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Yin F, Wang WY, Jiang WH. Human umbilical cord mesenchymal stem cells ameliorate liver fibrosis in vitro and in vivo: From biological characteristics to therapeutic mechanisms. World J Stem Cells 2019; 11:548-564. [PMID: 31523373 PMCID: PMC6716089 DOI: 10.4252/wjsc.v11.i8.548] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/26/2019] [Accepted: 07/17/2019] [Indexed: 02/06/2023] Open
Abstract
Liver fibrosis is a wound-healing response to chronic injuries, characterized by the excessive accumulation of extracellular matrix or scar tissue within the liver; in addition, its formation is associated with multiple cytokines as well as several cell types and a variety of signaling pathways. When liver fibrosis is not well controlled, it can progress to liver cirrhosis, but it is reversible in principle. Thus far, no efficient therapy is available for treatment of liver fibrosis. Although liver transplantation is the preferred strategy, there are many challenges remaining in this approach, such as shortage of donor organs, immunological rejection, and surgical complications. Hence, there is a great need for an alternative therapeutic strategy. Currently, mesenchymal stem cell (MSC) therapy is considered a promising therapeutic strategy for the treatment of liver fibrosis; advantageously, the characteristics of MSCs are continuous self-renewal, proliferation, multipotent differentiation, and immunomodulatory activities. The human umbilical cord-derived (hUC)-MSCs possess not only the common attributes of MSCs but also more stable biological characteristics, relatively easy accessibility, abundant source, and no ethical issues (e.g., bone marrow being the adult source), making hUC-MSCs a good choice for treatment of liver fibrosis. In this review, we summarize the biological characteristics of hUC-MSCs and their paracrine effects, exerted by secretion of various cytokines, which ultimately promote liver repair through several signaling pathways. Additionally, we discuss the capacity of hUC-MSCs to differentiate into hepatocyte-like cells for compensating the function of existing hepatocytes, which may aid in amelioration of liver fibrosis. Finally, we discuss the current status of the research field and its future prospects.
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Affiliation(s)
- Fei Yin
- Department of Histology and Embryology, Basic Medical College of Jilin University, Changchun 130021, Jilin Province, China
| | - Wen-Ying Wang
- Department of Histology and Embryology, Basic Medical College of Jilin University, Changchun 130021, Jilin Province, China
| | - Wen-Hua Jiang
- Department of Histology and Embryology, Basic Medical College of Jilin University, Changchun 130021, Jilin Province, China
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Makled MN, Sharawy MH, El-Awady MS. The dual PPAR-α/γ agonist saroglitazar ameliorates thioacetamide-induced liver fibrosis in rats through regulating leptin. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1569-1576. [DOI: 10.1007/s00210-019-01703-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
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Gui X, Chen H, Cai H, Sun L, Gu L. Leptin promotes pulmonary fibrosis development by inhibiting autophagy via PI3K/Akt/mTOR pathway. Biochem Biophys Res Commun 2018. [PMID: 29524411 DOI: 10.1016/j.bbrc.2018.03.039] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Leptin, a protein-related product of the obesity gene, plays an important role in the pathogenesis of fibrotic diseases including pulmonary fibrosis. As a highly conservative process, autophagy regulates various biological functions. Otherwise, insufficient autophagy has been described in alveolar epithelial cells (AEC) to cope with the progression of pulmonary fibrosis. Hence, this study is to investigate the effects of leptin on fibrosis in TGF-β1 induced epithelial mesenchymal transition (EMT) and the potential roles of autophagy in this processes. Our results showed that the elevated leptin level in serum correlated with the severity of lung fibrosis and leptin significantly promoted the EMT in A549 cells as evidenced by promoting collagen I and α-SMA production. Additionally, treatment with leptin decreased autophagosome formation, inhibited the lipidation of LC3I to LC3II, and up-regulated the expression of p62 via activating PI3K/Akt/mTOR pathway, which is indicative of inhibition of autophagy by leptin. Finally, rapmycin pretreatment reversed the pro-fibrogenic effects of leptin. Taken together, our study suggested that leptin accelerated the EMT of A549 cells through inhibiting autophagy via PI3K/Akt/mTOR pathway.
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Affiliation(s)
- Xianhua Gui
- Department of Respiratory Medicine, The Affiliated Nanjing Drum Tower clinical medical college of Nanjing Medical University, 210008, Nanjing, China; Department of Respiratory Medicine, The Affiliated Drum Tower Hospital, Nanjing University Medical School, 210008, Nanjing, China
| | - Hongwei Chen
- Department of Rheumatology and Immunology, The Affiliated Drum Tower Hospital, Nanjing University Medical School, 210008, Nanjing, China
| | - Hourong Cai
- Department of Respiratory Medicine, The Affiliated Nanjing Drum Tower clinical medical college of Nanjing Medical University, 210008, Nanjing, China
| | - Lingyun Sun
- Department of Rheumatology and Immunology, The Affiliated Nanjing Drum Tower Clinical Medical College of Nanjing Medical University, 210008, Nanjing, China.
| | - Luo Gu
- Department of Physiology of Nanjing Medical University, 211166, Nanjing, China.
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Zhang LT, Peng XB, Fang XQ, Li JF, Chen H, Mao XR. Human umbilical cord mesenchymal stem cells inhibit proliferation of hepatic stellate cells in vitro. Int J Mol Med 2018; 41:2545-2552. [PMID: 29484382 PMCID: PMC5846650 DOI: 10.3892/ijmm.2018.3500] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 01/22/2018] [Indexed: 12/13/2022] Open
Abstract
The effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) on the proliferation of hepatic stellate cells (HSCs) is largely unknown. The purpose of this study was to explore the mechanism of action of hUC-MSCs on the proliferation of HSCs in vitro. The upper and lower double-cell co-culture system was established between hUC-MSCs and HSCs in the experimental group. HSCs were cultured alone as a negative control group. Cell proliferation and apoptosis were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. Cell supernatants were harvested to determine the concentration of transforming growth factor-β1 (TGF-β1) by ELISA. mRNA and protein of TGF-β1, Smad3 and Smad7 in HSCs were determined by reverse transcription-polymerase chain reaction and western blotting, respectively. In the co-culture group, the proliferation of HSCs was significantly inhibited compared with the negative control group at 24 and 48 h (p<0.05). Apoptosis of HSCs in the co-culture group increased compared with that in the negative control group, which was more obvious at 48 h (p<0.05). The concentration of TGF-β1 in the co-culture group was significantly lower than in the HSCs cultured alone (p<0.05). After HSCs were co-cultured with hUC-MSCs for 48 h, expression of TGF-β1 and Smad3 mRNA and protein was reduced and expression of Smad7 mRNA and protein was increased compared with the negative control group (p<0.05). hUC-MSCs inhibited proliferation of HSCs, possibly through inhibiting TGF-β1 and Smad3 expression and increasing Smad7 protein expression.
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Affiliation(s)
- Li-Ting Zhang
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xue-Bin Peng
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xue-Qin Fang
- Department of Infectious Diseases, The Central Hospital of Baoji, Baoji, Shannxi 721008, P.R. China
| | - Jun-Feng Li
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Hong Chen
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xiao-Rong Mao
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
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Yuan X, Caron A, Wu H, Gautron L. Leptin Receptor Expression in Mouse Intracranial Perivascular Cells. Front Neuroanat 2018; 12:4. [PMID: 29410615 PMCID: PMC5787097 DOI: 10.3389/fnana.2018.00004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/08/2018] [Indexed: 12/28/2022] Open
Abstract
Past studies have suggested that non-neuronal brain cells express the leptin receptor. However, the identity and distribution of these leptin receptor-expressing non-neuronal brain cells remain debated. This study assessed the distribution of the long form of the leptin receptor (LepRb) in non-neuronal brain cells using a reporter mouse model in which LepRb-expressing cells are permanently marked by tdTomato fluorescent protein (LepRb-CretdTomato). Double immunohistochemistry revealed that, in agreement with the literature, the vast majority of tdTomato-tagged cells across the mouse brain were neurons (i.e., based on immunoreactivity for NeuN). Non-neuronal structures also contained tdTomato-positive cells, including the choroid plexus and the perivascular space of the meninges and, to a lesser extent, the brain. Based on morphological criteria and immunohistochemistry, perivascular cells were deduced to be mainly pericytes. Notably, tdTomato-positive cells were immunoreactive for vitronectin and platelet derived growth factor receptor beta (PDGFBR). In situ hybridization studies confirmed that most tdTomato-tagged perivascular cells were enriched in leptin receptor mRNA (all isoforms). Using qPCR studies, we confirmed that the mouse meninges were enriched in Leprb and, to a greater extent, the short isoforms of the leptin receptor. Interestingly, qPCR studies further demonstrated significantly altered expression for Vtn and Pdgfrb in the meninges and hypothalamus of LepRb-deficient mice. Collectively, our data demonstrate that the only intracranial non-neuronal cells that express LepRb in the adult mouse are cells that form the blood-brain barrier, including, most notably, meningeal perivascular cells. Our data suggest that pericytic leptin signaling plays a role in the integrity of the intracranial perivascular space and, consequently, may provide a link between obesity and numerous brain diseases.
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Affiliation(s)
- Xuefeng Yuan
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Alexandre Caron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Hua Wu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Laurent Gautron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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Takashima S, Ikejima K, Arai K, Yokokawa J, Kon K, Yamashina S, Watanabe S. Glycine prevents metabolic steatohepatitis in diabetic KK-Ay mice through modulation of hepatic innate immunity. Am J Physiol Gastrointest Liver Physiol 2016; 311:G1105-G1113. [PMID: 27659424 DOI: 10.1152/ajpgi.00465.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 09/15/2016] [Indexed: 01/31/2023]
Abstract
Strategies for prevention and treatment of nonalcoholic steatohepatitis remain to be established. We evaluated the effect of glycine on metabolic steatohepatitis in genetically obese, diabetic KK-Ay mice. Male KK-Ay mice were fed a diet containing 5% glycine for 4 wk, and liver pathology was evaluated. Hepatic mRNA levels for lipid-regulating molecules, cytokines/chemokines, and macrophage M1/M2 markers were determined by real-time RT-PCR. Hepatic expression of natural killer (NK) T cells was analyzed by flow cytometry. Body weight gain was significantly blunted and development of hepatic steatosis and inflammatory infiltration were remarkably prevented in mice fed the glycine-containing diet compared with controls. Indeed, hepatic induction levels of molecules related to lipogenesis were largely blunted in the glycine diet-fed mice. Elevations of hepatic mRNA levels for TNFα and chemokine (C-C motif) ligand 2 were also remarkably blunted in the glycine diet-fed mice. Furthermore, suppression of hepatic NK T cells was reversed in glycine diet-fed KK-Ay mice, and basal hepatic expression levels of NK T cell-derived cytokines, such as IL-4 and IL-13, were increased. Moreover, hepatic mRNA levels of arginase-1, a marker of macrophage M2 transformation, were significantly increased in glycine diet-fed mice. In addition, dietary glycine improved glucose tolerance and hyperinsulinemia in KK-Ay mice. These observations clearly indicate that glycine prevents maturity-onset obesity and metabolic steatohepatitis in genetically diabetic KK-Ay mice. The underlying mechanisms most likely include normalization of hepatic innate immune responses involving NK T cells and M2 transformation of Kupffer cells. It is proposed that glycine is a promising immunonutrient for prevention and treatment of metabolic syndrome-related nonalcoholic steatohepatitis.
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Affiliation(s)
- Shiori Takashima
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kenichi Ikejima
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kumiko Arai
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Junko Yokokawa
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kazuyoshi Kon
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shunhei Yamashina
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Sumio Watanabe
- Department of Gastroenterology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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8
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Tang Y. Curcumin targets multiple pathways to halt hepatic stellate cell activation: updated mechanisms in vitro and in vivo. Dig Dis Sci 2015; 60:1554-64. [PMID: 25532502 DOI: 10.1007/s10620-014-3487-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/07/2014] [Indexed: 12/12/2022]
Abstract
Nonalcoholic steatohepatitis (NASH) is the advanced form of nonalcoholic fatty liver disease, which is often accompanied by obese and/or type II diabetes mellitus. Approximately one-third of NASH patients develop hepatic fibrosis. Hepatic stellate cells are the major effector cells during liver fibrogenesis. Advanced liver fibrosis usually proceeds to cirrhosis and even hepatocellular carcinoma, leading to liver failure, portal hypertension and even death. Currently, there are no approved agents for treatment and prevention of liver fibrosis in human beings. Curcumin, the principal curcuminoid of turmeric, has been reported to show antitumor, antioxidant, and anti-inflammatory properties both in in vitro and in vivo systems. Accumulating data shows that curcumin plays a critical role in combating liver fibrogenesis. This review will discuss the inhibitory roles of curcumin and update the underlying mechanisms by which curcumin targets in inhibiting hepatic stellate cell activation.
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Affiliation(s)
- Youcai Tang
- Department of Pediatrics, The Second Affiliated Hospital, Zhengzhou University, 2 Jingba Road, Zhengzhou, 450014, Henan, China,
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9
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Moon HS, Chamberland JP, Mantzoros CS. Amylin and leptin activate overlapping signalling pathways in an additive manner in mouse GT1-7 hypothalamic, C₂C₁₂ muscle and AML12 liver cell lines. Diabetologia 2012; 55:215-25. [PMID: 21997794 PMCID: PMC3780406 DOI: 10.1007/s00125-011-2332-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/19/2011] [Indexed: 10/16/2022]
Abstract
AIMS/HYPOTHESIS It has been suggested that amylin amplifies leptin's effects and affects energy homeostasis synergistically with leptin in animals and humans. However, no previous study has reported on amylin and leptin signalling in hypothalamic, muscle and liver cells. METHODS Leptin and amylin signalling studies were performed in vitro in mouse GT1-7 hypothalamic, C₂C₁₂ muscle and AML12 liver cell lines. RESULTS Treatment of mouse GT1-7 and C₂C₁₂ cells with leptin or amylin increased signal transducer and activator of transcription 3 (STAT3) phosphorylation in a dose- and time-dependent manner. In mouse AML12 cells, leptin and amylin produced a biphasic response of STAT3 activity. Importantly, all leptin and amylin signalling pathways were saturable at leptin and amylin concentrations of ∼100 and ∼50 to 100 ng/ml, respectively. Leptin and amylin in combination activated STAT3, AMP-activated protein kinase (AMPK), extracellular signal-regulated kinase (ERK) 1/2 and Akt signalling pathways in an additive manner, effects that were abolished under endoplasmic reticulum (ER) stress. Leptin, but not amylin, increased IRS-1 phosphorylation in GT1-7 hypothalamic, but not in C₂C₁₂ muscle and AML12 liver cell lines. CONCLUSIONS/INTERPRETATION Our data suggest that leptin and amylin have overlapping and additive, but not synergistic, effects in the activation of intracellular signalling pathways. ER stress may induce leptin and amylin resistance in hypothalamic, muscle and liver cell lines. These novel insights into the mode of action of leptin and amylin suggest that these hormones may play an additive role in regulating energy homeostasis in humans.
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Affiliation(s)
- H.-S. Moon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - J. P. Chamberland
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA, USA
| | - C. S. Mantzoros
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA, USA; Department of Environmental Health, Harvard School of Public Health, FD-876, 330 Brookline Avenue, Boston, MA 02215, USA
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Alonci A, Allegra A, Russo S, Penna G, Bellomo G, D'Angelo A, Campo S, Cannavò A, Centorrino R, Musolino C. Imatinib mesylate therapy induces reduction in neutrophil gelatinase-associated lipocalin serum levels and increase in leptin concentrations in chronic myeloid leukemia patients in molecular remission. Acta Haematol 2011; 127:1-6. [PMID: 21986252 DOI: 10.1159/000330948] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/13/2011] [Indexed: 01/15/2023]
Abstract
The aim of the present study was to determine serum levels of neutrophil gelatinase-associated lipocalin (NGAL) and leptin in patients with chronic myeloid leukemia (CML) at diagnosis and after imatinib therapy when patients achieved a complete molecular remission. The study was conducted on 22 patients with CML in the chronic phase and 10 healthy subjects. The median serum NGAL levels in CML patients at diagnosis were significantly higher compared to age-matched controls. After imatinib therapy, all patients achieved complete molecular remission and NGAL levels decreased and were found significantly lower with respect to the baseline. No significant correlations were found between NGAL levels and other disease parameters. Before imatinib therapy, the median blood leptin levels were not significantly different from those of controls. After therapy with imatinib, all patients in molecular remission presented an increase in leptin levels. Future research is eagerly awaited as it may demonstrate the real role of NGAL and leptin in the onset and progression of CML.
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Affiliation(s)
- Andrea Alonci
- Division of Hematology, Medicinal Chemistry Section, University of Messina, Italy
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Choi SS, Syn WK, Karaca GF, Omenetti A, Moylan CA, Witek RP, Agboola KM, Jung Y, Michelotti GA, Diehl AM. Leptin promotes the myofibroblastic phenotype in hepatic stellate cells by activating the hedgehog pathway. J Biol Chem 2010; 285:36551-60. [PMID: 20843817 DOI: 10.1074/jbc.m110.168542] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Trans-differentiation of quiescent hepatic stellate cells (Q-HSCs), which exhibit epithelial and adipocytic features, into myofibroblastic-HSC (MF-HSCs) is a key event in liver fibrosis. Culture models demonstrated that Hedgehog (Hh) pathway activation is required for transition of epithelioid/adipocytic Q-HSCs into MF-HSCs. Hh signaling inhibits adiposity and promotes epithelial-to-mesenchymal transitions (EMTs). Leptin (anti-adipogenic, pro-EMT factor) promotes HSC trans-differentiation and liver fibrosis, suggesting that the pathways may interact to modulate cell fate. This study aimed to determine whether leptin activates Hh signaling and whether this is required for the fibrogenic effects of leptin. Cultures of primary HSCs from lean and fa/fa rats with an inherited ObRb defect were examined. Inhibitors of PI3K/Akt, JAK/STAT, and Hh signaling were used to delineate how ObRb activation influenced Hh signaling and HSC trans-differentiation. Fibrogenesis was compared in wild type and db/db mice (impaired ObRb function) to assess the profibrotic role of leptin. The results demonstrate that leptin-ObR interactions activate Hh signaling with the latter necessary to promote trans-differentiation. Leptin-related increases in Hh signaling required ObR induction of PI3K/Akt, which was sufficient for leptin to repress the epithelioid/adipocytic program. Leptin-mediated induction of JAK/STAT was required for mesenchymal gene expression. Leptin-ObRb interactions were not necessary for HSC trans-differentiation to occur in vitro or in vivo but are important because liver fibrogenesis was attenuated in db/db mice. These findings reveal that leptin activates Hh signaling to alter gene expression programs that control cell fate and have important implications for liver fibrosis and other leptin-regulated processes involving EMTs, including development, obesity, and cancer metastasis.
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Affiliation(s)
- Steve S Choi
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, North Carolina 27710, USA
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Sáinz N, Rodríguez A, Catalán V, Becerril S, Ramírez B, Gómez-Ambrosi J, Frühbeck G. Leptin administration favors muscle mass accretion by decreasing FoxO3a and increasing PGC-1alpha in ob/ob mice. PLoS One 2009; 4:e6808. [PMID: 19730740 PMCID: PMC2733298 DOI: 10.1371/journal.pone.0006808] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 07/31/2009] [Indexed: 12/26/2022] Open
Abstract
Absence of leptin has been associated with reduced skeletal muscle mass in leptin-deficient ob/ob mice. The aim of our study was to examine the effect of leptin on the catabolic and anabolic pathways regulating muscle mass. Gastrocnemius, extensor digitorum longus and soleus muscle mass as well as fiber size were significantly lower in ob/ob mice compared to wild type littermates, being significantly increased by leptin administration (P<0.001). This effect was associated with an inactivation of the muscle atrophy-related transcription factor forkhead box class O3 (FoxO3a) (P<0.05), and with a decrease in the protein expression levels of the E3 ubiquitin-ligases muscle atrophy F-box (MAFbx) (P<0.05) and muscle RING finger 1 (MuRF1) (P<0.05). Moreover, leptin increased (P<0.01) protein expression levels of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a regulator of muscle fiber type, and decreased (P<0.05) myostatin protein, a negative regulator of muscle growth. Leptin administration also activated (P<0.01) the regulators of cell cycle progression proliferating cell nuclear antigen (PCNA) and cyclin D1, and increased (P<0.01) myofibrillar protein troponin T. The present study provides evidence that leptin treatment may increase muscle mass of ob/ob mice by inhibiting myofibrillar protein degradation as well as enhancing muscle cell proliferation.
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Affiliation(s)
- Neira Sáinz
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Amaia Rodríguez
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Victoria Catalán
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Sara Becerril
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Beatriz Ramírez
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Javier Gómez-Ambrosi
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Gema Frühbeck
- Metabolic Research Laboratory, University of Navarra, Pamplona, Spain
- Department of Endocrinology, Clínica Universidad de Navarra, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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Abstract
BACKGROUND & AIMS Leptin has profibrogenic effects in liver, although the mechanisms of this process are unclear. We sought to elucidate the direct and indirect effects of leptin on hepatic stellate cells (HSCs). METHODS HSCs from Sprague-Dawley rats were exposed to leptin and expression of collagen-I, tissue inhibitor of matrix metalloproteinases-1 (TIMP1), transforming growth factor beta1 (TGF-beta1), and connective tissue growth factor (CTGF/CCN2) was assessed. The effects of medium from Kupffer cells (KCs) and sinusoidal endothelial cells (SECs) following leptin were evaluated in HSCs; alpha-smooth muscle actin (alphaSMA) production and KC signaling were analyzed. RESULTS HSCs were not activated by incubation with leptin. However, HSCs cultured with medium taken from KCs that were incubated with leptin had increased expression of collagen I, TIMP1, TGF-beta1, and CTGF/CCN2, as well as alphaSMA protein levels and proliferation. These effects were leptin receptor dependent because conditioned medium from KCs isolated from leptin receptor-deficient Zucker (fa/fa) rats did not activate HSCs. In KCs incubated with leptin, messenger RNA and protein expression of TGF-beta1 and CTGF/CCN2 increased. Leptin potentiated signal transducer and activator of transcription 3, AKT, and extracellular signal-related kinase 1/2 phosphorylation in KCs and increased AP-1 and nuclear factor-kappaB DNA binding. Finally, addition of anti-TGF-beta to KC-conditioned medium inhibited HSC expression of collagen I, TIMP1, and CTGF/CCN2, whereas signal transducer and activator of transcription 3 inhibitor attenuated TGF-beta1 production by KC. CONCLUSIONS Leptin mediates HSC activation and liver fibrosis through indirect effects on KC; these effects are partly mediated by TGF-beta1.
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Wang J, Leclercq I, Brymora JM, Xu N, Ramezani-Moghadam M, London RM, Brigstock D, George J. Kupffer cells mediate leptin-induced liver fibrosis. Gastroenterology 2009; 137:713-23. [PMID: 19375424 PMCID: PMC2757122 DOI: 10.1053/j.gastro.2009.04.011] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 03/30/2009] [Accepted: 04/08/2009] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Leptin has profibrogenic effects in liver, although the mechanisms of this process are unclear. We sought to elucidate the direct and indirect effects of leptin on hepatic stellate cells (HSCs). METHODS HSCs from Sprague-Dawley rats were exposed to leptin and expression of collagen-I, tissue inhibitor of matrix metalloproteinases-1 (TIMP1), transforming growth factor beta1 (TGF-beta1), and connective tissue growth factor (CTGF/CCN2) was assessed. The effects of medium from Kupffer cells (KCs) and sinusoidal endothelial cells (SECs) following leptin were evaluated in HSCs; alpha-smooth muscle actin (alphaSMA) production and KC signaling were analyzed. RESULTS HSCs were not activated by incubation with leptin. However, HSCs cultured with medium taken from KCs that were incubated with leptin had increased expression of collagen I, TIMP1, TGF-beta1, and CTGF/CCN2, as well as alphaSMA protein levels and proliferation. These effects were leptin receptor dependent because conditioned medium from KCs isolated from leptin receptor-deficient Zucker (fa/fa) rats did not activate HSCs. In KCs incubated with leptin, messenger RNA and protein expression of TGF-beta1 and CTGF/CCN2 increased. Leptin potentiated signal transducer and activator of transcription 3, AKT, and extracellular signal-related kinase 1/2 phosphorylation in KCs and increased AP-1 and nuclear factor-kappaB DNA binding. Finally, addition of anti-TGF-beta to KC-conditioned medium inhibited HSC expression of collagen I, TIMP1, and CTGF/CCN2, whereas signal transducer and activator of transcription 3 inhibitor attenuated TGF-beta1 production by KC. CONCLUSIONS Leptin mediates HSC activation and liver fibrosis through indirect effects on KC; these effects are partly mediated by TGF-beta1.
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Affiliation(s)
- Jianhua Wang
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
| | - Isabelle Leclercq
- Laboratory of Gastroenterology, Faculty of Medicine, Université catholique de Louvain, GAEN 53/79, Avenue Mounier, 53, B-1200 Brussels, Belgium
| | - Joanne M. Brymora
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
| | - Ning Xu
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
| | - Mehdi Ramezani-Moghadam
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
| | - Roslyn M. London
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
| | - David Brigstock
- Center for Cell and Vascular Biology, Children’s Research Institute, Columbus, OH 43205, USA
| | - Jacob George
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney and Westmead Hospital, Westmead 2145. Australia
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15
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Lautenbach A, Budde A, Wrann CD, Teichmann B, Vieten G, Karl T, Nave H. Obesity and the Associated Mediators Leptin, Estrogen and IGF-I Enhance the Cell Proliferation and Early Tumorigenesis of Breast Cancer Cells. Nutr Cancer 2009; 61:484-91. [DOI: 10.1080/01635580802610115] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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16
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Tang Y, Zheng S, Chen A. Curcumin eliminates leptin's effects on hepatic stellate cell activation via interrupting leptin signaling. Endocrinology 2009; 150:3011-20. [PMID: 19299451 PMCID: PMC2703516 DOI: 10.1210/en.2008-1601] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nonalcoholic steatohepatitis (NASH) is commonly found in patients with obesity and is often accompanied with abnormally elevated levels of plasma leptin, i.e. hyperleptinemia. A relatively high population of NASH patients develops hepatic fibrosis, even cirrhosis. Hepatic stellate cells (HSCs) are the major effector cells during liver fibrogenesis and could be activated by leptin. The antioxidant curcumin, a phytochemical from turmeric, has been shown to suppress HSC activation in vitro and in vivo. This project is to evaluate the effect of curcumin on leptin-induced HSC activation and to elucidate the underlying mechanisms. We hypothesize that curcumin abrogates the stimulatory effect of leptin on HSC activation by interrupting leptin signaling and attenuating leptin-induced oxidative stress. Curcumin eliminates the stimulatory effects of leptin on regulating expression of genes closely relevant to HSC activation. Curcumin interrupts leptin signaling by reducing phosphorylation levels of leptin receptor (Ob-R) and its downstream intermediators. In addition, curcumin suppresses gene expression of Ob-R in HSCs, which requires the activation of endogenous peroxisome proliferator-activated receptor-gamma and de novo synthesis of glutathione. In conclusion, our results demonstrate that curcumin abrogates the stimulatory effect of leptin on HSC activation in vitro by reducing the phosphorylation level of Ob-R, stimulating peroxisome proliferator-activated receptor-gamma activity, and attenuating oxidative stress, leading to the suppression of Ob-R gene expression and interruption of leptin signaling. These results provide novel insights into therapeutic mechanisms of curcumin in inhibiting HSC activation and intervening liver fibrogenesis associated with hyperleptinemia in NASH patients.
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Affiliation(s)
- Youcai Tang
- Department of Pathology, School of Medicine, Saint Louis University, 1100 S. Grand Boulevard, St. Louis, Missouri 63104, USA
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van der Poorten D, George J. Disease-specific mechanisms of fibrosis: hepatitis C virus and nonalcoholic steatohepatitis. Clin Liver Dis 2008; 12:805-24, ix. [PMID: 18984468 DOI: 10.1016/j.cld.2008.07.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our mechanistic understanding of liver fibrosis has increased dramatically in recent years for all liver diseases and for hepatitis C and nonalcoholic steatohepatitis (NASH) in particular. Hepatitis C causes liver injury and fibrosis through direct cytopathic means, direct and indirect interactions with hepatic stellate cells, and activation of the immune system. Steatosis and insulin resistance, which are intrinsic deficits in NASH, are also of great importance in hepatitis C and may be induced by viral or host metabolic factors. For NASH, the key mediators of damage include oxidative stress, fat compartmentalization, visceral fat, apoptosis, and adipokine derangement. This article explores in depth the disease-specific mechanisms of fibrosis in hepatitis C and NASH, with a focus on recent developments.
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Abstract
Adipose tissue is now recognized as the largest endocrine organ in the body, secreting over 100 proteins termed adipokines that influence energy homeostasis, lipid physiology, inflammation, immune function and wound healing. Some of these proteins, such as TNFalpha, have important proinflammatory effects, but during hepatic injury are principally secreted at a local level within the liver. Their role in liver injury and fibrosis is beyond the scope of this review. However, circulating adipose-derived proteins such as leptin, adiponectin and resistin have important systemic effects, including the modulation of injury and fibrosis. The activities of these adipokines in the pathogenesis of liver injury and fibrosis will be the topic of this review.
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Affiliation(s)
- Jianhua Wang
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney, NSW 2145, Australia.
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19
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Niu L, Wang X, Li J, Huang Y, Yang Z, Chen F, Ni H, Jin Y, Lu X, Cao Q. Leptin stimulates alpha1(I) collagen expression in human hepatic stellate cells via the phosphatidylinositol 3-kinase/Akt signalling pathway. Liver Int 2007; 27:1265-72. [PMID: 17919239 DOI: 10.1111/j.1478-3231.2007.01582.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND/AIMS Leptin has been recognized as a profibrogenic hormone in the liver and is involved in collagen type I formation by activated hepatic stellate cells (HSCs) in response to fibrogenic substances, but the molecular signal mechanisms by which leptin promotes liver fibrogenesis through upregulation of collagen type I expression is not clear. We investigated whether leptin-induced collagen type I is mediated by the Janus kinase-phosphatidylinositol 3-kinase-Akt (JAKs-PI3K-Akt) pathway in a human HSC cell line, LX-2. METHODS LX-2 cells were treated with or without various inhibitors in the presence of leptin. RESULTS Leptin increased alpha1(I) collagen mRNA and protein. JAK1, PI3K and Akt were activated after leptin stimulation. AG490, a JAK inhibitor, blocked JAK1 phosphorylation accompanied by inhibition of PI3K and Akt activation as well as alpha1(I) collagen mRNA expression, indicating a JAK1-dependent mechanism. Wortmannin, a PI3K inhibitor, prevented PI3K and Akt activation and resulted in suppression of alpha1(I) collagen mRNA expression, suggesting a PI3K-mediated process. These changes were reproduced by overexpression of the dominant-negative p85alpha mutant. A443654.3, an Akt inhibitor, opposed Akt activation, leading to downregulation of alpha1(I) collagen mRNA. Overexpression of the dominant-negative Akt mutant led to similar alterations. CONCLUSION Leptin has a direct action on liver fibrogenesis by stimulating alpha1(I) collagen production in activated HSC. The process appears to be mediated by the PI3K/Akt pathway through activated JAK1.
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Affiliation(s)
- Liwen Niu
- School of Pharmacy, Anhui Medical University, Anhui Province, China
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20
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Abstract
Obesity and insulin resistance are the key factors for progression of hepatic fibrosis in various chronic liver diseases including non-alcoholic steatohepatitis (NASH). Recently it has been shown that leptin plays a pivotal role in development of hepatic fibrosis. Leptin promotes hepatic fibrogenesis through upregulation of transforming growth factor-beta in Kupffer cells and sinusoidal endothelial cells. Further, leptin facilitates proliferation and prevents apoptosis of hepatic stellate cells. There is a paradox, however, in that ob/ob mice and Zucker rats, which are the obese and diabetic strains, had minimal profibrogenic responses in the liver, most likely because they lack leptin and its receptors. To establish a more clinically relevant model to study the mechanism of fibrogenesis under steatohepatitis, fatty changes and profibrogenic responses in the liver caused by methionine-choline deficiency (MCD) were investigated in the KK-A(y) mouse, which is an obese and diabetic strain. KK-A(y) mice developed more severe hepatic steatosis, inflammation and fibrosis induced by an MCD diet as compared to C57Bl/6 controls. Importantly, KK-A(y) mice lack physiological upregulation of adiponectin levels, suggesting that adiponectin plays a pivotal role not only in regulation of insulin sensitivity but also in modulation of inflammatory and profibrogenic responses in dietary steatohepatitis. Collectively, these findings support the hypothesis that the balance of adipocytokine expression is a key regulator for the progression of hepatic fibrosis in the setting of steatohepatitis.
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Affiliation(s)
- Kenichi Ikejima
- Department of Gastroenterology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
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21
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Abe W, Ikejima K, Lang T, Okumura K, Enomoto N, Kitamura T, Takei Y, Sato N. Low molecular weight heparin prevents hepatic fibrogenesis caused by carbon tetrachloride in the rat. J Hepatol 2007; 46:286-94. [PMID: 17166617 DOI: 10.1016/j.jhep.2006.08.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2006] [Revised: 08/18/2006] [Accepted: 08/27/2006] [Indexed: 01/03/2023]
Abstract
BACKGROUND/AIMS In this study, we investigated the effect of dalteparin sodium, a low molecular weight (LMW)-heparin, on hepatic fibrogenesis caused by chronic carbon tetrachloride (CCl4) administration in the rat. METHODS Female Wistar rats were given a single, or repeated intraperitoneal injections of CCl4 (1ml/kg, twice per week) and dalteparin (50IU/kg, daily) for 7 weeks. RESULTS Dalteparin did not prevent acute CCl4-induced hepatic necrosis and elevation in serum aminotransferases levels; however, proliferating cell nuclear antigen (PCNA)-positive hepatocytes were dramatically increased 24h after simultaneous administration of CCl4 and dalteparin. Interestingly, serum hepatocyte growth factor (HGF) levels 12h after injection of CCl4 were almost doubled when dalteparin was given simultaneously. Hepatic fibrosis following 7-week CCl4 treatment was markedly ameliorated by daily co-administration of dalteparin. Indeed, dalteparin largely inhibited CCl4-induction of smooth muscle alpha-actin expression, alpha1(I)procollagen and transforming growth factor (TGF)-beta1 mRNA levels in the liver. Further, dalteparin blunted platelet-derived growth factor (PDGF)-induced increases in 5-bromo-2'deoxyuridine (BrdU) uptake in 3-day cultured hepatic stellate cells (HSCs) in a dose-dependent manner. CONCLUSIONS Dalteparin enhances hepatic regeneration and minimizes hepatic fibrogenesis caused by chronic CCl4 treatment. The mechanism underlying these effects most likely involves both up-regulation of HGF and inhibition of HSC proliferation.
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Affiliation(s)
- Wataru Abe
- Department of Gastroenterology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
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Tsochatzis E, Papatheodoridis GV, Archimandritis AJ. The evolving role of leptin and adiponectin in chronic liver diseases. Am J Gastroenterol 2006; 101:2629-40. [PMID: 16952281 DOI: 10.1111/j.1572-0241.2006.00848.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Leptin and adiponectin, the main metabolic products of adipose tissue, have been implicated in a wide spectrum of human diseases. Given the frequent presence of hepatic steatosis in several chronic liver diseases, there is currently increasing interest in the role of these adipokines in the development of hepatic steatosis and also in necroinflammation and fibrosis, mostly in patients with nonalcoholic fatty liver disease or chronic hepatitis C. According to experimental data, reduced adiponectin levels and increased leptin levels associated with leptin resistance, which are usually observed in obese patients with or without metabolic syndrome, may result in fat accumulation in the liver and in the enhancement of liver inflammation and mostly fibrogenesis. Increased leptin and decreased adiponectin serum levels have been detected initially in patients with nonalcoholic steatohepatitis and more recently in patients with chronic hepatitis C compared to healthy controls in most but not all studies, while the data on the associations between these adipokine levels and the severity of hepatic steatosis or fibrosis are still rather conflicting. However, several potential confounding parameters were not evaluated in all studies. Therefore, the associations between adipokines and liver histological lesions and their effects on liver cells should be evaluated further in prospective, carefully designed studies, including larger cohorts of patients with detailed assessment of metabolic and other potential confounding factors.
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Affiliation(s)
- Emmanuel Tsochatzis
- 2nd Department of Internal Medicine, Medical School of Athens University, Hippokration General Hospital, Athens, Greece
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23
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Magariños MP, Sánchez-Margalet V, Kotler M, Calvo JC, Varone CL. Leptin promotes cell proliferation and survival of trophoblastic cells. Biol Reprod 2006; 76:203-10. [PMID: 17021346 DOI: 10.1095/biolreprod.106.051391] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Leptin, the 16-kDa protein product of the obese gene, was originally considered as an adipocyte-derived signaling molecule for the central control of metabolism. However, leptin has been suggested to be involved in other functions during pregnancy, particularly in placenta. In the present work, we studied a possible effect of leptin on trophoblastic cell proliferation, survival, and apoptosis. Recombinant human leptin added to JEG-3 and BeWo choriocarcinoma cell lines showed a stimulatory effect on cell proliferation up to 3 and 2.4 times, respectively, measured by (3)H-thymidine incorporation and cell counting. These effects were time and dose dependent. Maximal effect was achieved at 250 ng leptin/ml for JEG-3 cells and 50 ng leptin/ml for BeWo cells. Moreover, by inhibiting endogenous leptin expression with 2 microM of an antisense oligonucleotide (AS), cell proliferation was diminished. We analyzed cell population distribution during the different stages of cell cycle by fluorescence-activated cell sorting, and we found that leptin treatment displaced the cells towards a G2/M phase. We also found that leptin upregulated cyclin D1 expression, one of the key cell cycle-signaling proteins. Since proliferation and death processes are intimately related, the effect of leptin on cell apoptosis was investigated. Treatment with 2 microM leptin AS increased the number of apoptotic cells 60 times, as assessed by annexin V-fluorescein isothiocyanate/propidium iodide staining, and the caspase-3 activity was increased more than 2 fold. This effect was prevented by the addition of 100 ng leptin/ml. In conclusion, we provide evidence that suggests that leptin is a trophic and mitogenic factor for trophoblastic cells by virtue of its inhibiting apoptosis and promoting proliferation.
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Affiliation(s)
- María Paula Magariños
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
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Méndez-Sánchez N, Chávez-Tapia NC, Medina-Santillán R, Villa AR, Sánchez-Lara K, Ponciano-Rodríguez G, Ramos MH, Uribe M. The efficacy of adipokines and indices of metabolic syndrome as predictors of severe obesity-related hepatic steatosis. Dig Dis Sci 2006; 51:1716-22. [PMID: 17203555 DOI: 10.1007/s10620-006-9093-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The aim of this study was to investigate adiponectin, leptin, and metabolic syndrome as predictors of the severity of obesity-related steatosis. By ultrasonography steatosis-positive (cases) subjects (n = 141) were compared with controls (n = 111). Demographic and anthropometric data and serum concentrations of adiponectin, leptin, and insulin were measured. The impact of several criteria of metabolic syndrome, serum adiponectin concentrations, and serum leptin concentrations were tested using a multivariate logistic regression analysis. The frequency of metabolic syndrome was higher in cases (44.0% versus 9.2%; P < .0001). Cases were older and had higher insulin resistance, waist circumference, and lower concentrations of adiponectin (all P < .001). The upper adiponectin quartile was associated with a lesser grade of steatosis. Metabolic syndrome and adiponectin concentrations were independently associated with the probability of steatosis. In conclusion, adipokines and metabolic syndrome are useful indices for the prediction of the severity of obesity-related steatosis.
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Affiliation(s)
- Nahum Méndez-Sánchez
- Liver Research Unit, Medica Sur Clinic and Foundation, Mexico City, Mexico, USA.
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25
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Ikejima K. [Progress in the study of obesity. 2. The concept of leptin]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2006; 95:94-9. [PMID: 16499215 DOI: 10.2169/naika.95.94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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26
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Tsukada S, Parsons CJ, Rippe RA. Mechanisms of liver fibrosis. Clin Chim Acta 2005; 364:33-60. [PMID: 16139830 DOI: 10.1016/j.cca.2005.06.014] [Citation(s) in RCA: 275] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 06/07/2005] [Accepted: 06/08/2005] [Indexed: 01/18/2023]
Abstract
Liver fibrosis represents a significant health problem worldwide of which no acceptable therapy exists. The most characteristic feature of liver fibrosis is excess deposition of type I collagen. A great deal of research has been performed to understand the molecular mechanisms responsible for the development of liver fibrosis. The activated hepatic stellate cell (HSC) is the primary cell type responsible for the excess production of collagen. Following a fibrogenic stimulus, HSCs change from a quiescent to an activated, collagen-producing cell. Numerous changes in gene expression are associated with HSC activation including the induction of several intracellular signaling cascades, which help maintain the activated phenotype and control the fibrogenic and proliferative state of the cell. Detailed analyses in understanding the molecular basis of collagen gene regulation have revealed a complex process offering the opportunity for multiple potential therapeutic strategies. However, further research is still needed to gain a better understanding of HSC activation and how this cell maintains its fibrogenic nature. In this review we describe many of the molecular events that occur following HSC activation and collagen gene regulation that contribute to the fibrogenic nature of these cells and provide a review of therapeutic strategies to treat this disease.
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Affiliation(s)
- Shigeki Tsukada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, NC 27599-7032, USA
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Thirunavukkarasu C, Uemura T, Wang LF, Watkins SC, Gandhi CR. Normal rat hepatic stellate cells respond to endotoxin in LBP-independent manner to produce inhibitor(s) of DNA synthesis in hepatocytes. J Cell Physiol 2005; 204:654-65. [PMID: 15828022 DOI: 10.1002/jcp.20366] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Endotoxin is implicated in the pathology of acute liver failure. The mechanisms of its actions on quiescent hepatic stellate cells (qHSCs) and their implications in hepatocyte injury are incompletely understood. We investigated effects of endotoxin (bacterial lipopolysaccharide; LPS) on qHSCs and subsequently on hepatocytes. After overnight culture following their isolation, qHSCs were incubated with or without endotoxin for 24 h. The cells and the culture supernatant were analyzed for cytokines and nitric oxide (NO) synthesis. The effects of qHSC-conditioned media on hepatocytes were then determined. LPS increased inducible NO synthase expression, stimulated NO synthesis, and inhibited DNA synthesis in qHSCs. qHSC-conditioned medium inhibited DNA synthesis in hepatocytes without affecting NO synthesis, while LPS (1-1,000 ng/ml)-conditioned qHSC medium stimulated NO synthesis and caused further inhibition of DNA synthesis and apoptosis. These effects of LPS were more pronounced when qHSCs were incubated with serum, but not with LPS-binding protein (LBP) although CD14 (a receptor for LPS-LBP complex) was found in qHSCs. LPS stimulated the synthesis of TNF-alpha, interleukin (IL)-6, and IL-1beta but not of TGF-beta in qHSCs. Individually or together, L-N(G)-monomethylarginine and antibodies to IL-1beta, IL-6, and TNF-alpha only partly reversed qHSC + LPS-conditioned medium-induced inhibition of DNA synthesis in hepatocytes. These results suggest that the effects of LPS on qHSCs are novel, occurring without the aid of LBP/CD14. They also indicate that other factors, in addition to NO, TGF-beta, TNF-alpha, IL-1beta, and IL-6 are involved in the mechanisms of the growth inhibitory effects of qHSCs on hepatocytes.
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Affiliation(s)
- Chinnasamy Thirunavukkarasu
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
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