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Recombinant humanized IgG1 maintain liver triglyceride homeostasis through Arylacetamide deacetylase in ApoE -/- mice. Int Immunopharmacol 2022; 108:108741. [PMID: 35397394 DOI: 10.1016/j.intimp.2022.108741] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/11/2022] [Accepted: 03/28/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND & AIMS Hyperlipidemia is a lipid metabolism disorder associated with elevated serum triglyceride (TG) and/or cholesterol. Over the years, studies have shown that hyperlipidemia is associated with combordities, incluing diabetes and obesity, gradually becoming a public health concern. Current treatment approaches remain limited due to the lack of effective drugs. Here we investigated the function of recombinant humanized IgG1 in maintaining liver TG homeostasis and the underlying mechanisms. METHODS ApoE-/- mice were fed a high-fat diet (HFD) for 20 weeks to induce hyperlipidemia. RNA sequencing (RNA-Seq) was performed to identify differences in gene expression in different groups of ApoE-/- mice liver. In vitro lipid accumulation in primary mouse hepatocytes was induced using a free fatty acid (FFA) mixture. Gene and protein expression were assessed in primary mouse hepatocytes by qPCR and Western blot. Gene reporter assays and ChIP-PCR were used to determine arylacetamide deacetylase (Aadac) promoter activity. RESULTS Recombinant humanized IgG1 could significantly decrease the serum level of TG and low-density lipoproteins (LDL-C). Moreover, hepatic TG and lipid droplets were also reduced compared to the HFD group. Mouse liver RNA-Seq revealed that administration of recombinant humanized IgG1 significantly elevated the expression of Aadac. In vitro, knock-down of Aadac could nullify the effect of recombinant humanized IgG1 on decreasing the lipid droplets induced by FFA in primary mouse hepatocytes. Gene Reporter assays and ChIP-PCR demonstrated that the foxa1 response element in the Aadac promoter played a key role in Aadac expression induced by recombinant humanized IgG1. Moreover, recombinant humanized IgG1 repressed phosphorylation of PKCδ and resulted in foxa1 elevation. Finally, neonatal Fc receptor (FcRn) knock-down reversed the effect of recombinant humanized IgG1 on the expression of PKCδ phosphorylation, foxa1 and Aadac. CONCLUSIONS Our findings suggest that recombinant humanized IgG1 plays an important role in maintaining liver TG homeostasis via the FcRn/PKCδ/foxa1/Aadac pathway.
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Yin H, Shi A, Wu J. Platelet-Activating Factor Promotes the Development of Non-Alcoholic Fatty Liver Disease. Diabetes Metab Syndr Obes 2022; 15:2003-2030. [PMID: 35837578 PMCID: PMC9275506 DOI: 10.2147/dmso.s367483] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/28/2022] [Indexed: 11/23/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a multifaceted clinicopathological syndrome characterised by excessive hepatic lipid accumulation that causes steatosis, excluding alcoholic factors. Platelet-activating factor (PAF), a biologically active lipid transmitter, induces platelet activation upon binding to the PAF receptor. Recent studies have found that PAF is associated with gamma-glutamyl transferase, which is an indicator of liver disease. Moreover, PAF can stimulate hepatic lipid synthesis and cause hypertriglyceridaemia. Furthermore, the knockdown of the PAF receptor gene in the animal models of NAFLD helped reduce the inflammatory response, improve glucose homeostasis and delay the development of NAFLD. These findings suggest that PAF is associated with NAFLD development. According to reports, patients with NAFLD or animal models have marked platelet activation abnormalities, mainly manifested as enhanced platelet adhesion and aggregation and altered blood rheology. Pharmacological interventions were accompanied by remission of abnormal platelet activation and significant improvement in liver function and lipids in the animal model of NAFLD. These confirm that platelet activation may accompany a critical importance in NAFLD development and progression. However, how PAFs are involved in the NAFLD signalling pathway needs further investigation. In this paper, we review the relevant literature in recent years and discuss the role played by PAF in NAFLD development. It is important to elucidate the pathogenesis of NAFLD and to find effective interventions for treatment.
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Affiliation(s)
- Hang Yin
- Key Laboratory of Microcosmic Syndrome Differentiation, Yunnan University of Chinese Medicine, Kunming, People’s Republic of China
| | - Anhua Shi
- Key Laboratory of Microcosmic Syndrome Differentiation, Yunnan University of Chinese Medicine, Kunming, People’s Republic of China
| | - Junzi Wu
- Key Laboratory of Microcosmic Syndrome Differentiation, Yunnan University of Chinese Medicine, Kunming, People’s Republic of China
- Correspondence: Junzi Wu; Anhua Shi, Key Laboratory of Microcosmic Syndrome Differentiation, Yunnan University of Chinese Medicine, Kunming, People’s Republic of China, Tel/Fax +86 187 8855 7524; +86 138 8885 0813, Email ;
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3
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Koh EH, Yoon JE, Ko MS, Leem J, Yun JY, Hong CH, Cho YK, Lee SE, Jang JE, Baek JY, Yoo HJ, Kim SJ, Sung CO, Lim JS, Jeong WI, Back SH, Baek IJ, Torres S, Solsona-Vilarrasa E, Conde de la Rosa L, Garcia-Ruiz C, Feldstein AE, Fernandez-Checa JC, Lee KU. Sphingomyelin synthase 1 mediates hepatocyte pyroptosis to trigger non-alcoholic steatohepatitis. Gut 2021; 70:1954-1964. [PMID: 33208407 PMCID: PMC8458090 DOI: 10.1136/gutjnl-2020-322509] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Lipotoxic hepatocyte injury is a primary event in non-alcoholic steatohepatitis (NASH), but the mechanisms of lipotoxicity are not fully defined. Sphingolipids and free cholesterol (FC) mediate hepatocyte injury, but their link in NASH has not been explored. We examined the role of free cholesterol and sphingomyelin synthases (SMSs) that generate sphingomyelin (SM) and diacylglycerol (DAG) in hepatocyte pyroptosis, a specific form of programmed cell death associated with inflammasome activation, and NASH. DESIGN Wild-type C57BL/6J mice were fed a high fat and high cholesterol diet (HFHCD) to induce NASH. Hepatic SMS1 and SMS2 expressions were examined in various mouse models including HFHCD-fed mice and patients with NASH. Pyroptosis was estimated by the generation of the gasdermin-D N-terminal fragment. NASH susceptibility and pyroptosis were examined following knockdown of SMS1, protein kinase Cδ (PKCδ), or the NLR family CARD domain-containing protein 4 (NLRC4). RESULTS HFHCD increased the hepatic levels of SM and DAG while decreasing the level of phosphatidylcholine. Hepatic expression of Sms1 but not Sms2 was higher in mouse models and patients with NASH. FC in hepatocytes induced Sms1 expression, and Sms1 knockdown prevented HFHCD-induced NASH. DAG produced by SMS1 activated PKCδ and NLRC4 inflammasome to induce hepatocyte pyroptosis. Depletion of Nlrc4 prevented hepatocyte pyroptosis and the development of NASH. Conditioned media from pyroptotic hepatocytes activated the NOD-like receptor family pyrin domain containing 3 inflammasome (NLRP3) in Kupffer cells, but Nlrp3 knockout mice were not protected against HFHCD-induced hepatocyte pyroptosis. CONCLUSION SMS1 mediates hepatocyte pyroptosis through a novel DAG-PKCδ-NLRC4 axis and holds promise as a therapeutic target for NASH.
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Affiliation(s)
- Eun Hee Koh
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Ji Eun Yoon
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Myoung Seok Ko
- Biomedical Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Jaechan Leem
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Ji-Young Yun
- Biomedical Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Chung Hwan Hong
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Yun Kyung Cho
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Seung Eun Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Jung Eun Jang
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Ji Yeon Baek
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Hyun Ju Yoo
- The Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Su Jung Kim
- The Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Chang Ohk Sung
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Joon Seo Lim
- Clinical Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Won-Il Jeong
- Laboratory of Liver Research, Graduate School of Medical Science and Engineering, KAIST, Daejeon, South Korea
| | - Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, South Korea
| | - In-Jeoung Baek
- The Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Sandra Torres
- Department of Cell Death and Proliferation, Instituto Investigaciones Biomédicas de Barcelona (IIBB), CSIC, Barcelona, Spain and Liver Unit-IDIBAPS and Centro de Investigación Biomédica en Red (CIBERehd), Barcelona, Spain
| | - Estel Solsona-Vilarrasa
- Department of Cell Death and Proliferation, Instituto Investigaciones Biomédicas de Barcelona (IIBB), CSIC, Barcelona, Spain and Liver Unit-IDIBAPS and Centro de Investigación Biomédica en Red (CIBERehd), Barcelona, Spain
| | - Laura Conde de la Rosa
- Department of Cell Death and Proliferation, Instituto Investigaciones Biomédicas de Barcelona (IIBB), CSIC, Barcelona, Spain and Liver Unit-IDIBAPS and Centro de Investigación Biomédica en Red (CIBERehd), Barcelona, Spain
| | - Carmen Garcia-Ruiz
- Department of Cell Death and Proliferation, Instituto Investigaciones Biomédicas de Barcelona (IIBB), CSIC, Barcelona, Spain and Liver Unit-IDIBAPS and Centro de Investigación Biomédica en Red (CIBERehd), Barcelona, Spain,University of Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ariel E Feldstein
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
| | - Jose C Fernandez-Checa
- Department of Cell Death and Proliferation, Instituto Investigaciones Biomédicas de Barcelona (IIBB), CSIC, Barcelona, Spain and Liver Unit-IDIBAPS and Centro de Investigación Biomédica en Red (CIBERehd), Barcelona, Spain .,University of Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ki-Up Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
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Pérez-Rodriguez S, Wulff T, Voldborg BG, Altamirano C, Trujillo-Roldán MA, Valdez-Cruz NA. Compartmentalized Proteomic Profiling Outlines the Crucial Role of the Classical Secretory Pathway during Recombinant Protein Production in Chinese Hamster Ovary Cells. ACS OMEGA 2021; 6:12439-12458. [PMID: 34056395 PMCID: PMC8154153 DOI: 10.1021/acsomega.0c06030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/24/2021] [Indexed: 05/11/2023]
Abstract
Different cellular processes that contribute to protein production in Chinese hamster ovary (CHO) cells have been previously investigated by proteomics. However, although the classical secretory pathway (CSP) has been well documented as a bottleneck during recombinant protein (RP) production, it has not been well represented in previous proteomic studies. Hence, the significance of this pathway for production of RP was assessed by identifying its own proteins that were associated to changes in RP production, through subcellular fractionation coupled to shot-gun proteomics. Two CHO cell lines producing a monoclonal antibody with different specific productivities were used as cellular models, from which 4952 protein groups were identified, which represent a coverage of 59% of the Chinese hamster proteome. Data are available via ProteomeXchange with identifier PXD021014. By using SAM and ROTS algorithms, 493 proteins were classified as differentially expressed, of which about 80% was proposed as novel targets and one-third were assigned to the CSP. Endoplasmic reticulum (ER) stress, unfolded protein response, calcium homeostasis, vesicle traffic, glycosylation, autophagy, proteasomal activity, protein synthesis and translocation into ER lumen, and secretion of extracellular matrix components were some of the affected processes that occurred in the secretory pathway. Processes from other cellular compartments, such as DNA replication, transcription, cytoskeleton organization, signaling, and metabolism, were also modified. This study gives new insights into the molecular traits of higher producer cells and provides novel targets for development of new sub-lines with improved phenotypes for RP production.
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Affiliation(s)
- Saumel Pérez-Rodriguez
- Programa
de Investigación de Producción de Biomoléculas,
Departamento de Biología Molecular y Biotecnología,
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán 04510 Ciudad de
México, México
| | - Tune Wulff
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Bjørn G. Voldborg
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Claudia Altamirano
- Laboratorio
de Cultivos Celulares, Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2085 Valparaíso, Chile
| | - Mauricio A. Trujillo-Roldán
- Programa
de Investigación de Producción de Biomoléculas,
Departamento de Biología Molecular y Biotecnología,
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán 04510 Ciudad de
México, México
| | - Norma A. Valdez-Cruz
- Programa
de Investigación de Producción de Biomoléculas,
Departamento de Biología Molecular y Biotecnología,
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán 04510 Ciudad de
México, México
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Jobira B, Frank DN, Silveira LJ, Pyle L, Kelsey MM, Garcia-Reyes Y, Robertson CE, Ir D, Nadeau KJ, Cree-Green M. Hepatic steatosis relates to gastrointestinal microbiota changes in obese girls with polycystic ovary syndrome. PLoS One 2021; 16:e0245219. [PMID: 33465100 PMCID: PMC7815089 DOI: 10.1371/journal.pone.0245219] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/23/2020] [Indexed: 02/06/2023] Open
Abstract
Objective Hepatic steatosis (HS) is common in adolescents with obesity and polycystic ovary syndrome (PCOS). Gut microbiota are altered in adults with obesity, HS, and PCOS, which may worsen metabolic outcomes, but similar data is lacking in youth. Methods Thirty-four adolescents with PCOS and obesity underwent stool and fasting blood collection, oral glucose tolerance testing, and MRI for hepatic fat fraction (HFF). Fecal bacteria were profiled by high-throughput 16S rRNA gene sequencing. Results 50% had HS (N = 17, age 16.2±1.5 years, BMI 38±7 kg/m2, HFF 9.8[6.5, 20.7]%) and 50% did not (N = 17, age 15.8±2.2 years, BMI 35±4 kg/m2, HFF 3.8[2.6, 4.4]%). The groups showed no difference in bacterial α-diversity (richness p = 0.202; evenness p = 0.087; and diversity p = 0.069) or global difference in microbiota (β-diversity). Those with HS had lower % relative abundance (%RA) of Bacteroidetes (p = 0.013), Bacteroidaceae (p = 0.009), Porphyromonadaceae (p = 0.011), and Ruminococcaceae (p = 0.008), and higher Firmicutes:Bacteroidetes (F:B) ratio (47.8% vs. 4.3%, p = 0.018) and Streptococcaceae (p = 0.034). Bacterial taxa including phyla F:B ratio, Bacteroidetes, and family Bacteroidaceae, Ruminococcaceae and Porphyromonadaceae correlated with metabolic markers. Conclusions Obese adolescents with PCOS and HS have differences in composition of gut microbiota, which correlate with metabolic markers, suggesting a modifying role of gut microbiota in HS and PCOS.
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Affiliation(s)
- Beza Jobira
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Medicine, Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Daniel N. Frank
- Department of Medicine, Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Lori J. Silveira
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado, United States of America
| | - Laura Pyle
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado, United States of America
| | - Megan M. Kelsey
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Center for Women’s Health Research, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Yesenia Garcia-Reyes
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Charles E. Robertson
- Department of Medicine, Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Diana Ir
- Department of Medicine, Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Kristen J. Nadeau
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Center for Women’s Health Research, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Melanie Cree-Green
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Center for Women’s Health Research, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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Rives C, Fougerat A, Ellero-Simatos S, Loiseau N, Guillou H, Gamet-Payrastre L, Wahli W. Oxidative Stress in NAFLD: Role of Nutrients and Food Contaminants. Biomolecules 2020; 10:E1702. [PMID: 33371482 PMCID: PMC7767499 DOI: 10.3390/biom10121702] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is often the hepatic expression of metabolic syndrome and its comorbidities that comprise, among others, obesity and insulin-resistance. NAFLD involves a large spectrum of clinical conditions. These range from steatosis, a benign liver disorder characterized by the accumulation of fat in hepatocytes, to non-alcoholic steatohepatitis (NASH), which is characterized by inflammation, hepatocyte damage, and liver fibrosis. NASH can further progress to cirrhosis and hepatocellular carcinoma. The etiology of NAFLD involves both genetic and environmental factors, including an unhealthy lifestyle. Of note, unhealthy eating is clearly associated with NAFLD development and progression to NASH. Both macronutrients (sugars, lipids, proteins) and micronutrients (vitamins, phytoingredients, antioxidants) affect NAFLD pathogenesis. Furthermore, some evidence indicates disruption of metabolic homeostasis by food contaminants, some of which are risk factor candidates in NAFLD. At the molecular level, several models have been proposed for the pathogenesis of NAFLD. Most importantly, oxidative stress and mitochondrial damage have been reported to be causative in NAFLD initiation and progression. The aim of this review is to provide an overview of the contribution of nutrients and food contaminants, especially pesticides, to oxidative stress and how they may influence NAFLD pathogenesis.
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Affiliation(s)
- Clémence Rives
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Anne Fougerat
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Sandrine Ellero-Simatos
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Nicolas Loiseau
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Hervé Guillou
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Laurence Gamet-Payrastre
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
| | - Walter Wahli
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, EVT, INP-Purpan, UPS, 31300 Toulouse, France; (C.R.); (A.F.); (S.E.-S.); (N.L.); (H.G.)
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Clinical Sciences Building, 11 Mandalay Road, Singapore 308232, Singapore
- Center for Integrative Genomics, Université de Lausanne, Le Génopode, CH-1015 Lausanne, Switzerland
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7
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Yang M, Chen Z, Xiang S, Xia F, Tang W, Yao X, Zhou B. Hugan Qingzhi medication ameliorates free fatty acid-induced L02 hepatocyte endoplasmic reticulum stress by regulating the activation of PKC-δ. BMC Complement Med Ther 2020; 20:377. [PMID: 33308192 PMCID: PMC7730760 DOI: 10.1186/s12906-020-03164-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022] Open
Abstract
Background Previous studies have found that Hugan Qingzhi tablet (HQT) has significant lipid-lowering and antioxidant effects on non-alcoholic fatty liver disease (NAFLD). Moreover, the results of proteomic analysis confirmed that various proteins in endoplasmic reticulum stress (ERS) pathway were activated and recovered by HQT. However, its mechanism remains confused. The purpose of this study was to explore the effects of HQT-medicated serum on hepatic ERS and its relevant mechanisms. Methods L02 cells were induced by Free Fatty Acid (FFA) for 24 h to establish a model of hepatic ERS and pretreated with the drug-medicated rat serum for 24 h. Accumulation of intracellular lipid was evaluated using Oil Red O staining and Triglyceride detection kit. The morphological changes of ER were observed by TEM. PKC-δ was silenced by specific siRNA. Western blot and RT-qPCR were applied to detect the expression of markers related to ERS, calcium disorder, steatosis and insulin resistance. The fluorescence of Ca2+ influx was recorded using fluorescence spectrophotometer. Results HQT-medicated serum significantly decreased the intracellular TG content. Furthermore, it caused significant reduction in the expression of ERS markers and an improvement in ER structure of L02 cells. PKC-δ was activated into phosphorylated PKC-δ in FFA-induced L02 hepatocytes while these changes can be reversed by HQT-medicated serum. Silencing PKC-δ in L02 cells can restore the expression and activity of SERCA2 in ER and down-regulate the expression of IP3R protein to maintain intracellular calcium homeostasis, so as to relieve FFA-induced ERS and its lipid accumulation and insulin resistance. Conclusions The results concluded that HQT-medicated serum exerts protective effects against hepatic ERS, steatosis and insulin resistance in FFA-induced L02 hepatocyte. And its potential mechanism might be down-regulating the activation of PKC-δ and stabilization of intracellular calcium. Supplementary Information The online version contains supplementary material available at 10.1186/s12906-020-03164-3.
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Affiliation(s)
- Miaoting Yang
- Department of Pharmacy, People's Hospital of Longhua, Shenzhen, 518109, Guangdong, China
| | - Zhijuan Chen
- Department of Pharmacy, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, Guangdong, China
| | - Shijian Xiang
- Department of Pharmacy, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, Guangdong, China
| | - Fan Xia
- Department of Pharmacy, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, Guangdong, China
| | - Waijiao Tang
- Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, Guangdong, China
| | - Xiaorui Yao
- Department of Pharmacy, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, 515041, Guangdong, China
| | - Benjie Zhou
- Department of Pharmacy, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107, Guangdong, China.
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Kojima M, Takahashi H, Kuwashiro T, Tanaka K, Mori H, Ozaki I, Kitajima Y, Matsuda Y, Ashida K, Eguchi Y, Anzai K. Glucagon-Like Peptide-1 Receptor Agonist Prevented the Progression of Hepatocellular Carcinoma in a Mouse Model of Nonalcoholic Steatohepatitis. Int J Mol Sci 2020; 21:ijms21165722. [PMID: 32785012 PMCID: PMC7460814 DOI: 10.3390/ijms21165722] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/16/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonists are used to treat diabetes, but their effects on nonalcoholic steatohepatitis (NASH) and the development of hepatocellular carcinoma (HCC) remain unclear. In this study, mice with streptozotocin- and high-fat diet-induced diabetes and NASH were subcutaneously treated with liraglutide or saline (control) for 14 weeks. Glycemic control, hepatocarcinogenesis, and liver histology were compared between the groups. Fasting blood glucose levels were significantly lower in the liraglutide group than in the control group (210.0 ± 17.3 mg/dL vs. 601.8 ± 123.6 mg/dL), and fasting insulin levels were significantly increased by liraglutide (0.18 ± 0.06 ng/mL vs. 0.09 ± 0.03 ng/mL). Liraglutide completely suppressed hepatocarcinogenesis, whereas HCC was observed in all control mice (average tumor count, 5.5 ± 3.87; average tumor size, 8.1 ± 5.0 mm). Liraglutide significantly ameliorated steatosis, inflammation, and hepatocyte ballooning of non-tumorous lesions in the liver compared with the control findings, and insulin-positive β-cells were observed in the pancreas in liraglutide-treated mice but not in control mice. In conclusion, liraglutide ameliorated NASH and suppressed hepatocarcinogenesis in diabetic mice. GLP-1 receptor agonists can be used to improve the hepatic outcome of diabetes.
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Affiliation(s)
- Motoyasu Kojima
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
| | - Hirokazu Takahashi
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Liver Center, Saga University Hospital, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Takuya Kuwashiro
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
| | - Kenichi Tanaka
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
| | - Hitoe Mori
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
| | - Iwata Ozaki
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
| | - Yoichiro Kitajima
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Department of Radiology, Eguchi Hospital, Ogi 845-0032, Japan
| | - Yayoi Matsuda
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kenji Ashida
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Yuichiro Eguchi
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Liver Center, Saga University Hospital, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Keizo Anzai
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (M.K.); (H.T.); (T.K.); (K.T.); (H.M.); (I.O.); (Y.K.); (Y.M.); (K.A.); (Y.E.)
- Correspondence: ; Tel./Fax: +81-952-34-2362
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9
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Ishikawa T, Suwanai H, Shikuma J, Suzuki R, Yamanaka T, Odawara M, Inazu M. Protein kinase C promotes choline transporter‑like protein 1 function via improved cell surface expression in immortalized human hepatic cells. Mol Med Rep 2019; 21:777-785. [PMID: 31974614 PMCID: PMC6947888 DOI: 10.3892/mmr.2019.10894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022] Open
Abstract
Choline is used to synthesize phospholipids and a lack of choline induces a number of liver-related diseases, including non-alcoholic steatohepatitis. The current study characterized the choline uptake system, at molecular and functional levels, in the immortalized human hepatic cell line, Fa2N-4, to identify the specific choline transporter involved in choline uptake. The present study also assesed whether choline deficiency or the inhibited choline uptake affected cell viability and apoptosis. Reverse transcription-quantitative polymerase chain reaction (PCR) revealed choline transporter-like protein 1 (CTL1) and CTL2 mRNA and protein expression in Fa2N-4 cells. [Methyl-3H]choline studies revealed choline uptake was saturable and mediated by a single transport system that functioned in a Na+-independent but pH-dependent manner, which was similar to CTL1. Hemicholinium-3 (HC-3), which is a choline uptake inhibitor, and choline deficiency inhibited cell viability, increased caspase-3 and −7 activities, and increased fluorescein isothiocyanate-Annexin V immunofluorescent staining indicated apoptosis. Immunofluorescent staining also revealed CTL1 and CTL2 localized in plasma and mitochondrial membranes, respectively. [Methyl-3H]choline uptake was enhanced by a protein kinase C (PKC) activator, phorbol-12-myristate 13-acetate (PMA). Immunofluorescence staining and western blot analysis demonstrated increased CTL1 expression on the cell membrane following PMA treatment. The results of current study indicated that extracellular choline is primarily transported via CTL1, relying on a direct H+ gradient that functions as a driving force in Fa2N-4 cells. Furthermore, it was hypothesized that CTL1 and the choline uptake system are strongly associated with cell survival, and that the choline uptake system is modulated by PKC signaling via increased CTL1 expression on the cell surface. These findings provide further insights into the pathogenesis of liver disease involving choline metabolism.
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Affiliation(s)
- Takuya Ishikawa
- Department of Diabetes, Metabolism and Endocrinology, Tokyo Medical University, Tokyo 160‑0023, Japan
| | - Hirotsugu Suwanai
- Department of Diabetes, Metabolism and Endocrinology, Tokyo Medical University, Tokyo 160‑0023, Japan
| | - Junpei Shikuma
- Department of Diabetes, Metabolism and Endocrinology, Tokyo Medical University, Tokyo 160‑0023, Japan
| | - Ryo Suzuki
- Department of Diabetes, Metabolism and Endocrinology, Tokyo Medical University, Tokyo 160‑0023, Japan
| | - Tsuyoshi Yamanaka
- Department of Molecular Preventive Medicine, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Masato Odawara
- Department of Diabetes, Metabolism and Endocrinology, Tokyo Medical University, Tokyo 160‑0023, Japan
| | - Masato Inazu
- Department of Molecular Preventive Medicine, Tokyo Medical University, Tokyo 160‑8402, Japan
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10
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Ali ES, Rychkov GY, Barritt GJ. Deranged hepatocyte intracellular Ca 2+ homeostasis and the progression of non-alcoholic fatty liver disease to hepatocellular carcinoma. Cell Calcium 2019; 82:102057. [PMID: 31401389 DOI: 10.1016/j.ceca.2019.102057] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/29/2019] [Accepted: 07/01/2019] [Indexed: 12/12/2022]
Abstract
Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths in men, and the sixth in women. Non-alcoholic fatty liver disease (NAFLD) is now one of the major risk factors for HCC. NAFLD, which involves the accumulation of excess lipid in cytoplasmic lipid droplets in hepatocytes, can progress to non-alcoholic steatosis, fibrosis, and HCC. Changes in intracellular Ca2+ constitute important signaling pathways for the regulation of lipid and carbohydrate metabolism in normal hepatocytes. Recent studies of steatotic hepatocytes have identified lipid-induced changes in intracellular Ca2+, and have provided evidence that altered Ca2+ signaling exacerbates lipid accumulation and may promote HCC. The aims of this review are to summarise current knowledge of the lipid-induced changes in hepatocyte Ca2+ homeostasis, to comment on the mechanisms involved, and discuss the pathways leading from altered Ca2+ homeostasis to enhanced lipid accumulation and the potential promotion of HCC. In steatotic hepatocytes, lipid inhibits store-operated Ca2+ entry and SERCA2b, and activates Ca2+ efflux from the endoplasmic reticulum (ER) and its transfer to mitochondria. These changes are associated with changes in Ca2+ concentrations in the ER (decreased), cytoplasmic space (increased) and mitochondria (likely increased). They lead to: inhibition of lipolysis, lipid autophagy, lipid oxidation, and lipid secretion; activation of lipogenesis; increased lipid; ER stress, generation of reactive oxygen species (ROS), activation of Ca2+/calmodulin-dependent kinases and activation of transcription factor Nrf2. These all can potentially mediate the transition of NAFLD to HCC. It is concluded that lipid-induced changes in hepatocyte Ca2+ homeostasis are important in the initiation and progression of HCC. Further research is desirable to better understand the cause and effect relationships, the time courses and mechanisms involved, and the potential of Ca2+ transporters, channels, and binding proteins as targets for pharmacological intervention.
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Affiliation(s)
- Eunus S Ali
- Department of Medical Biochemistry, College of Medicine and Public Health, Flinders University, Adelaide, South Australia, 5001, Australia
| | - Grigori Y Rychkov
- School of Medicine, The University of Adelaide, and South Australian Health and Medical Research Institute, Adelaide, South Australia, 5005, Australia
| | - Greg J Barritt
- Department of Medical Biochemistry, College of Medicine and Public Health, Flinders University, Adelaide, South Australia, 5001, Australia.
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11
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He J, Ding J, Lai Q, Wang X, Li A, Liu S. Irbesartan Ameliorates Lipid Deposition by Enhancing Autophagy via PKC/AMPK/ULK1 Axis in Free Fatty Acid Induced Hepatocytes. Front Physiol 2019; 10:681. [PMID: 31191364 PMCID: PMC6548903 DOI: 10.3389/fphys.2019.00681] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/13/2019] [Indexed: 01/17/2023] Open
Abstract
Irbesartan has shown significant therapeutic effects in hypertensive patients with non-alcoholic fatty liver disease (NAFLD). To determine the underlying mechanisms of its action, we established an in vitro model of NAFLD by treating human and mouse hepatocytes with free fatty acids (FFAs) and angiotensin (Ang) II. Irbesartan significantly reversed AngII/FFA-induced lipid deposition and mitochondrial dysfunction by restoring ATP production and the mitochondrial membrane potential (MMP), and decreasing the levels of reactive oxygen species (ROS) and inflammatory markers. In addition, irbesartan also increased the autophagy flux, in terms of increased numbers of autolysosomes and autophagosomes, and the upregulation and mitochondrial localization of the autophagic proteins Atg5 and LC3BII/I. Activation of protein kinase C (PKC) and inhibition of the autophagic flux exacerbated mitochondrial dysfunction in the steatotic hepatocytes. Furthermore, AngII upregulated PKC which inhibited AMPK phosphorylation via direct interaction with the AngII receptor AT1-R. Irbesartan inhibited PKC and activated AMPK and its downstream effector ULK1, thereby inducing autophagy, decreasing lipid deposition, and restoring mitochondrial function. Taken together, irbesartan triggers autophagy via the PKC/AMPK/ULK1 axis to ameliorate the pathological changes in the steatotic hepatocytes.
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Affiliation(s)
- Juan He
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jian Ding
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qiuhua Lai
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xinke Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Aimin Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Side Liu
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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12
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Ali ES, Petrovsky N. Calcium Signaling As a Therapeutic Target for Liver Steatosis. Trends Endocrinol Metab 2019; 30:270-281. [PMID: 30850262 DOI: 10.1016/j.tem.2019.02.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 02/06/2019] [Accepted: 02/07/2019] [Indexed: 12/13/2022]
Abstract
Hepatic steatosis, the first step in nonalcoholic fatty liver disease (NAFLD), can arise from various pathophysiological conditions. While lipid metabolism in the liver is normally balanced such that there is no excessive lipid accumulation, when this homeostasis is disrupted lipid droplets (LDs) accumulate in hepatocytes resulting in cellular toxicity. The mechanisms underlying this accumulation and the subsequent hepatocellular damage are multifactorial and poorly understood, with the result that there are no currently approved treatments for NAFLD. Impaired calcium signaling has recently been identified as a cause of increased endoplasmic reticulum (ER) stress contributing to hepatic lipid accumulation. This review highlights new findings on the role of impaired Ca2+ signaling in the development of steatosis and discusses potential new approaches to NAFLD treatment based on these new insights.
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Affiliation(s)
- Eunüs S Ali
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Nikolai Petrovsky
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia; Vaxine Pty Ltd, 11 Walkley Avenue, Warradale, Adelaide, SA, Australia.
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13
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杨 妙, 陈 芝, 肖 淳, 唐 外, 周 本. [Effects of sera of rats fed with Huganqingzhi tablets on endoplasmic reticulum stress in a HepG2 cell model of nonalcoholic fatty liver disease]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2018; 38:1277-1287. [PMID: 30514673 PMCID: PMC6744118 DOI: 10.12122/j.issn.1673-4254.2018.11.01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the effects of sera from rats fed with Huganqingzhi tablets (HGT) on endoplasmic reticulum (ER) stress in a steatotic hepatocyte model of free fatty acids (FFAs)-induced nonalcoholic fatty liver disease (NAFLD) and explore the possible mechanism. METHODS FFAs prepared by mixing oleic acid and palmitic acid at the ratio of 2:1. HepG2 cells were treated with the sera from rats fed with low-, moderate-or high-dose HGT (HGT sera) or sera of rats fed with fenofibrate (fenofibrate sera), followed by treatment with 1 mmol/L FFAs for 24 h to induce hepatic steatosis. Oil red O staining was used to observe the distribution of lipid droplets in the cells. The biochemical parameters including triglyceride (TG), lactated hydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured using a commercial kit. The morphological changes of the ER in the cells were observed using transmission electron microscopy. The protein/mRNA expressions of ER stress-related signal molecules including GRP78, PERK, p-PERK, ATF6, ATF4, CASPASE-12, CHOP, XBP-1, PKC, and p-PKC-δ were detected using Western blotting and/or quantitative real-time PCR (qRT-PCR). The changes in the protein expressions of GRP78, p-PERK, CASPASE-12 and CHOP were also detected in cells with transient transfection of PKC-δ siRNA for PKC-δ knockdown. RESULTS Compared with the control cells, the cells treated with FFAs showed significantly increased levels of TG, AST, and ALT (P < 0.05). Compared with FFAs-treated cells, the cells pretreated with HGT sera or fenofibrate sera all showed significantly decreased TG, AST and ALT levels (P < 0.05), reduced accumulation of the lipid droplets (P < 0.05), and lowered protein or mRNA expression levels of GRP78, p-PERK, ATF6, ATF4, CHOP, CASPASE-12, XBP-1 and p-PKC-δ (P < 0.05). PKC-δ knockdown caused significantly reduced protein expressions of GRP78, p-PERK, CASPASE-12 and CHOP in the cells with FFA-induced hepatic steatosis (P < 0.001); treatment with high-dose HGT serum more significantly reduced the expressions of GRP78 (P < 0.001) and P-PERK (P < 0.01) in FFAs-induced cells with PKC-δ knockdown. CONCLUSIONS HGT serum can effectively prevent FFAs-induced steatosis in HepG2 cells by alleviating ER stress, in which PKC-δ may act as an important target.
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Affiliation(s)
- 妙婷 杨
- 南方医科大学珠江医院药学部,广东 广州 510282Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - 芝娟 陈
- 南方医科大学珠江医院药学部,广东 广州 510282Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - 淳欣 肖
- 深圳市贝美药业有限公司,广东 深圳 518057Shenzhen Beimei Pharmaceutical Co., Ltd, Shenzhen 518057, China
| | - 外姣 唐
- 南方医科大学珠江医院药学部,广东 广州 510282Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - 本杰 周
- 南方医科大学珠江医院药学部,广东 广州 510282Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
- 中山大学附属第七医院药学部,广东 深圳 518017Department of Pharmacy, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518017, China
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14
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Mai HN, Lee SH, Sharma G, Kim DJ, Sharma N, Shin EJ, Pham DT, Trinh QD, Jang CG, Nah SY, Jeong JH, Kim HC. Protein kinase Cδ knockout mice are protected from cocaine-induced hepatotoxicity. Chem Biol Interact 2018; 297:95-108. [PMID: 30393195 DOI: 10.1016/j.cbi.2018.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/09/2018] [Accepted: 10/22/2018] [Indexed: 12/25/2022]
Abstract
We investigated whether protein kinase Cδ (PKCδ) mediates cocaine-induced hepatotoxicity in mice. Cocaine treatment (60 mg/kg, i.p.) significantly increased cleaved PKCδ expression in the liver of wild-type (WT) mice, and led to significant increases in oxidative parameters (i.e., reactive oxygen species, 4-hydroxylnonenal and protein carbonyl). These cocaine-induced oxidative burdens were attenuated by pharmacological (i.e., rottlerin) or genetic depletion of PKCδ. We also demonstrated that treatment with cocaine resulted in significant increases in nuclear factor erythroid-2-related factor 2 (Nrf-2) nuclear translocation and increased Nrf-2 DNA-binding activity in wild-type (WT) mice. These increases were more pronounced in the rottlerin-treated WT or PKCδ knockout mice than in the saline-treated WT mice. Although cocaine treatment increased Nrf-2 nuclear translocation, DNA binding activity, and γ-glutamyl cysteine ligases (i.e., GCLc and GCLm) mRNA expressions, while it reduced the glutathione level and GSH/GSSG ratio. These decreases were attenuated by PKCδ depletion. Cocaine treatment significantly increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the serum of WT mice signifying the hepatic damage. These increases were also attenuated by PKCδ depletion. In addition, cocaine-induced hepatic degeneration in WT mice was evident 1 d post-cocaine. At that time, cocaine treatment decreased Bcl-2 and Bcl-xL levels, and increased Bax, cytosolic cytochrome c, and cleaved caspase-3 levels. Pharmacological or genetic depletion of PKCδ significantly ameliorated the pro-apoptotic properties and hepatic degeneration. Therefore, our results suggest that inhibition of PKCδ, as well as activation of Nrf-2, is important for protecting against hepatotoxicity induced by cocaine.
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Affiliation(s)
- Huynh Nhu Mai
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Sung Hoon Lee
- Department of Pharmacology, College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Garima Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Dae-Joong Kim
- Department of Anatomy and Cell Biology, Medical School, Kangwon National University, Chunchon, 24341, Republic of Korea.
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Duc Toan Pham
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Quynh Dieu Trinh
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
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15
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Pei E, Liu Y, Jiang W, Lin S, Huang L, Lin M, Cai L. Sleeve gastrectomy attenuates high fat diet-induced non-alcoholic fatty liver disease. Lipids Health Dis 2018; 17:243. [PMID: 30355361 PMCID: PMC6201512 DOI: 10.1186/s12944-018-0875-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/26/2018] [Indexed: 02/08/2023] Open
Abstract
Background A high-fat diet (HFD) is known to lead to obesity, and contributes to the progression of non-alcoholic fatty liver disease. The objective of this study was to evaluate the effects of sleeve gastrectomy (SG) on the progression of HFD-induced hepatic steatosis. Methods Fifteen 4-week-old, male Wistar rats were randomly assigned into three groups: NC, HFD + SHAM and HFD + SG. Their body weight, glucose-lipid metabolism, inflammation indices, hepatic steatosis and fibroblast growth factor 21 (FGF21) levels were measured. Results Postoperatively, body weights in the HFD + SHAM and HFD + SG group rats decreased during the first week. Thereafter, HFD + SG rats regained their body weight. Differences in insulin, homeostasis model assessment of insulin resistance, triglyceride, free fatty acid, tumor necrosis factor-α and monocyte chemotactic protein-1 levels were statistically significant across the three groups (all P < 0.05). Interestingly, FGF21 levels in the HFD + SG group were markedly lower than in the HFD + SHAM group (P = 0.015), however, there were no differences in the NC group. Hematoxylin and eosin staining demonstrated that more vacuoles were present in the HFD + SHAM liver when compared to the HFD + SG liver. Oil-red O staining showed less red dots in the HFD + SG liver. Conclusions Despite eating, surgical re-routing of the gut may prevent weight accumulation, regulate glucose-lipid metabolism and insulin sensitivity, control a chronic inflammatory state, change the secretion pattern of FGF21 and alleviate the severity of fatty liver.
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Affiliation(s)
- Erli Pei
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Yang Liu
- Department of Gerontology, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China
| | - Weiqing Jiang
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Songruo Lin
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Lei Huang
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Moubin Lin
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai, 200433, China.
| | - Li Cai
- Department of Science and Research, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China.
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16
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Bifari F, Manfrini R, Dei Cas M, Berra C, Siano M, Zuin M, Paroni R, Folli F. Multiple target tissue effects of GLP-1 analogues on non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Pharmacol Res 2018; 137:219-229. [PMID: 30359962 DOI: 10.1016/j.phrs.2018.09.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 09/11/2018] [Accepted: 09/24/2018] [Indexed: 12/12/2022]
Abstract
Accumulating experimental and clinical evidences over the last decade indicate that GLP-1 analogues have a series of central nervous system and peripheral target tissues actions which are able to significantly influence the liver metabolism. GLP-1 analogues pleiotropic effects proved to be efficacious in T2DM subjects not only reducing liver steatosis and ameliorating NAFLD and NASH, but also in lowering plasma glucose and liver inflammation, improving cardiac function and protecting from kidney dysfunction. While the experimental and clinical data are robust, the precise mechanisms of action potentially involved in these protective multi-target effects need further investigation. Here we present a systematic review of the most recent literature data on the multi-target effects of GLP-1 analogues on the liver, on adipose and muscular tissue and on the nervous system, all capable of influencing significant aspects of the fatty liver disease physiopathology. From this analysis, we can conclude that the multi-target beneficial action of the GLP-1 analogues could explain the positive effects observed in animal and human models on progression of NAFLD to NASH.
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Affiliation(s)
- Francesco Bifari
- Laboratory of Cell Metabolism and Regenerative Medicine, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Roberto Manfrini
- Department of Internal Medicine ASST Santi Paolo e Carlo, Milan, Italy
| | - Michele Dei Cas
- Laboratory of Clinical Biochemistry and Mass Spectrometry, Department of Health Science, University of Milan, Milan, Italy
| | - Cesare Berra
- Metabolic Disease and Diabetes, Humanitas Research Hospital, Rozzano, Milan, Italy
| | - Matteo Siano
- Department of Internal Medicine ASST Santi Paolo e Carlo, Milan, Italy
| | - Massimo Zuin
- Unit of Medicine, Gastroenterology and Hepatology, Milan, Italy
| | - Rita Paroni
- Laboratory of Clinical Biochemistry and Mass Spectrometry, Department of Health Science, University of Milan, Milan, Italy
| | - Franco Folli
- Unit of Endocrinology and Metabolism ASST Santi Paolo e Carlo, Department of Health Science, University of Milan, Milan, Italy.
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17
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Role of Oxidative Stress in Pathophysiology of Nonalcoholic Fatty Liver Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:9547613. [PMID: 29991976 PMCID: PMC6016172 DOI: 10.1155/2018/9547613] [Citation(s) in RCA: 416] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Liver steatosis without alcohol consumption, namely, nonalcoholic fatty liver disease (NAFLD), is a common hepatic condition that encompasses a wide spectrum of presentations, ranging from simple accumulation of triglycerides in the hepatocytes without any liver damage to inflammation, necrosis, ballooning, and fibrosis (namely, nonalcoholic steatohepatitis) up to severe liver disease and eventually cirrhosis and/or hepatocellular carcinoma. The pathophysiology of fatty liver and its progression is influenced by multiple factors (environmental and genetics), in a “multiple parallel-hit model,” in which oxidative stress plays a very likely primary role as the starting point of the hepatic and extrahepatic damage. The aim of this review is to give a comprehensive insight on the present researches and findings on the role of oxidative stress mechanisms in the pathogenesis and pathophysiology of NAFLD. With this aim, we evaluated the available data in basic science and clinical studies in this field, reviewing the most recent works published on this topic.
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Schmitz-Peiffer C. Anarchy in the UPR: A Ca 2+-insensitive PKC inhibits SERCA activity to promote ER stress. Biosci Rep 2018; 38:BSR20170966. [PMID: 29439143 PMCID: PMC5857902 DOI: 10.1042/bsr20170966] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 02/05/2018] [Accepted: 02/07/2018] [Indexed: 02/04/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in Western countries, and is linked to the development of liver cancer and Type 2 diabetes (T2D). It is strongly associated with obesity, but the dysregulation of liver lipid storage is not fully understood. Fatty acid oversupply to hepatocytes can establish a vicious cycle involving diminished protein folding, endoplasmic reticulum (ER) stress, insulin resistance and further lipogenesis. This commentary discusses the recent findings of Lai et al. published in Bioscience Reports, that implicate protein kinase C delta (PKCδ) activation by fatty acids in the inhibition of the SERCA Ca2+ pump, resulting in reduced ER Ca2+ loading and protein misfolding. PKCδ therefore represents a target for the treatment of both steatosis and insulin resistance, key to the prevention of NAFLD and T2D.
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Affiliation(s)
- Carsten Schmitz-Peiffer
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, and St Vincents Clinical School, University of New South Wales, Darlinghurst, Sydney, 2010, Australia
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Yu D, Chen G, Pan M, Zhang J, He W, Liu Y, Nian X, Sheng L, Xu B. High fat diet-induced oxidative stress blocks hepatocyte nuclear factor 4α and leads to hepatic steatosis in mice. J Cell Physiol 2018; 233:4770-4782. [PMID: 29150932 DOI: 10.1002/jcp.26270] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/14/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Dongsheng Yu
- Department of Pharmacology; School of Basic Medical Science; Nanjing Medical University; Nanjing Jiangsu China
| | - Gang Chen
- Department of Hepatobiliary Surgery; The First Affiliated Hospital of Wenzhou Medical University; Wenzhou Zhejiang China
| | - Minglin Pan
- Department of Endocrinology; The Second Affiliated Hospital of Nanjing Medical University; Nanjing Jiangsu China
| | - Jia Zhang
- Department of Pharmacology; School of Basic Medical Science; Nanjing Medical University; Nanjing Jiangsu China
| | - Wenping He
- Department of Pharmacology; School of Basic Medical Science; Nanjing Medical University; Nanjing Jiangsu China
| | - Yang Liu
- Department of Gastroenterology and Hepatology; Zhongda Hospital; Nanjing Jiangsu China
- Institute of Gastroenterology and Hepatology; School of Medicine; Southeast University; Nanjing Jiangsu China
| | - Xue Nian
- Department of Pharmacology; School of Basic Medical Science; Nanjing Medical University; Nanjing Jiangsu China
| | - Liang Sheng
- Department of Pharmacology; School of Basic Medical Science; Nanjing Medical University; Nanjing Jiangsu China
| | - Bin Xu
- Department of Internal Medicine; Division of Metabolism, Endocrinology and Diabetes; University of Michigan Medical Center; Ann Arbor Michigan
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Balachander GJ, Subramanian S, Ilango K. Rosmarinic acid attenuates hepatic steatosis by modulating ER stress and autophagy in oleic acid-induced HepG2 cells. RSC Adv 2018; 8:26656-26663. [PMID: 35547559 PMCID: PMC9087887 DOI: 10.1039/c8ra02849d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/23/2018] [Indexed: 12/13/2022] Open
Abstract
Non-alcoholic fatty acid disease (NAFLD) has become an emerging entity of liver disorders worldwide. Oxidative stress and deranged autophagy-induced endoplasmic reticulum (ER) stress has recently been recognized as one of the prime factors involved in the pathological mechanism underlying NAFLD and progressive non-alcoholic steato-hepatitis (NASH). Epidemiological and experimental data reveal the potency of dietary polyphenols in averting NAFLD. In this line, to analyse and address the underlying pathogenic mechanisms, in the present study, oleic acid-induced HepG2 cells were treated with rosmarinic acid (RA), a dietary polyphenol with well-established cytoprotective properties. Treatment with rosmarinic acid (20 μg) was found to potently counter the elevated levels of total cholesterol (TC) and triglycerides (TG). Additionally, exposure of oleic acid-induced HepG2 cells to rosmarinic acid showed reduced levels of ROS and increased activity of enzymic and non-enzymic antioxidants. The steatotic HepG2 cells presented a pronounced increase in the expression of key ER stress markers such as p-PERK, p-IRE-1, ATF-6, p-eIF-α and CHOP, which was considerably reduced upon treatment with rosmarinic acid. Moreover, exposure to rosmarinic acid altered the deranged autophagic mechanism in oleic acid-induced HepG2 cells, which was observed via the protein expression of Beclin 1, LC31, ATG5 and ATG7. This study demonstrates that rosmarinic acid abrogates NAFLD via diminishing ER stress by nullifying oxidative stress and restoring deranged autophagy and can be used as a potent adjunct in the treatment of NAFLD, thus illustrating the valuable application of polyphenols in combating NAFLD. Non-alcoholic fatty acid disease (NAFLD) has become an emerging entity of liver disorders worldwide.![]()
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Affiliation(s)
- Govindaraj Jayanthy Balachander
- Molecular Biology Division
- Interdisciplinary Institute of Indian System of Medicine (IIISM)
- SRM Institute of Science and Technology
- Kattankulathur
- India
| | | | - Kaliappan Ilango
- Molecular Biology Division
- Interdisciplinary Institute of Indian System of Medicine (IIISM)
- SRM Institute of Science and Technology
- Kattankulathur
- India
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21
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PKCδ silencing alleviates saturated fatty acid induced ER stress by enhancing SERCA activity. Biosci Rep 2017; 37:BSR20170869. [PMID: 29046367 PMCID: PMC5700272 DOI: 10.1042/bsr20170869] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/05/2017] [Accepted: 10/09/2017] [Indexed: 02/07/2023] Open
Abstract
Protein kinase C δ (PKCδ) plays an important role in nonalcoholic fatty liver disease (NAFLD), however, the mechanism remains unknown. The present study explored the role of PKCδ in NAFLD development and investigated the relationships between PKCδ, calcium homeostasis, and endoplasmic reticulum (ER) stress (ERS). Hepatic steatosis cell model was induced by palmitic acid (PA) in L02 cells. Lipid accretion was evaluated using Oil Red O staining and a triglyceride (TG) detection kit. PKCδ was down-regulated by siRNA. RT-PCR and Western blotting were used to detect the expression of ERS markers. The fluorescence of Ca2+ influx was recorded using confocal microscopy. Sarco-ER Ca2+-ATPase (SERCA) activity was measured by ultramicro-ATP enzyme test kit. PA treatment induced lipid accretion in L02 cells, destroyed the ER structure, and increased PKCδ activation in a time-dependent manner. Further, PA treatment significantly increased the expression of ERS markers, Ig heavy chain binding protein (Bip), and homologous proteins of CCAAT-enhancer binding proteins (CHOP). PKCδ silencing down-regulated Bip and CHOP expression, indicating a successful alleviation of ERS. The increased calcium storage induced by PA stimulation was significantly decreased in L02 cells treated with PKCδ siRNA compared with the negative control. Moreover, diminished SERCA activity caused by PA was recovered in PKCδ siRNA transfected cells. To the best of our knowledge, this is the first report demonstrating that the inhibition of PKCδ alleviates ERS by enhancing SERCA activity and stabilizing calcium homeostasis.
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Hydrophilic compartments of Capsosiphon fulvescens protein alleviate impaired spatial memory by regulating BDNF-mediated ER stress against chronic ethanol exposure. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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23
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Valdecantos MP, Pardo V, Ruiz L, Castro-Sánchez L, Lanzón B, Fernández-Millán E, García-Monzón C, Arroba AI, González-Rodríguez Á, Escrivá F, Álvarez C, Rupérez FJ, Barbas C, Konkar A, Naylor J, Hornigold D, Santos AD, Bednarek M, Grimsby J, Rondinone CM, Valverde ÁM. A novel glucagon-like peptide 1/glucagon receptor dual agonist improves steatohepatitis and liver regeneration in mice. Hepatology 2017; 65:950-968. [PMID: 27880981 DOI: 10.1002/hep.28962] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/11/2016] [Accepted: 11/20/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED Because nonalcoholic steatohepatitis (NASH) is associated with impaired liver regeneration, we investigated the effects of G49, a dual glucagon-like peptide-1/glucagon receptor agonist, on NASH and hepatic regeneration. C57Bl/6 mice fed chow or a methionine and choline-deficient (MCD) diet for 1 week were divided into 4 groups: control (chow diet), MCD diet, chow diet plus G49, and M+G49 (MCD diet plus G49). Mice fed a high-fat diet (HFD) for 10 weeks were divided into groups: HFD and H+G49 (HFD plus G49). Following 2 (MCD groups) or 3 (HFD groups) weeks of treatment with G49, partial hepatectomy (PH) was performed, and all mice were maintained on the same treatment schedule for 2 additional weeks. Analysis of liver function, hepatic regeneration, and comprehensive genomic and metabolic profiling were conducted. NASH was ameliorated in the M+G49 group, manifested by reduced inflammation, steatosis, oxidative stress, and apoptosis and increased mitochondrial biogenesis. G49 treatment was also associated with replenishment of intrahepatic glucose due to enhanced gluconeogenesis and reduced glucose use through the pentose phosphate cycle and oxidative metabolism. Following PH, G49 treatment increased survival, restored the cytokine-mediated priming phase, and enhanced the proliferative capacity and hepatic regeneration ratio in mice on the MCD diet. NASH markers remained decreased in M+G49 mice after PH, and glucose use was shifted to the pentose phosphate cycle and oxidative metabolism. G49 administered immediately after PH was also effective at alleviating the pathological changes induced by the MCD diet. Benefits in terms of liver regeneration were also found in mice fed HFD and treated with G49. CONCLUSION Dual-acting glucagon-like peptide-1/glucagon receptor agonists such as G49 represent a novel therapeutic approach for patients with NASH and particularly those requiring PH. (Hepatology 2017;65:950-968).
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Affiliation(s)
- M Pilar Valdecantos
- Instituto de Investigaciones Biomédicas Alberto Sols (Centro Mixto CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Virginia Pardo
- Instituto de Investigaciones Biomédicas Alberto Sols (Centro Mixto CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Laura Ruiz
- Instituto de Investigaciones Biomédicas Alberto Sols (Centro Mixto CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Borja Lanzón
- Centre for Metabolomics and Bioanalysis (CEMBIO), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Madrid, Spain
| | - Elisa Fernández-Millán
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain.,Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Carmelo García-Monzón
- Liver Research Unit, Instituto de Investigación Sanitaria Princesa, University Hospital Santa Cristina, CIBERehd, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana I Arroba
- Instituto de Investigaciones Biomédicas Alberto Sols (Centro Mixto CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Águeda González-Rodríguez
- Liver Research Unit, Instituto de Investigación Sanitaria Princesa, University Hospital Santa Cristina, CIBERehd, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Fernando Escrivá
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain.,Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Carmen Álvarez
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain.,Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Francisco J Rupérez
- Centre for Metabolomics and Bioanalysis (CEMBIO), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Madrid, Spain
| | - Coral Barbas
- Centre for Metabolomics and Bioanalysis (CEMBIO), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Madrid, Spain
| | | | | | | | | | | | | | | | - Ángela M Valverde
- Instituto de Investigaciones Biomédicas Alberto Sols (Centro Mixto CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
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Tubulin alpha 8 is expressed in hepatic stellate cells and is induced in transformed hepatocytes. Mol Cell Biochem 2017; 428:161-170. [DOI: 10.1007/s11010-016-2926-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/21/2016] [Indexed: 12/16/2022]
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25
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Metabolic Disorders and Cancer: Hepatocyte Store-Operated Ca2+ Channels in Nonalcoholic Fatty Liver Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:595-621. [DOI: 10.1007/978-3-319-57732-6_30] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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26
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Lu S, Mott JL, Harrison-Findik DD. Saturated fatty acids induce post-transcriptional regulation of HAMP mRNA via AU-rich element-binding protein, human antigen R (HuR). J Biol Chem 2015; 290:24178-89. [PMID: 26304124 DOI: 10.1074/jbc.m115.648212] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Indexed: 12/11/2022] Open
Abstract
Iron is implicated in fatty liver disease pathogenesis. The human hepcidin gene, HAMP, is the master switch of iron metabolism. The aim of this study is to investigate the regulation of HAMP expression by fatty acids in HepG2 cells. For these studies, both saturated fatty acids (palmitic acid (PA) and stearic acid (SA)) and unsaturated fatty acid (oleic acid (OA)) were used. PA and, to a lesser extent, SA, but not OA, up-regulated HAMP mRNA levels, as determined by real-time PCR. To understand whether PA regulates HAMP mRNA at the transcriptional or post-transcriptional level, the transcription inhibitor actinomycin D was employed. PA-mediated induction of HAMP mRNA expression was not blocked by actinomycin D. Furthermore, PA activated HAMP 3'-UTR, but not promoter, activity, as shown by reporter assays. HAMP 3'-UTR harbors a single AU-rich element (ARE). Mutation of this ARE abolished the effect of PA, suggesting the involvement of ARE-binding proteins. The ARE-binding protein human antigen R (HuR) stabilizes mRNA through direct interaction with AREs on 3'-UTR. HuR is regulated by phosphorylation-mediated nucleo-cytoplasmic shuttling. PA activated this process. The binding of HuR to HAMP mRNA was also induced by PA in HepG2 cells. Silencing of HuR by siRNA abolished PA-mediated up-regulation of HAMP mRNA levels. PKC is known to phosphorylate HuR. Staurosporine, a broad-spectrum PKC inhibitor, inhibited both PA-mediated translocation of HuR and induction of HAMP expression. Similarly, rottlerin, a novel class PKC inhibitor, abrogated PA-mediated up-regulation of HAMP expression. In conclusion, lipids mediate post-transcriptional regulation of HAMP throughPKC- and HuR-dependent mechanisms.
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Affiliation(s)
- Sizhao Lu
- From the Department of Biochemistry and Molecular Biology and
| | - Justin L Mott
- From the Department of Biochemistry and Molecular Biology and
| | - Duygu Dee Harrison-Findik
- the Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198-5820
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Pilar Valdecantos M, Prieto-Hontoria PL, Pardo V, Módol T, Santamaría B, Weber M, Herrero L, Serra D, Muntané J, Cuadrado A, Moreno-Aliaga MJ, Alfredo Martínez J, Valverde ÁM. Essential role of Nrf2 in the protective effect of lipoic acid against lipoapoptosis in hepatocytes. Free Radic Biol Med 2015; 84:263-278. [PMID: 25841776 DOI: 10.1016/j.freeradbiomed.2015.03.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/10/2015] [Accepted: 03/01/2015] [Indexed: 01/06/2023]
Abstract
Excess of saturated free fatty acids, such as palmitic acid (PA), in hepatocytes has been implicated in nonalcoholic fatty liver disease. α-Lipoic acid (LA) is an antioxidant that protects against oxidative stress conditions. We have investigated the effects of LA in the early activation of oxidative and endoplasmic reticulum stress, lipid accumulation, and Nrf2-mediated antioxidant defenses in hepatocytes treated with PA or in rats fed a high-fat diet. In primary human hepatocytes, a lipotoxic concentration of PA triggered endoplasmic reticulum stress, induced the apoptotic transcription factor CHOP, and increased the percentage of apoptotic cells. Cotreatment with LA prevented these effects. Similar results were found in mouse hepatocytes in which LA attenuated PA-mediated activation of caspase 3 and reduced lipid accumulation by decreasing PA uptake and increasing fatty acid oxidation and lipophagy, thereby preventing lipoapoptosis. Moreover, LA augmented the proliferation capacity of hepatocytes after PA challenge. Antioxidant effects of LA ameliorated reactive oxygen species production and endoplasmic reticulum stress and protected against mitochondrial apoptosis in hepatocytes treated with PA. Cotreatment with PA and LA induced an early nuclear translocation of Nrf2 and activated antioxidant enzymes, whereas reduction of Nrf2 by siRNA abolished the benefit of LA on PA-induced lipoapoptosis. Importantly, posttreatment with LA reversed the established damage induced by PA in hepatocytes, as well as preventing obesity-induced oxidative stress and lipoapoptosis in rat liver. In conclusion, our work has revealed that in hepatocytes, Nrf2 is an essential early player in the rescue of oxidative stress by LA leading to protection against PA-mediated lipoapoptosis.
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Affiliation(s)
- M Pilar Valdecantos
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain; Instituto de Investigación Sanitaria La Paz, 28029 Madrid, Spain
| | | | - Virginia Pardo
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Teresa Módol
- Department of Biochemistry and Genetics, University of Navarra, 31008 Pamplona, Spain
| | - Beatriz Santamaría
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain; Instituto de Investigación Sanitaria La Paz, 28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Minéia Weber
- Department of Biochemistry and Molecular Biology, Institut de Biomedicina, Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Laura Herrero
- Department of Biochemistry and Molecular Biology, Institut de Biomedicina, Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Dolors Serra
- Department of Biochemistry and Molecular Biology, Institut de Biomedicina, Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Jordi Muntané
- Departamento de Cirugía General y Digestiva, Hospital Universitario Virgen del Rocío-Virgen Macarena/IBiS/CSIC/University of Sevilla, 41013 Sevilla, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Antonio Cuadrado
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain; Instituto de Investigación Sanitaria La Paz, 28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - María Jesús Moreno-Aliaga
- Department of Nutrition, Food Science, and Physiology University of Navarra, 31008 Pamplona, Spain; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - J Alfredo Martínez
- Department of Nutrition, Food Science, and Physiology University of Navarra, 31008 Pamplona, Spain; Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ángela M Valverde
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain; Instituto de Investigación Sanitaria La Paz, 28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, 28029 Madrid, Spain.
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Jordy AB, Kraakman MJ, Gardner T, Estevez E, Kammoun HL, Weir JM, Kiens B, Meikle PJ, Febbraio MA, Henstridge DC. Analysis of the liver lipidome reveals insights into the protective effect of exercise on high-fat diet-induced hepatosteatosis in mice. Am J Physiol Endocrinol Metab 2015; 308:E778-91. [PMID: 25714675 DOI: 10.1152/ajpendo.00547.2014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/15/2015] [Indexed: 01/14/2023]
Abstract
The accumulation of lipid at ectopic sites, including the skeletal muscle and liver, is a common consequence of obesity and is associated with tissue-specific and whole body insulin resistance. Exercise is well known to improve insulin resistance by mechanisms not completely understood. We performed lipidomic profiling via mass spectrometry in liver and skeletal muscle samples from exercise-trained mice to decipher the lipid changes associated with exercise-induced improvements in whole body glucose metabolism. Obesity and insulin resistance were induced in C57BL/6J mice by high-fat feeding for 4 wk. Mice then underwent an exercise training program (treadmill running) 5 days/wk (Ex) for 4 wk or remained sedentary (Sed). Compared with Sed, Ex displayed improved (P < 0.01) whole body metabolism as measured via an oral glucose tolerance test. Deleterious lipid species such as diacylglycerol (P < 0.05) and cholesterol esters (P < 0.01) that accumulate with high-fat feeding were decreased in the liver of trained mice. Furthermore, the ratio of phosphatidylcholine (PC) to phosphatidylethanolamine (PE) (the PC/PE ratio), which is associated with membrane integrity and linked to hepatic disease progression, was increased by training (P < 0.05). These findings occurred without corresponding changes in the skeletal muscle lipidome. A concomitant decrease (P < 0.05) was observed for the fatty acid transporters CD36 and FATP4 in the liver, suggesting that exercise stimulates a coordinated reduction in fatty acid entry into hepatocytes. Given the important role of the liver in the regulation of whole body glucose homeostasis, hepatic lipid regression may be a key component by which exercise can improve metabolism.
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Affiliation(s)
- Andreas B Jordy
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Kraakman
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Tim Gardner
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Emma Estevez
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Helene L Kammoun
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Jacqui M Weir
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Bente Kiens
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
| | - Mark A Febbraio
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; and
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Liu J, Wang G, Jia Y, Xu Y. GLP-1 receptor agonists: effects on the progression of non-alcoholic fatty liver disease. Diabetes Metab Res Rev 2015; 31:329-35. [PMID: 25066109 DOI: 10.1002/dmrr.2580] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/15/2014] [Accepted: 07/06/2014] [Indexed: 12/21/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and its incidence has been increasing recently. In addition to hepatic complications, NAFLD is also recognized as an independent risk factor for cardiovascular disease. Unfortunately, the current therapies for NAFLD display variable efficacy; a novel and effective drug is urgently needed. Glucagon-like peptide-1 (GLP-1), a receptor agonist is a new drug approved for treating type 2 diabetes. Recently, these types of agents have shown a novel therapeutic effect on NAFLD. However, the mechanisms of GLP-1 receptor agonists on the treatment of NAFLD have not yet been explained precisely. Recent studies have demonstrated that GLP-1 reverses the progression of NAFLD not only indirectly through an incretin effect that improves key parameters involved in NAFLD, but also a direct effect on lipid metabolism of hepatocytes and inflammation in liver. In this review, we provided an overview of the role and mechanisms of GLP-1 in the therapy of NAFLD.
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Affiliation(s)
- Jia Liu
- Department of Endocrinology, Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing, 100020, People's Republic of China
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Steatosis inhibits liver cell store-operated Ca²⁺ entry and reduces ER Ca²⁺ through a protein kinase C-dependent mechanism. Biochem J 2015; 466:379-90. [PMID: 25422863 DOI: 10.1042/bj20140881] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lipid accumulation in hepatocytes can lead to non-alcoholic fatty liver disease (NAFLD), which can progress to non-alcoholic steatohepatitis (NASH) and Type 2 diabetes (T2D). Hormone-initiated release of Ca²⁺ from the endoplasmic reticulum (ER) stores and subsequent replenishment of these stores by Ca²⁺ entry through SOCs (store-operated Ca²⁺ channels; SOCE) plays a critical role in the regulation of liver metabolism. ER Ca²⁺ homoeostasis is known to be altered in steatotic hepatocytes. Whether store-operated Ca²⁺ entry is altered in steatotic hepatocytes and the mechanisms involved were investigated. Lipid accumulation in vitro was induced in cultured liver cells by amiodarone or palmitate and in vivo in hepatocytes isolated from obese Zucker rats. Rates of Ca²⁺ entry and release were substantially reduced in lipid-loaded cells. Inhibition of Ca²⁺ entry was associated with reduced hormone-initiated intracellular Ca²⁺ signalling and enhanced lipid accumulation. Impaired Ca²⁺ entry was not associated with altered expression of stromal interaction molecule 1 (STIM1) or Orai1. Inhibition of protein kinase C (PKC) reversed the impairment of Ca²⁺ entry in lipid-loaded cells. It is concluded that steatosis leads to a substantial inhibition of SOCE through a PKC-dependent mechanism. This enhances lipid accumulation by positive feedback and may contribute to the development of NASH and insulin resistance.
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Liu J, Xu Y, Hu Y, Wang G. The role of fibroblast growth factor 21 in the pathogenesis of non-alcoholic fatty liver disease and implications for therapy. Metabolism 2015; 64:380-90. [PMID: 25516477 DOI: 10.1016/j.metabol.2014.11.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/06/2014] [Accepted: 11/25/2014] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) includes a cluster of liver disorders ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH) and cirrhosis. Due to its liver and vascular complications, NAFLD has become a public health problem with high morbidity and mortality. The pathogenesis of NAFLD is considered a "multi-hit hypothesis" that involves lipotoxicity, oxidative stress, endoplasmic reticulum stress, a chronic inflammatory state and mitochondrial dysfunction. Fibroblast growth factor 21 (FGF21) is a member of the fibroblast growth factor family with multiple metabolic functions. FGF21 directly regulates lipid metabolism and reduces hepatic lipid accumulation in an insulin-independent manner. Several studies have shown that FGF21 can ameliorate the "multi-hits" in the pathogenesis of NAFLD. The administration of FGF21 reverses hepatic steatosis, counteracts obesity and alleviates insulin resistance in rodents and nonhuman primates. Using several strategies, we show that the reversal of simple fatty liver and NASH is mediated by activation of the FGF21 signaling pathway. In this review, we describe the molecular mechanisms involved in the onset and/or progression of NAFLD, and review the current literature to highlight the therapeutic procedures associated with the FGF21 signaling pathway for simple fatty liver and NASH, which are the two most important types of NAFLD.
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Affiliation(s)
- Jia Liu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Yuan Xu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Yanjin Hu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Guang Wang
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China.
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Green CJ, Pramfalk C, Morten KJ, Hodson L. From whole body to cellular models of hepatic triglyceride metabolism: man has got to know his limitations. Am J Physiol Endocrinol Metab 2015; 308:E1-20. [PMID: 25352434 PMCID: PMC4281685 DOI: 10.1152/ajpendo.00192.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The liver is a main metabolic organ in the human body and carries out a vital role in lipid metabolism. Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, encompassing a spectrum of conditions from simple fatty liver (hepatic steatosis) through to cirrhosis. Although obesity is a known risk factor for hepatic steatosis, it remains unclear what factor(s) is/are responsible for the primary event leading to retention of intrahepatocellular fat. Studying hepatic processes and the etiology and progression of disease in vivo in humans is challenging, not least as NAFLD may take years to develop. We present here a review of experimental models and approaches that have been used to assess liver triglyceride metabolism and discuss their usefulness in helping to understand the aetiology and development of NAFLD.
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Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
| | - Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
| | - Karl J Morten
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
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Webster CRL, Johnston AN, Anwer MS. Protein kinase Cδ protects against bile acid apoptosis by suppressing proapoptotic JNK and BIM pathways in human and rat hepatocytes. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1207-15. [PMID: 25359536 PMCID: PMC4269680 DOI: 10.1152/ajpgi.00165.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Retained bile acids, which are capable of inducing cell death, activate protein kinase Cδ (PKC-δ) in hepatocytes. In nonhepatic cells, both pro- and antiapoptotic effects of PKC-δ are described. The aim of this study was to determine the role of PKC-δ in glycochenodeoxycholate (GCDC)-induced apoptosis in rat hepatocytes and human HUH7-Na-taurocholate-cotransporting polypeptide (Ntcp) cells. Apoptosis was monitored morphologically by Hoechst staining and biochemically by immunoblotting for caspase 3 cleavage. The role of PKC-δ was evaluated with a PKC activator (phorbol myristate acetate, PMA) and PKC inhibitors (chelerythrine, H-7, or calphostin), PKC-δ knockdown, and wild-type (WT) or constitutively active (CA) PKC-δ. PKC-δ activation was monitored by immunoblotting for PKC-δ Thr505 and Tyr311 phosphorylation or by membrane translocation. JNK and Akt phosphorylation and the amount of total bisindolylmaleimide (BIM) were determined by immunoblotting. GCDC induced the translocation of PKC-δ to the mitochondria and/or plasma membrane in rat hepatocytes and HUH7-Ntcp cells and increased PKC-δ phosphorylation on Thr505, but not on Tyr311, in HUH7-Ntcp cells. GCDC-induced apoptosis was attenuated by PMA and augmented by PKC inhibition in rat hepatocytes. In HUH-Ntcp cells, transfection with CA or WT PKC-δ attenuated GCDC-induced apoptosis, whereas knockdown of PKC-δ increased GCDC-induced apoptosis. PKC-δ silencing increased GCDC-induced JNK phosphorylation, decreased GCDC-induced Akt phosphorylation, and increased expression of BIM. GCDC translocated BIM to the mitochondria in rat hepatocytes, and knockdown of BIM in HUH7-Ntcp cells decreased GCDC-induced apoptosis. Collectively, these results suggest that PKC-δ does not mediate GCDC-induced apoptosis in hepatocytes. Instead PKC-δ activation by GCDC stimulates a cytoprotective pathway that involves JNK inhibition, Akt activation, and downregulation of BIM.
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Affiliation(s)
- Cynthia R. L. Webster
- 1Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, Grafton, Massachusetts;
| | - Andrea N. Johnston
- 1Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, Grafton, Massachusetts;
| | - M. Sawkat Anwer
- 2Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, Grafton, Massachusetts
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Zhang J, Burrington CM, Davenport SK, Johnson AK, Horsman MJ, Chowdhry S, Greene MW. PKCδ regulates hepatic triglyceride accumulation and insulin signaling in Lepr(db/db) mice. Biochem Biophys Res Commun 2014; 450:1619-25. [PMID: 25035929 DOI: 10.1016/j.bbrc.2014.07.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/09/2014] [Indexed: 01/08/2023]
Abstract
PKCδ has been linked to key pathophysiological features of non-alcoholic fatty liver disease (NAFLD). Yet, our knowledge of PKCδ's role in NAFLD development and progression in obese models is limited. PKCδ(-/-)/Lepr(db)(/)(db) mice were generated to evaluate key pathophysiological features of NAFLD in mice. Hepatic histology, oxidative stress, apoptosis, gene expression, insulin signaling, and serum parameters were analyzed in Lepr(db)(/)(db) and PKCδ(-/-)/Lepr(db)(/)(db) mice. The absence of PKCδ did not abrogate the development of obesity in Lepr(db)(/)(db) mice. In contrast, serum triglyceride levels and epididymal white adipose tissue weight normalized to body weight were reduced in PKCδ(-/-)/Lepr(db)(/)(db) mice compared Lepr(db)(/)(db) mice. Analysis of insulin signaling in mice revealed that hepatic Akt and GSK3β phosphorylation were strongly stimulated by insulin in PKCδ(-/-)/Lepr(db)(/)(db) compared Lepr(db)(/)(db) mice. PKCδ may be involved in the development of obesity-associated NAFLD by regulating hepatic lipid metabolism and insulin signaling.
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Affiliation(s)
- Jian Zhang
- Boshell Diabetes and Metabolic Disease Research Program, Auburn University, Auburn, AL 36849, United States; College of Human Sciences, Auburn University, Auburn, AL 36849, United States
| | - Christine M Burrington
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States
| | - Samantha K Davenport
- Department of Pathology, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States
| | - Andrew K Johnson
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States
| | - Melissa J Horsman
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States
| | - Saleem Chowdhry
- Department of Internal Medicine, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States
| | - Michael W Greene
- Boshell Diabetes and Metabolic Disease Research Program, Auburn University, Auburn, AL 36849, United States; College of Human Sciences, Auburn University, Auburn, AL 36849, United States; Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, NY 13326, United States.
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González-Rodríguez Á, Mayoral R, Agra N, Valdecantos MP, Pardo V, Miquilena-Colina ME, Vargas-Castrillón J, Lo Iacono O, Corazzari M, Fimia GM, Piacentini M, Muntané J, Boscá L, García-Monzón C, Martín-Sanz P, Valverde ÁM. Impaired autophagic flux is associated with increased endoplasmic reticulum stress during the development of NAFLD. Cell Death Dis 2014; 5:e1179. [PMID: 24743734 PMCID: PMC4001315 DOI: 10.1038/cddis.2014.162] [Citation(s) in RCA: 425] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/05/2014] [Accepted: 03/10/2014] [Indexed: 02/06/2023]
Abstract
The pathogenic mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) are not fully understood. In this study, we aimed to assess the relationship between endoplasmic reticulum (ER) stress and autophagy in human and mouse hepatocytes during NAFLD. ER stress and autophagy markers were analyzed in livers from patients with biopsy-proven non-alcoholic steatosis (NAS) or non-alcoholic steatohepatitis (NASH) compared with livers from subjects with histologically normal liver, in livers from mice fed with chow diet (CHD) compared with mice fed with high fat diet (HFD) or methionine-choline-deficient (MCD) diet and in primary and Huh7 human hepatocytes loaded with palmitic acid (PA). In NASH patients, significant increases in hepatic messenger RNA levels of markers of ER stress (activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP)) and autophagy (BCN1) were found compared with NAS patients. Likewise, protein levels of GRP78, CHOP and p62/SQSTM1 (p62) autophagic substrate were significantly elevated in NASH compared with NAS patients. In livers from mice fed with HFD or MCD, ER stress-mediated signaling was parallel to the blockade of the autophagic flux assessed by increases in p62, microtubule-associated protein 2 light chain 3 (LC3-II)/LC3-I ratio and accumulation of autophagosomes compared with CHD fed mice. In Huh7 hepatic cells, treatment with PA for 8 h triggered activation of both unfolding protein response and the autophagic flux. Conversely, prolonged treatment with PA (24 h) induced ER stress and cell death together with a blockade of the autophagic flux. Under these conditions, cotreatment with rapamycin or CHOP silencing ameliorated these effects and decreased apoptosis. Our results demonstrated that the autophagic flux is impaired in the liver from both NAFLD patients and murine models of NAFLD, as well as in lipid-overloaded human hepatocytes, and it could be due to elevated ER stress leading to apoptosis. Consequently, therapies aimed to restore the autophagic flux might attenuate or prevent the progression of NAFLD.
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Affiliation(s)
- Á González-Rodríguez
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Barcelona, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
| | - R Mayoral
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
| | - N Agra
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
| | - M P Valdecantos
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Barcelona, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
| | - V Pardo
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Barcelona, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
| | - M E Miquilena-Colina
- Liver Research Unit, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - J Vargas-Castrillón
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
- Liver Research Unit, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - O Lo Iacono
- Gastroenterology Unit, Hospital del Tajo, Aranjuez, Madrid, Spain
| | - M Corazzari
- National Institute for Infectious Diseases IRCCS ‘L Spallanzani', Rome, Italy
| | - G M Fimia
- National Institute for Infectious Diseases IRCCS ‘L Spallanzani', Rome, Italy
| | - M Piacentini
- National Institute for Infectious Diseases IRCCS ‘L Spallanzani', Rome, Italy
- Department of Biology, University of Rome ‘Tor Vergata', Rome, Italy
| | - J Muntané
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
- Oncology Surgery, Cell Therapy and Transplant Organs, Institute of Biomedicine of Seville (IBiS)/Virgen del Rocio Universitary Hospital/CSIC/University of Seville, Seville, Spain
| | - L Boscá
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
| | - C García-Monzón
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
- Liver Research Unit, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
- Liver Research Unit, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa, Calle del Maestro Amadeo Vives, 2, 28009 Madrid, Spain. Tel: +34 91 5574402; Fax: +34 91 5574400; E-mail:
| | - P Martín-Sanz
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), ISCIII, Barcelona, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas, C/Arturo Duperier 4, 28029 Madrid, Spain. Tel: +34 91 4972746; Fax: +34 91 5854401; E-mail: (PM-S) or Tel: +34 915854497; Fax: +34 915854401; E-mail: (ÁMV)
| | - Á M Valverde
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Barcelona, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols' (CSIC/UAM), Madrid, Spain
- Instituto de Investigaciones Biomédicas ‘Alberto Sols', Consejo Superior de Investigaciones Científicas, C/Arturo Duperier 4, 28029 Madrid, Spain. Tel: +34 91 4972746; Fax: +34 91 5854401; E-mail: (PM-S) or Tel: +34 915854497; Fax: +34 915854401; E-mail: (ÁMV)
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Greene MW, Burrington CM, Lynch DT, Davenport SK, Johnson AK, Horsman MJ, Chowdhry S, Zhang J, Sparks JD, Tirrell PC. Lipid metabolism, oxidative stress and cell death are regulated by PKC delta in a dietary model of nonalcoholic steatohepatitis. PLoS One 2014; 9:e85848. [PMID: 24454937 PMCID: PMC3893275 DOI: 10.1371/journal.pone.0085848] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/03/2013] [Indexed: 12/31/2022] Open
Abstract
Steatosis, oxidative stress, and apoptosis underlie the development of nonalcoholic steatohepatitis (NASH). Protein kinase C delta (PKCδ) has been implicated in fatty liver disease and is activated in the methionine and choline-deficient (MCD) diet model of NASH, yet its pathophysiological importance towards steatohepatitis progression is uncertain. We therefore addressed the role of PKCδ in the development of steatosis, inflammation, oxidative stress, apoptosis, and fibrosis in an animal model of NASH. We fed PKCδ−/− mice and wildtype littermates a control or MCD diet. PKCδ−/− primary hepatocytes were used to evaluate the direct effects of fatty acids on hepatocyte lipid metabolism gene expression. A reduction in hepatic steatosis and triglyceride levels were observed between wildtype and PKCδ−/− mice fed the MCD diet. The hepatic expression of key regulators of β-oxidation and plasma triglyceride metabolism was significantly reduced in PKCδ−/− mice and changes in serum triglyceride were blocked in PKCδ−/− mice. MCD diet-induced hepatic oxidative stress and hepatocyte apoptosis were reduced in PKCδ−/− mice. MCD diet-induced NADPH oxidase activity and p47phox membrane translocation were blunted and blocked, respectively, in PKCδ−/− mice. Expression of pro-apoptotic genes and caspase 3 and 9 cleavage in the liver of MCD diet fed PKCδ−/− mice were blunted and blocked, respectively. Surprisingly, no differences in MCD diet-induced fibrosis or pro-fibrotic gene expression were observed in 8 week MCD diet fed PKCδ−/− mice. Our results suggest that PKCδ plays a role in key pathological features of fatty liver disease but not ultimately in fibrosis in the MCD diet model of NASH.
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Affiliation(s)
- Michael W. Greene
- Boshell Diabetes and Metabolic Disease Research Program, Auburn University, Auburn, Alabama, United States of America
- College of Human Sciences, Auburn University, Auburn, Alabama, United States of America
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
- * E-mail:
| | - Christine M. Burrington
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Darin T. Lynch
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Samantha K. Davenport
- Department of Pathology, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Andrew K. Johnson
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Melissa J. Horsman
- Bassett Research Institute, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Saleem Chowdhry
- Department of Internal Medicine, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
| | - Jian Zhang
- College of Human Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Janet D. Sparks
- University of Rochester Medical Center, School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Paul C. Tirrell
- Department of Internal Medicine, Bassett Medical Center, Bassett Healthcare Network, Cooperstown, New York, United States of America
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Madaro L, Marrocco V, Carnio S, Sandri M, Bouché M. Intracellular signaling in ER stress-induced autophagy in skeletal muscle cells. FASEB J 2013; 27:1990-2000. [PMID: 23388382 DOI: 10.1096/fj.12-215475] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Skeletal muscle remodeling in response to muscle disuse and unloading is known to be associated with so-called ER stress, which, in turn, activates autophagy and contributes to muscle atrophy. Different molecules are involved in ER stress-induced autophagy, among which PKCθ has recently been described. In this study, we dissected both in vitro and in vivo ER stress-induced autophagy pathways in muscle. Using C2C12 muscle cells in culture, we demonstrated that PKC activation induced autophagy in the absence of ER stress. We further demonstrated that PKCθ was strongly activated in cultured myoblasts and myotubes during ER stress induced by different stimuli, such as TG or TN treatment, and that it localized into Lc3-positive autophagic dots upon TG treatment. Neither Akt dephosphorylation nor Foxo or GSK3β activation was observed in these conditions. Moreover, PKCθ inhibition in myoblasts and myotubes prevented ER stress-induced Lc3 activation and autophagic dot formation, but not ER stress. In vivo, lack of PKCθ prevented both food deprivation- and immobilization-induced autophagy and muscle atrophy, irrespective of Akt pathway inhibition. Taken together, these results demonstrate that PKCθ functions as an ER stress sensor in skeletal muscle, required for ER-stress-dependent autophagy activation, and can be proposed as a novel molecular target to maintain muscle homeostasis in response to external stimuli, such as disuse and unloading, still allowing intracellular clearance.
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Affiliation(s)
- Luca Madaro
- DAHFMO, Unit of Histology, Sapienza University of Rome, Via A. Scarpa 14, 00161 Rome, Italy
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Zhu L, Baker SS, Gill C, Liu W, Alkhouri R, Baker RD, Gill SR. Characterization of gut microbiomes in nonalcoholic steatohepatitis (NASH) patients: a connection between endogenous alcohol and NASH. Hepatology 2013; 57:601-9. [PMID: 23055155 DOI: 10.1002/hep.26093] [Citation(s) in RCA: 1139] [Impact Index Per Article: 103.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/24/2012] [Indexed: 02/06/2023]
Abstract
UNLABELLED Nonalcoholic steatohepatitis (NASH) is a serious liver disease associated with obesity. Characterized by metabolic syndrome, hepatic steatosis, and liver inflammation, NASH is believed to be under the influence of the gut microflora. Here, the composition of gut bacterial communities of NASH, obese, and healthy children was determined by 16S ribosomal RNA pyrosequencing. In addition, peripheral blood ethanol was analyzed to monitor endogenous ethanol production of patients and healthy controls. UniFrac-based principle coordinates analysis indicated that most of the microbiome samples clustered by disease status. Each group was associated with a unique pattern of enterotypes. Differences were abundant at phylum, family, and genus levels between healthy subjects and obese patients (with or without NASH), and relatively fewer differences were observed between obese and the NASH microbiomes. Among those taxa with greater than 1% representation in any of the disease groups, Proteobacteria, Enterobacteriaceae, and Escherichia were the only phylum, family and genus types exhibiting significant difference between obese and NASH microbiomes. Similar blood-ethanol concentrations were observed between healthy subjects and obese non-NASH patients, but NASH patients exhibited significantly elevated blood ethanol levels. CONCLUSIONS The increased abundance of alcohol-producing bacteria in NASH microbiomes, elevated blood-ethanol concentration in NASH patients, and the well-established role of alcohol metabolism in oxidative stress and, consequently, liver inflammation suggest a role for alcohol-producing microbiota in the pathogenesis of NASH. We postulate that the distinct composition of the gut microbiome among NASH, obese, and healthy controls could offer a target for intervention or a marker for disease.
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Affiliation(s)
- Lixin Zhu
- Digestive Diseases and Nutrition Center, Department of Pediatrics, State University of New York at Buffalo, Buffalo, NY 14214, USA
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Henkel AS, Dewey AM, Anderson KA, Olivares S, Green RM. Reducing endoplasmic reticulum stress does not improve steatohepatitis in mice fed a methionine- and choline-deficient diet. Am J Physiol Gastrointest Liver Physiol 2012; 303:G54-9. [PMID: 22556147 PMCID: PMC3404574 DOI: 10.1152/ajpgi.00052.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of nonalcoholic steatohepatitis. The ER stress response is activated in the livers of mice fed a methionine- and choline-deficient (MCD) diet, yet the role of ER stress in the pathogenesis of MCD diet-induced steatohepatitis is unknown. Using chemical chaperones on hepatic steatosis and markers of inflammation and fibrosis in mice fed a MCD diet, we aim to determine the effects of reducing ER stress. C57BL/6J mice were fed a MCD diet with or without the ER chemical chaperones 4-phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) for 2 wk. TUDCA and PBA effectively attenuated the ER stress response in MCD diet-fed mice, as evidenced by reduced protein levels of phosphorylated eukaryotic initiation factor 2α and phosphorylated JNK and suppression of mRNA levels of CCAAT/enhancer binding protein homologous protein, glucose-regulated protein 78 kDa, and X-box binding protein 1. However, PBA and TUDCA did not decrease MCD diet-induced hepatic steatosis. MCD diet-induced hepatic inflammation, as evidenced by increased plasma alanine aminotransferase and induction of hepatic TNFα expression, was also not reduced by PBA or TUDCA. PBA and TUDCA did not attenuate MCD diet-induced upregulation of the fibrosis-associated genes tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9. ER chemical chaperones reduce MCD diet-induced ER stress, yet they do not improve MCD diet-induced hepatic steatosis, inflammation, or activation of genes associated with fibrosis. These data suggest that although the ER stress response is activated by the MCD diet, it does not have a primary role in the pathogenesis of MCD diet-induced steatohepatitis.
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Affiliation(s)
- Anne S. Henkel
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Amanda M. Dewey
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Kristy A. Anderson
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Shantel Olivares
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
| | - Richard M. Green
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois
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D'souza AM, Beaudry JL, Szigiato AA, Trumble SJ, Snook LA, Bonen A, Giacca A, Riddell MC. Consumption of a high-fat diet rapidly exacerbates the development of fatty liver disease that occurs with chronically elevated glucocorticoids. Am J Physiol Gastrointest Liver Physiol 2012; 302:G850-63. [PMID: 22268100 DOI: 10.1152/ajpgi.00378.2011] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chronically elevated glucocorticoids (GCs) and a high-fat diet (HFD) independently induce insulin resistance, abdominal obesity, and nonalcoholic fatty liver disease (NAFLD). GCs have been linked to increased food intake, particularly energy-dense "comfort" foods. Thus we examined the synergistic actions of GCs and HFD on hepatic disease development in a new rodent model of chronically elevated GCs. Six-week-old male Sprague-Dawley rats received exogenous GCs, via subcutaneous implantation of four 100-mg corticosterone (Cort) pellets, to elevate basal GC levels for 16 days (n = 8-10 per group). Another subset of animals received wax pellets (placebo) to serve as controls. Animals from each group were randomly assigned to receive a 60% HFD or a standard high-carbohydrate (13% fat and 60% carbohydrate) diet. Cort + HFD resulted in central obesity, despite a relative weight loss, a 4-fold increase in hepatic lipid content, hepatic fibrosis, and a 2.8-fold increase in plasma alanine aminotransferase levels compared with placebo + chow controls. Hepatic injury developed independent of inflammation, as plasma haptoglobin levels were reduced with Cort treatment. Insulin resistance and hepatic steatosis occurred with Cort alone; these outcomes were further exacerbated by the HFD in the presence of elevated Cort. In addition to fatty liver, the Cort + HFD group also developed severe insulin resistance, hyperinsulinemia, hyperglycemia, and hypertriglyceridemia, which were not evident with HFD or Cort alone. Thus a HFD dramatically exacerbates the development of NAFLD and characteristics of the metabolic syndrome in conditions of chronically elevated Cort.
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Affiliation(s)
- Anna M D'souza
- Muscle Health Research Center and Physical Activity and Chronic Disease Unit, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, Canada
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PERK utilizes intrinsic lipid kinase activity to generate phosphatidic acid, mediate Akt activation, and promote adipocyte differentiation. Mol Cell Biol 2012; 32:2268-78. [PMID: 22493067 DOI: 10.1128/mcb.00063-12] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The endoplasmic reticulum (ER) resident PKR-like kinase (PERK) is necessary for Akt activation in response to ER stress. We demonstrate that PERK harbors intrinsic lipid kinase, favoring diacylglycerol (DAG) as a substrate and generating phosphatidic acid (PA). This activity of PERK correlates with activation of mTOR and phosphorylation of Akt on Ser473. PERK lipid kinase activity is regulated in a phosphatidylinositol 3-kinase (PI3K) p85α-dependent manner. Moreover, PERK activity is essential during adipocyte differentiation. Because PA and Akt regulate many cellular functions, including cellular survival, proliferation, migratory responses, and metabolic adaptation, our findings suggest that PERK has a more extensive role in insulin signaling, insulin resistance, obesity, and tumorigenesis than previously thought.
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Park HS, Jeon BH, Woo SH, Leem J, Jang JE, Cho MS, Park IS, Lee KU, Koh EH. Time-dependent changes in lipid metabolism in mice with methionine choline deficiency-induced fatty liver disease. Mol Cells 2011; 32:571-7. [PMID: 22083307 PMCID: PMC3887687 DOI: 10.1007/s10059-011-0184-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/10/2011] [Accepted: 10/11/2011] [Indexed: 02/07/2023] Open
Abstract
Methionine and choline-deficient diet (MCD)-induced fatty liver is one of the best-studied animal models of fatty liver disease. The present study was performed to clarify the relative contributions of individual lipid metabolic pathways to the pathogenesis of MCD-induced fatty liver. Hepatic lipogenesis mediated by the sterol regulatory element-binding protein (SREBP-1c) was increased at 1 week, but not at 6 weeks, of MCD feeding. On the other hand, (14)C-palmitate oxidation did not change at 1 week, but significantly decreased at 6 weeks. This decrease was associated with increased expression of fatty acid translocase, a key enzyme involved in fatty acid uptake. Expression of endoplasmic reticulum stress markers was increased in mice given MCD for both 1 and 6 weeks. These findings suggest the presence of time-dependent differences in lipid metabolism in MCD-induced fatty liver disease: SREBP-1c-mediated lipogenesis is important in the early stages of fatty liver disease, whereas increased fatty acid uptake and decreased fatty acid oxidation become more important in the later stages.
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Affiliation(s)
- Han-Sol Park
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 138-736, Korea
- These authors contributed equally to this work
| | - Byeong Hwan Jeon
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 138-736, Korea
- These authors contributed equally to this work
| | - Sung Hoon Woo
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Jaechan Leem
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Jung Eun Jang
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Min Sock Cho
- Department of Anatomy, College of Medicine, Inha University, Incheon 401-103, Korea
| | - In-Sun Park
- Department of Anatomy, College of Medicine, Inha University, Incheon 401-103, Korea
| | - Ki-Up Lee
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Eun Hee Koh
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
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Birkenfeld AL, Lee HY, Majumdar S, Jurczak MJ, Camporez JP, Jornayvaz FR, Frederick DW, Guigni B, Kahn M, Zhang D, Weismann D, Arafat AM, Pfeiffer AF, Lieske S, Oyadomari S, Ron D, Samuel VT, Shulman GI. Influence of the hepatic eukaryotic initiation factor 2alpha (eIF2alpha) endoplasmic reticulum (ER) stress response pathway on insulin-mediated ER stress and hepatic and peripheral glucose metabolism. J Biol Chem 2011; 286:36163-70. [PMID: 21832042 PMCID: PMC3196114 DOI: 10.1074/jbc.m111.228817] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 07/05/2011] [Indexed: 11/06/2022] Open
Abstract
Recent studies have implicated endoplasmic reticulum (ER) stress in insulin resistance associated with caloric excess. In mice placed on a 3-day high fat diet, we find augmented eIF2α signaling, together with hepatic lipid accumulation and insulin resistance. To clarify the role of the liver ER stress-dependent phospho-eIF2α (eIF2α-P) pathway in response to acute caloric excess on liver and muscle glucose and lipid metabolism, we studied transgenic mice in which the hepatic ER stress-dependent eIF2α-P pathway was inhibited by overexpressing a constitutively active C-terminal fragment of GADD34/PPP1R15a, a regulatory subunit of phosphatase that terminates ER stress signaling by phospho-eIF2α. Inhibition of the eIF2α-P signaling in liver led to a decrease in hepatic glucose production in the basal and clamped state, which could be attributed to reduced gluconeogenic gene expression, resulting in reduced basal plasma glucose concentrations. Surprisingly, hepatic eIF2α inhibition also impaired insulin-stimulated muscle and adipose tissue insulin sensitivity. This latter effect could be attributed at least in part by an increase in circulating IGFBP-3 levels in the transgenic animals. In addition, infusion of insulin during a hyperinsulinemic-euglycemic clamp induced conspicuous ER stress in the 3-day high fat diet-fed mice, which was aggravated through continuous dephosphorylation of eIF2α. Together, these data imply that the hepatic ER stress eIF2α signaling pathway affects hepatic glucose production without altering hepatic insulin sensitivity. Moreover, hepatic ER stress-dependent eIF2α-P signaling is implicated in an unanticipated cross-talk between the liver and peripheral organs to influence insulin sensitivity, probably via IGFBP-3. Finally, eIF2α is crucial for proper resolution of insulin-induced ER stress.
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Affiliation(s)
- Andreas L. Birkenfeld
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
- Charité University School of Medicine, 10117 Berlin and German Institute of Human Nutrition Potsdam-Rehbrücke, Department of Clinical Nutrition, 14558 Nuthetal, Germany
| | - Hui-Young Lee
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Sachin Majumdar
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Michael J. Jurczak
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Joao Paulo Camporez
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Francois R. Jornayvaz
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - David W. Frederick
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Blas Guigni
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Mario Kahn
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Dongyang Zhang
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Dirk Weismann
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Ayman M. Arafat
- Charité University School of Medicine, 10117 Berlin and German Institute of Human Nutrition Potsdam-Rehbrücke, Department of Clinical Nutrition, 14558 Nuthetal, Germany
| | - Andreas F. Pfeiffer
- Charité University School of Medicine, 10117 Berlin and German Institute of Human Nutrition Potsdam-Rehbrücke, Department of Clinical Nutrition, 14558 Nuthetal, Germany
| | - Stefanie Lieske
- Charité University School of Medicine, 10117 Berlin and German Institute of Human Nutrition Potsdam-Rehbrücke, Department of Clinical Nutrition, 14558 Nuthetal, Germany
| | - Seiichi Oyadomari
- Institute for Genome Research, University of Tokushima, 3-18-15 Kuramoto, Tokushima, Japan, and
| | - David Ron
- the Kimmel Center for Biology and Medicine at Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, New York 10016
| | - Varman T. Samuel
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
- the Veterans Affairs Medical Center, West Haven, Connecticut 06516
| | - Gerald I. Shulman
- From the Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
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