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)

Understanding gut-liver axis nitrogen metabolism in Fatty Liver Disease

The homeostasis of the most important nitrogen-containing intermediates, ammonia and glutamine, is a tightly regulated process in which the gut-liver axis plays a central role. Several studies revealed that nitrogen metabolism is altered in Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD), a consensus-driven novel nomenclature for Non-Alcoholic Fatty Liver Disease (NAFLD), the most common chronic liver disease worldwide. Both increased ammonia production by gut microbiota and decreased ammonia hepatic removal due to impaired hepatic urea cycle activity or disrupted glutamine synthetase activity may contribute to hepatic ammonia accumulation underlying steatosis, which can eventually progress to hyperammonemia in more advanced stages of steatohepatitis and overt liver fibrosis. Furthermore, our group recently showed that augmented hepatic ammoniagenesis via increased glutaminase activity and overexpression of the high activity glutaminase 1 isoenzyme occurs in Fatty Liver Disease. Overall, the improved knowledge of disrupted nitrogen metabolism and metabolic miscommunication between the gut and the liver suggests that the reestablishment of altered gut-liver axis nitrogenous balance is an appealing and attractive therapeutic approach to tackle Fatty Liver Disease, a growing and unmet health problem.This work was supported by grants from Ministerio de Ciencia, Innovacion y Universidades (MICINN) PID2020-117116RB-I00 integrated in Plan Estatal de Investigacion Cientifica y Tecnica y Innovacion (to MLM-C), and co-funded with Fondos FEDER (to MLM-C), Subprograma Retos Colaboracion RTC2019-007125-1 (to MLM-C), La Caixa Foundation Program HR17-00601 (to MLM-C), Proyectos Investigacion en Salud DTS20/00138 (to MLM-C), Departamento de Industria del Gobierno Vasco (to MLM-C), and Ciberehd_ISCIII_MINECO, which is funded by the Instituto de Salud Carlos III. This work was partially funded by the Basque Department of Education (IT1281-19) (JdH), "Investigador AECC" (INVES18050CARD) and Ayuda RYC2020-029316-I financiada por MCIN/AEI/10.13039/501100011033 y por El FSE invierte en tu futuro (to TCD)

Hu Antigen R (HuR) Protein Structure, Function and Regulation in Hepatobiliary Tumors

Hepatobiliary tumors are a group of primary malignancies encompassing the liver, the intra- and extra-hepatic biliary tracts, and the gall bladder. Within the liver, hepatocellular carcinoma (HCC) is the most common type of primary cancer, which is, also, representing the third-most recurrent cause of cancer-associated death and the sixth-most prevalent type of tumor worldwide, nowadays. Although less frequent, cholangiocarcinoma (CCA) is, currently, a fatal cancer with limited therapeutic options. Here, we review the regulatory role of Hu antigen R (HuR), a ubiquitous member of the ELAV/Hu family of RNA-binding proteins (RBPs), in the pathogenesis, progression, and treatment of HCC and CCA. Overall, HuR is proposed as a valuable diagnostic and prognostic marker, as well as a therapeutic target in hepatobiliary cancers. Therefore, novel therapeutic approaches that can selectively modulate HuR function appear to be highly attractive for the clinical management of these types of tumors.España Ministerio de Ciencia, Innovación y Universidades (MICINN), integrated in the Plan Estatal de Investigación Científica y Técnica e Innovación, grant numbers PID2020-117116RB-I00 (to M.L.M.-C.) and PGC2018-096049-B-I00Gobierno de Andalucía, grant numbers BIO-198, US-1254317, US-1257019, P18-FR-3487, and P18-HO-4091Fondo Europeo de Desarrollo Regional (FEDER) (to MLM-C and I.D.-M.); and the La Caixa Foundation Program, grant number HR17-00601 (to M.L.M.-C.).España Ministerio de Educación, Cultura y Deporte, grant number FPU016/0151

GRK2-Dependent HuR Phosphorylation Regulates HIF1α Activation under Hypoxia or Adrenergic Stress.

Adaptation to hypoxia is a common feature in solid tumors orchestrated by oxygen-dependent and independent upregulation of the hypoxia-inducible factor-1α (HIF-1α). We unveiled that G protein-coupled receptor kinase (GRK2), known to be overexpressed in certain tumors, fosters this hypoxic pathway via phosphorylation of the mRNA-binding protein HuR, a central HIF-1α modulator. GRK2-mediated HuR phosphorylation increases the total levels and cytoplasmic shuttling of HuR in response to hypoxia, and GRK2-phosphodefective HuR mutants show defective cytosolic accumulation and lower binding to HIF-1α mRNA in hypoxic Hela cells. Interestingly, enhanced GRK2 and HuR expression correlate in luminal breast cancer patients. GRK2 also promotes the HuR/HIF-1α axis and VEGF-C accumulation in normoxic MCF7 breast luminal cancer cells and is required for the induction of HuR/HIF1-α in response to adrenergic stress. Our results point to a relevant role of the GRK2/HuR/HIF-1α module in the adaptation of malignant cells to tumor microenvironment-related stresses.This research was funded by the Instituto de Salud Carlos III: PI17-00576; Ministerio de Economia, Industria y Competitividad, Gobierno de Espana: SAF2017-84125-R; Ministerio de Economia, Industria y Competitividad, Gobierno de Espana: SAF2017-87301-R; Instituto de Salud Carlos III: CIBERCV CB16/11/00278; Instituto de Salud Carlos III: PI14-00435; Fundacion Ramon Areces and the Comunidad de Madrid: B2017/BMD-3671-INFLAMUNE.S

HuR biological function involves RRM3-mediated dimerization and RNA binding by all three RRMs

HuR/ELAVL1 is an RNA-binding protein involved in differentiation and stress response that acts primarily by stabilizing messenger RNA (mRNA) targets. HuR comprises three RNA recognition motifs (RRMs) where the structure and RNA binding of RRM3 and of full-length HuR remain poorly understood. Here, we report crystal structures of RRM3 free and bound to cognate RNAs. Our structural, NMR and biochemical data show that RRM3 mediates canonical RNA interactions and reveal molecular details of a dimerization interface localized on the -helical face of RRM3. NMR and SAXS analyses indicate that the three RRMs in full-length HuR are flexibly connected in the absence of RNA, while they adopt a more compact arrangement when bound to RNA. Based on these data and crystal structures of tandem RRM1,2- RNA and our RRM3-RNA complexes, we present a structural model of RNA recognition involving all three RRM domains of full-length HuR. Mutational analysis demonstrates that RRM3 dimerization and RNA binding is required for functional activity of fulllength HuR in vitro and to regulate target mRNAs levels in human cells, thus providing a fine-tuning for HuR activity in vivo.Peer reviewe

Atorvastatin Provides a New Lipidome Improving Early Regeneration After Partial Hepatectomy in Osteopontin Deficient Mice

Osteopontin (OPN), a multifunctional cytokine that controls liver glycerolipid metabolism, is involved in activation and proliferation of several liver cell types during regeneration, a condition of high metabolic demands. Here we investigated the role of OPN in modulating the liver lipidome during regeneration after partial-hepatectomy (PH) and the impact that atorvastatin treatment has over regeneration in OPN knockout (KO) mice. The results showed that OPN deficiency leads to remodeling of phosphatidylcholine and triacylglycerol (TG) species primarily during the first 24 h after PH, with minimal effects on regeneration. Changes in the quiescent liver lipidome in OPN-KO mice included TG enrichment with linoleic acid and were associated with higher lysosome TG-hydrolase activity that maintained 24 h after PH but increased in WT mice. OPN-KO mice showed increased beta-oxidation 24 h after PH with less body weight loss. In OPN-KO mice, atorvastatin treatment induced changes in the lipidome 24 h after PH and improved liver regeneration while no effect was observed 48 h post-PH. These results suggest that increased dietary-lipid uptake in OPN-KO mice provides the metabolic precursors required for regeneration 24 h and 48 h after PH. However, atorvastatin treatment offers a new metabolic program that improves early regeneration when OPN is deficient.This work was supported by IT-336-10 (Gobierno Vasco) (to PA) and SAF2015-64352-R (to PA), SAF2017-87301-R (to MLM-C) and EITB Maratoia BIO15/CA/014 (to MLM-C). MNG and DM were recipients of a predoctoral fellowship from the University of Basque Country UPV/EHU and BG-S and DS were recipients for predoctoral fellowships from the Basque Goverment. We thank technical support from Jose Antonio Lopez Gomez

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

Inhibition of NAE-dependent protein hyper-NEDDylation in cystic cholangiocytes halts cystogenesis in experimental models of polycystic liver disease

Background Polycystic liver diseases (PLDs) are genetic inherited disorders characterized by the progressive growth of numerous intrahepatic biliary cysts, which are the main cause of morbidity. Previous studies revealed that cystic cholangiocytes are characterized by endoplasmic reticulum stress and aberrant posttranslational modification (PTM) of proteins, in particular hyper-SUMOylation, that promote PLD pathobiology. Protein NEDDylation is a newly characterized PTM that modulates a plethora of biological processes and its dysregulation is associated with the development and progression of several human diseases. However, the role of NEDDylation in PLD remains elusive. Objective To explore the role of protein NEDDylation in PLD and its potential therapeutic regulatory value. Methods Levels and functional effects of NEDDylation, including response to Pevonedistat (first-in-class selective inhibitor of the NEDDylation E1 enzyme NAE), were assessed in vitro, in vivo, and/or in patients with PLD. NEDDylated protein levels in normal and cystic human cholangiocytes were assessed by immunoprecipitation, and the proteomic profile was further analyzed by mass spectrometry. Results and Conclusion The genes involved in the NEDDylation pathway were found overexpressed (mRNA) in polycystic human and rat liver tissue, as well as in cystic cholangiocytes in culture, compared to controls. Elevated levels of NEDDylated proteins were further confirmed in cystic cholangiocytes in vitro, which diminished under Pevonedistat incubation. Pevonedistat promoted apoptotic cell death and reduced proliferation in cystic cholangiocytes in vitro. Comparative proteomic profiling of NEDD8-immunoprecipitated proteins between normal and cystic cholangiocytes in culture reported candidate proteins involved in cystogenesis, mostly associated with protein biogenesis and quality control. All these data indicate that cystic cholangiocytes display increased protein NEDDylation, contributing to cell survival and proliferation, ultimately supporting hepatic cystogenesis. Targeting of protein hyper-NEDDylation in cystic cholangiocytes inhibits cystogenesis in experimental models, representing a novel therapeutic opportunity in PLD.Spanish Carlos III Health Institute (ISCIII), Grant/Award Numbers: CON14/00129, CPII19/00008, FIS PI12/00380, FIS PI14/ 00399, FIS PI15/01132, FIS PI17/00022, FIS PI18/01075, FIS PI20/00186, Sara Borrell CD19/00254; Diputacion Foral de Gipuzkoa, Grant/Award Numbers: DFG15/010, DFG16/004; Department of Health of the Basque Country, Grant/Award Numbers: 2015111100, 2017111010, 2019111024; Euskadi RIS3, Grant/Award Numbers: 2016222001, 2017222014, 2018222029, 2019222054, 2020333010; Department of Industry of the Basque Country, Grant/Award Number: KK-2020/00008; Spanish Ministry of Economy and Competitiveness, Grant/Award Number: RYC-2015-17755; Ministerio de Ciencia, Innovacion y Universidades, Grant/ Award Number: SAF2017-87301-R; Ayudas para apoyar grupos de investigacion del Sistema Universitario Vasco, Grant/Award Number: IT971-16; Universita Politecnica delle Marche, Grant/Award Number: PSA2017_UNIVPM; European Association for the Study of the Liver, Grant/Award Number: Sheila Sherlock Award 2017; Spanish Ministry of Science and Innovation, Grant/Award Number: BES-2014-069148; Basque Government, Grant/Award Number: PRE_2016_1_0269; Basque Foundation for Innovation and Health Research, Grant/Award Number: BIO15/CA/016/BD; Fundacion Cientifica de la Asociacion Espanola Contra el Cancer; La Caixa Scientific Foundation, Grant/ Award Number: HR17-00601; CIBERehd; Fondo Europeo de Desarrollo Regional Documen

S-adenosylmethionine Levels Regulate the Schwann Cell DNA Methylome

SummaryAxonal myelination is essential for rapid saltatory impulse conduction in the nervous system, and malformation or destruction of myelin sheaths leads to motor and sensory disabilities. DNA methylation is an essential epigenetic modification during mammalian development, yet its role in myelination remains obscure. Here, using high-resolution methylome maps, we show that DNA methylation could play a key gene regulatory role in peripheral nerve myelination and that S-adenosylmethionine (SAMe), the principal methyl donor in cytosine methylation, regulates the methylome dynamics during this process. Our studies also point to a possible role of SAMe in establishing the aberrant DNA methylation patterns in a mouse model of diabetic neuropathy, implicating SAMe in the pathogenesis of this disease. These critical observations establish a link between SAMe and DNA methylation status in a defined biological system, providing a mechanism that could direct methylation changes during cellular differentiation and in diverse pathological situations

Targeting UBC9-Mediated Protein Hyper-SUMOylation in Cystic Cholangiocytes Halts Polycystic Liver Disease in Experimental Models

BACKGROUND & AIMS: Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of multiple fluid-filled biliary cysts. Most PLD-causative genes participate in protein biogenesis and/or transport. Post-translational modifications (PTMs) are implicated in protein stability, localization and activity, contributing to human pathobiology; however, their role in PLD is unknown. Herein, we aimed to unveil the role of protein SUMOylation in PLD and its potential therapeutic targeting. METHODS: Levels and functional effects of SUMOylation, along with response to S-adenosylmethionine (SAMe, inhibitor of the SUMOylation enzyme UBC9) and/or short-hairpin RNAs (shRNAs) against UBE2I (UBC9), were evaluated invitro, invivo and/or in patients with PLD. SUMOylated proteins were determined by immunoprecipitation and proteomic analyses by mass spectrometry. RESULTS: Most SUMOylation-related genes were found overexpressed (mRNA) in polycystic human and rat liver tissue, as well as in cystic cholangiocytes in culture compared to controls. Increased SUMOylated protein levels were also observed in cystic human cholangiocytes in culture, which decreased after SAMe administration. Chronic treatment of polycystic (PCK: Pkdh1-mut) rats with SAMe halted hepatic cystogenesis and fibrosis, and reduced liver/body weight ratio and liver volume. Invitro, both SAMe and shRNA-mediated UBE2I knockdown increased apoptosis and reduced cell proliferation of cystic cholangiocytes. High-throughput proteomic analysis of SUMO1-immunoprecipitated proteins in cystic cholangiocytes identified candidates involved in protein biogenesis, ciliogenesis and proteasome degradation. Accordingly, SAMe hampered proteasome hyperactivity in cystic cholangiocytes, leading to activation of the unfolded protein response and stress-related apoptosis. CONCLUSIONS: Cystic cholangiocytes exhibit increased SUMOylation of proteins involved in cell survival and proliferation, thus promoting hepatic cystogenesis. Inhibition of protein SUMOylation with SAMe halts PLD, representing a novel therapeutic strategy. LAY SUMMARY: Protein SUMOylation is a dynamic post-translational event implicated in numerous cellular processes. This study revealed dysregulated protein SUMOylation in polycystic liver disease, which promotes hepatic cystogenesis. Administration of S-adenosylmethionine (SAMe), a natural UBC9-dependent SUMOylation inhibitor, halted polycystic liver disease in experimental models, thus representing a potential therapeutic agent for patients.Spanish Carlos III Health Institute (ISCIII) [J.M. Banales (FIS PI12/00380, PI15/01132, PI18/01075 and Miguel Servet Program CON14/00129 and CPII19/00008); M.J. Perugorria (FIS PI14/00399, PI17/00022 and PI20/00186); P.M. Rodrigues (Sara Borrell CD19/00254)] cofinanced by “Fondo Europeo de Desarrollo Regional” (FEDER); Ministerio de Ciencia, Innovación y Universidades (MICINN; M.L. Martinez-Chantar: SAF2017-87301-R); “Instituto de Salud Carlos III” [CIBERehd: J.M. Banales, M.J. Perugorria, M.L. Martinez-Chantar and L. Bujanda], Spain; “Diputación Foral Gipuzkoa” (J.M. Banales: DFG15/010, DFG16/004), Department of Health of the Basque Country (M.J. Perugorria: 2019111024, 2015111100 and J.M. Banales: 2017111010), “Euskadi RIS3” (J.M. Banales: 2016222001, 2017222014, 2018222029, 2019222054, 2020333010), BIOEF (Basque Foundation for Innovation and Health Research: EiTB Maratoia BIO15/CA/016/BD to J.M. Banales and M.L. Martinez-Chantar) and Department of Industry of the Basque Country (J.M. Banales: Elkartek: KK-2020/00008). La Caixa Scientific Foundation (J.M. Banales and M.L. Martinez-Chantar: HR17-00601). “Fundación Científica de la Asociación Española Contra el Cáncer” (AECC Scientific Foundation, to J.M. Banales and M.L. Martinez-Chantar). “Ayudas para apoyar grupos de investigación del Sistema Universitario Vasco” (IT971-16 to P.A.). Università Politecnica delle Marche PSA2017_UNIVPM grant (to M. Marzioni). National Institutes of Health (NIH) of United States of America (DK24031 to N.F. LaRusso). MJ Perugorria was funded by the Spanish Ministry of Economy and Competitiveness (MINECO: “Ramón y Cajal” Program RYC-2015-17755), P.Y. Lee-Law by the European Association for the Study of the Liver (EASL; Sheila Sherlock Award 2017), F.J. Caballero-Camino by the Spanish Ministry of Science and Innovation (BES-2014-069148), and P. Olaizola and A. Santos-Laso by the Basque Government (PRE_2016_1_0269, PRE_2015_1_0126). We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644). The funding sources had no involvement in study design, data collection and analysis, decision to publish, or preparation of the article