High fat diet-induced non alcoholic fatty liver disease in rats is associated with hyperhomocysteinemia caused by down regulation of the transsulphuration pathway

<p>Abstract</p> <p>Background</p> <p>Hyperhomocysteinemia (HHcy) causes increased oxidative stress and is an independent risk factor for cardiovascular disease. Oxidative stress is now believed to be a major contributory factor in the development of non alcoholic fatty liver disease, the most common liver disorder worldwide. In this study, the changes which occur in homocysteine (Hcy) metabolism in high fat-diet induced non alcoholic fatty liver disease (NAFLD) in rats were investigated.</p> <p>Methods and results</p> <p>After feeding rats a standard low fat diet (control) or a high fat diet (57% metabolisable energy as fat) for 18 weeks, the concentration of homocysteine in the plasma was significantly raised while that of cysteine was lowered in the high fat as compared to the control diet fed animals. The hepatic activities of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CGS), the enzymes responsible for the breakdown of homocysteine to cysteine via the transsulphuration pathway in the liver, were also significantly reduced in the high fat-fed group.</p> <p>Conclusions</p> <p>These results indicate that high fat diet-induced NAFLD in rats is associated with increased plasma Hcy levels caused by down-regulation of hepatic CBS and CGL activity. Thus, HHcy occurs at an early stage in high fat diet-induced NAFLD and is likely to contribute to the increased risk of cardiovascular disease associated with the condition.</p

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

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

p38γ and p38δ regulate postnatal cardiac metabolism through glycogen synthase 1

During the first weeks of postnatal heart development, cardiomyocytes undergo a major adaptive metabolic shift from glycolytic energy production to fatty acid oxidation. This metabolic change is contemporaneous to the up-regulation and activation of the p38γ and p38δ stress-activated protein kinases in the heart. We demonstrate that p38γ/δ contribute to the early postnatal cardiac metabolic switch through inhibitory phosphorylation of glycogen synthase 1 (GYS1) and glycogen metabolism inactivation. Premature induction of p38γ/δ activation in cardiomyocytes of newborn mice results in an early GYS1 phosphorylation and inhibition of cardiac glycogen production, triggering an early metabolic shift that induces a deficit in cardiomyocyte fuel supply, leading to whole-body metabolic deregulation and maladaptive cardiac pathogenesis. Notably, the adverse effects of forced premature cardiac p38γ/δ activation in neonate mice are prevented by maternal diet supplementation of fatty acids during pregnancy and lactation. These results suggest that diet interventions have a potential for treating human cardiac genetic diseases that affect heart metabolism.G.S. is a YIP EMBO member. B.G.T. was a fellow of the FPI Severo Ochoa CNIC program (SVP-2013-067639) and currently is funded by the AHA-CHF (AHA award number: 818798). V.M.R. is a FPI fellow (BES-2014-069332) and A.M.S. is a fellow of the FPI Severo Ochoa CNIC program (BES-2016-077635). This work was funded by the following grants: to G.S.: funding from the EFSD/Lilly European Diabetes Research Programme Dr Sabio, from Spanish Ministry of Science, Innovation and Universities (MINECO-FEDER SAF2016-79126-R and PID2019-104399RB-I00), Comunidad de Madrid (IMMUNOTHERCAN-CM S2010/BMD-2326 and B2017/BMD-3733) and Fundación Jesús Serra; to P.A.: Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT971-16 to P.A.), MCIU/AEI/FEDER, funding from Spanish Ministry of Science, Innovation and Universities (RTI2018-095134-B-100); Excellence Network Grant from MICIU/AEI (SAF2016-81975-REDT and 2018-PN188) to PA and GS; to J.V.: funding from Spanish Ministry of Science, Innovation and Universities (PGC2018-097019-B-I00), the Instituto de Salud Carlos III (Fondo de Investigación Sanitaria grant PRB3 (PT17/0019/0003- ISCIII-SGEFI / ERDF, ProteoRed), and “la Caixa” Banking Foundation (project code HR17-00247); to J.P.B.: funding from Spanish Ministry of Science, Innovation and Universities (PID2019-105699RB-I00, RED2018‐102576‐T) and Escalera de Excelencia (CLU-2017-03); to J.A.E.: funding from Spanish Ministry of Science, Innovation and Universities MINECO (RED2018-102576-T, RTI2018-099357-B-I00), CIBERFES (CB16/10/00282), and HFSP (RGP0016/2018). RAP (XPC/BBV1602 and MIN/RYC1102). The CNIC is supported by the Ministry of Science, Innovation and Universities and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Development and Validation of Hepamet Fibrosis Scoring System-a Simple, Non-invasive Test to Identify Patients With Nonalcoholic Fatty liver Disease With Advanced Fibrosis

BACKGROUND &amp; AIMS: Fibrosis affects prognoses for patients with nonalcoholic fatty liver disease (NAFLD). Several non-invasive scoring systems have aimed to identify patients at risk for advanced fibrosis, but inconclusive results and variations in features of patients (diabetes, obesity and older age) reduce their diagnostic accuracy. We sought to develop a scoring system based on serum markers to identify patients with NAFLD at risk for advanced fibrosis. METHODS: We collected data from 2452 patients with NAFLD at medical centers in Italy, France, Cuba, and China. We developed the Hepamet fibrosis scoring system using demographic, anthropometric, and laboratory test data, collected at time of liver biopsy, from a training cohort of patients from Spain (n=768) and validated the system using patients from Cuba (n=344), Italy (n=288), France (n=830), and China (n=232). Hepamet fibrosis score (HFS) were compared with those of previously developed fibrosis scoring systems (the NAFLD fibrosis score [NFS] and FIB-4). The diagnostic accuracy of the Hepamet fibrosis scoring system was assessed based on area under the receiver operating characteristic (AUROC) curve, sensitivity, specificity, diagnostic odds ratio, and positive and negative predictive values and likelihood ratios. RESULTS: Variables used to determine HFS were patient sex, age, homeostatic model assessment score, presence of diabetes, levels of aspartate aminotransferase, and albumin, and platelet counts; these were independently associated with advanced fibrosis. HFS discriminated between patients with and without advanced fibrosis with an AUROC curve value of 0.85 whereas NFS or FIB-4 did so with AUROC values of 0.80 (P=.0001). In the validation set, cut-off HFS of 0.12 and 0.47 identified patients with and without advanced fibrosis with 97.2% specificity, 74% sensitivity, a 92% negative predictive value, a 76.3% positive predictive value, a 13.22 positive likelihood ratio, and a 0.31 negative likelihood ratio. HFS were not affected by patient age, body mass index, hypertransaminasemia, or diabetes. The Hepamet fibrosis scoring system had the greatest net benefit in identifying patients who should undergo liver biopsy analysis and led to significant improvements in reclassification, reducing the number of patients with undetermined results to 20% from 30% for the FIB-4 and NFS systems (P&lt;.05). CONCLUSIONS: Using clinical and laboratory data from patients with NAFLD, we developed and validated the Hepamet fibrosis scoring system, which identified patients with advanced fibrosis with greater accuracy than the FIB-4 and NFS systems. the Hepamet system provides a greater net benefit for the decision-making process to identify patients who should undergo liver biopsy analysis

Hypothalamic AMPK-ER Stress-JNK1 Axis Mediates the Central Actions of Thyroid Hormones on Energy Balance

Thyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT. The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum(ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPK alpha 1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism. Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism.Peer reviewe

Hypothalamic AMPK-ER Stress-JNK1 Axis Mediates the Central Actions of Thyroid Hormones on Energy Balance

Thyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT. The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum(ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPK alpha 1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism. Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism

Genetics, pathobiology and therapeutic opportunities of polycystic liver disease.

Polycystic liver diseases (PLDs) are inherited genetic disorders characterized by progressive development of intrahepatic, fluid-filled biliary cysts (more than ten), which constitute the main cause of morbidity and markedly affect the quality of life. Liver cysts arise in patients with autosomal dominant PLD (ADPLD) or in co-occurrence with renal cysts in patients with autosomal dominant or autosomal recessive polycystic kidney disease (ADPKD and ARPKD, respectively). Hepatic cystogenesis is a heterogeneous process, with several risk factors increasing the odds of developing larger cysts. Depending on the causative gene, PLDs can arise exclusively in the liver or in parallel with renal cysts. Current therapeutic strategies, mainly based on surgical procedures and/or chronic administration of somatostatin analogues, show modest benefits, with liver transplantation as the only potentially curative option. Increasing research has shed light on the genetic landscape of PLDs and consequent cholangiocyte abnormalities, which can pave the way for discovering new targets for therapy and the design of novel potential treatments for patients. Herein, we provide a critical and comprehensive overview of the latest advances in the field of PLDs, mainly focusing on genetics, pathobiology, risk factors and next-generation therapeutic strategies, highlighting future directions in basic, translational and clinical research

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 in vitro, in vivo 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. In vitro, 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