101
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Lin CW, Mars WM, Paranjpe S, Donthamsetty S, Bhave VS, Kang LI, Orr A, Bowen WC, Bell AW, Michalopoulos GK. Hepatocyte proliferation and hepatomegaly induced by phenobarbital and 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene is suppressed in hepatocyte-targeted glypican 3 transgenic mice. Hepatology 2011; 54:620-30. [PMID: 21574168 PMCID: PMC9990398 DOI: 10.1002/hep.24417] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
UNLABELLED Glypican 3 (GPC3) is a family of glycosylphosphatidylinositol-anchored, cell-surface heparan sulfate proteoglycans. Loss-of-function mutations of GPC3 cause Simpson-Golabi-Behmel syndrome characterized by overgrowth of multiple organs, including liver. Our previous study showed that in GPC3 transgenic (TG) mice, hepatocyte-targeted overexpression of GPC3 suppresses hepatocyte proliferation and liver regeneration after partial hepatectomy and alters gene expression profiles and potential cell cycle-related proteins. This study investigates the role of GPC3 in hepatocyte proliferation and hepatomegaly induced by the xenobiotic mitogens phenobarbital (PB) and TCPOBOP (1, 4-bis [2-(3, 5-dichloropyridyloxy)] benzene). Wildtype (WT) and GPC3 TG mice were given 0.1% PB in drinking water for 10 days or a single dose of TCPOBOP (3 mg/kg) by oral gavage. At day 5 the WT mice showed a 2.2- and 3.0-fold increase in liver weight, whereas the GPC3 TG mice showed a 1.3- and 1.6-fold increase in liver weight after PB and TCPOBOP administration, respectively. There was a significant suppression of proliferative response in the GPC3 TG mice, as assessed by percent of Ki67-positive hepatocyte nuclei. Moreover, gene array analysis showed a panel of changes in the gene expression profile of TG mice, both before and after administration of the xenobiotic mitogens. Expression of cell cycle-related genes in the TG mice was also decreased compared to the WT mice. CONCLUSION Our results indicate that in GPC3 TG mice, hepatocyte-targeted overexpression of GPC3 plays an important role for regulation of liver size and termination of hepatocyte proliferation induced by the xenobiotic mitogens PB and TCPOBOP, comparable to the effects seen in the GPC3 TG mice during liver regeneration after partial hepatectomy.
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Affiliation(s)
- Chih-Wen Lin
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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102
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Enhanced liver regeneration in IL-10-deficient mice after partial hepatectomy via stimulating inflammatory response and activating hepatocyte STAT3. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1614-21. [PMID: 21435447 DOI: 10.1016/j.ajpath.2011.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 12/20/2010] [Accepted: 01/04/2011] [Indexed: 12/14/2022]
Abstract
Emerging evidence suggests that proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), play a critical role in the initiation and progression of liver regeneration; however, relatively little is known about the role of anti-inflammatory cytokine IL-10 in liver regeneration after partial hepatectomy (PHx). Here, we examined the role of IL-10 in liver regeneration using a model of PHx in several strains of genetically modified mice. After PHx, expression of IL-10 mRNA in the liver and spleen was significantly elevated. Such elevation was diminished in TLR4 mutant mice. Compared with wild-type mice, IL-10(-/-) mice had higher levels of expression of proinflammatory cytokines (IL-6, TNF-α, and IFN-γ) and inflammatory markers (CCR2 and F4/80) in the liver, as well as higher serum levels of proinflammatory cytokines after PHx. The number of neutrophils and macrophages was also higher in the livers of IL-10(-/-) mice than in wild-type mice after PHx. Liver regeneration as determined by BrdU incorporation after PHx was higher in IL-10(-/-) mice than in wild-type mice, which was associated with higher levels of activation of IL-6 downstream signal STAT3 in the liver. An additional deletion of STAT3 in hepatocytes significantly reduced liver regeneration in IL-10(-/-) mice after PHx. Collectively, IL-10 plays an important role in negatively regulating liver regeneration via limiting inflammatory response and subsequently tempering hepatic STAT3 activation.
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103
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Lang R, Stern MM, Smith L, Liu Y, Bharadwaj S, Liu G, Baptista PM, Bergman CR, Soker S, Yoo JJ, Atala A, Zhang Y. Three-dimensional culture of hepatocytes on porcine liver tissue-derived extracellular matrix. Biomaterials 2011; 32:7042-52. [PMID: 21723601 DOI: 10.1016/j.biomaterials.2011.06.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 06/03/2011] [Indexed: 10/18/2022]
Abstract
There is currently no optimal system to expand and maintain the function of human adult hepatocytes in culture. Recent studies have demonstrated that specific tissue-derived extracellular matrix (ECM) can serve as a culture substrate and that cells tend to proliferate and differentiate best on ECM derived from their tissue of origin. The goal of this study was to investigate whether three-dimensional (3D) ECM derived from porcine liver can facilitate the growth and maintenance of physiological functions of liver cells. Optimized decellularization/oxidation procedures removed up to 93% of the cellular components from porcine liver tissue and preserved key molecular components in the ECM, including collagen-I, -III, and -IV, proteoglycans, glycosaminoglycans, fibronectin, elastin, and laminin. When HepG2 cells or human hepatocytes were seeded onto ECM discs, uniform multi-layer constructs of both cell types were formed. Dynamic culture conditions yielded better cellular infiltration into the ECM discs. Human hepatocytes cultured on ECM discs expressed significantly higher levels of albumin over a 21-day culture period compared to cells cultured in traditional polystyrene cultureware or in a collagen gel "sandwich". The culture of hepatocytes on 3D liver-specific ECM resulted in considerably improved cell growth and maintained cell function; therefore, this system could potentially be used in liver tissue regeneration, drug discovery or toxicology studies.
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Affiliation(s)
- Ren Lang
- Department of Hepatobiliary Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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104
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Braeuning A, Heubach Y, Knorpp T, Kowalik MA, Templin M, Columbano A, Schwarz M. Gender-specific interplay of signaling through β-catenin and CAR in the regulation of xenobiotic-induced hepatocyte proliferation. Toxicol Sci 2011; 123:113-22. [PMID: 21705713 DOI: 10.1093/toxsci/kfr166] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Aberrant signaling through the Wnt/β-catenin pathway is a critical determinant in human and rodent liver carcinogenesis and generally accepted to be a potent driver of proliferation. Xenobiotic agonists of the constitutive androstane receptor (CAR) induce massive acute hyperplasia of mouse liver and facilitate the outgrowth of hepatocellular carcinomas with activated β-catenin. In the present study, the interplay of β-catenin-dependent and CAR-dependent signaling in the liver and its effect on hepatocyte proliferation were analyzed in transgenic mice with hepatocyte-specific knockout of Ctnnb1 (encoding β-catenin) following treatment with two CAR agonists, 1,4-bis[2-(3,5-dichloropyridyloxy)]-benzene (TCPOBOP) and phenobarbital. Hepatocyte-specific knockout of β-catenin inhibited CAR agonists-induced hepatocyte proliferation in male mice. By contrast, the proliferative effect of CAR agonists was strongly augmented in female β-catenin knockout animals. This was due to prolonged proliferation of the knockout hepatocytes. CAR-mediated hepatocyte proliferation was, at least in part, dependent on estrogen signaling and was associated with enhanced expression of FoxM1 and elevated activity of the PDK1/p90RSK pathway. In conclusion, our study shows that gender-specific factors determine whether β-catenin signaling plays a pro- or an antiproliferative role in the regulation of mouse hepatocyte proliferation induced by CAR agonists.
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Affiliation(s)
- Albert Braeuning
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, 72074 Tübingen, Germany
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105
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Yu YP, Luo JH. Phosphorylation and interaction of myopodin by integrin-link kinase lead to suppression of cell growth and motility in prostate cancer cells. Oncogene 2011; 30:4855-63. [PMID: 21643011 PMCID: PMC3170684 DOI: 10.1038/onc.2011.200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myopodin is a tumor-suppressor gene that suppresses growth of prostate and urothelial carcinomas. However, the mechanism of myopodin tumor-suppressor activity or signaling that leads to activation of myopodin remains unclear. In this report, we showed that the N-terminus of myopodin binds integrin-linked kinase (ILK) both in vivo and in vitro. An ILK interaction motif of 78 amino acids (amino acids 82-157) was identified in the N-terminus region of myopodin. Induction of ILK-dependent kinase activity by integrin α7 led to phosphorylation of myopodin both in vivo and in vitro. Knocking down ILK dramatically reduced the inhibition of cell growth and motility mediated by myopodin. A mutant of myopodin lacking the ILK interaction motif is inactive in suppressing the growth and motility of PC3 cells. As a result, this study showed a novel and critical signaling pathway that leads to activation of myopodin.
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Affiliation(s)
- Y-P Yu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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106
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Chen H, Sun Y, Dong R, Yang S, Pan C, Xiang D, Miao M, Jiao B. Mir-34a is upregulated during liver regeneration in rats and is associated with the suppression of hepatocyte proliferation. PLoS One 2011; 6:e20238. [PMID: 21655280 PMCID: PMC3105003 DOI: 10.1371/journal.pone.0020238] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 04/16/2011] [Indexed: 12/14/2022] Open
Abstract
Background MicroRNAs are a class of small regulatory RNAs that modulate a variety of biological processes, including cellular differentiation, apoptosis, metabolism and proliferation. This study aims to explore the effect of miR-34a in hepatocyte proliferation and its potential role in liver regeneration termination. Methodology/Principal Finding MiR-34a was highly induced after partial hepatectomy. Overexpression of miR-34a in BRL-3A cells could significantly inhibit cell proliferation and down-regulate the expression of inhibin βB (INHBB) and Met. In BRL-3A cells, INHBB was identified as a direct target of miR-34a by luciferase reporter assay. More importantly, INHBB siRNA significantly repressed cell proliferation. A decrease of INHBB and Met was detected in regenerating liver. Conclusion/Significance MiR-34a expression was upregulated during the late phase of liver regeneration. MiR-34a-mediated regulation of INHBB and Met may collectively contribute to the suppression of hepatocyte proliferation.
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Affiliation(s)
- Huan Chen
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
| | - Yimin Sun
- National Engineering Research Center for Beijing Biochip Technology, Beijing, China
| | - Ruiqi Dong
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
| | - Shengsheng Yang
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
| | - Chuanyong Pan
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
| | - Dao Xiang
- Department of Cellular Biology, Second Military Medical University, Shanghai, China
| | - Mingyong Miao
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
- * E-mail: (BJ); (MM)
| | - Binghua Jiao
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China
- * E-mail: (BJ); (MM)
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107
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Donthamsetty S, Bhave VS, Kliment CS, Bowen WC, Mars WM, Bell AW, Stewart RE, Orr A, Wu C, Michalopoulos GK. Excessive hepatomegaly of mice with hepatocyte-targeted elimination of integrin linked kinase following treatment with 1,4-bis [2-(3,5-dichaloropyridyloxy)] benzene. Hepatology 2011; 53:587-95. [PMID: 21274879 PMCID: PMC3062106 DOI: 10.1002/hep.24040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 09/30/2010] [Indexed: 12/07/2022]
Abstract
UNLABELLED TCBOPOP (1,4-bis [2-(3,5-dichaloropyridyloxy)] benzene) an agonist of the constitutive androstane receptor (CAR), produces rapid hepatocyte hyperplasia and hepatomegaly in the absence of hepatic injury. In this study we demonstrate that integrin-linked kinase (ILK), which is involved in transmission of the extracellular matrix (ECM) signaling by way of integrin receptors, plays an important role in regulating TCPOBOP-induced proliferation of hepatocytes and hepatomegaly. Hepatocyte-specific ILK knockout mice (ILK/liver-/- mice) and wildtype mice (WT) were given a single dose of TCPOBOP (3 mg/kg) by oral gavage. Mice were sacrificed at days 1, 2, 5, and 7 after TCPOBOP administration. WT mice showed maximum proliferation on days 1 and 2, which came back to baseline levels by days 5 and 7 after TCPOBOP administration. The ILK/liver-/- mice, on the other hand, showed a prolonged and a sustained proliferative response as evident by an increased number of proliferative cell nuclear antigen assay (PCNA)-positive cells even at days 5 and 7 after TCPOBOP administration. At day 7 the WT mice showed close to a 2.5-fold increase in liver weight, whereas the ILK/liver-/- mice showed a 3.7-fold increase in liver weight. The prolonged proliferative response in the ILK/liver-/- mice seems to be due to sustained induction of CAR leading to sustained induction of c-Myc, which is known to be a key mediator of TCPOPOP-CAR induced direct liver hyperplasia. CONCLUSION The data indicate that ECM-mediated signaling by way of ILK is essential for adjustment of final liver size and proper termination of TCPOBOP-induced proliferation of hepatocytes.
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Affiliation(s)
| | - Vishakha S. Bhave
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Corrine S Kliment
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - William C. Bowen
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Wendy M. Mars
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Aaron W. Bell
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Rachel E Stewart
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Anne Orr
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Chuanyue Wu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - George K. Michalopoulos
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA,Address reprint requests to: George K. Michalopoulos, Department of Pathology, University of Pittsburgh School of Medicine, S-410 Biomedical Science Tower, Pittsburgh, PA 15261,
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108
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Abstract
Liver regeneration is known to be a process involving highly organized and ordered tissue growth triggered by the loss of liver tissue, and remains a fascinating topic. A large number of genes are involved in this process, and there exists a sequence of stages that results in liver regeneration, while at the same time inhibitors control the size of the regenerated liver. The initiation step is characterized by priming of quiescent hepatocytes by factors such as TNF-α, IL-6 and nitric oxide. The proliferation step is the step during which hepatocytes enter into the cell cycle's G1 phase and are stimulated by complete mitogens including HGF, TGF-α and EGF. Hepatic stimulator substance, glucagon, insulin, TNF-α, IL-1 and IL-6 have also been implicated in regulating the regeneration process. Inhibitors and stop signals of hepatic regeneration are not well known and only limited information is available. Furthermore, the effects of other factors such as VEGF, PDGF, hypothyroidism, proliferating cell nuclear antigen, heat shock proteins, ischemic-reperfusion injury, steatosis and granulocyte colony-stimulating factor on liver regeneration are also systematically reviewed in this article. A tissue engineering approach using isolated hepatocytes for in vitro tissue generation and heterotopic transplantation of liver cells has been established. The use of stem cells might also be very attractive to overcome the limitation of donor liver tissue. Liver-specific differentiation of embryonic, fetal or adult stem cells is currently under investigation.
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Affiliation(s)
- Changku Jia
- Department of Hepatobiliary Surgery, Affiliated Hospital of Hainan Medical University, Haikou, Hainan Province, China.
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109
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110
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Abstract
The unique ability of the liver to regenerate itself has fascinated biologists for years and has made it the prototype for mammalian organ regeneration. Harnessing this process has great potential benefit in the treatment of liver failure and has been the focus of intense research over the past 50 years. Not only will detailed understanding of cell proliferation in response to injury be applicable to other dysfunction of organs, it may also shed light on how cancer develops in a cirrhotic liver, in which there is intense pressure on cells to regenerate. Advances in molecular techniques over the past few decades have led to the identification of many regulatory intermediates, and pushed us onto the verge of an explosive era in regenerative medicine. To date, more than 10 clinical trials have been reported in which augmented regeneration using progenitor cell therapy has been attempted in human patients. This review traces the path that has been taken over the last few decades in the study of liver regeneration, highlights new concepts in the field, and discusses the challenges that still stand between us and clinical therapy.
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Affiliation(s)
| | - Yock Young Dan
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Nelson Fausto
- Department of Pathology, University of Washington, Seattle, WA
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111
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Zellmer S, Schmidt-Heck W, Godoy P, Weng H, Meyer C, Lehmann T, Sparna T, Schormann W, Hammad S, Kreutz C, Timmer J, von Weizsäcker F, Thürmann PA, Merfort I, Guthke R, Dooley S, Hengstler JG, Gebhardt R. Transcription factors ETF, E2F, and SP-1 are involved in cytokine-independent proliferation of murine hepatocytes. Hepatology 2010; 52:2127-36. [PMID: 20979052 DOI: 10.1002/hep.23930] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 08/10/2010] [Indexed: 12/20/2022]
Abstract
UNLABELLED The cellular basis of liver regeneration has been intensely investigated for many years. However, the mechanisms initiating hepatocyte "plasticity" and priming for proliferation are not yet fully clear. We investigated alterations in gene expression patterns during the first 72 hours of C57BL/6N mouse hepatocyte culture on collagen monolayers (CM), which display a high basal frequency of proliferation in the absence of cytokines. Although many metabolic genes were down-regulated, genes related to mitogen-activated protein kinase (MAPK) signaling and cell cycle were up-regulated. The latter genes showed an overrepresentation of transcription factor binding sites (TFBS) for ETF (TEA domain family member 2), E2F1 (E2F transcription factor 1), and SP-1 (Sp1 transcription factor) (P < 0.001), all depending on MAPK signaling. Time-dependent increase of ERK1/2 phosphorylation occurred during the first 48 hours (and beyond) in the absence of cytokines, accompanied by an enhanced bromodeoxyuridine labeling index of 20%. The MEK inhibitor PD98059 blunted these effects indicating MAPK signaling as major trigger for this cytokine-independent proliferative response. In line with these in vitro findings, liver tissue of mice challenged with CCl(4) displayed hepatocytes with intense p-ERK1/2 staining and nuclear SP-1 and E2F1 expression. Furthermore, differentially expressed genes in mice after partial hepatectomy contained overrepresented TFBS for ETF, E2F1, and SP-1 and displayed increased expression of E2F1. CONCLUSION Cultivation of murine hepatocytes on CM primes cells for proliferation through cytokine-independent activation of MAPK signaling. The transcription factors ETF, E2F1, and SP-1 seem to play a pronounced role in mediating proliferation-dependent differential gene expression. Similar events, but on a shorter time-scale, occur very early after liver damage in vivo.
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Affiliation(s)
- Sebastian Zellmer
- Institute of Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany.
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112
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Liu B, Bell AW, Paranjpe S, Bowen WC, Khillan JS, Luo JH, Mars WM, Michalopoulos GK. Suppression of liver regeneration and hepatocyte proliferation in hepatocyte-targeted glypican 3 transgenic mice. Hepatology 2010; 52:1060-7. [PMID: 20812357 PMCID: PMC2936713 DOI: 10.1002/hep.23794] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
UNLABELLED Glypican 3 (GPC3) belongs to a family of glycosylphosphatidylinositol-anchored, cell-surface heparan sulfate proteoglycans. GPC3 is overexpressed in hepatocellular carcinoma. Loss-of-function mutations of GPC3 result in Simpson-Golabi-Behmel syndrome, an X-linked disorder characterized by overgrowth of multiple organs, including the liver. Our previous study showed that GPC3 plays a negative regulatory role in hepatocyte proliferation, and this effect may involve CD81, a cell membrane tetraspanin. To further investigate GPC3 in vivo, we engineered transgenic (TG) mice overexpressing GPC3 in the liver under the control of the albumin promoter. GPC3 TG mice with hepatocyte-targeted, overexpressed GPC3 developed normally in comparison with their nontransgenic littermates but had a suppressed rate of hepatocyte proliferation and liver regeneration after partial hepatectomy. Moreover, gene array analysis revealed a series of changes in the gene expression profiles in TG mice (both in normal mice and during liver regeneration). In unoperated GPC3 TG mice, there was overexpression of runt related transcription factor 3 (7.6-fold), CCAAT/enhancer binding protein alpha (2.5-fold), GABA A receptor (2.9-fold), and wingless-related MMTV integration site 7B (2.8-fold). There was down-regulation of insulin-like growth factor binding protein 1 (8.4-fold), Rab2 (5.6-fold), beta-catenin (1.7-fold), transforming growth factor beta type I (3.1-fold), nodal (1.8-fold), and yes-associated protein (1.4-fold). Changes after hepatectomy included decreased expression in several cell cycle-related genes. CONCLUSION Our results indicate that in GPC3 TG mice, hepatocyte overexpression of GPC3 suppresses hepatocyte proliferation and liver regeneration and alters gene expression profiles, and potential cell cycle-related proteins and multiple other pathways are involved and affected.
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Affiliation(s)
- Bowen Liu
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Aaron W. Bell
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Shirish Paranjpe
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - William C. Bowen
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jaspal S. Khillan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jian-Hua Luo
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Wendy M. Mars
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - George K. Michalopoulos
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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113
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Han YC, Yu YP, Nelson J, Wu C, Wang H, Michalopoulos GK, Luo JH. Interaction of integrin-linked kinase and miniature chromosome maintenance 7-mediating integrin {alpha}7 induced cell growth suppression. Cancer Res 2010; 70:4375-84. [PMID: 20460506 DOI: 10.1158/0008-5472.can-09-4403] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mutation of integrin alpha7 (ITGA7) was previously identified in multiple human malignancies. Restoration of ITGA7 expression in prostate cancer and leiomyosarcoma cell lines suppressed tumor growth and cell motility both in vitro and in vivo. In this study, we showed that integrin-linked kinase (ILK) binds with miniature chromosome maintenance 7 (MCM7), a DNA replication licensing protein. A 58-amino acid ILK binding motif was identified in the NH(2)-terminus of MCM7. The expression of ITGA7 induced the phosphorylation of MCM7. Knocking down of ILK abrogated ITGA7-induced MCM7 phosphorylation. ANK, the dominant-negative mutant of ILK, also blocked the phosphorylation of MCM7 induced by ITGA7. The phosphorylation of MCM7 reduced MCM7 chromatin association and inhibited cell growth. A MCM7 mutant that does not bind with ILK did not respond to ITGA7 stimulation, and behaved similarly to a dominant MCM7-negative mutant and neutralized the effect of ITGA7. We conclude that ILK interaction with MCM7 and MCM7 phosphorylation may be a critical event in ITGA7 signaling pathway, leading to tumor suppression.
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Affiliation(s)
- Yu-Chen Han
- Departments of Pathology and Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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114
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Kurinna S, Barton MC. Cascades of transcription regulation during liver regeneration. Int J Biochem Cell Biol 2010; 43:189-97. [PMID: 20307684 DOI: 10.1016/j.biocel.2010.03.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 01/13/2010] [Accepted: 03/15/2010] [Indexed: 01/20/2023]
Abstract
An increasing demand for new strategies in cancer prevention and regenerative medicine requires a better understanding of molecular mechanisms that control cell proliferation in tissue-specific manner. Regenerating liver is a unique model allowing use of biochemical, genetic, and engineering tools to uncover molecular mechanisms and improve treatment of hepatic cancers, liver failure, and fibrotic disease. Molecular mechanisms of liver regeneration involve extra- and intracellular factors to activate transcription of genes normally silenced in quiescent liver. While many upstream signaling pathways of the regenerating liver have been extensively studied, our knowledge of the downstream effectors, transcription factors (TFs), remains limited. This review describes consecutive engagement of pre-existing and de novo synthesized TFs, as cascades that regulate expression of growth-related and metabolic genes during liver regeneration after partial hepatectomy in mice. Several previously recognized regulators of regenerating liver are described in the light of recently identified co-activator and co-repressor complexes that interact with primary DNA-binding TFs. Published results of gene expression and chromatin immunoprecipitation analyses, as well as studies of transgenic mouse models, are used to emphasize new potential regulators of transcription during liver regeneration. Finally, a more detailed description of newly identified transcriptional regulators of liver regeneration illustrates the tightly regulated balance of proliferative and metabolic responses to partial hepatectomy.
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Affiliation(s)
- Svitlana Kurinna
- Department of Biochemistry and Molecular Biology, UT-Houston Graduate School of Biomedical Sciences, UT MD Anderson Cancer Center, Houston, TX 77030, USA
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115
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Mesenchymal stem cells as therapeutic tools and gene carriers in liver fibrosis and hepatocellular carcinoma. Gene Ther 2010; 17:692-708. [PMID: 20220785 DOI: 10.1038/gt.2010.10] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mesenchymal stem (stromal) cells (MSCs) are a source of circulating progenitors that are able to generate cells of all mesenchymal lineages and to cover cellular demands of injured tissues. The extent of their transdifferentiation plasticity remains controversial. Cells with MSC properties have been obtained from diverse tissues after purification and expansion in vitro. These cellular populations are heterogeneous and under certain conditions show pluripotent-like properties. MSCs present immunosuppressive and anti-inflammatory features and high migratory capacity toward inflamed or remodeling tissues. In this study we review available data regarding factors and signaling axes involved in the chemoattraction and engraftment of MSCs to an injured tissue or to a tissue undergoing active remodeling. Moreover, experimental evidence in support of uses of MSCs as vehicles of therapeutic genes is discussed. Because of its regenerative capacity and its particular immune properties, the liver is a good model to analyze the potential of MSC-based therapies. Finally, the potential application of MSCs and genetically modified MSCs in liver fibrosis and hepatocellular carcinoma (HCC) is proposed in view of available evidence.
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116
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Michalopoulos GK. Liver regeneration after partial hepatectomy: critical analysis of mechanistic dilemmas. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 176:2-13. [PMID: 20019184 DOI: 10.2353/ajpath.2010.090675] [Citation(s) in RCA: 536] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Liver regeneration after partial hepatectomy is one of the most studied models of cell, organ, and tissue regeneration. The complexity of the signaling pathways initiating and terminating this process have provided paradigms for regenerative medicine. Many aspects of the signaling mechanisms involved in hepatic regeneration are under active investigation. The purpose of this review is to focus on the areas still not well understood. The review also aims to provide insights into the ways by which current concepts of liver regeneration can provide understanding regarding malfunction of the regenerative process in liver diseases, such as acute liver failure.
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Affiliation(s)
- George K Michalopoulos
- University of Pittsburgh, Department of Pathology, School of Medicine, S-410 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
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Donthamsetty S, Bowen W, Mars W, Bhave V, Luo JH, Wu C, Hurd J, Orr A, Bell A, Michalopoulos G. Liver-specific ablation of integrin-linked kinase in mice results in enhanced and prolonged cell proliferation and hepatomegaly after phenobarbital administration. Toxicol Sci 2009; 113:358-66. [PMID: 19920070 DOI: 10.1093/toxsci/kfp281] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have recently demonstrated that disruption of extracellular matrix (ECM)/integrin signaling via elimination of integrin-linked kinase (ILK) in hepatocytes interferes with signals leading to termination of liver regeneration. This study investigates the role of ILK in liver enlargement induced by phenobarbital (PB). Wild-type (WT) and ILK:liver-/- mice were given PB (0.1% in drinking water) for 10 days. Livers were harvested on 2, 5, and 10 days during PB administration. In the hepatocyte-specific ILK/liver-/- mice, the liver:body weight ratio was more than double as compared to 0 h at day 2 (2.5 times), while at days 5 and 10, it was enlarged three times. In the WT mice, the increase was as expected from previous literature (1.8 times) and seems to have leveled off after day 2. There were slightly increased proliferating cell nuclear antigen-positive cells in the ILK/liver-/- animals at day 2 as compared to WT after PB administration. In the WT animals, the proliferative response had come back to normal by days 5 and 10. Hepatocytes of the ILK/liver-/- mice continued to proliferate up until day 10. ILK/liver-/- mice also showed increased expression of key genes involved in hepatocyte proliferation at different time points during PB administration. In summary, ECM proteins communicate with the signaling machinery of dividing cells via ILK to regulate hepatocyte proliferation and termination of the proliferative response. Lack of ILK in the hepatocytes imparts prolonged proliferative response not only to stimuli related to liver regeneration but also to xenobiotic chemical mitogens, such as PB.
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Affiliation(s)
- Shashikiran Donthamsetty
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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