service. Data were collected using two-stage cluster sampling. For data analysis, descriptive analysis, correlations and stepwise hierarchical regression were used to analyze the interaction between the variables. Results: Regression analysis draws a model where non-physical violence and low intrinsic and extrinsic job satisfaction act as modulators of non-physical violence, cynicism and emotional exhaustion. Conclusions: This study provides evidence of the psychological consequences of the perception of user violence in the PHC staff. Furthermore, it is evident that the emergence of burnout syndrome in these professionals is related to exposure to verbal or non-physical violence together with low job satisfaction. In this sense, a circular and bidirectional relationship between the variables studied is proposed as a possible explanatory model

CCR5 deficiency predisposes to fatal outcome in influenza virus infection

Influenza epidemics affect all age groups, although children, the elderly and those with underlying medical conditions are the most severely affected. Whereas co-morbidities are present in 50% of fatal cases, 25-50% of deaths are in apparently healthy individuals. This suggests underlying genetic determinants that govern infection severity. Although some viral factors that contribute to influenza disease are known, the role of host genetic factors remains undetermined. Data for small cohorts of influenza-infected patients are contradictory regarding the potential role of chemokine receptor 5 deficiency (CCR5-Δ32 mutation, a 32 bp deletion in the CCR5 gene) in the outcome of influenza virus infection. We tested 171 respiratory samples from influenza patients (2009 pandemic) for CCR5-Δ32 and evaluated its correlation with patient mortality. CCR5-Δ32 patients (17.4%) showed a higher mortality rate than WT individuals (4.7%; P = 0.021), which indicates that CCR5-Δ32 patients are at higher risk than the normal population of a fatal outcome in influenza infection.This work was supported by the Instituto de Salud Carlos III (Programa especial de investigación sobre la gripe pandémica GR09/0040 and GR09/0023), Centro de Investigación Biomédica en Red en Enfermedades Respiratorias (CIBERES) and the Spanish Ministry of Science and Innovation (BFU 2011-26175)S