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Ezhilarasan D. Deciphering the molecular pathways of saroglitazar: A dual PPAR α/γ agonist for managing metabolic NAFLD. Metabolism 2024; 155:155912. [PMID: 38609038 DOI: 10.1016/j.metabol.2024.155912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 04/14/2024]
Abstract
Saroglitazar (SARO), a dual peroxisome proliferator activated receptor (PPAR)-α/γ agonist, has been used to treat metabolic diseases such as insulin resistance and diabetic dyslipidemia in patients with non-alcoholic fatty liver disease (NAFLD). SARO, administered at a dose of 4 mg/day, has been consistently studied in clinical trials with different time points ranging from 4 to 24 weeks with NAFLD patients. Due to its PPAR-γ agonistic action, SARO prevents adipose tissue-mediated fatty acid delivery to the liver by increasing insulin sensitivity and regulating adiponectin and leptin levels in adipose tissue. In hepatocytes, SARO induces fatty acid β-oxidation in mitochondria and transcriptionally activates lipid metabolizing genes in peroxisomes. SARO inhibits insulin resistance, thereby preventing the activation of sterol regulatory element-binding proteins -1c and carbohydrate response element binding protein in hepatocytes through its PPAR-α agonistic action. SARO treatment reduces lipotoxicity-mediated oxidative stress by activating the nuclear factor erythroid 2-related factor 2 and transcriptionally expressing the antioxidants from the antioxidant response element in the nucleus through its PPAR-γ agonistic action. SARO provides a PPAR-α/γ-mediated anti-inflammatory effect by preventing the phosphorylation of mitogen-activated protein kinases (JNK and ERK) and nuclear factor kappa B in hepatocytes. Additionally, SARO interferes with transforming growth factor-β/Smad downstream signaling, thereby reducing liver fibrosis progression through its PPAR-α/γ agonistic actions. Thus, SARO improves insulin resistance and dyslipidemia in NAFLD, reduces lipid accumulation in the liver, and thereby prevents mitochondrial toxicity, oxidative stress, inflammation, and fibrosis progression. This review summarizes the possible molecular mechanism of SARO in the NAFLD.
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Affiliation(s)
- Devaraj Ezhilarasan
- Department of Pharmacology, Hepatology and Molecular Medicine Lab, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, Tamil Nadu 600 077, India.
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2
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Li J, Guo C, Wu J. The Agonists of Peroxisome Proliferator-Activated Receptor-γ for Liver Fibrosis. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:2619-2628. [PMID: 34168433 PMCID: PMC8219117 DOI: 10.2147/dddt.s310163] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/07/2021] [Indexed: 12/18/2022]
Abstract
Liver fibrosis is a common link in the transformation of acute and chronic liver diseases to cirrhosis. It is of great clinical significance to study the factors associated with the induction of liver fibrosis and elucidate the method of reversal. Peroxisome proliferator-activated receptors (PPARs) are a class of nuclear transcription factors that can be activated by peroxisome proliferators. PPARs play an important role in fibrosis of various organs, especially the liver, by regulating downstream targeted pathways, such as TGF-β, MAPKs, and NF-κB p65. In recent years, the development and screening of PPAR-γ ligands have become a focus of research. The PPAR-γ ligands include synthetic hypolipidemic and antidiabetic drugs. In addition, microRNAs, lncRNAs, circRNAs and nano new drugs have attracted research interest. In this paper, the research progress of PPAR-γ in the pathogenesis and treatment of liver fibrosis was discussed based on the relevant literature in recent years.
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Affiliation(s)
- Jingjing Li
- Department of Gastroenterology, Putuo People's Hospital, Tongji University, Shanghai, 200060, People's Republic of China.,Department of Gastroenterology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, 200072, People's Republic of China
| | - Chuanyong Guo
- Department of Gastroenterology, Putuo People's Hospital, Tongji University, Shanghai, 200060, People's Republic of China.,Department of Gastroenterology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, 200072, People's Republic of China
| | - Jianye Wu
- Department of Gastroenterology, Putuo People's Hospital, Tongji University, Shanghai, 200060, People's Republic of China
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3
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Gilgenkrantz H, Mallat A, Moreau R, Lotersztajn S. Targeting cell-intrinsic metabolism for antifibrotic therapy. J Hepatol 2021; 74:1442-1454. [PMID: 33631228 DOI: 10.1016/j.jhep.2021.02.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 12/12/2022]
Abstract
In recent years, there have been major advances in our understanding of the mechanisms underlying fibrosis progression and regression, and how coordinated interactions between parenchymal and non-parenchymal cells impact on the fibrogenic process. Recent studies have highlighted that metabolic reprogramming of parenchymal cells, immune cells (immunometabolism) and hepatic stellate cells is required to support the energetic and anabolic demands of phenotypic changes and effector functions. In this review, we summarise how targeting cell-intrinsic metabolic modifications of the main fibrogenic cell actors may impact on fibrosis progression and we discuss the antifibrogenic potential of metabolically targeted interventions.
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Affiliation(s)
- Helene Gilgenkrantz
- Université de Paris, INSERM, U1149, CNRS, ERL 8252, Centre de Recherche sur l'Inflammation (CRI), Laboratoire d'Excellence Inflamex, F-75018 Paris, France
| | - Ariane Mallat
- Université de Paris, INSERM, U1149, CNRS, ERL 8252, Centre de Recherche sur l'Inflammation (CRI), Laboratoire d'Excellence Inflamex, F-75018 Paris, France
| | - Richard Moreau
- Université de Paris, INSERM, U1149, CNRS, ERL 8252, Centre de Recherche sur l'Inflammation (CRI), Laboratoire d'Excellence Inflamex, F-75018 Paris, France
| | - Sophie Lotersztajn
- Université de Paris, INSERM, U1149, CNRS, ERL 8252, Centre de Recherche sur l'Inflammation (CRI), Laboratoire d'Excellence Inflamex, F-75018 Paris, France.
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Claveria-Cabello A, Colyn L, Arechederra M, Urman JM, Berasain C, Avila MA, Fernandez-Barrena MG. Epigenetics in Liver Fibrosis: Could HDACs be a Therapeutic Target? Cells 2020; 9:cells9102321. [PMID: 33086678 PMCID: PMC7589994 DOI: 10.3390/cells9102321] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/15/2020] [Accepted: 10/17/2020] [Indexed: 12/13/2022] Open
Abstract
Chronic liver diseases (CLD) represent a worldwide health problem. While CLDs may have diverse etiologies, a common pathogenic denominator is the presence of liver fibrosis. Cirrhosis, the end-stage of CLD, is characterized by extensive fibrosis and is markedly associated with the development of hepatocellular carcinoma. The most important event in hepatic fibrogenesis is the activation of hepatic stellate cells (HSC) following liver injury. Activated HSCs acquire a myofibroblast-like phenotype becoming proliferative, fibrogenic, and contractile cells. While transient activation of HSCs is part of the physiological mechanisms of tissue repair, protracted activation of a wound healing reaction leads to organ fibrosis. The phenotypic changes of activated HSCs involve epigenetic mechanisms mediated by non-coding RNAs (ncRNA) as well as by changes in DNA methylation and histone modifications. During CLD these epigenetic mechanisms become deregulated, with alterations in the expression and activity of epigenetic modulators. Here we provide an overview of the epigenetic alterations involved in fibrogenic HSCs transdifferentiation with particular focus on histones acetylation changes. We also discuss recent studies supporting the promising therapeutic potential of histone deacetylase inhibitors in liver fibrosis.
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Affiliation(s)
- Alex Claveria-Cabello
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
| | - Leticia Colyn
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
| | - Maria Arechederra
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain;
| | - Jesus M. Urman
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain;
- Department of Gastroenterology and Hepatology, Navarra University Hospital Complex, 31008 Pamplona, Spain
| | - Carmen Berasain
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain;
| | - Matias A. Avila
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain;
- Correspondence: (M.A.A.); (M.G.F.-B.); Tel.: +34-94-819-4700 (M.A.A.); +34-94-819-4700 (M.G.F.-B.)
| | - Maite G. Fernandez-Barrena
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (A.C.-C.); (L.C.); (M.A.); (C.B.)
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain;
- Correspondence: (M.A.A.); (M.G.F.-B.); Tel.: +34-94-819-4700 (M.A.A.); +34-94-819-4700 (M.G.F.-B.)
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Fabris L, Spirli C, Cadamuro M, Fiorotto R, Strazzabosco M. Emerging concepts in biliary repair and fibrosis. Am J Physiol Gastrointest Liver Physiol 2017; 313:G102-G116. [PMID: 28526690 PMCID: PMC5582882 DOI: 10.1152/ajpgi.00452.2016] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/20/2017] [Accepted: 05/11/2017] [Indexed: 01/31/2023]
Abstract
Chronic diseases of the biliary tree (cholangiopathies) represent one of the major unmet needs in clinical hepatology and a significant knowledge gap in liver pathophysiology. The common theme in cholangiopathies is that the target of the disease is the biliary tree. After damage to the biliary epithelium, inflammatory changes stimulate a reparative response with proliferation of cholangiocytes and restoration of the biliary architecture, owing to the reactivation of a variety of morphogenetic signals. Chronic damage and inflammation will ultimately result in pathological repair with generation of biliary fibrosis and clinical progression of the disease. The hallmark of pathological biliary repair is the appearance of reactive ductular cells, a population of cholangiocyte-like epithelial cells of unclear and likely mixed origin that are able to orchestrate a complex process that involves a number of different cell types, under joint control of inflammatory and morphogenetic signals. Several questions remain open concerning the histogenesis of reactive ductular cells, their role in liver repair, their mechanism of activation, and the signals exchanged with the other cellular elements cooperating in the reparative process. This review contributes to the current debate by highlighting a number of new concepts derived from the study of the pathophysiology of chronic cholangiopathies, such as congenital hepatic fibrosis, biliary atresia, and Alagille syndrome.
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Affiliation(s)
- Luca Fabris
- Department of Molecular Medicine, University of Padua School of Medicine, Padua, Italy; .,Liver Center, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut.,International Center for Digestive Health, University of Milan-Bicocca School of Medicine, Milan, Italy; and
| | - Carlo Spirli
- 2Liver Center, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; ,3International Center for Digestive Health, University of Milan-Bicocca School of Medicine, Milan, Italy; and
| | - Massimiliano Cadamuro
- 3International Center for Digestive Health, University of Milan-Bicocca School of Medicine, Milan, Italy; and ,4Department of Medicine and Surgery, University of Milan-Bicocca School of Medicine, Milan, Italy
| | - Romina Fiorotto
- 2Liver Center, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; ,3International Center for Digestive Health, University of Milan-Bicocca School of Medicine, Milan, Italy; and
| | - Mario Strazzabosco
- 2Liver Center, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; ,3International Center for Digestive Health, University of Milan-Bicocca School of Medicine, Milan, Italy; and ,4Department of Medicine and Surgery, University of Milan-Bicocca School of Medicine, Milan, Italy
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Rodríguez‐Aguilera JR, Guerrero‐Hernández C, Pérez‐Molina R, Cadena‐del‐Castillo CE, Pérez‐Cabeza de Vaca R, Guerrero‐Celis N, Domínguez‐López M, Murillo‐de‐Ozores AR, Arzate‐Mejía R, Recillas‐Targa F, Chagoya de Sánchez V. Epigenetic Effects of an Adenosine Derivative in a Wistar Rat Model of Liver Cirrhosis. J Cell Biochem 2017; 119:401-413. [DOI: 10.1002/jcb.26192] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/06/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Jesús Rafael Rodríguez‐Aguilera
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Carlos Guerrero‐Hernández
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Rosario Pérez‐Molina
- Departamento de Genética MolecularInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Carla Elizabeth Cadena‐del‐Castillo
- Departamento de Genética MolecularInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Rebeca Pérez‐Cabeza de Vaca
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Nuria Guerrero‐Celis
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Mariana Domínguez‐López
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Adrián Rafael Murillo‐de‐Ozores
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Rodrigo Arzate‐Mejía
- Departamento de Genética MolecularInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Félix Recillas‐Targa
- Departamento de Genética MolecularInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
| | - Victoria Chagoya de Sánchez
- Departamento de Biología Celular y DesarrolloInstituto de Fisiología Celular, UNAMCircuito Exterior s/n Ciudad UniversitariaCoyoacán 04510, Cd.Mx.México
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7
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The stellate cell system (vitamin A-storing cell system). Anat Sci Int 2017; 92:387-455. [PMID: 28299597 DOI: 10.1007/s12565-017-0395-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Past, present, and future research into hepatic stellate cells (HSCs, also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, or Ito cells) are summarized and discussed in this review. Kupffer discovered black-stained cells in the liver using the gold chloride method and named them stellate cells (Sternzellen in German) in 1876. Wake rediscovered the cells in 1971 using the same gold chloride method and various modern histological techniques including electron microscopy. Between their discovery and rediscovery, HSCs disappeared from the research history. Their identification, the establishment of cell isolation and culture methods, and the development of cellular and molecular biological techniques promoted HSC research after their rediscovery. In mammals, HSCs exist in the space between liver parenchymal cells (PCs) or hepatocytes and liver sinusoidal endothelial cells (LSECs) of the hepatic lobule, and store 50-80% of all vitamin A in the body as retinyl ester in lipid droplets in the cytoplasm. SCs also exist in extrahepatic organs such as pancreas, lung, and kidney. Hepatic (HSCs) and extrahepatic stellate cells (EHSCs) form the stellate cell (SC) system or SC family; the main storage site of vitamin A in the body is HSCs in the liver. In pathological conditions such as liver fibrosis, HSCs lose vitamin A, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan, glycosaminoglycan, and adhesive glycoproteins. The morphology of these cells also changes from the star-shaped HSCs to that of fibroblasts or myofibroblasts.
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Berberine Inhibition of Fibrogenesis in a Rat Model of Liver Fibrosis and in Hepatic Stellate Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:8762345. [PMID: 27239214 PMCID: PMC4867075 DOI: 10.1155/2016/8762345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/15/2016] [Indexed: 02/06/2023]
Abstract
Aim. To examine the effect of berberine (BBR) on liver fibrosis and its possible mechanisms through direct effects on hepatic stellate cells (HSC). Methods. The antifibrotic effect of BBR was determined in a rat model of bile duct ligation- (BDL-) induced liver fibrosis. Multiple cellular and molecular approaches were introduced to examine the effects of BBR on HSC. Results. BBR potently inhibited hepatic fibrosis induced by BDL in rats. It exhibited cytotoxicity to activated HSC at doses nontoxic to hepatocytes. High doses of BBR induced apoptosis of activated HSC, which was mediated by loss of mitochondrial membrane potential and Bcl-2/Bax imbalance. Low doses of BBR suppressed activation of HSC as evidenced by the inhibition of α-smooth muscle actin (α-SMA) expression and cell motility. BBR did not affect Smad2/3 phosphorylation but significantly activated 5' AMP-activated protein kinase (AMPK) signalling, which was responsible for the transcriptional inhibition by BBR of profibrogenic factors α-SMA and collagen in HSC. Conclusion. BBR is a promising agent for treating liver fibrosis through multiple mechanisms, at least partially by directly targeting HSC and by inhibiting the AMPK pathway. Its value as an antifibrotic drug in patients with liver disease deserves further investigation.
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van der Veen JN, Lingrell S, Gao X, Quiroga AD, Takawale A, Armstrong EA, Yager JY, Kassiri Z, Lehner R, Vance DE, Jacobs RL. Pioglitazone attenuates hepatic inflammation and fibrosis in phosphatidylethanolamine N-methyltransferase-deficient mice. Am J Physiol Gastrointest Liver Physiol 2016; 310:G526-38. [PMID: 26797396 DOI: 10.1152/ajpgi.00243.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/21/2015] [Indexed: 01/31/2023]
Abstract
Phosphatidylethanolamine N-methyltransferase (PEMT) is an important enzyme in hepatic phosphatidylcholine (PC) biosynthesis. Pemt(-/-) mice are protected against high-fat diet (HFD)-induced obesity and insulin resistance; however, these mice develop nonalcoholic fatty liver disease (NAFLD). We hypothesized that peroxisomal proliferator-activated receptor-γ (PPARγ) activation by pioglitazone might stimulate adipocyte proliferation, thereby directing lipids from the liver toward white adipose tissue. Pioglitazone might also act directly on PPARγ in the liver to improve NAFLD. Pemt(+/+) and Pemt(-/-) mice were fed a HFD with or without pioglitazone (20 mg·kg(-1)·day(-1)) for 10 wk. Pemt(-/-) mice were protected from HFD-induced obesity but developed NAFLD. Treatment with pioglitazone caused an increase in body weight gain in Pemt(-/-) mice that was mainly due to increased adiposity. Moreover, pioglitazone improved NAFLD in Pemt(-/-) mice, as indicated by a 35% reduction in liver weight and a 57% decrease in plasma alanine transaminase levels. Livers from HFD-fed Pemt(-/-) mice were steatotic, inflamed, and fibrotic. Hepatic steatosis was still evident in pioglitazone-treated Pemt(-/-) mice; however, treatment with pioglitazone reduced hepatic fibrosis, as evidenced by reduced Sirius red staining and lowered mRNA levels of collagen type Iα1 (Col1a1), tissue inhibitor of metalloproteinases 1 (Timp1), α-smooth muscle actin (Acta2), and transforming growth factor-β (Tgf-β). Similarly, oxidative stress and inflammation were reduced in livers from Pemt(-/-) mice upon treatment with pioglitazone. Together, these data show that activation of PPARγ in HFD-fed Pemt(-/-) mice improved liver function, while these mice were still protected against diet-induced obesity and insulin resistance.
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Affiliation(s)
- Jelske N van der Veen
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Susanne Lingrell
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Xia Gao
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ariel D Quiroga
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Abhijit Takawale
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Edward A Armstrong
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Jerome Y Yager
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Zamaneh Kassiri
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Richard Lehner
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Dennis E Vance
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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10
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Decoding liver injury: A regulatory role for histone modifications. Int J Biochem Cell Biol 2015; 67:188-93. [DOI: 10.1016/j.biocel.2015.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/05/2015] [Accepted: 03/11/2015] [Indexed: 01/05/2023]
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Tsukamoto H. Metabolic reprogramming and cell fate regulation in alcoholic liver disease. Pancreatology 2015; 15:S61-5. [PMID: 25800177 PMCID: PMC4515387 DOI: 10.1016/j.pan.2015.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 02/27/2015] [Accepted: 03/02/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Alcoholic liver disease (ALD) should be defined as a life-style metabolic disease. Its pathogenesis is driven by altered cell fate of both parenchymal and non-parenchymal liver cell types, contributing to different pathologic spectra. A critical turning point in progression of ALD is chronic alcoholic steatohepatitis (ASH) or alcoholic neutrophilic hepatitis (AH), which markedly predisposes patients to most devastating ALD sequela, cirrhosis and liver cancer. RESULTS Our research identifies the pivotal roles of unique metabolic reprogramming in M1 activation of hepatic macrophages (HM) and myofibroblastic activation (MF) of hepatic stellate cells (HSC) in the genesis of inflammation and fibrosis, the two key histological features of chronic ASH and neutrophilic AH. For M1 HM activation, heightened proinflammatory iron redox signaling in endosomes or caveosomes results from altered iron metabolism and storage, promoting IKK/NF-kB activation via interactive activation of p21ras, TAK1, and PI3K. For MF cell fate regulation of HSC, activation of the morphogen Wnt pathway caused by the nuclear protein NECDIN or the single-pass trans-membrane protein DLK1, reprograms lipid metabolism via MeCP2-mediated epigenetic repression of the key HSC quiescence gene Ppar-γ. CONCLUSIONS The findings from these studies re-enforce the importance of metabolic reprogramming in cell fate regulation required for the pathogenesis of ALD.
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Affiliation(s)
- Hidekazu Tsukamoto
- Southern California Research Center ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine of the University of Southern California, Greater Los Angeles VA Healthcare System, Los Angeles, California, USA
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12
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Sesame oil attenuates nutritional fibrosing steatohepatitis by modulating matrix metalloproteinases-2, 9 and PPAR-γ. J Nutr Biochem 2013; 25:337-44. [PMID: 24445078 DOI: 10.1016/j.jnutbio.2013.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 12/22/2022]
Abstract
Sesame oil is a nutrient-rich antioxidant popular in alternative medicine. It contains sesamin, sesamol, and sesamolin, all of which contribute to its improved liver function in various animal model studies. However, its effect on nutritional fibrosing steatohepatitis is unclear. We investigated therapeutic sesame oil on matrix metalloproteinases-2, 9 (MMP-2, 9) in nutritional fibrosing steatohepatitic mice. C57BL/6 J mice were fed with methionine-choline deficient (MCD) diet for 35 days to induce fibrosing steatohepatitis. Sesame oil was treated from 29-35th day. Body weight, steatosis, aspartate transaminase, alanine transaminase, peroxisome proliferator-activated receptor (PPAR)-γ, α-smooth muscle actin (α-SMA), MMP-2, 9, and tissue inhibitor of matrix metalloproteinases (TIMP)-1 were assessed after 35 days. All tested parameters except TIMP-1 and PPAR-γ were higher in MCD fed mice than in normal control mice. Mice fed with MCD diet for 4 weeks showed severe liver injury with steatosis, necrotic-inflammation, and fibrosis. In sesame-oil (4 ml)-treated mice, all tested parameters except TIMP-1, α-SMA, and PPAR-γ were significantly attenuated compared with MCD fed mice. Sesame oil inhibited MMP-2, 9 activities, but up-regulated TIMP-1 expression in MCD fed mice. In addition, a histological analysis of liver tissue samples showed that sesame oil provided significant protection against fibrosis. We conclude that therapeutic sesame oil protects against fibrosing steatohepatitis by inhibiting MMP-2, 9 activities, up-regulating TIMP-1 expression, and PPAR-γ.
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Bian EB, Huang C, Wang H, Chen XX, Tao H, Zhang L, Lv XW, Li J. The role of methyl-CpG binding protein 2 in liver fibrosis. Toxicology 2013; 309:9-14. [PMID: 23619607 DOI: 10.1016/j.tox.2013.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 04/15/2013] [Accepted: 04/15/2013] [Indexed: 01/07/2023]
Abstract
Liver injury is induced by various insults such as alcohol abuse, if insults persist, may result in the formation of liver fibrosis. Hepatic stellate cell (HSC) activation and transdifferentiation into hepatic myofibroblast, accompanied with potent pro-inflammatory and pro-fibrogenic activities and the down-regulation of anti-inflammatory anti-fibrogenic in gene expression in coordination with epigenetic modifications at the level of the chromatin structure, are pivotal events in liver fibrogenesis. In this review we focus on the role of the methyl-CpG binding protein 2 (MeCP2) transcriptional regulation of different target genes and the interaction MeCP2 with microRNAs (miRNAs) during liver fibrosis. In addition, we address different signaling pathways interacted with MeCP2 regulated HSC activation. Such approaches provide valuable insights into the potential targets of liver fibrosis, and are useful pointers for the development of future therapeutic strategies.
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Affiliation(s)
- Er-Bao Bian
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
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14
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Zhang F, Kong D, Lu Y, Zheng S. Peroxisome proliferator-activated receptor-γ as a therapeutic target for hepatic fibrosis: from bench to bedside. Cell Mol Life Sci 2013; 70:259-76. [PMID: 22699820 PMCID: PMC11113701 DOI: 10.1007/s00018-012-1046-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/18/2012] [Accepted: 05/29/2012] [Indexed: 02/07/2023]
Abstract
Hepatic fibrosis is a dynamic chronic liver disease occurring as a consequence of wound-healing responses to various hepatic injuries. This disorder is one of primary predictors for liver-associated morbidity and mortality worldwide. To date, no pharmacological agent has been approved for hepatic fibrosis or could be recommended for routine use in clinical context. Cellular and molecular understanding of hepatic fibrosis has revealed that peroxisome proliferator-activated receptor-γ (PPARγ), the functioning receptor for antidiabetic thiazolidinediones, plays a pivotal role in the pathobiology of hepatic stellate cells (HSCs), whose activation is the central event in the pathogenesis of hepatic fibrosis. Activation of PPARγ inhibits HSC collagen production and modulates HSC adipogenic phenotype at transcriptional and epigenetic levels. These molecular insights indicate PPARγ as a promising drug target for antifibrotic chemotherapy. Intensive animal studies have demonstrated that stimulation of PPARγ regulatory system through gene therapy approaches and PPARγ ligands has therapeutic promise for hepatic fibrosis induced by a variety of etiologies. At the same time, thiazolidinedione agents have been investigated for their clinical benefits primarily in patients with nonalcoholic steatohepatitis, a common metabolic liver disorder with high potential to progress to fibrosis and liver-related death. Although some studies have shown initial promise, none has established long-term efficacy in well-controlled randomized clinical trials. This comprehensive review covers the 10-year discoveries of the molecular basis for PPARγ regulation of HSC pathophysiology and then focuses on the animal investigations and clinical trials of various therapeutic modalities targeting PPARγ for hepatic fibrosis.
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Affiliation(s)
- Feng Zhang
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Desong Kong
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Yin Lu
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210046 China
- National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing, 210046 China
| | - Shizhong Zheng
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210046 China
- National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing, 210046 China
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15
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Yang MD, Chiang YM, Higashiyama R, Asahina K, Mann DA, Mann J, Wang C, Tsukamoto H. Rosmarinic acid and baicalin epigenetically derepress peroxisomal proliferator-activated receptor γ in hepatic stellate cells for their antifibrotic effect. Hepatology 2012; 55:1271-81. [PMID: 22095555 PMCID: PMC3302956 DOI: 10.1002/hep.24792] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 10/25/2011] [Indexed: 01/20/2023]
Abstract
UNLABELLED Hepatic stellate cells (HSCs) undergo myofibroblastic transdifferentiation (activation) to participate in liver fibrosis and identification of molecular targets for this cell fate regulation is essential for development of efficacious therapeutic modalities for the disease. Peroxisomal proliferator-activated receptor γ (PPARγ) is required for differentiation of HSCs and its epigenetic repression underlies HSC activation. The herbal prescription Yang-Gan-Wan (YGW) prevents liver fibrosis, but its active ingredients and molecular mechanisms are unknown. Here we demonstrate YGW prevents and reverses HSC activation by way of epigenetic derepression of Pparγ involving reductions in MeCP2 expression and its recruitment to Pparγ promoter, suppressed expression of PRC2 methyltransferase EZH2, and consequent reduction of H2K27di-methylation at the 3' exon. High-performance liquid chromatography / mass spectrometry (HPLC/MS) and nuclear magnetic resonance (NMR) analyses identify polyphenolic rosmarinic acid (RA) and baicalin (BC) as active phytocompounds. RA and BC suppress the expression and signaling by canonical Wnts, which are implicated in the aforementioned Pparγ epigenetic repression. RA treatment in mice with existing cholestatic liver fibrosis inhibits HSC activation and progression of liver fibrosis. CONCLUSION These results demonstrate a therapeutic potential of YGW and its active component RA and BC for liver fibrosis by way of Pparγ derepression mediated by suppression of canonical Wnt signaling in HSCs.
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Affiliation(s)
- Melissa D. Yang
- Southern California Research Center for ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Yi-Ming Chiang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Reiichi Higashiyama
- Southern California Research Center for ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Kinji Asahina
- Southern California Research Center for ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Derek A. Mann
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, UK
| | - Jelena Mann
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, UK
| | - Clay Wang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Hidekazu Tsukamoto
- Southern California Research Center for ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA
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Tsukamoto H, Zhu NL, Wang J, Asahina K, Machida K. Morphogens and hepatic stellate cell fate regulation in chronic liver disease. J Gastroenterol Hepatol 2012; 27 Suppl 2:94-8. [PMID: 22320925 PMCID: PMC3337168 DOI: 10.1111/j.1440-1746.2011.07022.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hepatic stellate cells (HSC) are the liver mesenchymal cell type which responds to hepatocellular damage and participates in wound healing. Although HSC myofibroblastic trans-differentiation (activation) is implicated in excessive extracellular matrix deposition, molecular understanding of this phenotypic switch from the viewpoint of cell fate regulation is limited. Recent studies demonstrate the roles of anti-adipogenic morphogens (Wnt, Necdin, Shh) in epigenetic repression of the HSC differentiation gene Pparγ as a causal event in HSC activation. These morphogens have positive cross-interactions which converge to epigenetic repression of Pparγ involving the methyl-CpG binding protein MeCP2. However, these morphogens expressed by activated HSC may also participate in cross-talk between HSC and hepatoblasts/hepatocytes to support liver regeneration, and their aberrant regulation may contribute to liver tumorigenesis. Implications of HSC-derived morphogens in these possibilities are discussed.
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Affiliation(s)
- Hidekazu Tsukamoto
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA,Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Nian-Ling Zhu
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Jiaohong Wang
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Kinji Asahina
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Keigo Machida
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA
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17
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Tailleux A, Wouters K, Staels B. Roles of PPARs in NAFLD: potential therapeutic targets. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:809-18. [PMID: 22056763 DOI: 10.1016/j.bbalip.2011.10.016] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/14/2011] [Accepted: 10/18/2011] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a liver pathology with increasing prevalence due to the obesity epidemic. Hence, NAFLD represents a rising threat to public health. Currently, no effective treatments are available to treat NAFLD and its complications such as cirrhosis and liver cancer. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors which regulate lipid and glucose metabolism as well as inflammation. Here we review recent findings on the pathophysiological role of PPARs in the different stages of NAFLD, from steatosis development to steatohepatitis and fibrosis, as well as the preclinical and clinical evidence for potential therapeutical use of PPAR agonists in the treatment of NAFLD. PPARs play a role in modulating hepatic triglyceride accumulation, a hallmark of the development of NAFLD. Moreover, PPARs may also influence the evolution of reversible steatosis toward irreversible, more advanced lesions. Presently, large controlled trials of long duration are needed to assess the long-term clinical benefits of PPAR agonists in humans. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Anne Tailleux
- Université Lille Nord de France, F-59000 Lille, France
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18
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Castilho-Fernandes A, de Almeida DC, Fontes AM, Melo FUF, Picanço-Castro V, Freitas MC, Orellana MD, Palma PVB, Hackett PB, Friedman SL, Covas DT. Human hepatic stellate cell line (LX-2) exhibits characteristics of bone marrow-derived mesenchymal stem cells. Exp Mol Pathol 2011; 91:664-72. [PMID: 21930125 DOI: 10.1016/j.yexmp.2011.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 09/02/2011] [Accepted: 09/02/2011] [Indexed: 12/13/2022]
Abstract
The LX-2 cell line has characteristics of hepatic stellate cells (HSCs), which are considered pericytes of the hepatic microcirculatory system. Recent studies have suggested that HSCs might have mesenchymal origin. We have performed an extensive characterization of the LX-2 cells and have compared their features with those of mesenchymal cells. Our data show that LX-2 cells have a phenotype resembling activated HSCs as well as bone marrow-derived mesenchymal stem cells (BM-MSCs). Our immunophenotypic analysis showed that LX-2 cells are positive for activated HSC markers (αSMA, GFAP, nestin and CD271) and classical mesenchymal makers (CD105, CD44, CD29, CD13, CD90, HLA class-I, CD73, CD49e, CD166 and CD146) but negative for the endothelial marker CD31 and endothelial progenitor cell marker CD133 as well as hematopoietic markers (CD45 and CD34). LX-2 cells also express the same transcripts found in immortalized and primary BM-MSCs (vimentin, annexin 5, collagen 1A, NG2 and CD140b), although at different levels. We show that LX-2 cells are capable to differentiate into multilineage mesenchymal cells in vitro and can stimulate new blood vessel formation in vivo. LX-2 cells appear not to possess tumorigenic potential. Thus, the LX-2 cell line behaves as a multipotent cell line with similarity to BM-MSCs. This line should be useful for further studies to elucidate liver regeneration mechanisms and be the foundation for development of hepatic cell-based therapies.
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Affiliation(s)
- Andrielle Castilho-Fernandes
- Faculty of Medicine of Ribeirão Preto, Department of Clinical Medicine, University of São Paulo, Av. Bandeirantes, 3900 (6° andar do HC) Ribeirão Preto 14048-900, Brazil.
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19
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Peroxisome proliferator-activated receptor γ: innate protection from excessive fibrogenesis and potential therapeutic target in systemic sclerosis. Curr Opin Rheumatol 2011; 22:671-6. [PMID: 20693905 DOI: 10.1097/bor.0b013e32833de1a7] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW Progressive organ fibrosis and pulmonary arterial hypertension (PAH) are the leading causes of death in patients with systemic sclerosis (SSc). However, the pathogenesis and the link between these two processes remain obscure. A better understanding of these events is needed in order to facilitate the discovery and development of effective therapies for SSc. RECENT FINDINGS Recent reports provide evidence that the orphan receptor peroxisome proliferator-activated receptor γ (PPARγ), better known for its pivotal role in metabolism, has potent effects on inflammation, fibrogenesis and vascular remodeling and is important in the pathogenesis of fibrosis and PAH, and as a potential therapeutic target in SSc. The studies discussed in this review indicate that ligands of PPARγ potently modulate connective tissue turnover and suggest that aberrant expression or function of PPARγ is associated with, and very likely contributes to, the progression of pathological fibrosis and vascular remodeling. These observations are of particularly relevance because FDA-approved drugs of the thiazolidinedione class currently used for the treatment of obesity-associated type 2 diabetes activate PPARγ signaling. Moreover, novel PPARγ ligands with selective activity are under development or in clinical trials for inflammatory diseases, asthma, Alzheimer disease and cancer. SUMMARY Drugs targeting the PPARγ pathway might be effective for the control of fibrosis as well as pathological vascular remodeling underlying PAH and, therefore, might have a therapeutic potential in SSc. A greater understanding of the mechanisms underlying the antifibrogenic and vascular remodeling activities of PPARγ ligands will be necessary in order to advance these drugs into clinical use.
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20
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Abstract
In most cholangiopathies, liver diseases of different etiologies in which the biliary epithelium is the primary target in the pathogenic sequence, the central mechanism involves inflammation. Inflammation, characterized by pleomorphic peribiliary infiltrate containing fibroblasts, macrophages, lymphocytes, as well as endothelial cells and pericytes, is associated to the emergence of "reactive cholangiocytes." These biliary cells do not possess bile secretory functions, are in contiguity with terminal cholangioles, and are of a less-differentiated phenotype. They have acquired several mesenchymal properties, including motility and ability to secrete a vast number of proinflammatory chemo/cytokines and growth factors along with de novo expression of a rich receptor machinery. These functional properties enable reactive cholangiocytes to establish intimate contacts and to mutually exchange a variety of paracrine signals with the different mesenchymal cell types populating the portal infiltrate. The extensive crosstalk between the epithelial and mesenchymal compartments is the driver of liver repair mechanisms in cholangiopathies, ultimately evolving toward portal fibrosis. Herein, the authors first review the properties of the different cell types involved in their interaction, and then analyze the underlying molecular mechanisms as they relate to liver repair in cholangiopathies.
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Affiliation(s)
- Luca Fabris
- Department of Surgical and Gastroenterological Sciences, University of Padua, Padova, Italy,Center for Liver Research (CeLiveR), Bergamo, Italy
| | - Mario Strazzabosco
- Center for Liver Research (CeLiveR), Bergamo, Italy,Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut,Department of Clinical Medicine, University of Milano-Bicocca, Milan, Italy
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21
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Abstract
Fibrosis is a common feature of chronic liver injury and is initiated by cell death inside the liver. Hepatocyte death results in apoptotic bodies and other cellular debris, which are phagocytosed by hepatic stellate cells (HSCs), resulting in their activation, proliferation, differentiation, and matrix deposition. This profibrotic effect of cellular death is balanced by an antifibrotic effect of HSC death. Many HSC survival signals are obtained from the extracellular matrix, and active proapoptotic signals are provided by immune cells, particularly natural killer (NK) cells. Quiescent HSCs are relatively resistant to apoptotic signals but become sensitive after activation. The important role of NK cells in inducing HSC apoptosis may explain the increased fibrosis associated with immune suppression (e.g., in the transplant recipient) and HIV infection. HSCs also undergo senescence, which limits their function and sensitizes them to apoptosis.
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Affiliation(s)
- Wajahat Mehal
- Section of Digestive Diseases, Yale University, New Haven, Connecticut
| | - Avlin Imaeda
- Section of Digestive Diseases, Yale University, New Haven, Connecticut
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22
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Son G, Hines IN, Lindquist J, Schrum LW, Rippe RA. Inhibition of phosphatidylinositol 3-kinase signaling in hepatic stellate cells blocks the progression of hepatic fibrosis. Hepatology 2009; 50:1512-23. [PMID: 19790269 PMCID: PMC2913293 DOI: 10.1002/hep.23186] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
UNLABELLED The hepatic stellate cell (HSC) is the primary cell type in the liver responsible for excess collagen deposition during fibrosis. Following a fibrogenic stimulus the cell changes from a quiescent vitamin A-storing cell to an activated cell type associated with increased extracellular matrix synthesis and increased cell proliferation. The phosphatidylinositol 3-kinase (PI3K) signaling pathway has been shown to regulate several aspects of HSC activation in vitro, including collagen synthesis and cell proliferation. Using a targeted approach to inhibit PI3K signaling specifically in HSCs, we investigated the role of PI3K in HSCs using a rodent model of hepatic fibrosis. An adenovirus expressing a dominant negative form of PI3K under control of the smooth muscle alpha-actin (alphaSMA) promoter was generated (Ad-SMAdnPI3K). Transducing HSCs with Ad-SMAdnPI3K resulted in decreased proliferation, migration, collagen expression, and several additional profibrogenic genes, while also promoting cell death. Inhibition of PI3K signaling was also associated with reduced activation of Akt, p70 S6 kinase, and extracellular regulated kinase signaling as well as reduced cyclin D1 expression. Administering Ad-SMAdnPI3K to mice following bile duct ligation resulted in reduced HSC activation and decreased extracellular matrix deposition, including collagen expression. A reduction in profibrogenic mediators, including transforming growth factor beta, tissue inhibitor of metalloproteinase 1, and connective tissue growth factor was also noted. However, liver damage, assessed by alanine aminotransferase levels, was not reduced. CONCLUSION Inhibition of PI3K signaling in HSCs during active fibrogenesis inhibits extracellular matrix deposition, including synthesis of type I collagen, and reduces expression of profibrogenic factors. These data suggest that targeting PI3K signaling in HSCs may represent an effective therapeutic target for hepatic fibrosis.
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Affiliation(s)
- Gakuhei Son
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Ian N. Hines
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Jeff Lindquist
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Laura W. Schrum
- Department of Biology, University of North Carolina, Charlotte, North Carolina
| | - Richard A. Rippe
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
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Abstract
Liver cirrhosis is a major cause of morbidity and mortality worldwide and has very limited therapeutic options. Regardless of the aetiology, hepatic fibrosis is a characteristic feature of chronic liver disease. Our knowledge regarding the pathogenesis of this scarring has grown exponentially in the past 25 years. It has now clear that this is a highly dynamic process and the long-held dogma that it is irreversible and relentlessly progressive is now being challenged. In this review, we will summarise the key pathogenic mechanisms at play and will focus on the evidence demonstrating that liver fibrosis is reversible in humans and animal models. In particular, we will examine the role of hepatic stellate cells, MMPs, TIMPs and macrophages in this process. Finally, we will discuss some of the studies aimed to therapeutically target the resolution of fibrosis and their potential for translation into a badly-needed treatment modality in the clinical setting.
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Affiliation(s)
- Prakash Ramachandran
- Centre for Inflammation Research to MRC, University of Edinburgh Centre for Inflammation Research, Edinburgh, United Kingdom
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24
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Zhang GY, Cheng T, Zheng MH, Yi CG, Pan H, Li ZJ, Chen XL, Yu Q, Jiang LF, Zhou FY, Li XY, Yang JQ, Chu TG, Gao WY. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist inhibits transforming growth factor-beta1 and matrix production in human dermal fibroblasts. J Plast Reconstr Aesthet Surg 2009; 63:1209-16. [PMID: 19617014 DOI: 10.1016/j.bjps.2009.06.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 03/31/2009] [Accepted: 06/08/2009] [Indexed: 11/25/2022]
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists are increasingly used in patients with diabetes, and some studies have suggested a beneficial effect on organ fibrosis, but their effects on dermal cell growth and extracellular matrix (ECM) turnover are unknown. To investigate the effect of the PPAR-gamma agonist troglitazone on cell growth and matrix production in human dermal fibroblasts (HDF), HDF were cultured and grown in a different concentration of troglitazone. PPAR-gamma expression and matrix production were measured in HDF in the presence of troglitazone. The mRNA expressions of TGF-beta1, collagen I (Col I) and fibronectin (FN) were determined by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). The protein of transforming growth factor-beta1 (TGF-beta1) was determined by enzyme-linked immunosorbent assay (ELISA) and proteins of Col I and FN were determined by Western blotting. The mRNA expression of TGF-beta1, Col I and FN were significantly decreased in HDF in 15-30 micromol l(-1) troglitazone compared to the control group with Dulbecco's modified Eagle's medium (P<0.01). An obvious decrease of TGF-beta1 protein was found in troglitazone-treated groups as compared to the control group (P<0.05). Exposure of HDF to troglitazone reduced col I secretion (P<0.05), and fibronectin secretion (P<0.05). This study suggests that PPAR-gamma agonist will provide a novel approach with therapeutic potential in dermal fibrosis, such as hypertrophic scar, keloid and so on.
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Affiliation(s)
- Guo-You Zhang
- Department of Hand and Plastic Surgery, The second Affiliated Hospital of Wenzhou Medical College, Xueyuan West Road 109#, Wenzhou 325027, Zhejiang Province, PR China
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25
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Rosiglitazone prevents high glucose-induced vascular endothelial growth factor and collagen IV expression in cultured mesangial cells. EXPERIMENTAL DIABETES RESEARCH 2009; 2009:910783. [PMID: 19609456 PMCID: PMC2709725 DOI: 10.1155/2009/910783] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/13/2008] [Accepted: 03/27/2009] [Indexed: 11/18/2022]
Abstract
Peroxisome proliferator-activated receptor (PPARγ), a ligand-dependent transcription factor, negatively modulates high glucose effects. We postulated that rosiglitazone (RSG), an activator of PPARγ prevents the upregulation of vascular endothelial growth factor (VEGF) and collagen IV by mesangial cells exposed to high glucose. Primary cultured rat mesangial cells were growth-arrested in 5.6 mM (NG) or 25 mM D-glucose (HG) for up to 48 hours. In HG, PPARγ mRNA and protein were reduced within 3 h, and enhanced ROS generation, expression of p22phox, VEGF and collagen IV, and PKC-ζ membrane association were prevented by RSG. In NG, inhibition of PPARγ caused ROS generation and VEGF expression that were unchanged by RSG. Reduced AMP-activated protein kinase (AMPK) phosphorylation in HG was unchanged with RSG, and VEGF expression was unaffected by AMPK inhibition. Hence, PPARγ is a negative modulator of HG-induced signaling that acts through PKC-ζ but not AMPK and regulates VEGF and collagen IV expression by mesangial cells.
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26
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Mann J, Mann DA. Transcriptional regulation of hepatic stellate cells. Adv Drug Deliv Rev 2009; 61:497-512. [PMID: 19393271 DOI: 10.1016/j.addr.2009.03.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 03/10/2009] [Indexed: 02/08/2023]
Abstract
Hepatic stellate cell (HSC) activation is a process of cellular transdifferentiation in which, upon liver injury, the quiescent vitamin A storing perisinusoidal HSC is converted into a wound-healing myofibroblast and acquires potent pro-inflammatory and pro-fibrogenic activities. This remarkable phenotypic transformation is underpinned by changes in the expression of a vast number of genes. In this review we survey current knowledge of the transcription factors that either control HSC activation or which regulate specific fibrogenic functions of the activated HSC such as collagen expression, proliferation and resistance to apoptosis.
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Gressner OA. About coffee, cappuccino and connective tissue growth factor-Or how to protect your liver!? ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2009; 28:1-10. [PMID: 21783975 DOI: 10.1016/j.etap.2009.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 02/05/2009] [Accepted: 02/11/2009] [Indexed: 05/31/2023]
Abstract
Several epidemiological studies suggest that coffee drinking is inversely correlated with the risk of development of liver fibrosis. However, a causal, mechanistic explanation has long been pending. New results indicate that the methylxanthine caffeine, major component of coffee and the most widely consumed pharmacologically active substance in the world, might be responsible for this phenomenon as it, and even more potently its derived primary metabolite paraxanthine, inhibits transforming growth factor (TGF)-β-dependent and -independent synthesis of connective tissue growth factor (CTGF/CCN2) in liver parenchymal cells in vitro and in vivo. CTGF plays a crucial role in the fibrotic remodeling of various organs which has therefore frequently been proposed as therapeutic target in the management of fibrotic disorders. This article summarizes the clinical-epidemiological observations as well as the pathophysiological background of the antifibrotic effects of coffee consumption and provides suggestions for the therapeutic use of caffeine and its derived metabolic methylxanthines as potentially powerful drugs in patients with chronic fibrogenic liver disease by their inhibitory effect on (hepatocellular) CTGF synthesis.
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Affiliation(s)
- Olav A Gressner
- Institute of Clinical Chemistry and Pathobiochemistry, Central Laboratory, RWTH-University Hospital, Pauwelsstraße 30, 52074 Aachen, Germany
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28
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Mallat A, Lotersztajn S. [Liver fibrosis: from pathophysiology to therapeutic openings]. ACTA ACUST UNITED AC 2009; 33:789-98. [PMID: 19560889 DOI: 10.1016/j.gcb.2009.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Understanding of liver fibrosis pathogenesis has undergone tremendous advances over the past twenty years. In this respect, demonstration of the reversibility of fibrosis was a major turnpoint. The panel of therapeutic targets is continuously expanding. Clinical development has however remained limited, heretofore, but should rapidly progress owing to the availability of accurate non-invasive methods for assessment of fibrosis, to improvement in the selection patients included in therapeutic trials, and to the development of cell specific targeting devices for agents at risk of adverse effects.
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Affiliation(s)
- A Mallat
- Service d'Hépatologie et de Gastroentérologie, Groupe Hospitalier Henri-Mondor-Albert-Chenevier, Assistance Publique-Hôpitaux de Paris, 94010 Créteil cedex, France.
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29
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Kong X, Fang M, Fang F, Li P, Xu Y. PPARgamma enhances IFNgamma-mediated transcription and rescues the TGFbeta antagonism by stimulating CIITA in vascular smooth muscle cells. J Mol Cell Cardiol 2009; 46:748-57. [PMID: 19358337 DOI: 10.1016/j.yjmcc.2009.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Chronic inflammatory response and active vascular remodeling are two featured pathophysiological events during atherogenesis. Gamma interferon (IFN-gamma) modulates these two processes through transcriptional control of major histocompatibility complex II (MHC II) and collagen type I (COL1A2) genes, mediated by class II transactivator (CIITA). Transforming growth factor (TGF-beta) antagonizes the effect of IFN-gamma in part by dampening the expression of CIITA. Here we report that peroxisome proliferator activated receptor gamma (PPARgamma) enhanced MHC II activation and COL1A2 repression by IFN-gamma while rescuing the antagonism by TGF-beta in a CIITA-dependent manner in human aortic smooth muscle cells judged by quantitative PCR and luciferase reporter assays. PPARgamma exerted its effect by augmenting the levels of CIITA and stimulating CIITA recruitment to target promoters as evidenced by chromatin immunoprecipitation assays. The up-regulation of CIITA levels was the result of PPARgamma-mediated transcriptional activation of CIITA through promoter IV, and increased CIITA protein stability. Thus, our data suggest that PPARgamma could be a key factor in fine-tuning inflammation as well as restructuring of vessel walls during atherogenesis by acting as a "balance tipper" of the differential effects exerted by cytokines.
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Affiliation(s)
- Xiaocen Kong
- Atherosclerosis Research Center, Nanjing Medical University, Nanjing, Jiangsu 210029, China
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30
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Ghosh AK, Bhattacharyya S, Wei J, Kim S, Barak Y, Mori Y, Varga J. Peroxisome proliferator-activated receptor-gamma abrogates Smad-dependent collagen stimulation by targeting the p300 transcriptional coactivator. FASEB J 2009; 23:2968-77. [PMID: 19395477 DOI: 10.1096/fj.08-128736] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ligands of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) abrogate the stimulation of collagen gene transcription induced by transforming growth factor-beta (TGF-beta). Here, we delineate the mechanisms underlying this important novel physiological function for PPAR-gamma in connective tissue homeostasis. First, we demonstrated that antagonistic regulation of TGF-beta activity by PPAR-gamma ligands involves cellular PPAR-gamma, since 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)) failed to block TGF-beta-induced responses in either primary cultures of PPAR-gamma-null murine embryonic fibroblasts, or in normal human skin fibroblasts with RNAi-mediated knockdown of PPAR-gamma. Next, we examined the molecular basis underlying the abrogation of TGF-beta signaling by PPAR-gamma in normal human fibroblasts in culture. The results demonstrated that Smad-dependent transcriptional responses were blocked by PPAR-gamma without preventing Smad2/3 activation. In contrast, the interaction between activated Smad2/3 and the transcriptional coactivator and histone acetyltransferase p300 induced by TGF-beta, and the accumulation of p300 on consensus Smad-binding DNA sequences and histone H4 hyperacetylation at the COL1A2 locus, were all prevented by PPAR-gamma. Wild-type p300, but not a mutant form of p300 lacking functional histone acetyltransferase, was able to restore TGF-beta-induced stimulation of COL1A2 in the presence of PPAR-gamma ligands. Collectively, these results indicate that PPAR-gamma blocked Smad-mediated transcriptional responses by preventing p300 recruitment and histone H4 hyperacetylation, resulting in the inhibition of TGF-beta-induced collagen gene expression. Pharmacological activation of PPAR-gamma thus may represent a novel therapeutic approach to target p300-dependent TGF-beta profibrotic responses such as stimulation of collagen gene expression.
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Affiliation(s)
- Asish K Ghosh
- Feinberg Cardiovascular Research Institute, Chicago, IL 60611, USA.
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31
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Smedsrød B, Le Couteur D, Ikejima K, Jaeschke H, Kawada N, Naito M, Knolle P, Nagy L, Senoo H, Vidal-Vanaclocha F, Yamaguchi N. Hepatic sinusoidal cells in health and disease: update from the 14th International Symposium. Liver Int 2009; 29:490-501. [PMID: 19210626 DOI: 10.1111/j.1478-3231.2009.01979.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review aims to give an update of the field of the hepatic sinusoid, supported by references to presentations given at the 14th International Symposium on Cells of the Hepatic Sinusoid (ISCHS2008), which was held in Tromsø, Norway, August 31-September 4, 2008. The subtitle of the symposium, 'Integrating basic and clinical hepatology', signified the inclusion of both basal and applied clinical results of importance in the field of liver sinusoidal physiology and pathophysiology. Of nearly 50 oral presentations, nine were invited tutorial lectures. The authors of the review have avoided writing a 'flat summary' of the presentations given at ISCHS2008, and instead focused on important novel information. The tutorial presentations have served as a particularly important basis in the preparation of this update. In this review, we have also included references to recent literature that may not have been covered by the ISCHS2008 programme. The sections of this review reflect the scientific programme of the symposium (http://www.ub.uit.no/munin/bitstream/10037/1654/1/book.pdf): 1. Liver sinusoidal endothelial cells. 2. Kupffer cells. 3. Hepatic stellate cells. 4. Immunology. 5. Tumor/metastasis. Symposium abstracts are referred to by a number preceded by the letter A.
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Affiliation(s)
- Bård Smedsrød
- Department of Cell Biology and Histology, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
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Velayudham A, Dolganiuc A, Ellis M, Petrasek J, Kodys K, Mandrekar P, Szabo G. VSL#3 probiotic treatment attenuates fibrosis without changes in steatohepatitis in a diet-induced nonalcoholic steatohepatitis model in mice. Hepatology 2009; 49:989-97. [PMID: 19115316 PMCID: PMC3756672 DOI: 10.1002/hep.22711] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) and its advanced stage, nonalcoholic steatohepatitis (NASH), are the most common causes of chronic liver disease in the United States. NASH features the metabolic syndrome, inflammation, and fibrosis. Probiotics exhibit immunoregulatory and anti-inflammatory activity. We tested the hypothesis that probiotic VSL#3 may ameliorate the methionine-choline-deficient (MCD) diet-induced mouse model of NASH. MCD diet resulted in NASH in C57BL/6 mice compared to methionine-choline-supplemented (MCS) diet feeding evidenced by liver steatosis, increased triglycerides, inflammatory cell accumulation, increased tumor necrosis factor alpha levels, and fibrosis. VSL#3 failed to prevent MCD-induced liver steatosis or inflammation. MCD diet, even in the presence of VSL#3, induced up-regulation of serum endotoxin and expression of the Toll-like receptor 4 signaling components, including CD14 and MD2, MyD88 adaptor, and nuclear factor kappaB activation. In contrast, VSL#3 treatment ameliorated MCD diet-induced liver fibrosis resulting in diminished accumulation of collagen and alpha-smooth muscle actin. We identified increased expression of liver peroxisome proliferator-activated receptors and decreased expression of procollagen and matrix metalloproteinases in mice fed MCD+VSL#3 compared to MCD diet alone. MCD diet triggered up-regulation of transforming growth factor beta (TGFbeta), a known profibrotic agent. In the presence of VSL#3, the MCD diet-induced expression of TGFbeta was maintained; however, the expression of Bambi, a TGFbeta pseudoreceptor with negative regulatory function, was increased. In summary, our data indicate that VSL#3 modulates liver fibrosis but does not protect from inflammation and steatosis in NASH. The mechanisms of VSL#3-mediated protection from MCD diet-induced liver fibrosis likely include modulation of collagen expression and impaired TGFbeta signaling.
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Affiliation(s)
- Arumugam Velayudham
- Department of Medicine, Liver Center, University of Massachusetts Medical School, Worcester, MA 01605-2324, USA
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33
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Michalik L, Wahli W. PPARs Mediate Lipid Signaling in Inflammation and Cancer. PPAR Res 2008; 2008:134059. [PMID: 19125181 PMCID: PMC2606065 DOI: 10.1155/2008/134059] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 09/17/2008] [Indexed: 02/06/2023] Open
Abstract
Lipid mediators can trigger physiological responses by activating nuclear hormone receptors, such as the peroxisome proliferator-activated receptors (PPARs). PPARs, in turn, control the expression of networks of genes encoding proteins involved in all aspects of lipid metabolism. In addition, PPARs are tumor growth modifiers, via the regulation of cancer cell apoptosis, proliferation, and differentiation, and through their action on the tumor cell environment, namely, angiogenesis, inflammation, and immune cell functions. Epidemiological studies have established that tumor progression may be exacerbated by chronic inflammation. Here, we describe the production of the lipids that act as activators of PPARs, and we review the roles of these receptors in inflammation and cancer. Finally, we consider emerging strategies for therapeutic intervention.
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Affiliation(s)
- Liliane Michalik
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Walter Wahli
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, 1015 Lausanne, Switzerland
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Pharmacological application of caffeine inhibits TGF-beta-stimulated connective tissue growth factor expression in hepatocytes via PPARgamma and SMAD2/3-dependent pathways. J Hepatol 2008; 49:758-67. [PMID: 18486259 DOI: 10.1016/j.jhep.2008.03.029] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 03/29/2008] [Accepted: 03/31/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Epidemiological studies suggest that coffee drinking is inversely correlated with the risk of development of liver fibrosis but the molecular basis is unknown. METHODS We investigated the pharmacological mechanisms involved in caffeine-dependent regulation of CTGF expression, an important modulator protein of fibrogenic TGF-beta, in rat hepatocytes using Western-blot, co-immunoprecipitations, reporter-gene-assays and ELISAs. RESULTS It is demonstrated that caffeine, similar to 8-Br-cAMP, suppresses CTGF expression, decreases SMAD2 protein levels and inhibits SMAD1/3-phosphorylation. The SMAD2 level can be restored by a proteasome inhibitor. Additionally, caffeine leads to an up-regulation of PPARgamma expression, that enhances the inhibitory effect of the natural PPARgamma agonist 15-PGJ(2) on CTGF expression by inducing a dissociation of the SMAD2/3-CBP/p300-transcriptional complex. CONCLUSIONS We show that caffeine strongly down-modulates TGF-beta-induced CTGF expression in hepatocytes by stimulation of degradation of the TGF-beta effector SMAD 2, inhibition of SMAD3 phosphorylation and up-regulation of the PPARgamma-receptor. Long-term caffeinization might be an option for anti-fibrotic trials in chronic liver diseases.
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35
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Ghosh AK, Wei J, Wu M, Varga J. Constitutive Smad signaling and Smad-dependent collagen gene expression in mouse embryonic fibroblasts lacking peroxisome proliferator-activated receptor-gamma. Biochem Biophys Res Commun 2008; 374:231-6. [PMID: 18627765 PMCID: PMC3157939 DOI: 10.1016/j.bbrc.2008.07.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 07/02/2008] [Indexed: 02/09/2023]
Abstract
Transforming growth factor-beta (TGF-beta), a potent inducer of collagen synthesis, is implicated in pathological fibrosis. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a nuclear hormone receptor that regulates adipogenesis and numerous other biological processes. Here, we demonstrate that collagen gene expression was markedly elevated in mouse embryonic fibroblasts (MEFs) lacking PPAR-gamma compared to heterozygous control MEFs. Treatment with the PPAR-gamma ligand 15d-PGJ(2) failed to down-regulate collagen gene expression in PPAR-gamma null MEFs, whereas reconstitution of these cells with ectopic PPAR-gamma resulted in their normalization. Compared to control MEFs, PPAR-gamma null MEFs displayed elevated levels of the Type I TGF-beta receptor (TbetaRI), and secreted more TGF-beta1 into the media. Furthermore, PPAR-gamma null MEFs showed constitutive phosphorylation of cellular Smad2 and Smad3, even in the absence of exogenous TGF-beta, which was abrogated by the ALK5 inhibitor SB431542. Constitutive Smad2/3 phosphorylation in PPAR-gamma null MEFs was associated with Smad3 binding to its cognate DNA recognition sequences, and interaction with coactivator p300 previously implicated in TGF-beta responses. Taken together, these results indicate that loss of PPAR-gamma in MEFs is associated with upregulation of collagen synthesis, and activation of intracellular Smad signal transduction, due, at least in part, to autocrine TGF-beta stimulation.
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Affiliation(s)
- Asish K Ghosh
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Jun Wei
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Minghua Wu
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - John Varga
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Abstract
Substantial improvements in the treatment of chronic liver disease have accelerated interest in uncovering the mechanisms underlying hepatic fibrosis and its resolution. Activation of resident hepatic stellate cells into proliferative, contractile, and fibrogenic cells in liver injury remains a dominant theme driving the field. However, several new areas of rapid progress in the past 5-10 years also have taken root, including: (1) identification of different fibrogenic populations apart from resident stellate cells, for example, portal fibroblasts, fibrocytes, and bone-marrow-derived cells, as well as cells derived from epithelial mesenchymal transition; (2) emergence of stellate cells as finely regulated determinants of hepatic inflammation and immunity; (3) elucidation of multiple pathways controlling gene expression during stellate cell activation including transcriptional, post-transcriptional, and epigenetic mechanisms; (4) recognition of disease-specific pathways of fibrogenesis; (5) re-emergence of hepatic macrophages as determinants of matrix degradation in fibrosis resolution and the importance of matrix cross-linking and scar maturation in determining reversibility; and (6) hints that hepatic stellate cells may contribute to hepatic stem cell behavior, cancer, and regeneration. Clinical and translational implications of these advances have become clear, and have begun to impact significantly on the management and outlook of patients with chronic liver disease.
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Abstract
Alcoholic and non-alcoholic steatohepatitis (ASH and NASH) constitute two major types of chronic liver disease with worldwide prevalence and are histologically indistinguishable with shared pathogenetic mechanisms. More importantly, they have synergistic interactions for liver pathology. Comparative studies on ASH and NASH have been hampered by the use of different animal models with confounding variables, particularly those with extreme genetic, toxic, and malnutrition etiologies. The mouse intragastric model circumvents these problems and reproduces the natural course and etiological background of ASH and NASH. Further, our recent work reproduces a profound synergism between the two in the model. Intracellular accumulation of neural lipids is a hallmark biochemical feature of ASH and NASH. Although impaired lipid oxidation and export may contribute to this pathological change, enhanced lipogenic regulation is frequently encountered, as characterized by induction of lipogenic or adipogenic transcription factors (peroxisome proliferator-activated receptor [PPAR gamma], liver X receptor alpha[LXR alpha], sterol-regulatory element-binding protein-1c [SREBP-1c]). In contrast, we have recently defined transdifferentiation of hepatic stellate cells (HSC), a pivotal event in liver fibrogenesis, as an 'antilipogenic' or 'anti-adipogenic' phenomenon. Thus, there is an apparent paradox between hepatocytes and HSC in steatohepatitis in terms of the outcome of lipogenic regulation. Our recent work suggests that defective insulin signaling in activated HSC may be responsible for this paradox. Further, activated Wnt signaling is implicated in 'anti-adipogenic' stellate cell transdifferentiation in liver fibrogenesis.
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Affiliation(s)
- Hidekazu Tsukamoto
- USC-UCLA Research Center of ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
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38
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Abstract
The hepatic stellate cell has surprised and engaged physiologists, pathologists, and hepatologists for over 130 years, yet clear evidence of its role in hepatic injury and fibrosis only emerged following the refinement of methods for its isolation and characterization. The paradigm in liver injury of activation of quiescent vitamin A-rich stellate cells into proliferative, contractile, and fibrogenic myofibroblasts has launched an era of astonishing progress in understanding the mechanistic basis of hepatic fibrosis progression and regression. But this simple paradigm has now yielded to a remarkably broad appreciation of the cell's functions not only in liver injury, but also in hepatic development, regeneration, xenobiotic responses, intermediary metabolism, and immunoregulation. Among the most exciting prospects is that stellate cells are essential for hepatic progenitor cell amplification and differentiation. Equally intriguing is the remarkable plasticity of stellate cells, not only in their variable intermediate filament phenotype, but also in their functions. Stellate cells can be viewed as the nexus in a complex sinusoidal milieu that requires tightly regulated autocrine and paracrine cross-talk, rapid responses to evolving extracellular matrix content, and exquisite responsiveness to the metabolic needs imposed by liver growth and repair. Moreover, roles vital to systemic homeostasis include their storage and mobilization of retinoids, their emerging capacity for antigen presentation and induction of tolerance, as well as their emerging relationship to bone marrow-derived cells. As interest in this cell type intensifies, more surprises and mysteries are sure to unfold that will ultimately benefit our understanding of liver physiology and the diagnosis and treatment of liver disease.
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Affiliation(s)
- Scott L Friedman
- Division of Liver Diseases, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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Akahori T, Sho M, Hamada K, Suzaki Y, Kuzumoto Y, Nomi T, Nakamura S, Enomoto K, Kanehiro H, Nakajima Y. Importance of peroxisome proliferator-activated receptor-gamma in hepatic ischemia/reperfusion injury in mice. J Hepatol 2007; 47:784-92. [PMID: 17936399 DOI: 10.1016/j.jhep.2007.07.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 07/02/2007] [Accepted: 07/20/2007] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a transcriptional factor belonging to the nuclear receptor superfamily. Recent studies have suggested that PPARgamma regulates inflammatory responses and PPARgamma specific agonists have beneficial effects on several disease conditions in the various organs. However, the precise role of PPARgamma in acute liver injury remains unknown. METHODS We investigated the pathophysiological role of PPARgamma and the effect of the selective PPARgamma agonist, pioglitazone, on the hepatic ischemia/reperfusion (I/R) injury. RESULTS PPARgamma expression in the liver was upregulated after reperfusion following ischemia. Pioglitazone treatment significantly inhibited hepatic I/R injury as determined by serological and histological analyses. The protective effect was associated with downregulation of the local expression of several potent proinflammatory cytokines, chemokines and adhesion molecules after reperfusion. The neutrophil accumulation was also inhibited by the treatment. Furthermore, the treatment inhibited the induction of apoptosis on hepatocytes. Finally, pioglitazone significantly improved the mouse survival in a lethal model of hepatic I/R injury. CONCLUSIONS PPARgamma plays an inhibitory role in hepatic I/R injury and the stimulation by selective agonist has a significant beneficial effect. Thus, PPARgamma may be a new therapeutic target for the protection of the liver against acute injury.
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Rekha RD, Amali AA, Her GM, Yeh YH, Gong HY, Hu SY, Lin GH, Wu JL. Thioacetamide accelerates steatohepatitis, cirrhosis and HCC by expressing HCV core protein in transgenic zebrafish Danio rerio. Toxicology 2007; 243:11-22. [PMID: 17997003 DOI: 10.1016/j.tox.2007.09.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 09/03/2007] [Accepted: 09/03/2007] [Indexed: 12/19/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the common cancers worldwide, caused by Hepatitis C virus (HCV) and hepatotoxins. Here we report the development of HCC in wild type as well as HCV core protein (HCP)-transgenic zebrafish upon treatment with a hepatotoxin, thioacetamide (TAA). Two-fold accelerated HCC development could be achieved in the TAA-treated transgenic fish, that is, the progression of the disease in TAA-treated wild type zebrafish developed HCC in 12 weeks whereas that of HCP-transgenic zebrafish shortened the HCC progression to 6 weeks. Histopathological observation showed the specific pathological features of HCC. The HCC progression was confirmed through RT-PCR that revealed an up and down regulation of different marker genes at various stages of HCC progression such as, steatohepatitis, fibrosis and HCC. Moreover, HCV core protein expressed in the HCP-transgenic zebrafish and TAA synergistically accelerate the HCC development. It must be mentioned that, this is the first report revealing HCV core protein along with TAA to induce HCC in zebrafish, particularly, in a short period of time comparing to mice model. As zebrafish has already been considered as a good human disease model and in this context, this HCC-zebrafish model may serve as a powerful preclinical platform to study the molecular events in hepatocarcinogenesis, therapeutic strategies and for evaluating chemoprevention strategies in HCC.
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Affiliation(s)
- Ravikumar Deepa Rekha
- Laboratory of Marine Molecular Biology and Biotechnology, Institute of Cellular and Organismic Biology, Academia Sinica, NanKang, Taipei 11529, Taiwan
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Saika S, Yamanaka O, Okada Y, Miyamoto T, Kitano A, Flanders KC, Ohnishi Y, Nakajima Y, Kao WWY, Ikeda K. Effect of overexpression of PPARgamma on the healing process of corneal alkali burn in mice. Am J Physiol Cell Physiol 2007; 293:C75-86. [PMID: 17625041 DOI: 10.1152/ajpcell.00332.2006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Wound healing involves both local cells and inflammatory cells. Alkali burn of ocular surface tissue is a serious clinical problem often leading to permanent visual impairment resulting from ulceration, scarring and neovascularization during healing. Behaviors of corneal cells and inflammatory cells are orchestrated by growth factor signaling networks that have not been fully uncovered. Here we showed that adenoviral gene introduction of peroxisome proliferator-activated receptor-gamma (PPARgamma) inhibits activation of ocular fibroblasts and macrophages in vitro and also induced anti-inflammatory and anti-fibrogenic responses in an alkali-burned mouse cornea. PPARgamma overexpression suppressed upregulation of inflammation/scarring-related growth factors and matrix metalloproteinases (MMPs) in macrophages. It also suppressed expression of such growth factors and collagen Ialpha2 and myofibroblast generation upon exposure to TGFbeta1. Exogenous PPARgamma did not alter phosphorylation of Smad2, but inhibited its nuclear translocation. PPARgamma overexpression enhanced proliferation of corneal epithelial cells, but not of fibroblasts in vitro. Epithelial cell expression of MMP-2/-9 and TGFbeta1 and its migration were suppressed by PPARgamma overexpression. In vivo experiments showed that PPARgamma gene introduction suppressed monocytes/macrophages invasion and suppressed the generation of myofibroblasts, as well as upregulation of cytokines/growth factors and MMPs in a healing cornea. In vivo re-epitheliazation with basement membrane reconstruction in the healing, burned, cornea was accelerated by PPARgamma-Ad expression, although PPARgamma overexpression was considered to be unfavorable for cell migration. Together, these data suggest that overexpression of PPARgamma may represent an effective new strategy for treatment of ocular surface burns.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Basement Membrane/metabolism
- Burns, Chemical/etiology
- Burns, Chemical/genetics
- Burns, Chemical/metabolism
- Burns, Chemical/physiopathology
- Burns, Chemical/therapy
- Cell Movement
- Cell Proliferation
- Cells, Cultured
- Cicatrix/genetics
- Cicatrix/metabolism
- Cicatrix/physiopathology
- Cicatrix/therapy
- Cornea/metabolism
- Cornea/pathology
- Cornea/physiopathology
- Corneal Diseases/chemically induced
- Corneal Diseases/genetics
- Corneal Diseases/metabolism
- Corneal Diseases/physiopathology
- Corneal Diseases/therapy
- Disease Models, Animal
- Epithelium, Corneal/metabolism
- Epithelium, Corneal/pathology
- Eye Burns/chemically induced
- Eye Burns/genetics
- Eye Burns/metabolism
- Eye Burns/physiopathology
- Eye Burns/therapy
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Fibrosis
- Gelatinases/metabolism
- Genetic Therapy/methods
- Genetic Vectors
- Inflammation/genetics
- Inflammation/metabolism
- Inflammation/physiopathology
- Inflammation/therapy
- Intercellular Signaling Peptides and Proteins/metabolism
- Macrophages/metabolism
- Macrophages/pathology
- Mice
- Mice, Inbred C57BL
- Neovascularization, Pathologic/genetics
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/physiopathology
- Neovascularization, Pathologic/therapy
- PPAR gamma/genetics
- PPAR gamma/metabolism
- RNA, Messenger/metabolism
- Signal Transduction
- Smad Proteins/metabolism
- Sodium Hydroxide
- Transfection
- Up-Regulation
- Wound Healing
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Affiliation(s)
- Shizuya Saika
- Dept. of Ophthalmology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-0012, Japan.
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Xu Y, Farmer SR, Smith BD. Peroxisome proliferator-activated receptor gamma interacts with CIITA x RFX5 complex to repress type I collagen gene expression. J Biol Chem 2007; 282:26046-56. [PMID: 17611194 DOI: 10.1074/jbc.m703652200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent reports demonstrate that peroxisome proliferator-activated receptor gamma (PPARgamma), a member of the nuclear receptor superfamily, acts as a repressor of type I collagen synthesis. Our data demonstrate that exogenously expressed PPARgamma down-regulates collagen expression in a dose-responsive manner in human lung fibroblast cells. Silencing PPARgamma using lentiviruses expressing short hairpin RNAs partially reverses interferon-gamma (IFN-gamma)-induced repression and activates collagen mRNA levels. Previous studies indicate that IFN-gamma represses collagen gene expression and induces major histocompatibility complex II (MHC II) expression by activating the formation of a regulatory factor for X-box 5 (RFX5) complex with class II transactivator (CIITA). This report demonstrates that PPARgamma is within the RFX5.CIITA complex as judged by co-immunoprecipitation and DNA affinity precipitation studies. Most importantly, occupancy of PPARgamma on the collagen transcription start site and MHC II promoter increases with IFN-gamma treatment. The PPARgamma agonist, troglitazone, sensitizes the cells to IFN-gamma treatment by increasing recruitment of PPARgamma to collagen gene while repressing collagen expression, and these effects are blocked by the PPARgamma antagonist T0070907. PPARgamma may mediate IFN-gamma-stimulated collagen transcription down-regulation and MHC II up-regulation by interacting with CIITA as well as regulating CIITA expression. Therefore, PPARgamma is a critical target for investigations into therapeutics of diseases involving extracellular matrix remodeling and the immune response.
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Affiliation(s)
- Yong Xu
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Murad H, Fiatte C, Brunner E, Huin-Schohn C, Schohn H, Bécuwe P, Domenjoud L, Dauça M. [PPARs and cell-cell or cell-extracellular matrix interactions]. Med Sci (Paris) 2007; 23:515-8. [PMID: 17502068 DOI: 10.1051/medsci/2007235515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) are transcription factors and belong to the superfamily of nuclear receptors. They are encoded by three genes located on different chromosomes: PPARalpha, PPARbeta/delta and PPARgamma. PPARalpha plays a key role in the control of lipid metabolism and homeostasis. PPARbeta/delta is expressed ubiquitously and participates in skeletal muscle physiology. PPARbeta/delta and PPARgamma are important factors for placental development and function as well as for embryo implantation. In addition, PPARgamma is mainly involved in adipogenesis. PPARs also participate more or less to cell proliferation, differentiation and apoptosis. Surprisingly, the involvement of these transcription factors in cell-cell and/or cell-matrix interactions has not yet been reviewed except for their role as therapeutic agents in inflammation. Nevertheless, several pioneer reports have recently provided some new insights in this research field, by suggesting that PPARs are involved, directly or indirectly, in these interactions and that their activation by specific ligands may lead to potential therapeutic approaches.
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Affiliation(s)
- Hossam Murad
- EA3446, Proliférateurs de Peroxysomes, Faculté des Sciences, Vandoeuvre-les-Nancy, France
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Shen YM, Zhu X. Signal transduction and activation of hepatic stellate cells. Shijie Huaren Xiaohua Zazhi 2007; 15:873-878. [DOI: 10.11569/wcjd.v15.i8.873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Liver fibrosis, which leads to cirrhosis, occurs as a result of various injurious processes and it is the common pathologic basis of all the chronic hepatic diseases. At present, a good many researches demonstrate that the activation of hepatic stellate cells play a critical role in fibrogenesis. Prolonged liver injury results in hepatocyte damages and secretion of many fibrogenic cytokines such as transforming growth factor-beta 1, angiotensin, and leptin, which triggers the activation of hepatic stellate cells through different intracellular signal transduction pathways. In this article, we reviewed the research advancement in the signal transduction pathway of nuclear receptor and membrane receptor during the activation of hepatic stellate cells.
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Di Paola R, Cuzzocrea S. Peroxisome proliferator-activated receptors ligands and ischemia-reperfusion injury. Naunyn Schmiedebergs Arch Pharmacol 2007; 375:157-75. [PMID: 17394034 DOI: 10.1007/s00210-007-0141-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Accepted: 01/28/2007] [Indexed: 12/19/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) belong to a subfamily of transcription nuclear factors. Three isoforms of PPARs have been identified: alpha, beta/delta and gamma, encoded by different genes and distributed in various tissues. They play important roles in metabolic processes like regulation of glucose and lipid redistribution. They also have anti-atherogenic, anti-inflammatory as well as antihypertensive functions. There is good evidence that ligands of PPARs reduce tissue injury associated with ischemia and reperfusion. The potential utility of PPAR ligands in ischemia and reperfusion will be discussed in this review.
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Affiliation(s)
- Rosanna Di Paola
- Department of Clinical and Experimental Medicine and Pharmacology, School of Medicine, University of Messina, Torre Biologica-Policlinico Universitario, Via C. Valeria-Gazzi, 98100 Messina, Italy
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Sakimura R, Tanaka K, Yamamoto S, Matsunobu T, Li X, Hanada M, Okada T, Nakamura T, Li Y, Iwamoto Y. The Effects of Histone Deacetylase Inhibitors on the Induction of Differentiation in Chondrosarcoma Cells. Clin Cancer Res 2007; 13:275-82. [PMID: 17200366 DOI: 10.1158/1078-0432.ccr-06-1696] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Histologically, chondrosarcomas represent the degree of chondrogenic differentiation, which is associated with the prognosis of the disease. Histone acetylation and deacetylation play key roles in the regulation of chondrocytic differentiation. Here, we describe the antitumor effects of histone deacetylase (HDAC) inhibitors as differentiating reagents on chondrosarcomas. EXPERIMENTAL DESIGN We examined the effects of a HDAC inhibitor, depsipeptide, on the growth of chondrosarcoma cell lines. We also investigated the modulation of the expression levels of extracellular matrix genes and the induction of phenotypic change in chondrosarcoma cells treated with depsipeptide. Finally, we examined the antitumor effect of depsipeptide on chondrosarcoma in vivo. RESULTS Depsipeptide inhibited the growth of chondrosarcoma cells by inducing cell cycle arrest and/or apoptosis. HDAC inhibitors increased the expression of the alpha1 chain of type II collagen (COL2A1) gene due to the enhanced histone acetylation in the promoter and enhancer. Depsipeptide also up-regulated the expressions of aggrecan and the alpha2 chain of type XI collagen (COL11A2) mRNA in a dose-dependent manner. Moreover, long-term treatment with a low dose of depsipeptide resulted in the induction of differentiation into hypertrophic phenotype, as shown by the increment of the alpha1 chain of type X collagen (COL10A1) expression in chondrosarcoma cells. In vivo studies and histologic analyses confirmed that depsipeptide significantly inhibited tumor growth and induced differentiation into the hypertrophic and mineralized state in chondrosarcoma cells. CONCLUSIONS These results strongly suggest that HDAC inhibitors may be promising reagents for use as a differentiating chemotherapy against chondrosarcomas.
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Affiliation(s)
- Riku Sakimura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka City, Japan
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Ceni E, Crabb DW, Foschi M, Mello T, Tarocchi M, Patussi V, Moraldi L, Moretti R, Milani S, Surrenti C, Galli A. Acetaldehyde inhibits PPARgamma via H2O2-mediated c-Abl activation in human hepatic stellate cells. Gastroenterology 2006; 131:1235-52. [PMID: 17030193 DOI: 10.1053/j.gastro.2006.08.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Accepted: 07/05/2006] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Accumulating evidence indicates that acetaldehyde (AcCHO) is one of the main mediators of fibrogenesis in alcoholic liver disease. AcCHO stimulates synthesis of fibrillar collagens in hepatic stellate cells, but the molecular events directly involved in the activation of collagen genes are debatable. METHODS Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that is expressed in stellate cells, and its activation by specific ligands inhibits collagen synthesis. In this study, we evaluated the effects of AcCHO on PPARgamma transcriptional activity and its correlation with the AcCHO-induced collagen synthesis in hepatic stellate cells. RESULTS AcCHO treatment inhibited ligand-dependent and -independent PPARgamma transcriptional activity, and this effect was correlated with an increased phosphorylation of a mitogen-activated protein kinase site at serine 84 of the human PPARgamma. Transfection of the PPARgammaSer84Ala mutant completely prevented the effect of AcCHO on PPARgamma activity and in parallel abrogated the induction of collagen gene expression by AcCHO. The effect of AcCHO on PPARgamma activity and phosphorylation was blocked by extracellular signal-regulated kinase (ERK) 1/2 and protein kinase C (PKC)delta inhibitors as well as by catalase, suggesting that hydrogen peroxide is involved in the molecular cascade responsible for PPARgamma phosphorylation via activation of the PKCdelta/ERK pathway. Furthermore, inhibition of c-Abl completely abrogated the effect of AcCHO on either PPARgamma function or collagen synthesis; in addition, expression of the PPARgammaSer84Ala mutant prevented the profibrogenic signals mediated by c-Abl activation. CONCLUSIONS Our results showed that the induction of collagen expression by AcCHO in stellate cells is dependent on PPARgamma phosphorylation induced by a hydrogen peroxide-mediated activation of the profibrogenic c-Abl signaling pathway.
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Affiliation(s)
- Elisabetta Ceni
- Gastroenterology Unit, Department of Clinical Pathophysiology, University of Florence, Viale Morgagni 85, 50134 Florence, Italy
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Abstract
The identification of activated hepatic stellate cells and related cell types as key fibrogenic effectors during liver injury has led to intense evaluation of transcriptional events underlying their behavior. While initial studies focused on characterizing interactions between transcription factors and regulatory regions within gene promoters, epigenetic mechanisms have emerged as major determinants of gene activation and repression, in particular histone acetylation and promoter methylation, as well as other complex conditional interactions that underlie global changes in gene expression. Three examples are provided that illustrate how stellate cell activation may be controlled by widely divergent regulatory pathways, including alternative splicing of a growth inhibitory transcription factor (Kruppel-like factor-6), epigenetic regulation of a factor regulating stellate cell survival (nuclear factor kappaB), and regulation of a transcription factor whose expression maintains stellate cell quiescence (LIM homeobox gene 2 [Lhx2]). These complex cascades illustrate how clarifying the finely tuned interdependent layers of transcriptional, translational, post-translational and epigenetic gene regulation in stellate cells is raising new prospects for therapy of hepatic fibrosis.
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Affiliation(s)
- Scott L Friedman
- Division of Liver Diseases, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Michalik L, Wahli W. Involvement of PPAR nuclear receptors in tissue injury and wound repair. J Clin Invest 2006; 116:598-606. [PMID: 16511592 PMCID: PMC1386118 DOI: 10.1172/jci27958] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tissue damage resulting from chemical, mechanical, and biological injury, or from interrupted blood flow and reperfusion, is often life threatening. The subsequent tissue response involves an intricate series of events including inflammation, oxidative stress, immune cell recruitment, and cell survival, proliferation, migration, and differentiation. In addition, fibrotic repair characterized by myofibroblast transdifferentiation and the deposition of ECM proteins is activated. Failure to initiate, maintain, or stop this repair program has dramatic consequences, such as cell death and associated tissue necrosis or carcinogenesis. In this sense, inflammation and oxidative stress, which are beneficial defense processes, can become harmful if they do not resolve in time. This repair program is largely based on rapid and specific changes in gene expression controlled by transcription factors that sense injury. PPARs are such factors and are activated by lipid mediators produced after wounding. Here we highlight advances in our understanding of PPAR action during tissue repair and discuss the potential for these nuclear receptors as therapeutic targets for tissue injury.
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Affiliation(s)
- Liliane Michalik
- Center for Integrative Genomics, National Research Centre Frontiers in Genetics, University of Lausanne, Lausanne, Switzerland.
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