Role of mitochondria in liver diseases

252 p.La disfunción mitocondrial desempeña un papel clave en el inicio y desarrollo de las enfermedades hepáticas crónicas. La proteína J controlada por metilación (MCJ) es un inhibidor endógeno de laactividad mitocondrial, y previamente hemos podido demostrar niveles significativamente aumentados deMCJ en pacientes con hígado graso, daño hepático inducido por paracetamol y lesión hepática debido a la colestasis, lo que sugiere una posible asociación entre MCJ y la disfunción mitocondrial. La enfermedad hepática alcohólica causa más de 2 millones de fallecimientos en el mundo y es la segunda causa detrasplante hepático. Sin embargo, carece de un tratamiento específico. Por otro lado, las tasas actuales de trasplante hepático cubren menos del 10% de las necesidades globales, y entre las estrategias paraaumentar el grupo de donantes, se ha propuesto el uso de hígado con criterio expandido, aquellos queprovienen de hígados añosos o esteatóticos. Sin embargo, el uso de estos órganos aumenta el fallo hepático post trasplante, ya que su capacidad regenerativa está limitada y sufren una alta susceptibilidad hacia el daño por isquemia. En ambos modelos la disfunción mitocondrial es un indicador temprano deldaño hepático y hemos podido comprobar la sobreexpresión de MCJ en estadios avanzados. De hecho, elsilenciamiento hepático de MCJ (1) recupera la actividad mitocondrial, alivia la esteatosis y evita la inflamación y el estrés oxidativo en modelos preclínicos de enfermedad hepática alcohólica, y (2) acelerala regeneración hepática y reduce la lesión isquémica en ratones jóvenes, pero significativamente,también en ratones añosos y esteatóticos, promoviendo su uso para el trasplante hepático, reduciendo así la escasez existente de donantes. En resumen, este proyecto muestra la contribución de la disfunción mitocondrial, en especial de la proteína MCJ, en el desarrollo de la enfermedad hepática alcohólica y la regeneración limitada junto con mayor susceptibilidad isquémica que se observa en hígados con un metabolismo comprometido, con el objetivo de establecer dicha proteína como futura diana terapéutica para el tratamiento de enfermedades hepáticas crónica

Nutraceutical Properties of Polyphenols against Liver Diseases

Current food tendencies, suboptimal dietary habits and a sedentary lifestyle are spreading metabolic disorders worldwide. Consequently, the prevalence of liver pathologies is increasing, as it is the main metabolic organ in the body. Chronic liver diseases, with non-alcoholic fatty liver disease (NAFLD) as the main cause, have an alarming prevalence of around 25% worldwide. Otherwise, the consumption of certain drugs leads to an acute liver failure (ALF), with drug-induced liver injury (DILI) as its main cause, or alcoholic liver disease (ALD). Although programs carried out by authorities are focused on improving dietary habits and lifestyle, the long-term compliance of the patient makes them difficult to follow. Thus, the supplementation with certain substances may represent a more easy-to-follow approach for patients. In this context, the consumption of polyphenol-rich food represents an attractive alternative as these compounds have been characterized to be effective in ameliorating liver pathologies. Despite of their structural diversity, certain similar characteristics allow to classify polyphenols in 5 groups: stilbenes, flavonoids, phenolic acids, lignans and curcuminoids. Herein, we have identified the most relevant compounds in each group and characterized their main sources. By this, authorities should encourage the consumption of polyphenol-rich products, as most of them are available in quotidian life, which might reduce the socioeconomical burden of liver diseases.We thank University of Basque Country (UPV/EHU), Basque Government and Asociacion Espanola Contra el Cancer (AECC) for the Pre-doctoral grants to M.C.-A., N.G.-U. and M.S.-M., respectively. 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)

Restoring cellular magnesium balance through Cyclin M4 protects against acetaminophen-induced liver damage

Acetaminophen overdose is one of the leading causes of acute liver failure and liver transplantation in the Western world. Magnesium is essential in several cellular processess. The Cyclin M family is involved in magnesium transport across cell membranes. Herein, we identify that among all magnesium transporters, only Cyclin M4 expression is upregulated in the liver of patients with acetaminophen overdose, with disturbances in magnesium serum levels. In the liver, acetaminophen interferes with the mitochondrial magnesium reservoir via Cyclin M4, affecting ATP production and reactive oxygen species generation, further boosting endoplasmic reticulum stress. Importantly, Cyclin M4 mutant T495I, which impairs magnesium flux, shows no effect. Finally, an accumulation of Cyclin M4 in endoplasmic reticulum is shown under hepatoxicity. Based on our studies in mice, silencing hepatic Cyclin M4 within the window of 6 to 24 h following acetaminophen overdose ingestion may represent a therapeutic target for acetaminophen overdose induced liver injury.Acknowledgements: This work was supported by Ministerio de Ciencia, Innovación y Universidades MICINN: PID2020-117116RB-I00 integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación, cofinanciado con Fondos FEDER (to MLM-C), Ministerio de Ciencia e Innovación CONSOLIDER-INGENIO 2010 Program Grant CSD2008-00005 (to LAMC); Spanish Ministry of Economy and Competitiveness Grant BFU2013-47531-R, BFU2016-77408-R, PID2019-109055RB-100 (to L.A.M.-C.) (MINECO/FEDER, UE); Asociación Española contra el Cáncer (MLM-C, TC-D), Fundación Científica de la Asociación Española Contra el Cáncer (AECC Scientific Foundation) Rare Tumor Calls 2017 (to M.L.M.-C.), La Caixa Foundation Program (to M.L.M.-C.), Fundacion BBVA UMBRELLA project (to M.L.M.-C.), Ayuda RYC2020-029316-I financiada por MICIN/AEI/10.13039/501100011033 (to TC-D), Plataforma de Investigación Clínica-SCReN (PT17 0017 0020) (to M.I.-L.), programa retos RTC2019-007125-1 (to M.L.M.-C, J.S.), Proyectos Investigacion en Salud DTS20/00138 (to M.L.M.-C., J.S), ERA-Net E-Rare EJP RD Joint Translational Call for Rare Diseases FIGHT-CNNM2 (EJPRD19-040) and from Instituto Carlos III, Spain (REF G95229142) (to L.A.M.-C.), US National Institutes of Health under grant CA217817 (to D.B.), Ciberehd_ISCIII_MINECO is funded by the Instituto de Salud Carlos III. We thankMINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644) and PhD fellowship fromMINECO (REF BES-2017-080435) awarded to I.G.-R. The collection and storage of patients tissues was supported by the Newcastle Biomedicine Biobank and the European Community’s Seventh Framework Programme (FP7/2001–2013) and Cancer Research UK awards Cancer Research UK grants C18342/A23390; C9380/A18084 and C9380/A26813. Finally, we would like to acknowledge Begoña Rodríguez Iruretagoyena for the technical support provided

Mitochondrial bioenergetics boost macrophage activation, promoting liver regeneration in metabolically compromised animals

Background and aims: Hepatic ischemia-reperfusion injury (IRI) is the leading cause of early posttransplantation organ failure as mitochondrial respiration and ATP production are affected. A shortage of donors has extended liver donor criteria, including aged or steatotic livers, which are more susceptible to IRI. Given the lack of an effective treatment and the extensive transplantation waitlist, we aimed at characterizing the effects of an accelerated mitochondrial activity by silencing methylation-controlled J protein (MCJ) in three preclinical models of IRI and liver regeneration, focusing on metabolically compromised animal models. Approach and results: Wild-type (WT), MCJ knockout (KO), and Mcj silenced WT mice were subjected to 70% partial hepatectomy (Phx), prolonged IRI, and 70% Phx with IRI. Old and young mice with metabolic syndrome were also subjected to these procedures. Expression of MCJ, an endogenous negative regulator of mitochondrial respiration, increases in preclinical models of Phx with or without vascular occlusion and in donor livers. Mice lacking MCJ initiate liver regeneration 12 h faster than WT and show reduced ischemic injury and increased survival. MCJ knockdown enables a mitochondrial adaptation that restores the bioenergetic supply for enhanced regeneration and prevents cell death after IRI. Mechanistically, increased ATP secretion facilitates the early activation of Kupffer cells and production of TNF, IL-6, and heparin-binding EGF, accelerating the priming phase and the progression through G1 /S transition during liver regeneration. Therapeutic silencing of MCJ in 15-month-old mice and in mice fed a high-fat/high-fructose diet for 12 weeks improves mitochondrial respiration, reduces steatosis, and overcomes regenerative limitations. Conclusions: Boosting mitochondrial activity by silencing MCJ could pave the way for a protective approach after major liver resection or IRI, especially in metabolically compromised, IRI-susceptible organs.Funding information: Supported by grants from Ministerio de Ciencia, Innovación y Universidades MICINN (PID2020-117116RB-100, RTI2018-096759-A-100, RTI2018-095114-B-I00, PID2019-108977RB-100 and RTI2018-095700-B100, integrado en el Plan Estatal de Investigación Científica y Técnica y Innovación, cofinanciado con Fondos FEDER, to M.L.M.-C., T.C.D., C.P., P.M.-S., and N.G.A.A., respectively), Subprograma Retos Colaboración RTC2019-007125-1; Fundación Científica de la Asociación Española Contra el Cáncer (AECC Scientific Foundation) Rare Tumor Calls 2017 (to M.L.M.-C.); Asociación Española contra el Cáncer (to T.C.D. and M.S.-M); La Caixa Foundation Program (HR17-00601, to M.L.M.-C.), Proyectos Investigación en Salud DTS20/00138 (to M.L.M.-C.); Departamento de Industria del Gobierno Vasco (to M.L.M.-C.); Departamento de Educación del Gobierno Vasco (to N.G.-U. and J.S.); Acción Estratégica Ciber Emergentes 2018 (Ciberehd-ISCIII) and Gilead Sciences International Research Scholars Program in Liver Disease (to M.V.-R.); Ciberehd_ISCIII_MINECO is funded by the Instituto de Salud Carlos IIIAcknowledgments: We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644). We acknowledge Begoña Rodríguez Iruretagoyena for the technical support provided

Enhanced mitochondrial activity reshapes a gut microbiota profile that delays NASH progression

[EN] Background and Aims: Recent studies suggest that mitochondrial dysfunction promotes progression to NASH by aggravating the gut-liver status. However, the underlying mechanism remains unclear. Herein, we hypothesized that enhanced mitochondrial activity might reshape a specific microbiota signature that, when transferred to germ-free (GF) mice, could delay NASH progression. Approach and Results: Wild-type and methylation-controlled J protein knockout (MCJ-KO) mice were fed for 6 weeks with either control or a choline-deficient, L-amino acid–defined, high-fat diet (CDA-HFD). One mouse of each group acted as a donor of cecal microbiota to GF mice, who also underwent the CDA-HFD model for 3 weeks. Hepatic injury, intestinal barrier, gut microbiome, and the associated fecal metabolome were then studied. Following 6 weeks of CDA-HFD, the absence of methylation-controlled J protein, an inhibitor of mitochondrial complex I activity, reduced hepatic injury and improved gut-liver axis in an aggressive NASH dietary model. This effect was transferred to GF mice through cecal microbiota transplantation. We suggest that the specific microbiota profile of MCJ-KO, characterized by an increase in the fecal relative abundance of Dorea and Oscillospira genera and a reduction in AF12, Allboaculum, and [Ruminococcus], exerted protective actions through enhancing short-chain fatty acids, nicotinamide adenine dinucleotide (NAD+) metabolism, and sirtuin activity, subsequently increasing fatty acid oxidation in GF mice. Importantly, we identified Dorea genus as one of the main modulators of this microbiota-dependent protective phenotype. Conclusions: Overall, we provide evidence for the relevance of mitochondria–microbiota interplay during NASH and that targeting it could be a valuable therapeutic approach.S

Boosting mitochondria activity by silencing MCJ overcomes cholestasis-induced liver injury

Background & Aims: Mitochondria are the major organelles for the formation of reactive oxygen species (ROS) in the cell, and mitochondrial dysfunction has been described as a key factor in the pathogenesis of cholestatic liver disease. The methylation-controlled J-protein (MCJ) is a mitochondrial protein that interacts with and represses the function of complex I of the electron transport chain. The relevance of MCJ in the pathology of cholestasis has not yet been explored. Methods: We studied the relationship between MCJ and cholestasis-induced liver injury in liver biopsies from patients with chronic cholestatic liver diseases, and in livers and primary hepatocytes obtained from WT and MCJ-KO mice. Bile duct ligation (BDL) was used as an animal model of cholestasis, and primary hepatocytes were treated with toxic doses of bile acids. We evaluated the effect of MCJ silencing for the treatment of cholestasis-induced liver injury. Results: Elevated levels of MCJ were detected in the liver tissue of patients with chronic cholestatic liver disease when compared with normal liver tissue. Likewise, in mouse models, the hepatic levels of MCJ were increased. After BDL, MCJ-KO animals showed significantly decreased inflammation and apoptosis. In an in vitro model of bile-acid induced toxicity, we observed that the loss of MCJ protected mouse primary hepatocytes from bile acid-induced mitochondrial ROS over-production and ATP depletion, enabling higher cell viability. Finally, the in vivo inhibition of the MCJ expression, following BDL, showed reduced liver injury and a mitigation of the main cholestatic characteristics. Conclusions: We demonstrated that MCJ is involved in the progression of cholestatic liver injury, and our results identified MCJ as a potential therapeutic target to mitigate the liver injury caused by cholestasis. Lay summary: In this study, we examine the effect of mitochondrial respiratory chain inhibition by MCJ on bile acid-induced liver toxicity. The loss of MCJ protects hepatocytes against apoptosis, mitochondrial ROS overproduction, and ATP depletion as a result of bile acid toxicity. Our results identify MCJ as a potential therapeutic target to mitigate liver injury in cholestatic liver diseases.Acknowledgements: We thank MINECO for the Severo Ochoa Excellence Accreditation of CIC bioGUNE [SEV-2016-0644]

The lipopolysaccharide-TLR4 axis regulates hepatic glutaminase 1 expression promoting liver ammonia build-up as steatotic liver disease progresses to steatohepatitis

Introduction Ammonia is a pathogenic factor implicated in the progression of metabolic-associated steatotic liver disease (MASLD). The contribution of the glutaminase 1 (GLS) isoform, an enzyme converting glutamine to glutamate and ammonia, to hepatic ammonia build-up and the mechanisms underlying its upregulation in metabolic-associated steatohepatitis (MASH) remain elusive. Methods Multiplex transcriptomics and targeted metabolomics analysis of liver biopsies in dietary mouse models representing the whole spectra of MASLD were carried out to characterize the relevance of hepatic GLS during disease pathological progression. In addition, the acute effect of liver-specific GLS inhibition in hepatic ammonia content was evaluated in cultured hepatocytes and in in vivo mouse models of diet-induced MASLD. Finally, the regulatory mechanisms of hepatic GLS overexpression related to the lipopolysaccharide (LPS)/Toll-like receptor 4 (TLR4) axis were explored in the context of MASH. Results In mouse models of diet-induced MASLD, we found that augmented liver GLS expression is closely associated with the build-up of hepatic ammonia as the disease progresses from steatosis to steatohepatitis. Importantly, the acute silencing/pharmacological inhibition of GLS diminishes the ammonia burden in cultured primary mouse hepatocytes undergoing dedifferentiation, in steatotic hepatocytes, and in a mouse model of diet-induced steatohepatitis, irrespective of changes in ureagenesis and gut permeability. Under these conditions, GLS upregulation in the liver correlates positively with the hepatic expression of TLR4 that recognizes LPS. In agreement, the pharmacological inhibition of TLR4 reduces GLS and hepatic ammonia content in LPS-stimulated mouse hepatocytes and hyperammonemia animal models of endotoxemia. Conclusions Overall, our results suggest that the LPS/TLR4 axis regulates hepatic GLS expression promoting liver ammonia build-up as steatotic liver disease progresses to steatohepatitis.TC Delgado is funded by “Ayuda RYC2020-029316-I financiada por MCIN/AEI/10.13039/501100011033 y por El FSE invierte en tu future”. This work was supported by the Gilead Sciences Research Scholars Program in Global Liver (to TCD), Nanostring® grant (to TCD); grant from Ministerio de Ciencia, Innovación y Universidades (MICINN: PID2022-139395OB-100 integrado en el Plan Estatal de Investigación Científica y Técnica e Innovación, con Fondos FEDER); grants from Ministerio de Ciencia, Innovación y Universidades MICINN: PID2020-117116RB-I00 CEX2021-001136-S integrado en el Plan Estatal de Investigación Científica y Técnica e Innovación, cofinanciado con Fondos FEDER for (MLM-C); Project funded by CIBEREHD; La Caixa Scientific Foundation (HR17-00601) (for MLM-C); ERA-Net E-Rare EJP RD Joint Translational Call for Rare Diseases FIGHT-CNNM2 (EJPRD19-040), and from Instituto Carlos III, Spain (for MLM-C, JH); the Basque Department of Education (IT1739-22) (for JH). JH and TCD are members of the European Reference Network for Rare Hereditary Metabolic Disorders (MetabERN) Project ID No. 739543

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

Multi-Omics Integration Highlights the Role of Ubiquitination in CCl4-Induced Liver Fibrosis

Liver fibrosis is the excessive accumulation of extracellular matrix proteins that occurs in chronic liver disease. Ubiquitination is a post-translational modification that is crucial for a plethora of physiological processes. Even though the ubiquitin system has been implicated in several human diseases, the role of ubiquitination in liver fibrosis remains poorly understood. Here, multi-omics approaches were used to address this. Untargeted metabolomics showed that carbon tetrachloride (CCl4)-induced liver fibrosis promotes changes in the hepatic metabolome, specifically in glycerophospholipids and sphingolipids. Gene ontology analysis of public deposited gene array-based data and validation in our mouse model showed that the biological process “protein polyubiquitination” is enriched after CCl4-induced liver fibrosis. Finally, by using transgenic mice expressing biotinylated ubiquitin (bioUb mice), the ubiquitinated proteome was isolated and characterized by mass spectrometry in order to unravel the hepatic ubiquitinated proteome fingerprint in CCl4-induced liver fibrosis. Under these conditions, ubiquitination appears to be involved in the regulation of cell death and survival, cell function, lipid metabolism, and DNA repair. Finally, ubiquitination of proliferating cell nuclear antigen (PCNA) is induced during CCl4-induced liver fibrosis and associated with the DNA damage response (DDR). Overall, hepatic ubiquitome profiling can highlight new therapeutic targets for the clinical management of liver fibrosis.This 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, SAF2017-88041-R, RTI2018-096759-A-100 and SAF2016-76898-P integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación, cofinanciado con Fondos FEDER (to M.L.M.-C., J.M.M., T.C.D. and U.M. respectively); AECC Bizkaia (M.S.-M.); Asociación Española contra el Cáncer (T.C.D.), Fundación Científica de la Asociación Española Contra el Cancer (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.), 2018 BBVA Foundation Grants for Scientific Research Teams (to M.L.M.-C.). This research was also 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 (to J.J.G.M.). The UPV/EHU Lab and the Proteomics Platform are members of Proteored, PRB3 and is supported by grant PT17/0019, of the PE I + D + i 2013-2016, funded by ISCIII and ERDF. 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)

Methionine Cycle Rewiring by Targeting miR-873-5p Modulates Ammonia Metabolism to Protect the Liver from Acetaminophen

Drug-induced liver injury (DILI) development is commonly associated with acetaminophen (APAP) overdose, where glutathione scavenging leads to mitochondrial dysfunction and hepatocyte death. DILI is a severe disorder without effective late-stage treatment, since N-acetyl cysteine must be administered 8 h after overdose to be efficient. Ammonia homeostasis is altered during liver diseases and, during DILI, it is accompanied by decreased glycine N-methyltransferase (GNMT) expression and S-adenosylmethionine (AdoMet) levels that suggest a reduced methionine cycle. Anti-miR-873-5p treatment prevents cell death in primary hepatocytes and the appearance of necrotic areas in liver from APAP-administered mice. In our study, we demonstrate a GNMT and methionine cycle activity restoration by the anti-miR-873-5p that reduces mitochondrial dysfunction and oxidative stress. The lack of hyperammoniemia caused by the therapy results in a decreased urea cycle, enhancing the synthesis of polyamines from ornithine and AdoMet and thus impacting the observed recovery of mitochondria and hepatocyte proliferation for regeneration. In summary, anti-miR-873-5p appears to be an effective therapy against APAP-induced liver injury, where the restoration of GNMT and the methionine cycle may prevent mitochondrial dysfunction while activating hepatocyte proliferative response.We thank Ministerio de Ciencia e Innovación, Programa Retos-Colaboración RTC2019- 007125-1 (for J.S. and M.L.M.-C.); Instituto de Salud Carlos III: Proyectos de Investigación en Salud DTS20/00138 (for J.S. and M.L.M.-C.), PI20/00690 (for R.J.) and PT20/000127 (for M.I.L.); CIBERehd: EHD21TRF01/2022 (to M.L.M.-C.); Departamento de Industria del Gobierno Vasco (for M.L.M.-C.); Ministerio de Ciencia, Innovación y Universidades MICINN: PID2020-117116RB-I00 and RTI2018- 096759-1-100 integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación, cofinanciado con Fondos FEDER (for M.L.M.-C. and T.C.D., respectively); BIOEF (Basque Foundation for Innovation and Health Research); Asociación Española contra el Cáncer (AECC) (to M.L.M.-C., T.C.D.); AECC: GCTRA18006CARR (to A.C.); Fundación Científica de la Asociación Española Contra el Cancer (AECC Scientific Foundation) Rare Tumor Calls 2017 (for M.L.M.); La Caixa Foundation Program (for M.L.M.); BFU2015-70067-REDC, BFU2016-77408-R and BES-2017-080435 (MINECO/FEDER, UE); Ministerio de Ciencia, Innovación y universidades PID2019-108787RB-100 (to A.C.), PID2019- 109055RB-I00 (L.A.M.-C.), PID2020-117941RB-100 (to F.J.C.); Spanish Ministry of Economy and Competitiveness Grants BFU2013-47531-R and BFU2016-77408-R (L.A.M.-C.) and the FIGHT-CNNM2 project from the EJP RD Joint Transnational Call (JTC2019) (Ref. AC19/00073) (for L.A.M.-C.); Comunidad de Madrid: EXOHEP-CM S2017/BMD-3727 and NanoLiver-CM Y2018/NMT-4949 co-funded by European Structural and Investment Fund and COST Action CA17112 (to F.J.C.); Vencer el Cáncer Foundation (to A.C.); European Research Council: Consolidator Grant 819242 (to A.C.); CIBERONC and CIBERehd were funded by the Instituto de Salud Carlos III and Cofunded by FEDER funds. Partial funding for open access charge: Universidad de Málag