Expresión génica alterada en obesidad: estudio de los genes y rutas metabólicas implicadas

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 1 de Julio de 201

Symmetries in Fluctuations Far from Equilibrium

Fluctuations arise universally in Nature as a reflection of the discrete microscopic world at the macroscopic level. Despite their apparent noisy origin, fluctuations encode fundamental aspects of the physics of the system at hand, crucial to understand irreversibility and nonequilibrium behavior. In order to sustain a given fluctuation, a system traverses a precise optimal path in phase space. Here we show that by demanding invariance of optimal paths under symmetry transformations, new and general fluctuation relations valid arbitrarily far from equilibrium are unveiled. This opens an unexplored route toward a deeper understanding of nonequilibrium physics by bringing symmetry principles to the realm of fluctuations. We illustrate this concept studying symmetries of the current distribution out of equilibrium. In particular we derive an isometric fluctuation relation which links in a strikingly simple manner the probabilities of any pair of isometric current fluctuations. This relation, which results from the time-reversibility of the dynamics, includes as a particular instance the Gallavotti-Cohen fluctuation theorem in this context but adds a completely new perspective on the high level of symmetry imposed by time-reversibility on the statistics of nonequilibrium fluctuations. The new symmetry implies remarkable hierarchies of equations for the current cumulants and the nonlinear response coefficients, going far beyond Onsager's reciprocity relations and Green-Kubo formulae. We confirm the validity of the new symmetry relation in extensive numerical simulations, and suggest that the idea of symmetry in fluctuations as invariance of optimal paths has far-reaching consequences in diverse fields.Comment: 8 pages, 4 figure

A Receptor of the Immunoglobulin Superfamily Regulates Adaptive Thermogenesis

Exquisite regulation of energy homeostasis protects from nutrient deprivation but causes metabolic dysfunction upon nutrient excess. In human and murine adipose tissue, the accumulation of ligands of the receptor for advanced glycation end products (RAGE) accompanies obesity, implicating this receptor in energy metabolism. Here, we demonstrate that mice bearing global- or adipocyte-specific deletion of Ager, the gene encoding RAGE, display superior metabolic recovery after fasting, a cold challenge, or high-fat feeding. The RAGE-dependent mechanisms were traced to suppression of protein kinase A (PKA)-mediated phosphorylation of its key targets, hormone-sensitive lipase and p38 mitogen-activated protein kinase, upon beta-adrenergic receptor stimulation-processes that dampen the expression and activity of uncoupling protein 1 (UCP1) and thermogenic programs. This work identifies the innate role of RAGE as a key node in the immunometabolic networks that control responses to nutrient supply and cold challenges, and it unveils opportunities to harness energy expenditure in environmental and metabolic stress

Desarrollo de sistemas virtuales para la generación de competencias relacionadas con la sostenibilidad ambiental en los estudios universitarios de economía e ingeniería

El trabajo empírico que desarrollamos a continuación tiene como objetivo principal contribuir al mejor conocimiento del estado actual y las previsiones de futuro en cuanto al desarrollo de competencias genéricas relacionadas con la sostenibilidad ambiental en los estudios universitarios. El trabajo final se ha centrado en dos ámbitos diferenciados de estudios, relacionados con las áreas de de economía e ingeniería, respectivamente. Para conseguir este objetivo hemos realizado un estudio de campo, remitiendo un cuestionario estructurado a los directores de los departamentos implicados en la docencia de los planes de estudios de la titulación de Administración y Dirección de Empresas y de las Ingenierías de Informática y Telecomunicaciones. En los siguientes apartados explicaremos con cierto detalle la planificación de la investigación empírica llevada a cabo y realizaremos los análisis oportunos para conseguir los objetivos propuestos. La estructura del trabajo empírico desarrollado engloba tres grandes partes. En primer lugar hemos realizado un análisis descriptivo de la población considerada así como de la muestra. A continuación, pasamos a estudiar, para cada una de las titulaciones objeto de estudio, cuál es la situación actual y previsión futura en cuanto al desarrollo de competencias relacionadas con la sostenibilidad ambiental. Posteriormente, identificamos la posible existencia de diferencias significativas entre las mismas.Ministerio de Ciencia e Innovació

Obesity-associated insulin resistance is correlated to adipose tissue vascular endothelial growth factors and metalloproteinase levels

<p>Abstract</p> <p>Background</p> <p>The expansion of adipose tissue is linked to the development of its vasculature, which appears to have the potential to regulate the onset of obesity. However, at present, there are no studies highlighting the relationship between human adipose tissue angiogenesis and obesity-associated insulin resistance (IR).</p> <p>Results</p> <p>Our aim was to analyze and compare angiogenic factor expression levels in both subcutaneous (SC) and omentum (OM) adipose tissues from morbidly obese patients (n = 26) with low (OB/L-IR) (healthy obese) and high (OB/H-IR) degrees of IR, and lean controls (n = 17). Another objective was to examine angiogenic factor correlations with obesity and IR.</p> <p>Here we found that <it>VEGF-A </it>was the isoform with higher expression in both OM and SC adipose tissues, and was up-regulated 3-fold, together with <it>MMP9 </it>in OB/L-IR as compared to leans. This up-regulation decreased by 23% in OB/-H-IR compared to OB/L-IR. On the contrary, <it>VEGF-B</it>, <it>VEGF-C </it>and <it>VEGF-D</it>, together with <it>MMP15 </it>was down-regulated in both OB/H-IR and OB/L-IR compared to lean patients. Moreover, <it>MMP9 </it>correlated positively and <it>VEGF-C</it>, <it>VEGF-D </it>and <it>MMP15 </it>correlated negatively with HOMA-IR, in both SC and OM.</p> <p>Conclusion</p> <p>We hereby propose that the alteration in <it>MMP15</it>, <it>VEGF-B</it>, <it>VEGF-C </it>and <it>VEGF-D </it>gene expression may be caused by one of the relevant adipose tissue processes related to the development of IR, and the up-regulation of <it>VEGF-A </it>in adipose tissue could have a relationship with the prevention of this pathology.</p

Human soluble ACE2 improves the effect of remdesivir in SARS-CoV-2 infection

There is a critical need for safe and effective drugs for COVID-19. Only remdesivir has received authorization for COVID-19 and has been shown to improve outcomes but not decrease mortality. However, the dose of remdesivir is limited by hepatic and kidney toxicity. ACE2 is the critical cell surface receptor for SARS-CoV-2. Here, we investigated additive effect of combination therapy using remdesivir with recombinant soluble ACE2 (high/low dose) on Vero E6 and kidney organoids, targeting two different modalities of SARS-CoV-2 life cycle: cell entry via its receptor ACE2 and intracellular viral RNA replication. This combination treatment markedly improved their therapeutic windows against SARS-CoV-2 in both models. By using single amino-acid resolution screening in haploid ES cells, we report a singular critical pathway required for remdesivir toxicity, namely, Adenylate Kinase 2. The data provided here demonstrate that combining two therapeutic modalities with different targets, common strategy in HIV treatment, exhibit strong additive effects at sub-toxic concentrations. Our data lay the groundwork for the study of combinatorial regimens in future COVID-19 clinical trials

Fine tuning the extracellular environment accelerates the derivation of kidney organoids from human pluripotent stem cells

The generation of organoids is one of the biggest scientific advances in regenerative medicine. Here, by lengthening the time that human pluripotent stem cells (hPSCs) were exposed to a three-dimensional microenvironment, and by applying defined renal inductive signals, we generated kidney organoids that transcriptomically matched second-trimester human fetal kidneys. We validated these results using ex vivo and in vitro assays that model renal development. Furthermore, we developed a transplantation method that utilizes the chick chorioallantoic membrane. This approach created a soft in vivo microenvironment that promoted the growth and differentiation of implanted kidney organoids, as well as providing a vascular component. The stiffness of the in ovo chorioallantoic membrane microenvironment was recapitulated in vitro by fabricating compliant hydrogels. These biomaterials promoted the efficient generation of renal vesicles and nephron structures, demonstrating that a soft environment accelerates the differentiation of hPSC-derived kidney organoids