Hypothalamic mTOR signaling mediates the orexigenic action of ghrelin

Current evidence suggests that ghrelin, a stomach derived peptide, exerts its orexigenic action through specific modulation of Sirtuin1 (SIRT1)/p53 and AMP-activated protein kinase (AMPK) pathways, which ultimately increase the expression of agouti-related protein (AgRP) and neuropeptide Y (NPY) in the arcuate nucleus of the hypothalamus (ARC). However, there is a paucity of data about the possible action of ghrelin on alternative metabolic pathways at this level. Here, we demonstrate that ghrelin elicits a marked upregulation of the hypothalamic mammalian target of rapamycin (mTOR) signaling pathway. Of note, central inhibition of mTOR signaling with rapamycin decreased ghrelin's orexigenic action and normalized the mRNA expression of AgRP and NPY, as well as their key downstream transcription factors, namely cAMP response-element binding protein (pCREB) and forkhead box O1 (FoxO1, total and phosphorylated). Taken together, these data indicate that, in addition to previous reported mechanisms, ghrelin also promotes feeding through modulation of hypothalamic mTOR pathway

Neonatal events, such as androgenization and postnatal overfeeding, modify the response to ghrelin

It is currently accepted that ambient, non-genetic factors influence perinatal development and evoke structural and functional changes that may persist throughout life. Overfeeding and androgenization after birth are two of these key factors that could result in “metabolic imprinting” of neuronal circuits early in life and, thereby, increase the body weight homeostatic “set point”, stimulate appetite and result in obesity. Our aim was to determine the influence of these obesogenic factors on the response to ghrelin. We observed the expected orexigenic effect of ghrelin regardless of the nutritional or hormonal manipulations to which the animals were subjected to at early postnatal development and this effect remained intact at later stages of development. In fact, ghrelin responses increased significantly when the animals were subjected to one of the two manipulations, but not when both were combined. An increased response to ghrelin could explain the obese phenotype displayed by individuals with modified perinatal environment.This work has been supported by grants from Ministerio de Educacion y Ciencia (CD: BFU2011-29102) and Centro de Investigación Biomédica en Red (CIBER) de Fisiopatología de la Obesidad y Nutrición (CIBERobn). CIBERobn is an initiative of the Instituto de Salud Carlos III (ISCIII) of Spain which is supported by FEDER funds. The research leading to these results has also received funding from the European Community's Seventh Framework Programme under the following grant: CD: FP7/2007-2013: n° 245009: NeuroFASTS

Hypothalamic mTOR signaling mediates the orexigenic action of ghrelin

Current evidence suggests that ghrelin, a stomach derived peptide, exerts its orexigenic action through specific modulation of Sirtuin1 (SIRT1)/p53 and AMP-activated protein kinase (AMPK) pathways, which ultimately increase the expression of agouti-related protein (AgRP) and neuropeptide Y (NPY) in the arcuate nucleus of the hypothalamus (ARC). However, there is a paucity of data about the possible action of ghrelin on alternative metabolic pathways at this level. Here, we demonstrate that ghrelin elicits a marked upregulation of the hypothalamic mammalian target of rapamycin (mTOR) signaling pathway. Of note, central inhibition of mTOR signaling with rapamycin decreased ghrelin’s orexigenic action and normalized the mRNA expression of AgRP and NPY, as well as their key downstream transcription factors, namely cAMP response-element binding protein (pCREB) and forkhead box O1 (FoxO1, total and phosphorylated). Taken together, these data indicate that, in addition to previous reported mechanisms, ghrelin also promotes feeding through modulation of hypothalamic mTOR pathway.The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement n° 281854 - the ObERStress project (ML) and 245009 - the Neurofast project (RN, CD and ML), Xunta de Galicia (ML: 10PXIB208164PR; RN: 2010/14), Junta de Andalucía (MTS: P08-CVI-03788), Instituto de Salud Carlos III (ISCIII) (ML: PS09/01880), MINECO co-funded by the FEDER Program of EU (MTS: BFU2011-25021; RN: RyC-2008-02219 and SAF2009-07049; ML: RyC-2007-00211; CD: BFU2011-29102). LM is a recipient of a fellowship from Fundação para a Ciência e Tecnologia (FCT), Portugal (SFRH/BD/65379/2009). CIBER de Fisiopatología de la Obesidad y Nutrición is an initiative of ISCIIIS

Ghrelin effects on neuropeptides in the rat hypothalamus depend on fatty acid metabolism actions on BSX but not on gender

"This is the peer reviewed version of the following article: Lage, R., Vázquez, M.J., Varela, L., Saha, A.K., Vidal-Puig, A., Nogueiras, R., Diéguez, C. and López, M. (2010), Ghrelin effects on neuropeptides in the rat hypothalamus depend on fatty acid metabolism actions on BSX but not on gender. The FASEB Journal, 24: 2670-2679, which has been published in final form at https://doi.org/10.1096/fj.09-150672. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited."The orexigenic effect of ghrelin is mediated by neuropeptide Y (NPY) and agouti-related protein (AgRP) in the hypothalamic arcuate nucleus (ARC). Recent evidence also indicates that ghrelin promotes feeding through a mechanism involving activation of hypothalamic AMP-activated protein kinase (AMPK) and inactivation of acetyl-CoA carboxylase and fatty acid synthase (FAS). This results in decreased hypothalamic levels of malonyl-CoA, increased carnitine palmitoyltransferase 1 (CPT1) activity, and mitochondrial production of reactive oxygen species. We evaluated whether these molecular events are part of a unique signaling cascade or whether they represent alternative pathways mediating the orexigenic effect of ghrelin. Moreover, we examined the gender dependency of these mechanisms, because recent evidence has proposed that ghrelin orexigenic effect is reduced in female rats. We studied in both genders the effect of ghrelin on the expression of AgRP and NPY, as well as their transcription factors: cAMP response-element binding protein (CREB and its phosphorylated form, pCREB), forkhead box O1 (FoxO1 and its phosphorylated form, pFoxO1), and brain-specific homeobox transcription factor (BSX). In addition, to establish a mechanistic link between ghrelin, fatty acid metabolism, and neuropeptides, we evaluated the effect of ghrelin after blockage of hypothalamic fatty acid β oxidation, by using the CPT1 inhibitor etomoxir. Ghrelin-induced changes in the AMPK-CPT1 pathway are associated with increased levels of AgRP and NPY mRNA expression through modulation of BSX, pCREB, and FoxO1, as well as decreased expression of endoplasmic reticulum (ER) stress markers in a gender-independent manner. In addition, blockage of hypothalamic fatty acid β oxidation prevents the ghrelin-promoting action on AgRP and NPY mRNA expression, also in a gender-independent manner. Notably, this effect is associated with decreased BSX expression and reduced food intake. Overall, our data suggest that BSX integrates changes in neuronal metabolic status with ARC-derived neuropeptides in a gender-independent mannerS

Resistin Regulates Pituitary Lipid Metabolism and Inflammation In Vivo and In Vitro

The adipokine resistin is an insulin-antagonizing factor that also plays a regulatory role in inflammation, immunity, food intake, and gonadal function and also regulates growth hormone (GH) secretion in rat adenopituitary cells cultures with the adipokine. Although adipose tissue is the primary source of resistin, it is also expressed in other tissues, including the pituitary. The aim of this study is to investigate the possible action of resistin on the lipid metabolism in the pituitary gland in vivo (rats in two different nutritional status, fed and fast, treated with resistin on acute and a chronic way) and in vitro (adenopituitary cell cultures treated with the adipokine). Here, by a combination of in vivo and in vitro experimental models, we demonstrated that central acute and chronic administration of resistin enhance mRNA levels of the lipid metabolic enzymes which participated on lipolysis and moreover inhibiting mRNA levels of the lipid metabolic enzymes involved in lipogenesis. Taken together, our results demonstrate for the first time that resistin has a regulatory role on lipid metabolism in the pituitary gland providing a novel insight in relation to the mechanism by which this adipokine can participate in the integrated control of lipid metabolism.Sara Borrell Postdoctoral program; BFU 2011 and CIBER Obesidad y Nutricion (Instituto de Salud Carlos Tercero (ISCIII), Ministerio de Ciencia e Innovacion). Juan de la Cierva Program (Ministerio de Educacion y Ciencia)S

Desarrollo de líneas experimentales para su aplicación en los Trabajos de Fin de Grado en Química

Desde el punto de vista académico, los Trabajos Fin de Grado en Ciencias Químicas se presentan como proyectos experimentales relacionados con problemas reales, orientados a progresar en conocimientos y fortalecer competencias adquiridas, convirtiéndose en claves del currículo para el mundo profesional. Se abordan una serie de proyectos de laboratorio como una aproximación más realista al aprendizaje integral. La metodología docente propuesta favorece la búsqueda de información, pensamiento crítico, superación continua y éxito de los estudiantes, similar a la que se realiza en el mundo real, estimulando su interés y motivación durante el proceso de aprendizaje.Des del punt de vista acadèmic, els Treballs Fi de Grau en Ciències Químiques es presenten com a projectes experimentals relacionats amb problemes reals, orientats a progressar en coneixements i enfortir competències adquirides, convertint-se en claus del currículum per al món professional. S'aborden una sèrie de projectes integrals de laboratori com una aproximació més realista a l'aprenentatge integral. La metodologia docent proposta afavoreix la busca d'informació, pensament crític, superació contínua i èxit dels estudiants, semblant a la què es realitza en el món real, estimulant el seu interès i motivació durant el procés d'aprenentatge.From the academic point of view, the bachelor thesis in Chemistry is presented as a project based on a real problem. The goal is to progress in strengthening knowledge and skills already acquired. This is a key element for the students curricula related to their integration into the professional world. A comprehensive series of laboratory projects have been developed as a more realistic approach to the concept of integral learning. Teaching methodology promotes information searching, critical thinking, continuous improvement and success. The procedure is performed in conditions close to the real world, stimulating interest and motivation during the learning process

Integrated flow cytometry and sequencing to reconstruct evolutionary patterns from dysplasia to acute myeloid leukemia

Clonal evolution in acute myeloid leukemia (AML) originates long before diagnosis and is a dynamic process that may affect survival. However, it remains uninvestigated during routine diagnostic workups. We hypothesized that the mutational status of bone marrow dysplastic cells and leukemic blasts, analyzed at the onset of AML using integrated multidimensional flow cytometry (MFC) immunophenotyping and fluorescence-activated cell sorting (FACS) with next-generation sequencing (NGS), could reconstruct leukemogenesis. Dysplastic cells were detected by MFC in 285 of 348 (82%) newly diagnosed patients with AML. Presence of dysplasia according to MFC and World Health Organization criteria had no prognostic value in older adults. NGS of dysplastic cells and blasts isolated at diagnosis identified 3 evolutionary patterns: stable (n = 12 of 21), branching (n = 4 of 21), and clonal evolution (n = 5 of 21). In patients achieving complete response (CR), integrated MFC and FACS with NGS showed persistent measurable residual disease (MRD) in phenotypically normal cell types, as well as the acquisition of genetic traits associated with treatment resistance. Furthermore, whole-exome sequencing of dysplastic and leukemic cells at diagnosis and of MRD uncovered different clonal involvement in dysplastic myelo-erythropoiesis, leukemic transformation, and chemoresistance. Altogether, we showed that it is possible to reconstruct leukemogenesis in ∼80% of patients with newly diagnosed AML, using techniques other than single-cell multiomics.This work was supported by grants from the Área de Oncología del Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red (CIBER-ONC) (CB16/12/00369, CB16/12/00233, CB16/12/00489, and CB16/12/00284), Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS numbers PI16/01661, PI16/00517, and PI19/01518), and the Plan de Investigación de la Universidad de Navarra (PIUNA 2014-18). This work was supported internationally by the Cancer Research UK, FCAECC, and AIRC under the Accelerator Award Program (EDITOR)

An increase in erythromycin resistance in methicillin-susceptible Staphylococcus aureus from blood correlates with the use of macrolide/lincosamide/streptogramin antibiotics. EARS-Net Spain (2004–2020)

ObjectivesTo describe and analyse erythromycin resistance trends in blood isolates of Staphylococcus aureus (EARS-Net Spain, 2004–2020) and the association of these trends with the consumption of macrolide, lincosamide, and streptogramin B (MLSB) antibiotics. To assess molecular changes that could be involved in erythromycin resistance trends by whole genome analysis of representative isolates.Materials and methodsWe collected antibiotic susceptibility data for all first-blood S. aureus isolates in patients from 47 Spanish hospitals according to EARS-Net criteria. MLSB antibiotic consumption was obtained from the Spanish Agency for Medicines and Medical Devices (2008–2020). We sequenced 137 representative isolates for core genome multilocus sequence typing, resistome and virulome analysis.ResultsFor the 36,612 invasive S. aureus isolates, methicillin resistance decreased from 26.4% in 2004 to 22.4% in 2020. Erythromycin resistance in methicillin-susceptible S. aureus (MSSA) increased from 13.6% in 2004 to 28.9% in 2020 (p < 0.001); however, it decreased from 68.7 to 61.8% (p < 0.0001) in methicillin-resistant S. aureus (MRSA). Total consumption of MLSB antibiotics increased from 2.72 defined daily doses per 1,000 inhabitants per day (DID) in 2014 to 3.24 DID in 2016. By WGS, the macrolide resistance genes detected were erm (59.8%), msrA (46%), and mphC (45.2%). The erm genes were more prevalent in MSSA (44/57, 77.2%) than in MRSA (38/80, 47.5%). Most of the erm genes identified in MSSA after 2013 differed from the predominant ermC gene (17/22, 77.3%), largely because ermT was significantly associated with MSSA after 2013 (11/29, 37.9%). All 13 ermT isolates in this study, except one, belonged to ST398 and came from 10 hospitals and six Spanish provinces.ConclusionThe significant increase in erythromycin resistance in blood MSSA correlated with the consumption of the MLSB antibiotics in Spain. These preliminary data seem support the hypothesis that the human ST398 MSSA clade with ermT-mediated resistance to erythromycin may be involved in this trend

The Strait of Gibraltar: submarine morphology, oceanogra- phic connections and evolution

32 pages, 10 figures[EN] The Strait of Gibraltar is a first-order physiographic feature between southern Iberia and northern Africa. It has been excavated over the Arc of Gibraltar in favor of a conjugated ENE-WSW and WNW-ESE fault system that have acted as weakness structures. The Strait was generated by erosive processes of the water masses coming from the Atlantic Ocean in the lower Pliocene, due to the rude and rapid flooding of the Alboran Sea basin. Once the flood stabilized the exchange and interaction of the Atlantic and Mediterranean water masses began as we know it today; the Atlantic water that circulates on the surface of the Strait towards the Alborán Sea, and the Mediterranean water masses that circulate in depth towards the Atlantic Ocean. The acceleration of the Atlantic and Mediterranean water masses in the Strait corridor has favored the development of erosive processes.These processeshave allowed the outcrops of the rocky substratum, the development of sedimentary instabilities and the generation of paleochannels, carbonate crusts and cold-water coral formations during the Pliocene and Quaternary. Likewise, the acceleration of the Mediterranean water masses on their way in and out of the Strait and their interaction with the sea floor have controlled sedimentation both in the Alborán Sea basin and in the Gulf of Cádiz, forming contouritic depositional systems[ES] El estrecho de Gibraltar es un rasgo fisiográfico de primer orden entre el sur de Iberia y el norte de África. Ha sido excavado sobre el Arco de Gibraltar a favor de un sistema de fallas conjugadas de direcciones ENE-OSO y ONO-ESE que han actuado como estructuras de debilidad. El Estrecho fue generado por procesos erosivos de las masas de agua procedentes del océano Atlántico en el Plioceno inferior, al producirse de forma brusca y rápida la inundación de la cuenca del mar de Alborán. Una vez estabilizada la inundación comenzó el intercambio y la interacción de las masas de agua atlántica y mediterránea tal y como hoy la conocemos: el agua atlántica que circula en la superficie del Estrecho hacia el mar de Alborán, y las masas de agua mediterráneas que transitan en profundidad hacia el océano Atlántico. La aceleración de las masas de agua atlántica y mediterránea en el corredor del Estrecho ha favorecido el desarrollo de procesos erosivos. Estos procesos han permitido los afloramientos del substrato rocoso, el desarrollo de inestabilidades sedimentarias, generación de paleocanales, costras carbonatas y formaciones coralígenas de aguas frías durante el Plioceno y el Cuaternario.Asimismo, la aceleración de las masas de agua mediterráneas en su camino de entrada y salida del Estrecho y su interacción con el suelo marino han controlado la sedimentación tanto en la cuenca del mar de Alborán como en el golfo de Cádiz, formando sistemas deposicionales contorníticosWith the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe