Papel de p53 en la gluconeogénesis hepática

El objetivo de esta tesis es el estudio del papel de p53 en la gluconeogénesis hepática. Los niveles de proteína del factor de transcripción p53 en el hígado se incrementan en condiciones de ayuno o restricción de alimentos, mediante un mecanismo de estabilización mediado por la modificación postraduccional de la O-GlcNAcilación. En estas condiciones, p53 promueve la transcripción y actividad de PCK1, una de las principales enzimas involucradas en la producción de glucosa, fundamental para mantener la euglicemia en condiciones de ayuno o restricción calórica. Los modelos in vivo e in vitro que carecen de p53 en el hígado, son incapaces de realizar la gluconeogénesis, así como de promover la actividad y función de PCK1. La recuperación específica de p53 en estos modelos restablece la capacidad de producir glucosa, y la plena funcionalidad de PCK1. Además, se demuestra que p53 es también imprescindible para la acción de las hormonas contra reguladoras glucagón, adrenalina y cortisol, quienes necesitan de la actividad transcripcional de p53 sobre PCK1 para sus efectos gluconeogénicos. Del mismo modo, una producción hepática de glucosa descontrolada, promovida por niveles elevados de p53, generan resistencia a insulina, tanto en modelos in vivo como in vitro. Este hallazgo preclínico se corrobora en pacientes con diabetes tipo 2, quienes muestran elevados niveles de PCK1, p53 y las enzimas involucradas en la O-GlcNAcilación

Liver osteopontin is required to prevent the progression of age-related nonalcoholic fatty liver disease

[EN] Osteopontin (OPN), a senescence-associated secretory phenotype factor, is increased in patients with nonalcoholic fatty liver disease (NAFLD). Cellular senescence has been associated with age-dependent hepatosteatosis. Thus, we investigated the role of OPN in the age-related hepatosteatosis. For this, human serum samples, animal models of aging, and cell lines in which senescence was induced were used. Metabolic fluxes, lipid, and protein concentration were determined. Among individuals with a normal liver, we observed a positive correlation between serum OPN levels and increasing age. This correlation with age, however, was absent in patients with NAFLD. In wild-type (WT) mice, serum and liver OPN were increased at 10 months old (m) along with liver p53 levels and remained elevated at 20m. Markers of liver senescence increased in association with synthesis and concentration of triglycerides (TG) in 10m OPN-deficient (KO) hepatocytes when compared to WT hepatocytes. These changes in senescence and lipid metabolism in 10m OPN-KO mice liver were associated with the decrease of 78 kDa glucose-regulated protein (GRP78), induction of ER stress, and the increase in fatty acid synthase and CD36 levels. OPN deficiency in senescent cells also diminished GRP78, the accumulation of intracellular TG, and the increase in CD36 levels. In 20m mice, OPN loss led to increased liver fibrosis. Finally, we showed that OPN expression in vitro and in vivo was regulated by p53. In conclusion, OPN deficiency leads to earlier cellular senescence, ER stress, and TG accumulation during aging. The p53-OPN axis is required to inhibit the onset of agerelated hepatosteatosis.This work was supported by Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT971‐16 to P.A.), MINECO‐FEDER (SAF2017‐87301‐R to M.L.M‐Ch) MCIU/AEI/FEDER, UE (RTI2018‐095134‐B‐100 to P.A. and RTI2018‐099413‐B‐I00 to RN, Asociación Española contra el Cáncer, Canceres raros (M.L.M‐Ch), La Caixa Foundation (to M.L.M‐Ch), Ayudas Fundación BBVA a equipos de Investigación Científica 2018 (to M.L.M‐Ch), Xunta de Galicia (RN: 2015‐CP080 and 2016‐ PG057), Fundación BBVA (RN), and European Foundation for the Study of Diabetes (RN). ISCIII‐FEDER PI17/00535 (to C.G‐M.), ISCIII‐FEDER CP14/00181 and PI16/00823 (to A.G‐ R.), and Francisco Cobos Foundation (to A.G‐R.). CiC bioGUNE thanks MINECO for the Severo Ochoa Excellence Accreditation (SEV‐2016‐ 0644

Inhibition of ATG3 ameliorates liver steatosis by increasing mitochondrial function

Non-alcoholic fatty liver disease (NAFLD) is a major health threat in both developed and developing countries and is a precursor of the more advanced liver diseases, including non-alcoholic steatohepatitis (NASH), cirrhosis, and liver cancer. Currently, understanding the multiple and complex molecular pathways implicated in NAFLD onset and progression is a major priority. The transcription factor p63, which belongs to a family comprising p53, p63, and p73,1 is one of many factors that contributes to the development of liver steatosis. The role of p63 as a tumor suppressor and in cell maintenance and renewal is well studied, but we have recently reported that it is also relevant in the control of lipid metabolism.2 p63 encodes multiple isoforms that can be grouped into 2 categories; isoforms with an acidic transactivation domain (TA) and those without this domain (domain negative). The TAp63α isoform is elevated in the liver of animal models of NAFLD as well as in liver biopsies from obese patients with NAFLD. Furthermore, downregulation of p63α in the liver attenuates liver steatosis in diet-induced obese (DIO) mice, while the activation of TAp63α increases hepatic fat content, mediated by the activation of IKKβ and endoplasmic reticulum stress.2 A specialized form of autophagy that degrades lipid droplets, termed “lipophagy”, is a major pathway of lipid mobilization in hepatocytes. Lipophagy is elevated in hepatoma cells upon exposure to free fatty acids,3 and reduces the fatty acid load in mouse hepatocytes.4 Its impairment has been associated with the development of fatty liver and insulin resistance3,5; in contrast, the autophagic flux is increased during the activation of hepatic stellate cells.6 In the present study, we used an unbiased proteomics approach to gain insight into novel proteins modulating lipid metabolism in the liver of mice with genetic knockdown or overexpression of TAp63α. We found that autophagy-related gene 3 (ATG3) was upregulated by TAp63α activation and downregulated after p63α inhibition. ATG3 is elevated in several animal models of NAFLD and in the liver of patients with NAFLD. Genetic overexpression of ATG3 increased the lipid load in hepatocytes, while its repression alleviated TAp63α- and diet-induced steatosis. ATG3 exerted its role in lipid metabolism by regulating SIRT1 and mitochondrial function. Collectively, these findings identify ATG3 as a novel factor implicated in the development of steatosisThis work has been supported by grants from FEDER/Ministerio de Ciencia, Innovación y Universidades-Agencia Estatal de Investigación (PA: RTI2018-095134-B-100; DS and LH: SAF2017-83813-C3-1-R; MLMC: RTC2019-007125-1; CD: BFU2017-87721; ML: RTI2018–101840-B-I00; GS; PID2019-104399RB-I00; RN: RTI2018-099413-B-I00 and RED2018-102379-T; MLMC: SAF2017-87301-R; TCD: RTI2018-096759-A-100), FEDER/Instituto de Salud Carlos III (AGR: PI19/00123), Xunta de Galicia (ML: 2016-PG068; RN: 2015-CP080 and 2016-PG057), Fundación BBVA (RN, GS and MLM), Proyectos Investigación en Salud (MLMC: DTS20/00138), Sistema Universitario Vasco (PA: IT971-16); Fundación Atresmedia (ML and RN), Fundación La Caixa (M.L., R.N. and M.C.), Gilead Sciences International Research Scholars Program in Liver Disease (MVR), Marató TV3 Foundation (DS: 201627), Government of Catalonia (DS: 2017SGR278) and European Foundation for the Study of Diabetes (RN and GS). This research also received funding from the European Community’s H2020 Framework Programme (ERC Synergy Grant-2019-WATCH- 810331, to RN, VP and MS). Centro de Investigación Biomédica en Red (CIBER) de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem). CIBERobn, CIBERehd and CIBERdem are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain which is supported by FEDER funds. We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644)S

Neddylation inhibition ameliorates steatosis in NAFLD by boosting hepatic fatty acid oxidation via the DEPTOR-mTOR axis

Objective: Neddylation is a druggable and reversible ubiquitin-like post-translational modification upregulated in many diseases, including liver fibrosis, hepatocellular carcinoma, and more recently, non-alcoholic fatty liver disease (NAFLD). Herein, we propose to address the effects of neddylation inhibition and the underlying mechanisms in pre-clinical models of NAFLD. Methods: Hepatic neddylation measured by immunohistochemical analysis and NEDD8 serum levels measured by ELISA assay were evaluated in NAFLD clinical and pre-clinical samples. The effects of neddylation inhibition by using a pharmacological small inhibitor, MLN4924, or molecular approaches were assessed in isolated mouse hepatocytes and pre-clinical mouse models of diet-induced NAFLD, male adult C57BL/6 mice, and the AlfpCre transgenic mice infected with AAV-DIO-shNedd8. Results: Neddylation inhibition reduced lipid accumulation in oleic acid-stimulated mouse primary hepatocytes and ameliorated liver steatosis, preventing lipid peroxidation and inflammation in the mouse models of diet-induced NAFLD. Under these conditions, increased Deptor levels and the concomitant repression of mTOR signaling were associated with augmented fatty acid oxidation and reduced lipid content. Moreover, Deptor silencing in isolated mouse hepatocytes abolished the anti-steatotic effects mediated by neddylation inhibition. Finally, serum NEDD8 levels correlated with hepatic neddylation during the disease progression in the clinical and pre-clinical models. Conclusions: Overall, the upregulation of Deptor, driven by neddylation inhibition, is proposed as a novel effective target and therapeutic approach to tackle NAFLDThis work was supported by grants from Gobierno Vasco-Departamento de Salud 2013111114 (to M.L.M.-C), ELKARTEK 2016, Departamento de Industria del Gobierno Vasco (to M.L.M−C), Ministerio de Ciencia, Innovación y Universidades MICINN: SAF2017-87301-R, and RTI2018-096759-A-100 integrado en el Plan Estatal de Investigación Científica y Técnica y Innovación, cofinanciado con Fondos FEDER (to M.L.M− T.C.D respectively); MCIU/AEI/FEDER, UE (RTI2018-095134-B-100) (to P.A.), AECC Bizkaia (M.S-M); Asociación Española contra el Cáncer (T.C.D), Fundación Científica de la Asociación Española Contra el Cáncer (AECC Scientific Foundation) Rare Tumor Calls 2017 (to M.L.M, J.M.B., M.A.A., J.J.G.M.), La Caixa Foundation Program (to M.L.M and J.M.B.), 2018 BBVA Foundation Grants for Scientific Research Teams (to M.L.M.-C.), Ayudas para apoyar grupos de investigación del sistema Universitario Vasco IT971-16 (P.A.). MyFirst Grant AIRC n.16888, Ricerca Finalizzata Ministero della Salute RF-2016-02364358, Ricerca corrente Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico (to LV), the European Union (EU) Programme Horizon 2020 (under grant agreement No. 777377) for the project LITMUS- “Liver Investigation: Testing Marker Utility in Steatohepatitis” (to LV), Fondazione IRCCS Ca’ Granda “Liver BIBLE” PR-0391, Fondazione IRCCS Ca’ Granda core COVID-19 Biobank (RC100017A) (to LV). This research was funded by the CIBERehd (EHD15PI05/2016) and “Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III”, Spain (PI16/00598 and PI19/00819, co-funded by European Regional Development Fund/European Social Fund, “Investing in your future”); Spanish Ministry of Economy, Industry and Competitiveness (SAF2016-75197-R); “Junta de Castilla y Leon” (SA063P17); AECC Scientific Foundation (2017/2020), Spain; “Centro Internacional sobre el Envejecimiento” (OLD-HEPAMARKER, 0348_CIE_6_E), Spain; University of Salamanca Foundation, Spain (PC-TCUE18-20_051), and Fundació Marato TV3 (Ref. 201916–31), Spain. RB acknowledges BFU2017-84653-P (MINECO/FEDER, EU), SEV-2016-0644 (Severo Ochoa Excellence Program), 765445-EU (UbiCODE Program), SAF2017-90900-REDT (UBIRed Program), and IT1165-19 (Basque Country Government). Ciberehd_ISCIII_MINECO is funded by the Instituto de Salud Carlos III. We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644)S

Hepatic levels of S-adenosylmethionine regulate the adaptive response to fasting

26 p.-6 fig.-1 tab.-1 graph. abst.There has been an intense focus to uncover the molecular mechanisms by which fasting triggers the adaptive cellular responses in the major organs of the body. Here, we show that in mice, hepatic S-adenosylmethionine (SAMe)—the principal methyl donor—acts as a metabolic sensor of nutrition to fine-tune the catabolic-fasting response by modulating phosphatidylethanolamine N-methyltransferase (PEMT) activity, endoplasmic reticulum-mitochondria contacts, β-oxidation, and ATP production in the liver, together with FGF21-mediated lipolysis and thermogenesis in adipose tissues. Notably, we show that glucagon induces the expression of the hepatic SAMe-synthesizing enzyme methionine adenosyltransferase α1 (MAT1A), which translocates to mitochondria-associated membranes. This leads to the production of this metabolite at these sites, which acts as a brake to prevent excessive β-oxidation and mitochondrial ATP synthesis and thereby endoplasmic reticulum stress and liver injury. This work provides important insights into the previously undescribed function of SAMe as a new arm of the metabolic adaptation to fasting.M.V.-R. is supported by Proyecto PID2020-119486RB-100 (funded by MCIN/AEI/10.13039/501100011033), Gilead Sciences International Research Scholars Program in Liver Disease, Acción Estratégica Ciberehd Emergentes 2018 (ISCIII), Fundación BBVA, HORIZON-TMA-MSCA-Doctoral Networks 2021 (101073094), and Redes de Investigación 2022 (RED2022-134485-T). M.L.M.-C. is supported by La CAIXA Foundation (LCF/PR/HP17/52190004), Proyecto PID2020-117116RB-I00 (funded by MCIN/AEI/10.13039/501100011033), Ayudas Fundación BBVA a equipos de investigación científica (Umbrella 2018), and AECC Scientific Foundation (Rare Cancers 2017). A.W. is supported by RTI2018-097503-B-I00 and PID2021-127169OB-I00, (funded by MCIN/AEI/10.13039/501100011033) and by “ERDF A way of making Europe,” Xunta de Galicia (Ayudas PRO-ERC), Fundación Mutua Madrileña, and European Community’s H2020 Framework Programme (ERC Consolidator grant no. 865157 and MSCA Doctoral Networks 2021 no. 101073094). C.M. is supported by CIBERNED. P.A. is supported by Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT1476-22), PID2021-124425OB-I00 (funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe,” MCI/UE/ISCiii [PMP21/00080], and UPV/EHU [COLAB20/01]). M.F. and M.G.B. are supported by PID2019-105739GB-I00 and PID2020-115472GB-I00, respectively (funded by MCIN/AEI/10.13039/501100011033). M.G.B. is supported by Xunta de Galicia (ED431C 2019/013). C.A., T.L.-D., and J.B.-V. are recipients of pre-doctoral fellowships from Xunta de Galicia (ED481A-2020/046, ED481A-2018/042, and ED481A 2021/244, respectively). T.C.D. is supported by Fundación Científica AECC. A.T.-R. is a recipient of a pre-doctoral fellowship from Fundación Científica AECC. S.V.A. and C.R. are recipients of Margarita Salas postdoc grants under the “Plan de Recuperación Transformación” program funded by the Spanish Ministry of Universities with European Union’s NextGeneration EU funds (2021/PER/00020 and MU-21-UP2021-03071902373A, respectively). T.C.D., A.S.-R., and M.T.-C. are recipients of Ayuda RYC2020-029316-I, PRE2019/088960, and BES-2016/078493, respectively, supported by MCIN/AEI/10.13039/501100011033 and by El FSE invierte en tu futuro. S.L.-O. is a recipient of a pre-doctoral fellowship from the Departamento de Educación del Gobierno Vasco (PRE_2018_1_0372). P.A.-G. is recipient of a FPU pre-doctoral fellowship from the Ministry of Education (FPU19/02704). CIC bioGUNE is supported by Ayuda CEX2021-001136-S financiada por MCIN/AEI/10.13039/501100011033. A.B.-C. was funded by predoctoral contract PFIS (FI19/00240) from Instituto de Salud Carlos III (ISCIII) co-funded by Fondo Social Europeo (FSE), and A.D.-L. was funded by contract Juan Rodés (JR17/00016) from ISCIII. A.B.-C. is a Miguel Servet researcher (CPII22/00008) from ISCIII.Peer reviewe

Uroguanylin Improves Leptin Responsiveness in Diet-Induced Obese Mice

The gastrointestinal-brain axis is a key mediator of the body weight and energy homeostasis regulation. Uroguanylin (UGN) has been recently proposed to be a part of this gut-brain axis regulating food intake, body weight and energy expenditure. Expression of UGN is regulated by the nutritional status and dependent on leptin levels. However, the exact molecular mechanisms underlying this UGN-leptin metabolic regulation at a hypothalamic level still remains unclear. Using leptin resistant diet-induced obese (DIO) mice, we aimed to determine whether UGN could improve hypothalamic leptin sensitivity. The present work demonstrates that the central co-administration of UGN and leptin potentiates leptin’s ability to decrease the food intake and body weight in DIO mice, and that UGN activates the hypothalamic signal transducer and activator of transcription 3 (STAT3) and phosphatidylinositide 3-kinases (PI3K) pathways. At a functional level, the blockade of PI3K, but not STAT3, blunted UGN-mediated leptin responsiveness in DIO mice. Overall, these findings indicate that UGN improves leptin sensitivity in DIO mice

Neddylation of phosphoenolpyruvate carboxykinase 1 controls glucose metabolism

Neddylation is a post-translational mechanism that adds a ubiquitin-like protein, namely neural precursor cell expressed developmentally downregulated protein 8 (NEDD8). Here, we show that neddylation in mouse liver is modulated by nutrient availability. Inhibition of neddylation in mouse liver reduces gluconeogenic capacity and the hyperglycemic actions of counter-regulatory hormones. Furthermore, people with type 2 diabetes display elevated hepatic neddylation levels. Mechanistically, fasting or caloric restriction of mice leads to neddylation of phosphoenolpyruvate carboxykinase 1 (PCK1) at three lysine residues—K278, K342, and K387. We find that mutating the three PCK1 lysines that are neddylated reduces their gluconeogenic activity rate. Molecular dynamics simulations show that neddylation of PCK1 could re-position two loops surrounding the catalytic center into an open configuration, rendering the catalytic center more accessible. Our study reveals that neddylation of PCK1 provides a finely tuned mechanism of controlling glucose metabolism by linking whole nutrient availability to metabolic homeostasis.Ministerio de Ciencia, Innovación y Universidades PID2020-117116RB-I00, BFU2017-87721, RTI2018-101840-BI00, PID2021-126096NB-I00, RED2018-102379-TXunta de Galicia 2021-CP085, 2020-PG0157Fundación BBVA RTC2019-007125-1Proyectos Investigación en Salud DTS20/00138, DTS20/00138European Community 2019-WATCH- 81033

Zotracos surveys: basic hydrographic and chemical data

Este dataset está compuesto por 2 archivos, de los cuales el primero es el conjunto de datos con 371 análisis de muestras de agua de temperatura, salinidad, oxígeno, nutrientes, pH, alcalinidad, clorofila y materia orgánica, y el otro (Readme.txt) incluye una pequeña descripción de las variables calculadasLa zona costera de transición del noroeste de la Península Ibérica fue objeto de muestreo en tres cruceros realizados del 4 al 2 de diciembre de 2004, del 7 al 14 de febrero y del 23 al 30 de octubre de 2005 a bordo del buque oceanográfico "Cornide de Saavedra". Se muestreo a lo largo de un transecto latitudinal centrado a 41.92°N, cerca de la desembocadura del río Miño y otro frente a la Ría de Vigo. Un total de 5 a 7 estaciones fueron ocupadas durante cada crucero. La salinidad y la temperatura se registraron con una sonda de profundidad de conductividad-temperatura SBE 9/11 conectada al muestreador de roseta con doce botellas de PVC Niskin de 10 L con muelles internos de acero inoxidable. Las mediciones de la conductividad se convirtieron en valores prácticos de la escala de salinidad con la ecuación de la UNESCO (1986). La precisión de las mediciones de CTD para temperatura y salinidad fueron de 0,004 DEG-C y 0,005, respectivamente. Las muestras para los análisis de oxígeno disuelto, pH, alcalinidad total, sales de nutrientes, carbono orgánico disuelto y particulado y nitrógeno fueron recogidas semanalmente con la roseta de 12 botellas Niskin. Para la determinación de nutrientes, las muestras de agua se recogieron en botellas de polietileno de 50 ml y se mantuvieron frías (4ºC) hasta su análisis en el laboratorio utilizando procedimientos estándar de análisis de flujo segmentado. Las precisiones fueron 0,02 micromol/kg para nitrito, 0,1 micromol/kg para nitrato, 0,05 microM para amonio, 0,02 micromol/kg para fosfato y 0,05 micromol/kg para silicato. El oxígeno se determinó por titulación potenciométrica de Winkler utilizando un analizador Titrino 720 con una precisión de ±0,5 micromol/kg. Las muestras de alcalinidad total (TA) y pH (escala de concentración total de hidrógeno, 25°C) se recogieron en frascos de vidrio de 500 ml y se analizaron en pocas horas en el laboratorio base. El pH del agua de mar se midió espectrofotométricamente siguiendo a Clayton y Byrne (1993) aplicándose una adición de 0,0047 (DelValls & Dickson, 1998). La precisión fue 0,003 unidades de pH. El TA se determinó por titulación a pH 4,4 con HCl, según el método potenciométrico de Pérez y Fraga (1987) con una precisión de ±2 micromol/kg. La materia orgánica suspendida se recolectó bajo vacío en filtros precombustionados (450ºC, 4 horas) Whatman GF/F de 25 mm de diámetro y 0,7 micrómetros de tamaño nominal de poro (POC/PON, 0,5-1,5 L de agua de mar). Todos los filtros se secaron durante la noche y se congelaron (-20ºC) antes del análisis. Las mediciones de POC y PON se realizaron con un analizador Perkin Elmer 2400 CHN. Se utilizó un estándar de acetanilida diariamente. La precisión del método es de 0,3 micromol C/L y 0,1 micromol N/LCSIC y Plan Nacional de I+D del Gobierno de España1 data csv ‘29CS20041004_hy1.csv’ file and 1 readme.txt filePeer reviewe

Inhibition of carnitine palmitoyltransferase 1A in hepatic stellate cells protects against fibrosis

One of the most common types of fibrotic liver occurs in patients with non-alcoholic fatty liver disease (NAFLD), which may develop into non-alcoholic steatohepatitis (NASH). Hepatic stellate cells (HSCs) are the primary fibrogenic cell type activated following liver injury, moving from a quiescent phenotype rich in vitamin A into activated myofibroblast-like cells with proliferative and migratory properties.This work has been supported by grants from FEDER/Ministerio de Ciencia, Innovación y Universidades-Agencia Estatal de Investigación (DS and LH: SAF2017-83813-C3-1-R; MLMC: RTC2019-007125-1; CD: BFU2017-87721; ML: RTI2018–101840-B-I00; RN: RTI2018-099413-B-I00 and RED2018-102379-T; MLMC: SAF2017-87301-R; TCD: RTI2018-096759-A-100), Xunta de Galicia (ML: 2016-PG068; RN: 2015-CP080 and 2016-PG057), Fundación BBVA (RN and MLM), Proyectos Investigación en Salud (MLMC: DTS20/00138), Sistema Universitario Vasco (PA: IT971-16); Fundacion Araucaria (ML and RN), Gilead Sciences International Research Scholars Program in Liver Disease (MVR), Marató TV3 Foundation (DS: 201627), Government of Catalonia (DS: 2017SGR278) and European Foundation for the Study of Diabetes (RN). This research also received funding from the European Community’s H2020 Framework Programme (ERC Synergy Grant-2019-WATCH- 810331, to RN, VP and MS). Centro de Investigación Biomédica en Red (CIBER) de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd). CIBERobn and CIBERehd are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain which is supported by FEDER funds. We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644)S

The L-Alpha-Lysophosphatidylinositol/G Protein-Coupled Receptor 55 System Induces the Development of Nonalcoholic Steatosis and Steatohepatitis

Background and Aims G protein-coupled receptor (GPR) 55 is a putative cannabinoid receptor, and l-alpha-lysophosphatidylinositol (LPI) is its only known endogenous ligand. Although GPR55 has been linked to energy homeostasis in different organs, its specific role in lipid metabolism in the liver and its contribution to the pathophysiology of nonalcoholic fatty liver disease (NAFLD) remains unknown. Approach and Results We measured (1) GPR55 expression in the liver of patients with NAFLD compared with individuals without obesity and without liver disease, as well as animal models with steatosis and nonalcoholic steatohepatitis (NASH), and (2) the effects of LPI and genetic disruption of GPR55 in mice, human hepatocytes, and human hepatic stellate cells. Notably, we found that circulating LPI and liver expression of GPR55 were up-regulated in patients with NASH. LPI induced adenosine monophosphate-activated protein kinase activation of acetyl-coenzyme A carboxylase (ACC) and increased lipid content in human hepatocytes and in the liver of treated mice by inducing de novo lipogenesis and decreasing beta-oxidation. The inhibition of GPR55 and ACC alpha blocked the effects of LPI, and the in vivo knockdown of GPR55 was sufficient to improve liver damage in mice fed a high-fat diet and in mice fed a methionine-choline-deficient diet. Finally, LPI promoted the initiation of hepatic stellate cell activation by stimulating GPR55 and activation of ACC. Conclusions The LPI/GPR55 system plays a role in the development of NAFLD and NASH by activating ACC.Supported by grants from the Fondo Europeo de Desarrollo Regional (FEDER)/Ministerio de Ciencia, Innovacion y Universidades (MCIU)/Agencia Estatal de Investigacion (AEI) (C.D.: BFU2017-87721; M.L.: RTI2018-101840-B-I00; R.N.: BFU2015-70664R; A.G.-R.: PI16/00823; C.G.-M.: PI17/00535), Xunta de Galicia (M.L.: 2015-CP079 and 2016-PG068; R.N.: 2015-CP080 and 2016-PG057), Fundacion Banco Bilbao Vizcaya Argentaria (BBVA; to R.N.), Fundacion Atresmedia (M.L. and R.N.), European Foundation for the Study of Diabetes (R. N.), and Fundacion Francisco Cobos (A.G.-R.). MCIU/AEI/FEDER, European Union, (RTI2018-095134-B-100 to P.A.) provided aid to support the research groups of Sistema Universitario Vasco (IT971-16 to P. A). MCIU provided SAF2017-87301-R and RTI2018-096759-1-100, which were integrated into the Plan Estatal de Investigacion Cientifica y Tecnica e Innovacion and were cofinanced with FEDER (to M.L.M.-C. and T.C. D. respectively), and La Caixa Foundation Program and 2018 Fundacion BBVA Grants for Scientific Research Teams (to M.L.M.-C.). The research leading to these results has also received funding from the European Community's H2020 Framework Programme under the following grant: European Research Council Synergy Grant 2019-WATCH-810331 to R.N. Centro de Investigacion Biomedica en Red (CIBER) de Fisiopatologia de la Obesidad y Nutricion and CIBER de Enfermedades Hepaticas y Digestivas are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain, which is supported by FEDER funds, Gilead Sciences International Research Scholars Program in Liver Disease (to MVR), PI16/01548 (to MM) and the Red de Trastornos Adictivos-RTA (RD16/0017/0023). This article was partially supported by grants from the Fondo Nacional de Desarrollo Cientifico y Tecnologico grants 1191145 (to M.A.), 1200227 to JPA and 1191183 (to F. B.) and by the Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT, AFB170005, CARE Chile UC, Basal Centre for Excellence in Science and Technology; to M.A.). We thank MINECO for the Severo Ochoa Excellence Accreditation provided to the Center for Cooperative Research in Biosciences (SEV-2016-0644)