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Böhm F, Köhler UA, Speicher T, Werner S. Regulation of liver regeneration by growth factors and cytokines. EMBO Mol Med 2010; 2:294-305. [PMID: 20652897 PMCID: PMC3377328 DOI: 10.1002/emmm.201000085] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The capability of the liver to fully regenerate after injury is a unique phenomenon essential for the maintenance of its important functions in the control of metabolism and xenobiotic detoxification. The regeneration process is histologically well described, but the genes that orchestrate liver regeneration have been only partially characterized. Of particular interest are cytokines and growth factors, which control different phases of liver regeneration. Historically, their potential functions in this process were addressed by analyzing their expression in the regenerating liver of rodents. Some of the predicted roles were confirmed using functional studies, including systemic delivery of recombinant growth factors, neutralizing antibodies or siRNAs prior to liver injury or during liver regeneration. In particular, the availability of genetically modified mice and their use in liver regeneration studies has unraveled novel and often unexpected functions of growth factors, cytokines and their downstream signalling targets in liver regeneration. This review summarizes the results obtained by functional studies that have addressed the roles and mechanisms of action of growth factors and cytokines in liver regeneration after acute injury to this organ.
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Affiliation(s)
- Friederike Böhm
- Department of Biology, Institute of Cell Biology, ETH Zurich, Zurich, Switzerland
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102
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Junyent F, Alvira D, Yeste-Velasco M, de la Torre AV, Beas-Zarate C, Sureda FX, Folch J, Pallàs M, Camins A, Verdaguer E. Prosurvival role of JAK/STAT and Akt signaling pathways in MPP+-induced apoptosis in neurons. Neurochem Int 2010; 57:774-82. [PMID: 20817061 DOI: 10.1016/j.neuint.2010.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 08/09/2010] [Accepted: 08/14/2010] [Indexed: 12/23/2022]
Abstract
In the present study the role of JAK/STAT and Akt in apoptosis was evaluated in cerebellar granule cells after treatment with the mitochondrial toxin MPP(+). Firstly, we evaluated the role of the prosurvival Akt pathway in MPP(+)-induced apoptosis and found that MPP(+) rapidly reduced the phosphorylation of Akt at Ser473. Since PTEN is an upstream regulator of Akt, its inhibition with bpV(pic) (1-30 μM) should activate Akt, however, it did not attenuate CGC cell death mediated by MPP(+) but protected CGC from apoptosis mediated by S/K deprivation. We also demonstrated that after the treatment with the complex I inhibitor, the expression levels of STAT1 increased and the levels of STAT3 decreased at the time points tested (0.5-8h). Meanwhile, pharmacological inhibition of the JAK/STAT pathway with AG490 (10-40 μM) was neuroprotective, probably due to its antioxidant properties, the Jak2-inhibitor-II potentiated MPP(+) neurotoxicity. Collectively, our data indicate that the treatment of CGC with the neurotoxin MPP(+) decreased two prosurvival pathways: STAT3 and Akt. Meanwhile Akt activation, using a PTEN inhibitor, did not play a prominent role in neuroprotection; loss of STAT3 could be a signal pathway involved in neuroprotection against the Parkinsonian neurotoxin MPP(+).
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Affiliation(s)
- Felix Junyent
- Institut de Biomedicina (IBUB), Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
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103
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Ho KJ, Do NL, Otu HH, Dib MJ, Ren X, Enjyoji K, Robson SC, Terwilliger EF, Karp SJ. Tob1 is a constitutively expressed repressor of liver regeneration. J Exp Med 2010; 207:1197-208. [PMID: 20513747 PMCID: PMC2882843 DOI: 10.1084/jem.20092434] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 04/28/2010] [Indexed: 01/20/2023] Open
Abstract
How proliferative and inhibitory signals integrate to control liver regeneration remains poorly understood. A screen for antiproliferative factors repressed after liver injury identified transducer of ErbB2.1 (Tob1), a member of the PC3/BTG1 family of mito-inhibitory molecules as a target for further evaluation. Tob1 protein decreases after 2/3 hepatectomy in mice secondary to posttranscriptional mechanisms. Deletion of Tob1 increases hepatocyte proliferation and accelerates restoration of liver mass after hepatectomy. Down-regulation of Tob1 is required for normal liver regeneration, and Tob1 controls hepatocyte proliferation in a dose-dependent fashion. Tob1 associates directly with both Caf1 and cyclin-dependent kinase (Cdk) 1 and modulates Cdk1 kinase activity. In addition, Tob1 has significant effects on the transcription of critical cell cycle components, including E2F target genes and genes involved in p53 signaling. We provide direct evidence that levels of an inhibitory factor control the rate of liver regeneration, and we identify Tob1 as a crucial check point molecule that modulates the expression and activity of cell cycle proteins.
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Affiliation(s)
- Karen J. Ho
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA 02115
| | - Nhue L. Do
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA 02115
| | - Hasan H. Otu
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Martin J. Dib
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Xianghui Ren
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Keiichi Enjyoji
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Simon C. Robson
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Ernest F. Terwilliger
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Seth J. Karp
- Department of Surgery, Department of Medicine, and the Transplant Institute, Beth Israel Deaconess Medical Center, Boston, MA 02215
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104
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Kostromina E, Gustavsson N, Wang X, Lim CY, Radda GK, Li C, Han W. Glucose intolerance and impaired insulin secretion in pancreas-specific signal transducer and activator of transcription-3 knockout mice are associated with microvascular alterations in the pancreas. Endocrinology 2010; 151:2050-9. [PMID: 20215569 PMCID: PMC2869255 DOI: 10.1210/en.2009-1199] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Maintenance of glucose homeostasis depends on adequate amount and precise pattern of insulin secretion, which is determined by both beta-cell secretory processes and well-developed microvascular network within endocrine pancreas. The development of highly organized microvasculature and high degrees of capillary fenestrations in endocrine pancreas is greatly dependent on vascular endothelial growth factor-A (VEGF-A) from islet cells. However, it is unclear how VEGF-A production is regulated in endocrine pancreas. To understand whether signal transducer and activator of transcription (STAT)-3 is involved in VEGF-A regulation and subsequent islet and microvascular network development, we generated a mouse line carrying pancreas-specific deletion of STAT3 (p-KO) and performed physiological analyses both in vivo and using isolated islets, including glucose and insulin tolerance tests, and insulin secretion measurements. We also studied microvascular network and islet development by using immunohistochemical methods. The p-KO mice exhibited glucose intolerance and impaired insulin secretion in vivo but normal insulin secretion in isolated islets. Microvascular density in the pancreas was reduced in p-KO mice, along with decreased expression of VEGF-A, but not other vasotropic factors in islets in the absence of pancreatic STAT3 signaling. Together, our study suggests that pancreatic STAT3 signaling is required for the normal development and maintenance of endocrine pancreas and islet microvascular network, possibly through its regulation of VEGF-A.
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Affiliation(s)
- Elena Kostromina
- Singapore Bioimaging Consortium, Agency for Science, Technology, and Research, Singapore 138667
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105
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Wang H, Park O, Lafdil F, Shen K, Horiguchi N, Yin S, Fu XY, Kunos G, Gao B. Interplay of hepatic and myeloid signal transducer and activator of transcription 3 in facilitating liver regeneration via tempering innate immunity. Hepatology 2010; 51:1354-62. [PMID: 20041412 PMCID: PMC2850952 DOI: 10.1002/hep.23430] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED Liver regeneration triggered by two-thirds partial hepatectomy is accompanied by elevated hepatic levels of endotoxin, which contributes to the regenerative process, but liver inflammation and apoptosis remain paradoxically limited. Here, we show that signal transducer and activator of transcription 3 (STAT3), an important anti-inflammatory signal, is activated in myeloid cells after partial hepatectomy and its conditional deletion results in an enhanced inflammatory response. Surprisingly, this is accompanied by an improved rather than impaired regenerative response with increased hepatic STAT3 activation, which may contribute to the enhanced liver regeneration. Indeed, conditional deletion of STAT3 in both hepatocytes and myeloid cells results in elevated activation of STAT1 and apoptosis of hepatocytes, and a dramatic reduction in survival after partial hepatectomy, whereas additional global deletion of STAT1 protects against these effects. CONCLUSION An interplay of myeloid and hepatic STAT3 signaling is essential to prevent liver failure during liver regeneration through tempering a strong innate inflammatory response mediated by STAT1 signaling.
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Affiliation(s)
- Hua Wang
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ogyi Park
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Fouad Lafdil
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kezhen Shen
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Norio Horiguchi
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shi Yin
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xin-Yuan Fu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - George Kunos
- Section on Neuroendocrinology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bin Gao
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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106
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Miller AM, Wang H, Park O, Horiguchi N, Lafdil F, Mukhopadhyay P, Moh A, Fu XY, Kunos G, Pacher P, Gao B. Anti-inflammatory and anti-apoptotic roles of endothelial cell STAT3 in alcoholic liver injury. Alcohol Clin Exp Res 2010; 34:719-25. [PMID: 20102572 DOI: 10.1111/j.1530-0277.2009.01141.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND It is generally believed that the hepatoprotective effect of interleukin-6 (IL-6) is mediated via activation of signal transducer and activator of transcription 3 (STAT3) in hepatocytes. IL-6-deficient mice are more susceptible to alcohol-induced hepatocyte apoptosis and steatosis and elevation of serum alanine transaminase (ALT); however, whereas hepatocyte-specific STAT3 knockout mice are more susceptible to alcohol-induced hepatic steatosis, they have similar hepatocyte apoptosis and serum ALT after alcohol feeding compared with wild-type mice. This suggests that the hepatoprotective effect of IL-6 in alcoholic liver injury may be mediated via activation of STAT3-independent signals in hepatocytes, activation of STAT3 in nonparenchymal cells, or both. We have previously shown that IL-6 also activates STAT3 in sinusoidal endothelial cells (SECs). Thus, the purpose of this study was to investigate whether STAT3 in endothelial cells also plays a protective role in alcoholic liver injury. METHODS Wild-type and endothelial cell-specific STAT3 knockout (STAT3(E-/-)) mice were pair-fed and fed ethanol containing diet for 4 weeks. Liver injury and inflammation were determined. RESULTS Feeding mice with ethanol-containing diet for 4 weeks induced greater hepatic injury (elevation of serum ALT) and liver weight in STAT3(E-/-) mice than wild-type control groups. In addition, ethanol-fed STAT3(E-/-) mice displayed greater hepatic inflammation and substantially elevated serum and hepatic levels of IL-6 and TNF-alpha compared with wild-type mice. Furthermore, ethanol-fed STAT3(E-/-) mice displayed a greater abundance of apoptotic SECs and higher levels of serum hyaluronic acid than wild-type controls. CONCLUSIONS These data suggest that endothelial cell STAT3 plays important dual functions of attenuating hepatic inflammation and SEC death during alcoholic liver injury.
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Affiliation(s)
- Andrew M Miller
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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107
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Ren X, Hu B, Colletti LM. IL-22 is involved in liver regeneration after hepatectomy. Am J Physiol Gastrointest Liver Physiol 2010; 298:G74-80. [PMID: 19875704 PMCID: PMC2806105 DOI: 10.1152/ajpgi.00075.2009] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 10/20/2009] [Indexed: 02/07/2023]
Abstract
Hepatocyte proliferation following partial hepatectomy is an important component of liver regeneration, and recent in vitro studies have shown that IL-22 is involved in cellular proliferation in a variety of cell types, including hepatocytes. IL-22 functions through IL-10Rbeta and IL-22Ralpha. The goal of this study was to investigate the potential role of IL-22 in liver regeneration after 70% hepatectomy. Following 70% hepatectomy, done under general anesthesia in mice, serum IL-22 and hepatic IL-22Ralpha mRNA were significantly increased. Although administration of exogenous IL-22 prior to hepatectomy did not increase hepatocyte proliferation, administration of anti-IL-22 antibody before hepatectomy did significantly decrease hepatocyte proliferation. Furthermore, IL-22 treatment prior to 70% hepatectomy induced stat-3 activation; no significant changes were seen in ERK1/2 activation, stat-1 activation, or stat-5 activation. IL-22 pretreatment also significantly increased hepatic and serum IL-6 levels. In addition, animals treated with anti-IL-22 antibody also expressed less TGF-alpha. In conclusion, these data suggest that IL-22 is involved in liver regeneration and this may be due to interaction with IL-6 and TGF-alpha cascades.
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Affiliation(s)
- Xiaodan Ren
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
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108
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Boles MK, Wilkinson BM, Wilming LG, Liu B, Probst FJ, Harrow J, Grafham D, Hentges KE, Woodward LP, Maxwell A, Mitchell K, Risley MD, Johnson R, Hirschi K, Lupski JR, Funato Y, Miki H, Marin-Garcia P, Matthews L, Coffey AJ, Parker A, Hubbard TJ, Rogers J, Bradley A, Adams DJ, Justice MJ. Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin. PLoS Genet 2009; 5:e1000759. [PMID: 20011118 PMCID: PMC2782131 DOI: 10.1371/journal.pgen.1000759] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 11/09/2009] [Indexed: 12/13/2022] Open
Abstract
An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU) mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn), inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing.
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Affiliation(s)
- Melissa K. Boles
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Bonney M. Wilkinson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Laurens G. Wilming
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Bin Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Frank J. Probst
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jennifer Harrow
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Darren Grafham
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Kathryn E. Hentges
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Lanette P. Woodward
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrea Maxwell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Karen Mitchell
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Michael D. Risley
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Randy Johnson
- The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Karen Hirschi
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children's Hospital, Houston, Texas, United States of America
| | - Yosuke Funato
- Laboratory of Intracellular Signaling, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Hiroaki Miki
- Laboratory of Intracellular Signaling, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Pablo Marin-Garcia
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Lucy Matthews
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Alison J. Coffey
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Anne Parker
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Tim J. Hubbard
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Jane Rogers
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Allan Bradley
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - David J. Adams
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- * E-mail: (MJJ); (DJA)
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (MJJ); (DJA)
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Buettner C, Camacho RC. Hypothalamic control of hepatic glucose production and its potential role in insulin resistance. Endocrinol Metab Clin North Am 2008; 37:825-40. [PMID: 19026934 DOI: 10.1016/j.ecl.2008.09.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The liver plays a pivotal role in the regulation of glucose metabolism because it is the key organ that maintains glucose levels during fasting. An emerging body of literature has demonstrated the important role of the hypothalamus in controlling hepatic glucose production (HGP). The hypothalamus senses circulating nutrients and hormones, conveying the energy status to the central nervous system, which, in turn, controls HGP in part by way of the autonomic nervous system. Overfeeding results in the failure of the hypothalamus to sense circulating nutrients and hormones, and in a loss of the central control of HGP.
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Affiliation(s)
- Christoph Buettner
- Department of Medicine and Neuroscience, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
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110
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Sookoian S, Castaño G, Gianotti TF, Gemma C, Rosselli MS, Pirola CJ. Genetic variants in STAT3 are associated with nonalcoholic fatty liver disease. Cytokine 2008; 44:201-6. [PMID: 18789715 DOI: 10.1016/j.cyto.2008.08.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2008] [Revised: 07/28/2008] [Accepted: 08/01/2008] [Indexed: 02/08/2023]
Abstract
AIMS To investigate the role of gene variants and derived haplotypes of the STAT3 transcription factor in nonalcoholic fatty liver disease (NAFLD) and their relation with the clinical disease severity. PATIENTS AND METHODS 108 patients with NAFLD and different stages of clinical disease severity, and a group of 55 healthy individuals were included in a Hospital-based study. We selected 3 tagSNPs showing a minor allele frequency >10% (rs2293152 C/G, rs6503695 C/T, and rs9891119 A/C) encompassing 68.55kb in chromosome 17, representing 24 polymorphic sites (r(2)>0.8). RESULTS In univariate analysis, there were significant differences in the allele frequency of the rs6503695 and rs9891119 between the healthy individuals and NAFLD patients (empiric P=0.021 and 0.020, respectively). The test results for the multi-marker analysis showed that haplotypes TA and CC of tagSNPs rs6503695, rs9891119 were significantly associated with NAFLD (empiric P=0.035 and 0.015, respectively). When we tested the hypothesis of a relation between the gene variants and the clinical and histological spectrum of NAFLD by multinomial analysis, a significant association was observed with rs9891119 (P=0.02). CONCLUSIONS Our study suggests a potential role of the STAT3 polymorphisms and their haplotypes in susceptibility to NAFLD and disease severity.
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Affiliation(s)
- Silvia Sookoian
- Department of Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research A. Lanari, University of Buenos Aires-CONICET, Ciudad Autónoma de Buenos Aires, Argentina.
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111
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Myronovych A, Murata S, Chiba M, Matsuo R, Ikeda O, Watanabe M, Hisakura K, Nakano Y, Kohno K, Kawasaki T, Hashimoto I, Shibasaki Y, Yasue H, Ohkohchi N. Role of platelets on liver regeneration after 90% hepatectomy in mice. J Hepatol 2008; 49:363-72. [PMID: 18602717 DOI: 10.1016/j.jhep.2008.04.019] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/17/2008] [Accepted: 04/17/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIMS Mortality after 90% partial hepatectomy in mice was associated with severe acute liver failure. Recently, we revealed that platelets have a strong promotional effect on hepatic regeneration. In the present study, we investigated the effect of thrombocytosis on liver regeneration after 90% hepatectomy in mice. METHODS For thrombocytosis induction PEG-rHuMGDF was injected 5 days before operation. Hepatectomy, sparing only the caudate lobe, was performed in normal and thrombocytotic BALB/c mice. Survival rate, platelet number, liver weight/body weight ratio, proliferating cell nuclear antigen, serum parameters, signal transduction and overexpressed genes were examined. RESULTS Platelet number was significantly higher in thrombocytotic group. All mice in normal group died within 30 h after hepatectomy. Survival rate in thrombocytotic group was 6/11 at 30 h and 3/11 one week after hepatectomy. Activation of Akt and STAT3 signaling pathways in thrombocytotic group was observed earlier and recognized to be stronger compared to normal group. Cell cycle, signaling pathways, metabolism and transport genes were significantly overexpressed in thrombocytotic group up to 24h after hepatectomy. CONCLUSIONS Under the thrombocytotic condition, liver regeneration occurred even in 90% hepatectomized mice. Platelets contribute to cell cycle progression and metabolic pathways in addition to preventing acute liver failure.
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Affiliation(s)
- Andriy Myronovych
- Department of Surgery, Advanced Biomedical Applications, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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112
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Moh A, Zhang W, Yu S, Wang J, Xu X, Li J, Fu XY. STAT3 sensitizes insulin signaling by negatively regulating glycogen synthase kinase-3 beta. Diabetes 2008; 57:1227-35. [PMID: 18268048 DOI: 10.2337/db06-1582] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Glucose homeostasis is achieved by triggering regulation of glycogen synthesis genes in response to insulin when mammals feed, but the underlying molecular mechanism remains largely unknown. The aim of our study was to examine the role of the signal transducers and activators of transcription 3 (STAT3) in insulin signaling. RESEARCH DESIGN AND METHODS We generated a strain of mice carrying a targeted disruption of Stat3 gene in the liver (L-Stat3(-/-) mice). Hepatocytes of the L-Stat3(-/-) mice were isolated to establish cell lines for mechanistic studies. Nuclear translocation and DNA-protein interaction of STAT3 was analyzed with immunofluorescent and chromatin immunoprecipitation methods, respectively. Levels of glucose, insulin, leptin, and glucagon were profiled, and putative downstream molecules of STAT3 were examined in the presence of various stimuli in L-Stat3(-/-) and control mice. RESULTS STAT3 was found to sensitize the insulin signaling through suppression of GSK-3beta, a negative regulator of insulin signaling pathway. During feeding, both mRNA and protein levels of GSK-3beta decreased in Stat3(f/+) mice, which reflected the need of hepatocytes for insulin to induce glycogen synthesis. In contrast, the L-Stat3(-/-) mice lost this control and showed a monophasic increase in the GSK-3beta level in response to insulin. Administration of GSK-3beta inhibitors lithium chloride and L803-mts restored glucose homeostasis and rescued the glucose intolerance and impaired insulin response in L-Stat3(-/-) mice. CONCLUSIONS These data indicate that STAT3 sensitizes insulin signaling by negatively regulating GSK-3beta. Inactivation of STAT3 in the liver contributes significantly to the pathogenesis of insulin resistance.
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Affiliation(s)
- Akira Moh
- Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Dr. MS 420, Indianapolis, IN 46202, USA.
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113
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Shen K, Zheng SS, Park O, Wang H, Sun Z, Gao B. Activation of innate immunity (NK/IFN-gamma) in rat allogeneic liver transplantation: contribution to liver injury and suppression of hepatocyte proliferation. Am J Physiol Gastrointest Liver Physiol 2008; 294:G1070-7. [PMID: 18292182 PMCID: PMC2405895 DOI: 10.1152/ajpgi.00554.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Liver transplantation is presently the only curative treatment for patients with end-stage liver disease. However, the mechanisms underlying liver injury and hepatocyte proliferation posttransplantation remain obscure. In this investigation, liver injury and hepatocyte proliferation in syngeneic and allogeneic animal models were compared. Male Lewis and Dark Agouti (DA) rats were subjected to orthotopic liver transplantation (OLT). Rat OLT was performed in syngeneic (Lewis-Lewis) and allogeneic (Lewis-DA or DA-Lewis) animal models. Allogeneic liver grafts exhibited greater injury and cellular apoptosis than syngeneic grafts but less hepatocyte proliferation after OLT. Expression of IFN-gamma mRNA and activation of the downstream signal transducer and activator of transcription 1 (STAT1) and genes (interferon regulatory factor-1 and cyclin-dependent kinase inhibitor p21(CDKN1A)) were also greater in the allogeneic grafts compared with the syngeneic grafts. In contrast, STAT3 activation was lower in the allogeneic grafts. Furthermore, in the allogeneic grafts, depletion of natural killer (NK) cells decreased IFN-gamma/STAT1 activation but enhanced hepatocyte proliferation. These findings suggest that, compared with syngeneic transplantation, innate immunity (NK/IFN-gamma) is activated after allogeneic transplantation, which likely contributes to liver injury and inhibits hepatocyte proliferation.
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Affiliation(s)
- Kezhen Shen
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China,Section on Liver Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shu-Sen Zheng
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Ogyi Park
- Section on Liver Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hua Wang
- Section on Liver Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA,Department of Oncology, The Affiliated Provincial Hospital of Anhui Medical University, Anhui, 230032, China
| | - Zhaoli Sun
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Bin Gao
- Section on Liver Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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