1
|
The Active Role of Pericytes During Neuroinflammation in the Adult Brain. Cell Mol Neurobiol 2023; 43:525-541. [PMID: 35195811 DOI: 10.1007/s10571-022-01208-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/13/2022] [Indexed: 12/11/2022]
Abstract
Microvessels in the central nervous system (CNS) have one of the highest populations of pericytes, indicating their crucial role in maintaining homeostasis. Pericytes are heterogeneous cells located around brain microvessels; they present three different morphologies along the CNS vascular tree: ensheathing, mesh, and thin-strand pericytes. At the arteriole-capillary transition ensheathing pericytes are found, while mesh and thin-strand pericytes are located at capillary beds. Brain pericytes are essential for the establishment and maintenance of the blood-brain barrier, which restricts the passage of soluble and potentially toxic molecules from the circulatory system to the brain parenchyma. Pericytes play a key role in regulating local inflammation at the CNS. Pericytes can respond differentially, depending on the degree of inflammation, by secreting a set of neurotrophic factors to promote cell survival and regeneration, or by potentiating inflammation through the release of inflammatory mediators (e.g., cytokines and chemokines), and the overexpression of cell adhesion molecules. Under inflammatory conditions, pericytes may regulate immune cell trafficking to the CNS and play a role in perpetuating local inflammation. In this review, we describe pericyte responses during acute and chronic neuroinflammation.
Collapse
|
2
|
Huang X, Khoong Y, Han C, Su D, Ma H, Gu S, Li Q, Zan T. Targeting Dermal Fibroblast Subtypes in Antifibrotic Therapy: Surface Marker as a Cellular Identity or a Functional Entity? Front Physiol 2021; 12:694605. [PMID: 34335301 PMCID: PMC8319956 DOI: 10.3389/fphys.2021.694605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/16/2021] [Indexed: 02/01/2023] Open
Abstract
Fibroblasts are the chief effector cells in fibrotic diseases and have been discovered to be highly heterogeneous. Recently, fibroblast heterogeneity in human skin has been studied extensively and several surface markers for dermal fibroblast subtypes have been identified, holding promise for future antifibrotic therapies. However, it has yet to be confirmed whether surface markers should be looked upon as merely lineage landmarks or as functional entities of fibroblast subtypes, which may further complicate the interpretation of cellular function of these fibroblast subtypes. This review aims to provide an update on current evidence on fibroblast surface markers in fibrotic disorders of skin as well as of other organ systems. Specifically, studies where surface markers were treated as lineage markers and manipulated as functional membrane proteins are both evaluated in parallel, hoping to reveal the underlying mechanism behind the pathogenesis of tissue fibrosis contributed by various fibroblast subtypes from multiple angles, shedding lights on future translational researches.
Collapse
Affiliation(s)
- Xin Huang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yimin Khoong
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chengyao Han
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Dai Su
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Ma
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Shuchen Gu
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qingfeng Li
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Tao Zan
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
3
|
Papadopoulos N, Lennartsson J. The PDGF/PDGFR pathway as a drug target. Mol Aspects Med 2018; 62:75-88. [DOI: 10.1016/j.mam.2017.11.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/10/2017] [Indexed: 02/07/2023]
|
4
|
Abstract
Stellate cells are resident lipid-storing cells of the pancreas and liver that transdifferentiate to a myofibroblastic state in the context of tissue injury. Beyond having roles in tissue homeostasis, stellate cells are increasingly implicated in pathological fibrogenic and inflammatory programs that contribute to tissue fibrosis and that constitute a growth-permissive tumor microenvironment. Although the capacity of stellate cells for extracellular matrix production and remodeling has long been appreciated, recent research efforts have demonstrated diverse roles for stellate cells in regulation of epithelial cell fate, immune modulation, and tissue health. Our present understanding of stellate cell biology in health and disease is discussed here, as are emerging means to target these multifaceted cells for therapeutic benefit.
Collapse
Affiliation(s)
- Mara H Sherman
- Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, Portland, Oregon 97201, USA;
| |
Collapse
|
5
|
PDGF-Mediated Regulation of Liver Fibrosis. CURRENT PATHOBIOLOGY REPORTS 2015. [DOI: 10.1007/s40139-015-0096-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
6
|
Borkham-Kamphorst E, Weiskirchen R. The PDGF system and its antagonists in liver fibrosis. Cytokine Growth Factor Rev 2015; 28:53-61. [PMID: 26547628 DOI: 10.1016/j.cytogfr.2015.10.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/19/2015] [Indexed: 01/18/2023]
Abstract
Platelet derived growth factor (PDGF) signaling plays an important role in activated hepatic stellate cells and portal fibroblast proliferation, chemotaxis, migration and cell survival. PDGF receptors and ligands are upregulated in experimental liver fibrotic models as well as in human liver fibrotic diseases. Blocking of PDGF signaling ameliorates experimental liver fibrogenesis. The plurality of molecular and cellular activities of PDGF and its involvement in initiation, progression and resolution of hepatic fibrogenesis offers an infinite number of therapeutic possibilities. These include the application of therapeutic antibodies (e.g. AbyD3263, MOR8457) which specifically sequester individual PDGF isoforms or the inhibition of PDGF isoforms by synthetic aptamers. In particular, the isolation of innovative slow off-rate modified aptamers (e.g., SOMAmer SL1 and SL5) that carry functional groups absent in natural nucleic acids by the Systematic Evolution of Ligands by EXponential (SELEX) enrichment technique offers the possibility to design high affinity aptamers that target PDGF isoforms for clinical purposes. Dominant-negative soluble PDGF receptors are also effective in attenuation of hepatic stellate cell proliferation and hepatic fibrogenesis. Moreover, some multikinase inhibitors targeting PDGF signaling have been intensively tested during the last decade and are on the way into advanced preclinical studies and clinical trials. This narrative review aims to gauge the recent progression of research into PDGF systems and liver fibrosis.
Collapse
Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Aachen, Germany.
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Aachen, Germany.
| |
Collapse
|
7
|
Borkham-Kamphorst E, Meurer SK, Van de Leur E, Haas U, Tihaa L, Weiskirchen R. PDGF-D signaling in portal myofibroblasts and hepatic stellate cells proves identical to PDGF-B via both PDGF receptor type α and β. Cell Signal 2015; 27:1305-14. [PMID: 25819339 DOI: 10.1016/j.cellsig.2015.03.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/12/2015] [Indexed: 02/07/2023]
Abstract
UNLABELLED Platelet-derived growth factor-D (PDGF-D) is one member of PDGF growth factors and known to signal by binding to and activating its cognate receptor type β (PDGFR-β). Beside PDGF-B, PDGF-D is a potent growth factor for stellate cell growth and proliferation and therefore potentiates the extracellular matrix deposition in liver fibrogenesis. We aimed to explore the signaling and molecular mechanisms of PDGF-D in liver fibrogenesis using the primary liver portal myofibroblasts and hepatic stellate cells. Unexpectedly we found PDGF-D to bind to PDGFR-α, thus inducing receptor endocytosis and decreasing the amount of PDGFR-α significantly. PDGF-D activates PDGFR-α specific tyrosine 754 and -1018 phosphorylation and CrkII, the adaptor protein that is specifically recruited by activated PDGFR-α. As a novel finding we could also demonstrate that recombinant PDGFR-α-Fc chimera homodimer is able to bind PDGF-D and thus prevent PDGF-D signaling. PDGF-D does induce individual PDGFR-β specific tyrosine phosphorylation similar to the PDGF-B. Additionally, PDGF-D enhances extracellular matrix accumulation comparable to the PDGF-B isoform. CONCLUSION PDGF-D signaling in pMF and HSC is identical to that of PDGF-B by binding to both PDGFR-α and -β.
Collapse
Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany.
| | - Steffen K Meurer
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany
| | - Eddy Van de Leur
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany
| | - Ute Haas
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany
| | - Lidia Tihaa
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, Germany.
| |
Collapse
|
8
|
Borkham-Kamphorst E, Alexi P, Tihaa L, Haas U, Weiskirchen R. Platelet-derived growth factor-D modulates extracellular matrix homeostasis and remodeling through TIMP-1 induction and attenuation of MMP-2 and MMP-9 gelatinase activities. Biochem Biophys Res Commun 2015; 457:307-13. [PMID: 25576870 DOI: 10.1016/j.bbrc.2014.12.106] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 12/24/2014] [Indexed: 10/24/2022]
Abstract
Platelet-derived growth factor-D (PDGF-D) is a more recent recognized growth factor involved in the regulation of several cellular processes, including cell proliferation, transformation, invasion, and angiogenesis by binding to and activating its cognate receptor PDGFR-β. After bile duct ligation or in the carbon tetrachloride-induced hepatic fibrosis model, PDGF-D showed upregulation comparable to PDGF-B. Moreover, adenoviral PDGF-D gene transfer induced hepatic stellate cell proliferation and liver fibrosis. We here investigated the molecular mechanism of PDGF-D involvement in liver fibrogenesis. Therefore, the GRX mouse cell line was stimulated with PDGF-D and evaluated for fibrotic markers and PDGF-D signaling pathways in comparison to the other PDGF isoforms. We found that PDGF-D failed to enhance Col I and α-smooth muscle actin (α-SMA) production but has capacity to upregulate expression of the tissue inhibitor of metalloprotease 1 (TIMP-1) resulting in attenuation of MMP-2 and MMP-9 gelatinase activity as indicated by gelatinase zymography. This phenomenon was restored through application of a PDGF-D neutralizing antibody. Unexpectedly, PDGF-D incubation decreased both PDGFR-α and -β in mRNA and protein levels, and PDGF-D phosphorylated typrosines specific for PDGFR-α and -β. We conclude that PDGF-D intensifies fibrogenesis by interfering with the fibrolytic activity of the TIMP-1/MMP system and that PDGF-D signaling is mediated through both PDGF-α and -β receptors.
Collapse
Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH Aachen University Hospital, Germany.
| | - Pascal Alexi
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH Aachen University Hospital, Germany
| | - Lidia Tihaa
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH Aachen University Hospital, Germany
| | - Ute Haas
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH Aachen University Hospital, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH Aachen University Hospital, Germany.
| |
Collapse
|
9
|
Lu SC. Glutathione synthesis. Biochim Biophys Acta Gen Subj 2012; 1830:3143-53. [PMID: 22995213 DOI: 10.1016/j.bbagen.2012.09.008] [Citation(s) in RCA: 1467] [Impact Index Per Article: 122.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/05/2012] [Accepted: 09/10/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Glutathione (GSH) is present in all mammalian tissues as the most abundant non-protein thiol that defends against oxidative stress. GSH is also a key determinant of redox signaling, vital in detoxification of xenobiotics, and regulates cell proliferation, apoptosis, immune function, and fibrogenesis. Biosynthesis of GSH occurs in the cytosol in a tightly regulated manner. Key determinants of GSH synthesis are the availability of the sulfur amino acid precursor, cysteine, and the activity of the rate-limiting enzyme, glutamate cysteine ligase (GCL), which is composed of a catalytic (GCLC) and a modifier (GCLM) subunit. The second enzyme of GSH synthesis is GSH synthetase (GS). SCOPE OF REVIEW This review summarizes key functions of GSH and focuses on factors that regulate the biosynthesis of GSH, including pathological conditions where GSH synthesis is dysregulated. MAJOR CONCLUSIONS GCL subunits and GS are regulated at multiple levels and often in a coordinated manner. Key transcription factors that regulate the expression of these genes include NF-E2 related factor 2 (Nrf2) via the antioxidant response element (ARE), AP-1, and nuclear factor kappa B (NFκB). There is increasing evidence that dysregulation of GSH synthesis contributes to the pathogenesis of many pathological conditions. These include diabetes mellitus, pulmonary and liver fibrosis, alcoholic liver disease, cholestatic liver injury, endotoxemia and drug-resistant tumor cells. GENERAL SIGNIFICANCE GSH is a key antioxidant that also modulates diverse cellular processes. A better understanding of how its synthesis is regulated and dysregulated in disease states may lead to improvement in the treatment of these disorders. This article is part of a Special Issue entitled Cellular functions of glutathione.
Collapse
Affiliation(s)
- Shelly C Lu
- Keck School of Medicine USC, Los Angeles, CA 90033, USA.
| |
Collapse
|
10
|
Yu J, Wang Y, Qian H, Zhao Y, Liu B, Fu C. Polyprenols from Taxus chinensis var. mairei prevent the development of CCl₄-induced liver fibrosis in rats. JOURNAL OF ETHNOPHARMACOLOGY 2012; 142:151-160. [PMID: 22543175 DOI: 10.1016/j.jep.2012.04.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/22/2012] [Accepted: 04/10/2012] [Indexed: 05/27/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The aim of this study was to investigate the anti-fibrotic effects and the possible underlying mechanisms of taxus polyprenols (TPs) isolated from the needles of Taxus chinensis var. mairei. MATERIALS AND METHODS The animals were randomly divided into normal control with vehicles only (olive oil), rat model given CCl₄ only, CCl₄+low TPs (48 mg/kg), CCl₄+medium TPs (120 mg/kg), CCl₄+high TPs (300 mg/kg), and CCl₄+Polyene phosphatidylcholine (PP, 120 mg/kg). The rat model of liver fibrosis was induced by subcutaneous injection of 40% (v/v) of CCl₄ diluted in olive oil (3 mL/kg body weight) twice per week for 8 weeks. Liver histopathological study was performed. Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and albumin (ALB) of the serum were determined for evaluating the liver function. In order to reveal the possible mechanisms of the anti-fibrotic effects, oxidative stress level, hepatic collagen metabolism, and hepatic stellate cells (HSCs) activation were investigated. Furthermore, the mRNA expression of the fibrotic-related factors was measured by the quantitative real-time RT-PCR. RESULTS TPs successfully attenuated liver injury induced by CCl₄ shown by histopathological sections of livers and improved liver function as indicated by decreased ALT, AST and ALP levels and increased ALB levels in serum of the rats. TPs significantly increased the hepatic Cu/Zn SOD and GSH-Px activities along with GSH content while a remarkable decrease in MDA content. Both immunohistochemical staining and mRNA expression levels of α-SMA indicated a profound suppression of HSCs activation. Furthermore, it significantly inhibited the mRNA expression of the pro-fibrotic cytokines Col α1(I), Col α1(Ш), MMP-2, TIMP-1, TIMP-2, PDGF-β, TGF-β1, CTGF and TNF-α and restored the hepatoprotective factor HGF. CONCLUSION These results suggest that the protective effects of TPs in chronic CCl₄-induced liver fibrosis might be related with the reduction of oxidative damage, the inhibition of HSCs activation, the down-regulation of pro-fibrogenic stimuli and the protection of hepatocytes.
Collapse
Affiliation(s)
- Jinhui Yu
- The Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Yuhangtang Road 388, Hangzhou, Zhejiang 310023, PR China
| | | | | | | | | | | |
Collapse
|
11
|
Reyes-Gordillo K, Shah R, Popratiloff A, Fu S, Hindle A, Brody F, Rojkind M. Thymosin-β4 (Tβ4) blunts PDGF-dependent phosphorylation and binding of AKT to actin in hepatic stellate cells. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2100-8. [PMID: 21514425 DOI: 10.1016/j.ajpath.2011.01.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 12/22/2010] [Accepted: 01/18/2011] [Indexed: 01/18/2023]
Abstract
Hepatic stellate cell transdifferentiation is a key event in the fibrogenic cascade. Therefore, attempts to prevent and/or revert the myofibroblastic phenotype could result in novel therapeutic approaches to treat liver cirrhosis. The expression of platelet-derived growth factor (PDGF)-β receptor and the proliferative response to platelet-derived growth factor-ββ (PDGF-ββ) are hallmarks of the transdifferentiation of hepatic stellate cells (HSC). In this communication, we investigated whether thymosin-β4 (Tβ4), a chemokine expressed by HSC could prevent PDGF-BB-mediated proliferation and migration of cultured HSC. Using early passages of human HSC, we showed that Tβ4 inhibited cell proliferation and migration and prevented the expression of PDGF-β receptor (PDGF-βr), α-smooth muscle actin and α1(I) collagen mRNAs. Tβ4 also inhibited the reappearance of PDGF-βr after its PDGF-BB-dependent degradation. These PDGF-dependent events were associated with the inhibition of AKT phosphorylation at both T308 and S473 amino acid residues. The lack of AKT phosphorylation was not due to the inhibition of PDGF-βr phosphorylation, the activation of phosphoinositide 3-kinase (PI3K), pyruvate dehydrogenase kinase isozyme 1 (PDK1), and mammalian target of rapamycin (mTOR). We found that PDGF-BB induced AKT binding to actin, and that Tβ4 prevented this effect. Tβ4 also prevented the activation of freshly isolated HSC cultured in the presence of Dulbecco's modified Eagle's medium or Dulbecco's minimal essential medium containing 10% fetal bovine serum. In conclusion, overall, our findings suggest that Tβ4 by sequestering actin prevents binding of AKT, thus inhibiting its phosphorylation. Therefore, Tβ4 has the potential to be an antifibrogenic agent.
Collapse
Affiliation(s)
- Karina Reyes-Gordillo
- Department of Biochemistry and Molecular Biology, The George Washington University Medical Center, Washington, DC, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Borkham-Kamphorst E, van Roeyen CR, Van de Leur E, Floege J, Weiskirchen R. CCN3/NOV small interfering RNA enhances fibrogenic gene expression in primary hepatic stellate cells and cirrhotic fat storing cell line CFSC. J Cell Commun Signal 2011; 6:11-25. [PMID: 21748432 DOI: 10.1007/s12079-011-0141-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Accepted: 06/14/2011] [Indexed: 12/20/2022] Open
Abstract
Nephroblastoma overexpressed gene encodes a matricellular protein (CCN3/NOV) of the CCN family, comprising CCN1 (CYR61), CCN2 (CTGF), CCN4 (WISP-1), CCN5 (WISP-2), and CCN6 (WISP-3). CCN proteins are involved in the regulation of mitosis, adhesion, apoptosis, extracellular matrix production, growth arrest and migration in multiple cell types. Compared to CCN2/CTGF, known as a profibrotic protein, the biological role of CCN3/NOV in liver fibrosis remains obscure. In this study we showed ccn3/nov mRNA to increase dramatically following hepatic stellate cell activation, reaching peak levels in fully transdifferentiated myofibroblasts. In models of experimental hepatic fibrosis, CCN3/NOV increased significantly at the mRNA and protein levels. CCN3/NOV was found mainly in non-parenchymal cells along the areas of tissue damage and repair. In the bile-duct ligation model, CCN3/NOV was localized mainly along portal tracts, while the repeated application of carbon tetrachloride resulted in CCN3/NOV expression mainly in the centrilobular areas. In contrast to CCN2/CTGF, the profibrotic cytokines platelet-derived growth factor-B and -D as well as transforming growth factor-β suppressed CCN3/NOV expression. In vitro, CCN3/NOV siRNA attenuated migration in the cirrhotic fat storing cell line CFSC well in line with in vivo findings that various types of cells expressing CCN3/NOV migrate into the area of tissue damage and regeneration. The suppression of CCN3/NOV enhanced expression of profibrotic marker proteins, such as α-smooth muscle actin, collagen type I, fibronectin, CCN2/CTGF and TIMP-1 in primary rat hepatic stellate cells and in CFSC. We further found that adenoviral overexpression of CCN2/CTGF suppressed CCN3/NOV expression, while the overexpression of CCN3/NOV as well as the suppression of CCN3/NOV by targeting siRNAs both resulted in enhanced CCN2/CTGF expression. These results indicate the complexity of CCN actions that are far beyond the classic Yin/Yang interplay.
Collapse
Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH-University Hospital, 52074, Aachen, Germany,
| | | | | | | | | |
Collapse
|
13
|
Recombinant expression, purification, and functional characterisation of connective tissue growth factor and nephroblastoma-overexpressed protein. PLoS One 2010; 5:e16000. [PMID: 21209863 PMCID: PMC3012735 DOI: 10.1371/journal.pone.0016000] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/01/2010] [Indexed: 01/24/2023] Open
Abstract
The CCN family of proteins, especially its prominent member, the Connective tissue growth factor (CTGF/CCN2) has been identified as a possible biomarker for the diagnosis of fibrotic diseases. As a downstream mediator of TGF-β1 signalling, it is involved in tissue scarring, stimulates interstitial deposition of extracellular matrix proteins, and promotes proliferation of several cell types. Another member of this family, the Nephroblastoma-Overexpressed protein (NOV/CCN3), has growth-inhibiting properties. First reports further suggest that these two CCN family members act opposite to each other in regulating extracellular matrix protein expression and reciprocally influence their own expression when over-expressed. We have established stable HEK and Flp-In-293 clones as productive sources for recombinant human CCN2/CTGF. In addition, we generated an adenoviral vector for recombinant expression of rat NOV and established protocols to purify large quantities of these CCN proteins. The identity of purified human CCN2/CTGF and rat CCN3/NOV was proven by In-gel digest followed by ESI-TOF/MS mass spectrometry. The biological activity of purified proteins was demonstrated using a Smad3-sensitive reporter gene and BrdU proliferation assay in permanent cell line EA•hy 926 cells. We further demonstrate for the first time that both recombinant CCN proteins are N-glycosylated.
Collapse
|
14
|
Ramani K, Yang H, Kuhlenkamp J, Tomasi L, Tsukamoto H, Mato JM, Lu SC. Changes in the expression of methionine adenosyltransferase genes and S-adenosylmethionine homeostasis during hepatic stellate cell activation. Hepatology 2010; 51:986-95. [PMID: 20043323 PMCID: PMC2905860 DOI: 10.1002/hep.23411] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hepatic stellate cell (HSC) activation is an essential event during liver fibrogenesis. Methionine adenosyltransferase (MAT) catalyzes biosynthesis of S-adenosylmethionine (SAMe), the principle methyl donor. SAMe metabolism generates two methylation inhibitors, methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH). Liver cell proliferation is associated with induction of two nonliver-specific MATs: MAT2A, which encodes the catalytic subunit alpha2, and MAT2beta, which encodes a regulatory subunit beta that modulates the activity of the MAT2A-encoded isoenzyme MATII. We reported that MAT2A and MAT2beta genes are required for liver cancer cell growth that is induced by the profibrogenic factor leptin. Also, MAT2beta regulates leptin signaling. The strong association of MAT genes with proliferation and leptin signaling in liver cells led us to examine the role of these genes during HSC activation. MAT2A and MAT2beta are induced in culture-activated primary rat HSCs and HSCs from 10-day bile duct ligated (BDL) rat livers. HSC activation led to a decline in intracellular SAMe and MTA levels, a drop in the SAMe/SAH ratio, and global DNA hypomethylation. The decrease in SAMe levels was associated with lower MATII activity during activation. MAT2A silencing in primary HSCs and MAT2A or MAT2beta silencing in the human stellate cell line LX-2 resulted in decreased collagen and alpha-smooth muscle actin (alpha-SMA) expression and cell growth and increased apoptosis. MAT2A knockdown decreased intracellular SAMe levels in LX-2 cells. Activation of extracellular signal-regulated kinase and phosphatidylinositol-3-kinase signaling in LX-2 cells required the expression of MAT2beta but not that of MAT2A. CONCLUSION MAT2A and MAT2beta genes are induced during HSC activation and are essential for this process. The SAMe level falls, resulting in global DNA hypomethylation.
Collapse
Affiliation(s)
- Komal Ramani
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, HMR Bldg., 413, Department of Medicine, Keck School of Medicine USC, 2011 Zonal Ave., Los Angeles, CA 90033, USA.
| | - Heping Yang
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Keck School of Medicine University of Southern California, Los Angeles, California 90033
| | - John Kuhlenkamp
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Keck School of Medicine University of Southern California, Los Angeles, California 90033
| | - Lauda Tomasi
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Keck School of Medicine University of Southern California, Los Angeles, California 90033
| | - Hidekazu Tsukamoto
- Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine University of Southern California, Los Angeles, California 90033
| | - José M. Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology, Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Shelly C. Lu
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Keck School of Medicine University of Southern California, Los Angeles, California 90033, Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine University of Southern California, Los Angeles, California 90033
| |
Collapse
|
15
|
Gamblin TC, Krasinskas AM, Slivka AS, Tublin ME, Demetris J, Shue E, Caro S, Marsh JW, James Moser A. Fibroinflammatory biliary stricture: a rare bile duct lesion masquerading as cholangiocarcinoma. J Gastrointest Surg 2009; 13:713-21. [PMID: 19057967 DOI: 10.1007/s11605-008-0750-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 10/28/2008] [Indexed: 01/31/2023]
Abstract
INTRODUCTION Fibroinflammatory biliary stricture (FIBS) is a rare benign tumor-like process of the extrahepatic bile duct that masquerades as cholangiocarcinoma. METHODS In order to distinguish this unusual entity from cancer, we performed a systematic analysis of 11 patients with FIBS. All patients presented with jaundice; six patients had coexisting autoimmune disease. Preoperative evaluation included computed tomography scan and endoscopic retrograde cholangiopancreatography with benign brush cytology. Surgical treatment included nine bile duct resections with five concurrent liver resections and two incisional biopsies. Light microscopy demonstrated fibrous lesions admixed with chronic inflammation. RESULTS AND DISCUSSION Immunohistochemistry demonstrated smooth muscle actin expression in all lesions except one; five tumors exhibited IgG4 positive plasma cells. The lesions were negative for cytokeratin, ALK1, CD21, S100, Ki67, and p53. Six patients received postoperative immunosuppression. At 41 month median follow-up (range 15-58 months), there was no evidence of recurrent FIBS in ten patients, while one was lost to follow-up. CONCLUSION FIBS is a rare myofibroblastic lesion with an immunohistochemical profile distinct from other epithelial and stromal neoplasms of the extrahepatic bile duct. A subset of these cases appear to represent IgG4-related sclerosing cholangitis. Because preoperative cytology is not diagnostic of FIBS, surgical resection remains the mainstay of diagnosis and treatment, while immunosuppression may reduce the risk of recurrence.
Collapse
Affiliation(s)
- T Clark Gamblin
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Wang GJ, Huang YJ, Chen DH, Lin YL. Ganoderma lucidum
extract attenuates the proliferation of hepatic stellate cells by blocking the PDGF receptor. Phytother Res 2008; 23:833-9. [DOI: 10.1002/ptr.2687] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
17
|
Chen SW, Zhang XR, Wang CZ, Chen WZ, Xie WF, Chen YX. RNA interference targeting the platelet-derived growth factor receptor beta subunit ameliorates experimental hepatic fibrosis in rats. Liver Int 2008; 28:1446-57. [PMID: 18466260 PMCID: PMC2710794 DOI: 10.1111/j.1478-3231.2008.01759.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND/AIMS Platelet-derived growth factor (PDGF) is the strongest stimulator of the proliferation of hepatic stellate cells (HSCs). PDGF receptor beta subunit (PDGFR-beta) is acquired on HSCs proliferation induced by PDGF. In this study, we aim to investigate the effect of PDGFR-beta small interference RNA (siRNA) on experimental hepatic fibrosis. METHODS We constructed a PDGFR-beta siRNA expression plasmid and investigated its effect on the activation of HSCs. Bromodeoxyuridine incorporation was performed to investigate the effect of PDGFR-beta siRNA on HSCs proliferation. A hydrodynamics-based transfection method was used to deliver PDGFR-beta siRNA to rats with hepatic fibrosis. The distribution of transgenes in the liver was observed by immunofluorescence. The antifibrogenic effect of PDGFR-beta siRNA was investigated pathologically. RESULTS Platelet-derived growth factor receptor-beta subunit siRNA could significantly downregulate PDGFR-beta expression, suppress HSCs activation, block the mitogen-activated protein kinase signalling pathway and inhibit HSCs proliferation in vitro. PDGFR-beta siRNA expression plasmid could be delivered into activated HSCs by the hydrodynamics-based transfection method, and remarkably improve the liver function of the rat model induced by dimethylnitrosamine and bile duct ligation. Furthermore, the progression of fibrosis in the liver was significantly suppressed by PDGFR-beta siRNA in both animal models. CONCLUSIONS Platelet-derived growth factor receptor-beta subunit siRNA may be presented as an effective antifibrogenic gene therapeutic method for hepatic fibrosis.
Collapse
Affiliation(s)
- Si-Wen Chen
- Department of Gastroenterology, Changzheng Hospital, Second Military Medical UniversityShanghai, China
| | - Xing-Rong Zhang
- Department of Gastroenterology, Changzheng Hospital, Second Military Medical UniversityShanghai, China
| | - Chong-Ze Wang
- Department of Geriatrics, Renji Hospital, Shanghai Jiaotong University School of MedicineShanghai, China
| | - Wei-Zhong Chen
- Department of Gastroenterology, Changzheng Hospital, Second Military Medical UniversityShanghai, China
| | - Wei-Fen Xie
- Department of Gastroenterology, Changzheng Hospital, Second Military Medical UniversityShanghai, China
| | - Yue-Xiang Chen
- Department of Gastroenterology, Changzheng Hospital, Second Military Medical UniversityShanghai, China
| |
Collapse
|
18
|
Targeted inhibition of platelet-derived growth factor receptor-beta subunit in hepatic stellate cells ameliorates hepatic fibrosis in rats. Gene Ther 2008; 15:1424-35. [PMID: 18509379 DOI: 10.1038/gt.2008.93] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The activation of hepatic stellate cells (HSCs) is the key event of the pathogenesis of hepatic fibrosis. Platelet-derived growth factor (PDGF) is the most potent mitogen for HSCs, and PDGF receptor-beta subunit (PDGFR-beta) is required for the proliferation of HSCs induced by PDGF. In this study, a high gene-silencing-efficacy PDGFR-beta small interference RNA (siRNA) was synthesized that could suppress the PDGFR-beta expression and inhibit the activation and proliferation but could not induce the apoptosis of HSCs in vitro. To avoid the side effect of nonspecific interference of PDGFR-beta, we constructed an HSCs-specific short hairpin RNA (shRNA) expression plasmid in which PDGFR-beta shRNA was driven by a glial fibrillary acidic protein (GFAP) promoter. The double-staining immunofluorescence examination indicated that GFAP promoter could target the transgene expression into HSCs in carbon tetrachloride induced acute injured rat's liver and bile duct ligation (BDL)-induced chronic injured rat's liver. Furthermore, HSCs-specific PDGFR-beta shRNA could relieve liver injury and hepatic fibrosis in the rat's model induced by BDL. This study demonstrates that PDGFR-beta siRNA may be presented as an antifibrogenic agent. The application of HSCs-specific RNA interference induced by the GFAP promoter might supply a new powerful tool for cell-specific gene therapy of hepatic fibrogenesis.
Collapse
|
19
|
Lin J, Chen A. Activation of peroxisome proliferator-activated receptor-gamma by curcumin blocks the signaling pathways for PDGF and EGF in hepatic stellate cells. J Transl Med 2008; 88:529-40. [PMID: 18332871 PMCID: PMC2673570 DOI: 10.1038/labinvest.2008.20] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
During hepatic fibrogenesis, reduction in the abundance of peroxisome proliferator-activated receptor-gamma (PPARgamma) is accompanied by activation of mitogenic signaling for platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) in hepatic stellate cells (HSCs), the major effector cells. We previously reported that curcumin, the yellow pigment in curry, interrupted PDGF and EGF signaling, stimulated PPARgamma gene expression, and enhanced its activity, leading to inhibition of cell proliferation of activated HSC in vitro and in vivo. The aim of this study was to elucidate the underlying mechanisms. We hypothesized that the enhancement of PPARgamma activity by curcumin might result in the interruption of PDGF and EGF signaling. Our experiments demonstrated that curcumin, with different treatment strategies, showed different efficiencies in the inhibition of PDGF- or EGF-stimulated HSC proliferation. Further experiments observed that curcumin dose dependently reduced gene expression of PDGF and EGF receptors (ie, PDGF-betaR and EGFR), which required PPARgamma activation. The activation of PPARgamma by its agonist suppressed pdgf-betar and egfr expression in HSC. In addition, curcumin reduced the phosphorylation levels of PDGF-betaR and EGFR, as well as their downstream signaling cascades, including ERK1/2 and JNK1/2. Moreover, activation of PPARgamma induced gene expression of glutamate-cysteine ligase, the rate-limiting enzyme in de novo synthesis of the major intracellular antioxidant, glutathione. De novo synthesis of glutathione was required for curcumin to suppress pdgf-betar and egfr expression in activated HSCs. Our results collectively demonstrated that enhancement of PPARgamma activity by curcumin interrupted PDGF and EGF signaling in activated HSCs by reducing the phosphorylation levels of PDGF-betaR and EGFR, and by suppressing the receptor gene expression. These results provide novel insights into the mechanisms of curcumin in the inhibition of HSC activation and the suppression of hepatic fibrogenesis.
Collapse
|
20
|
Borkham-Kamphorst E, van Roeyen CRC, Ostendorf T, Floege J, Gressner AM, Weiskirchen R. Pro-fibrogenic potential of PDGF-D in liver fibrosis. J Hepatol 2007; 46:1064-74. [PMID: 17397961 DOI: 10.1016/j.jhep.2007.01.029] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 11/28/2006] [Accepted: 01/08/2007] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS We analyzed the expression of platelet-derived growth factor D (PDGF-D) in an experimental bile duct-ligated (BDL) rat model and assessed its biological function in cultured hepatic stellate cells (HSC) and myofibroblasts (MFB). METHODS The mRNA for PDGF-A, -B, -C, -D and for PDGF receptor-alpha and -beta chains (PDGFRalpha and PDGFRbeta) in normal and fibrotic rat livers was assessed quantitatively. Protein levels of PDGF-D were quantified by immunoblotting and immunohistochemistry. RESULTS The relative mRNA expression of all PDGF isoforms and receptors upregulated upon BDL and PDGF-A, -B and -D expression was significantly higher than that of PDGF-C. PDGF-D and PDGFRbeta protein also increased markedly. Immunostaining revealed that PDGF-D is localized along the fibrotic septa of the periportal- and perisinusoidal areas. Besides PDGF-B, PDGF-D is the second most potent PDGF isoform in PDGFRbeta signaling within HSC/MFB, evidenced by PDGFRbeta autophosphorylation and activation of the downstream signaling molecules ERK1/2-, JNK-, p38 MAPK, and PKB/Akt while PDGF-C effects were minimal. PDGF-D exerted mitogenic and fibrogenic effects in both cultured HSC and MFB comparable to PDGF-B but PDGF-A and -C showed only marginal fibrogenic effects. CONCLUSIONS PDGF-D possesses potential pathogenetic properties for HSC activation and matrix remodeling in liver fibrosis.
Collapse
Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Clinical Chemistry and Pathobiochemistry, and Division of Nephrology, RWTH-University Hospital Aachen, D-52074 Aachen, Germany
| | | | | | | | | | | |
Collapse
|
21
|
Shen YM, Zhu X. Signal transduction and activation of hepatic stellate cells. Shijie Huaren Xiaohua Zazhi 2007; 15:873-878. [DOI: 10.11569/wcjd.v15.i8.873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Liver fibrosis, which leads to cirrhosis, occurs as a result of various injurious processes and it is the common pathologic basis of all the chronic hepatic diseases. At present, a good many researches demonstrate that the activation of hepatic stellate cells play a critical role in fibrogenesis. Prolonged liver injury results in hepatocyte damages and secretion of many fibrogenic cytokines such as transforming growth factor-beta 1, angiotensin, and leptin, which triggers the activation of hepatic stellate cells through different intracellular signal transduction pathways. In this article, we reviewed the research advancement in the signal transduction pathway of nuclear receptor and membrane receptor during the activation of hepatic stellate cells.
Collapse
|
22
|
Lin YL, Lee TF, Huang YJ, Huang YT. Antiproliferative effect of salvianolic acid A on rat hepatic stellate cells. J Pharm Pharmacol 2006; 58:933-9. [PMID: 16805953 DOI: 10.1211/jpp.58.7.0008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Suppression of activation or proliferation, or induction of apoptosis in hepatic stellate cells (HSCs) have been proposed as therapeutic strategies against liver fibrosis. Salvia miltiorrhiza has been reported to exert antifibrotic effects in rats with hepatic fibrosis, but its mechanisms of action remain to be clarified. We have investigated the effects of salvianolic acid A (Sal A), an active principle from S. miltiorrhiza, on the proliferation-related biomarkers in a cell line of rat HSCs (HSC-T6) stimulated with platelet-derived growth factor-BB homodimer (PDGF-BB). DNA synthesis (bromodeoxyuridine (BrdU) incorporation), cell cycle related proteins and apoptosis markers were determined to evaluate the inhibitory effects of Sal A. The results showed that Sal A (1-10 microM) concentration-dependently attenuated PDGF-BB-stimulated proliferation (BrdU incorporation) in HSC-T6 cells. Sal A at 10 microM induced cell apoptosis in PDGF-BB-incubated HSCs, together with a reduction of Bcl-2 protein expression, induction of cell cycle inhibitory proteins p21 and p27, and down-regulation of cyclins D1 and E, suppression of Akt phosphorylation, reduction in PDGF receptor phosphorylation, and an increase in caspase-3 activity. Sal A exerted no direct cytotoxicity on primary hepatocytes and HSC-T6 cells under experimental concentrations. Our results suggested that Sal A inhibited PDGF-BB-activated HSC proliferation, partially through apoptosis induction.
Collapse
Affiliation(s)
- Yun-Lian Lin
- National Research Institute of Chinese Medicine, Taipei 112, Taiwan
| | | | | | | |
Collapse
|
23
|
Gressner AM, Weiskirchen R. Modern pathogenetic concepts of liver fibrosis suggest stellate cells and TGF-beta as major players and therapeutic targets. J Cell Mol Med 2006. [PMID: 16563223 DOI: 10.1634/stemcells.2007-0252"> [doi: 10.1111/j.1582-4934.2006.tb00292.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hepatic fibrosis is a scarring process that is associated with an increased and altered deposition of extracellular matrix in liver. At the cellular and molecular level, this progressive process is mainly characterized by cellular activation of hepatic stellate cells and aberrant activity of transforming growth factor-beta1 and its downstream cellular mediators. Although the cellular responses to this cytokine are complex, the signalling pathways of this pivotal cytokine during the fibrogenic response and its connection to other signal cascades are now understood in some detail. Based on the current advances in understanding the pleiotropic reactions during fibrogenesis, various inhibitors of transforming growth factor-beta were developed and are now being investigated as potential drug candidates in experimental models of hepatic injury. Although it is too early to favour one of these antagonists for the treatment of hepatic fibrogenesis in human, the experimental results obtained yet provide stimulatory impulses for the development of an effective treatment of choice in the not too distant future. The present review summarises the actual knowledge on the pathogenesis of hepatic fibrogenesis, the role of transforming growth factor-beta and its signalling pathways in promoting the fibrogenic response, and the therapeutic modalities that are presently in the spotlight of many investigations and are already on the way to take the plunge into clinical studies.
Collapse
Affiliation(s)
- A M Gressner
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH Aachen University--Hospital, D-52074 Aachen, Germany.
| | | |
Collapse
|
24
|
Gressner AM, Weiskirchen R. Modern pathogenetic concepts of liver fibrosis suggest stellate cells and TGF-beta as major players and therapeutic targets. J Cell Mol Med 2006; 10:76-99. [PMID: 16563223 PMCID: PMC3933103 DOI: 10.1111/j.1582-4934.2006.tb00292.x] [Citation(s) in RCA: 599] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatic fibrosis is a scarring process that is associated with an increased and altered deposition of extracellular matrix in liver. At the cellular and molecular level, this progressive process is mainly characterized by cellular activation of hepatic stellate cells and aberrant activity of transforming growth factor-beta1 and its downstream cellular mediators. Although the cellular responses to this cytokine are complex, the signalling pathways of this pivotal cytokine during the fibrogenic response and its connection to other signal cascades are now understood in some detail. Based on the current advances in understanding the pleiotropic reactions during fibrogenesis, various inhibitors of transforming growth factor-beta were developed and are now being investigated as potential drug candidates in experimental models of hepatic injury. Although it is too early to favour one of these antagonists for the treatment of hepatic fibrogenesis in human, the experimental results obtained yet provide stimulatory impulses for the development of an effective treatment of choice in the not too distant future. The present review summarises the actual knowledge on the pathogenesis of hepatic fibrogenesis, the role of transforming growth factor-beta and its signalling pathways in promoting the fibrogenic response, and the therapeutic modalities that are presently in the spotlight of many investigations and are already on the way to take the plunge into clinical studies.
Collapse
Affiliation(s)
- A M Gressner
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH Aachen University - HospitalAachen, Germany
- *Correspondence to: A. M. GRESSNER/R. WEISKIRCHEN Institute of Clinical Chemistry and Pathobiochemistry, RWTH Aachen University Hospital, D-52074 Aachen, Germany. Tel.: +49-241-8088678/9 Fax: +49-241-8082512 E-mails:
| | - R Weiskirchen
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH Aachen University - HospitalAachen, Germany
| |
Collapse
|
25
|
Gressner AM, Weiskirchen R. Modern pathogenetic concepts of liver fibrosis suggest stellate cells and TGF-beta as major players and therapeutic targets. J Cell Mol Med 2006. [PMID: 16563223 DOI: 10.1111/j.1528-4934.2006.th00292.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hepatic fibrosis is a scarring process that is associated with an increased and altered deposition of extracellular matrix in liver. At the cellular and molecular level, this progressive process is mainly characterized by cellular activation of hepatic stellate cells and aberrant activity of transforming growth factor-beta1 and its downstream cellular mediators. Although the cellular responses to this cytokine are complex, the signalling pathways of this pivotal cytokine during the fibrogenic response and its connection to other signal cascades are now understood in some detail. Based on the current advances in understanding the pleiotropic reactions during fibrogenesis, various inhibitors of transforming growth factor-beta were developed and are now being investigated as potential drug candidates in experimental models of hepatic injury. Although it is too early to favour one of these antagonists for the treatment of hepatic fibrogenesis in human, the experimental results obtained yet provide stimulatory impulses for the development of an effective treatment of choice in the not too distant future. The present review summarises the actual knowledge on the pathogenesis of hepatic fibrogenesis, the role of transforming growth factor-beta and its signalling pathways in promoting the fibrogenic response, and the therapeutic modalities that are presently in the spotlight of many investigations and are already on the way to take the plunge into clinical studies.
Collapse
Affiliation(s)
- A M Gressner
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH Aachen University--Hospital, D-52074 Aachen, Germany.
| | | |
Collapse
|
26
|
Czochra P, Klopcic B, Meyer E, Herkel J, Garcia-Lazaro JF, Thieringer F, Schirmacher P, Biesterfeld S, Galle PR, Lohse AW, Kanzler S. Liver fibrosis induced by hepatic overexpression of PDGF-B in transgenic mice. J Hepatol 2006; 45:419-28. [PMID: 16842882 DOI: 10.1016/j.jhep.2006.04.010] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 04/04/2006] [Accepted: 04/18/2006] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS In hepatic fibrogenesis, stellate cells are activated leading to production and deposition of extracellular matrix. To clarify the role of PDGF-B in liver fibrogenesis, we overexpressed PDGF-B in the liver of transgenic mice. METHODS Transgenic mice for the conditional overexpression of PDGF-B in the liver under control of an albumin promoter were generated utilising the Cre/loxP system. Constitutive PDGF-B expression was achieved after breeding with mice expressing Cre-recombinase under actin promoter control. Tamoxifen inducible expression was achieved after breeding with mice expressing Cre under transthyretin receptor promoter control. Levels of fibrosis were assessed and the expression of regulators of matrix remodelling was measured. RESULTS PDGF-B expression caused hepatic stellate cell and myofibroblast activation marked by alpha-smooth muscle actin and PDGFR-beta expression. Liver fibrosis was verified macroscopically, histologically and by collagen I mRNA quantification in 4-6 week-old animals. MMP-2, MMP-9 and TIMP-1 were upregulated whereas TGF-beta expression was unchanged. CONCLUSIONS We identified PDGF-B as a proliferative and profibrogenic stimulus and potential inducer of stellate cell transdifferentiation in vivo. PDGF-B overexpression causes liver fibrosis without significantly upregulating TGF-beta1, suggesting a TGF-beta-independent mechanism. The established model provides a tool for testing anti-PDGF-B therapeutic strategies in liver fibrosis in vivo.
Collapse
Affiliation(s)
- Piotr Czochra
- Department of Medicine, Johannes Gutenberg-University, Mainz, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Ben-Ari Z, Tambur AR, Pappo O, Sulkes J, Pravica V, Hutchinson I, Klein T, Tur-Kaspa R, Mor E. Platelet-Derived Growth Factor Gene Polymorphism in Recurrent Hepatitis C Infection after Liver Transplantation. Transplantation 2006; 81:392-7. [PMID: 16477226 DOI: 10.1097/01.tp.0000173645.89064.c7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Recurrent hepatitis C virus (HCV) infection is particularly aggressive in the post liver transplantation setting, with rapid progression of liver fibrosis. Platelet-derived growth factor (PDGF) is reportedly involved in the pathogenesis of liver fibrosis. The aim of this study was to evaluate the possible contribution of molecular variants of the PDGF-B gene to recurrent HCV infection after liver transplantation. METHODS DNA was extracted from peripheral blood mononuclear cells of 40 patients who underwent liver transplantation for chronic HCV infection and genotyped for polymorphisms in PDGF-B at positions +1135 (A to C) and +286 (A to G). Intrahepatic PDGF-B expression was detected by immunohistochemistry and assessed semiquantitatively. Forty-seven healthy individuals served as controls. RESULTS Recurrent HCV infection occurred in 34 patients (85%) after a median interval of 10.5 months (range 1.5-60.0). A statistically significant difference was observed in the distribution of the PDGF-B gene polymorphism at position +1135, but not +286 between patients and controls (P=0.05). The A/A genotype occurred at a highly significantly increased rate in patients with recurrent HCV infection than in those without (64.7% vs. 16.67%, P=0.0001), and in patients with severe than in those with nonsevere recurrence (100% vs. 53.85%, P=0.05). The expression level of intrahepatic PDGF-B was found to be highly correlated with the fibrosis stage (P<0.0001). Further analysis yielded a highly statistically significant relationship between the PDGF-B gene polymorphism at position +1135 and clinical parameters of disease severity. CONCLUSIONS PDGF-B gene polymorphism appears to be associated with severe recurrent HCV infection after liver transplantation. PDGF-B may play an essential role in the development and progression of hepatic fibrosis. These findings, if confirmed, may have important therapeutic implications.
Collapse
Affiliation(s)
- Ziv Ben-Ari
- Liver Institute and Department of Medicine D, Rabin Medical Center, Beilinson Campus, Petah Tiqva and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
Hepatic fibrosis is a wound healing response, involving pathways of inflammation and fibrogenesis. In response to various insults, such as alcohol, ischemia, viral agents, and medications or hepatotoxins, hepatocyte damage will cause the release of cytokines and other soluble factors by Kupffer cells and other cell types in the liver. These factors lead to activation of hepatic stellate cells, which synthesize large amounts of extracellular matrix components. With chronic injury and fibrosis, liver architecture and metabolism are disrupted, eventually manifesting as cirrhosis and its complications. In addition to eliminating etiology, such as antiviral therapy and pharmacological intervention, it is encouraging that novel strategies are being developed to directly address hepatic injury and fibrosis at the subcellular and molecular levels. With improvement in understanding these mechanisms and pathways, key steps in injury, signaling, activation, and gene expression are being targeted by molecular modalities and other molecular or gene therapy approaches. This article intends to provide an update in terms of the current status of molecular therapy for hepatic injury and fibrosis and how far we are from clinical utilization of these new therapeutic modalities.
Collapse
|
29
|
Neef M, Ledermann M, Saegesser H, Schneider V, Widmer N, Decosterd LA, Rochat B, Reichen J. Oral imatinib treatment reduces early fibrogenesis but does not prevent progression in the long term. J Hepatol 2006; 44:167-75. [PMID: 16168515 DOI: 10.1016/j.jhep.2005.06.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 06/16/2005] [Accepted: 06/24/2005] [Indexed: 01/18/2023]
Abstract
BACKGROUND/AIMS Transactivated hepatic stellate cells (HSCs) represent the key source of extra cellular matrix (ECM) in fibrotic liver. Imatinib, a potent inhibitor of the PDGF receptor tyrosine kinase, reduces HSC proliferation and fibrogenesis when treatment is initiated before fibrosis has developed. We tested the antifibrotic potential of imatinib in ongoing liver injury and in established fibrosis. METHODS BDL-rats were gavage fed with 20 mg/kg/d imatinib either early (days 0-21) or late (days 22-35) after BDL. Untreated BDL-rats served as controls. ECM and activated HSCs were quantified by morphometry. Tissue activity of MMP-2 was determined by gelatin zymography. mRNA expression of TIMP-1 and procollagen alpha1(I) were measured by RT-PCR. Liver tissue concentration of imatinib was measured by tandem mass spectrometry. RESULTS Early imatinib reduced ECM formation by 30% (P=0.0455) but left numbers of activated HSCs and procollagen I expression unchanged. MMP-2 activity and TIMP-1 expression were reduced by 50%. Late imatinib treatment did not alter histological or molecular markers of fibrogenesis despite high imatinib tissue levels. CONCLUSIONS The antifibrotic effectiveness of imatinib is limited to the early phase of fibrogenesis. In ongoing liver injury other mediators most likely compensate for the inhibited PDGF effect.
Collapse
Affiliation(s)
- Markus Neef
- Institute of Clinical Pharmacology, University of Berne, Berne, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Fuja TJ, Probst-Fuja MN, Titze IR. Changes in expression of extracellular matrix genes, fibrogenic factors, and actin cytoskeletal organization in retinol treated and untreated vocal fold stellate cells. Matrix Biol 2006; 25:59-67. [PMID: 16253491 DOI: 10.1016/j.matbio.2005.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 08/16/2005] [Accepted: 08/22/2005] [Indexed: 01/18/2023]
Abstract
The regulation of extracellular matrix (ECM) constituency is critical in maintaining vocal cord biomechanical viscoelasticity required for phonation. Recently our laboratory successfully isolated and cultured a novel cell called a vocal fold stellate cell (VFSC), thought to play a central role in laryngeal ECM metabolism, aging, scarring and cancer. Our laboratory has shown that these cells undergo transdifferentiation that is partially reversed by exposure to all-trans retinol (ATROH). Here we make the first report on the expression of various ECM components, MMPs, TIMPs, pro-fibrogenic cytokines, and other ECM modulators in transdifferentiated and deactivated VFSCs. We show that VFSCs maintain an ECM expression pattern similar to laryngeal cancer and scars but distinct from tracheal fibroblasts. Exposure to ATROH differentially affects the VFSC expression of ECM components, matrix-regulating enzymes, and fibrogenic factors suggesting that the inhibitory effects of this synthetic cofactor should be studied further in laryngeal fibrosis and scarring. We also show that increased exposure to retinol induces sequential reorganization of the actin cytoskeleton in activated VFSCs. Our findings demonstrate that VFSCs are capable of regulating vocal fold ECM constituency important throughout normal laryngeal development. Furthermore, our results implicate VFSC activation in ECM misregulation which is a hallmark of several laryngeal pathologies.
Collapse
Affiliation(s)
- Tannin J Fuja
- National Center for Voice and Speech, Department of Speech Pathology and Audiology, University of Iowa, 330 Wendell Johnson Speech and Hearing Center, Iowa City, IA 52242, USA.
| | | | | |
Collapse
|
31
|
Borkham-Kamphorst E, Meurer SK, Gressner AM, Weiskirchen R. Disruption of intermolecular disulfide bonds in PDGF-BB dimers by N-acetyl-L-cysteine does not prevent PDGF signaling in cultured hepatic stellate cells. Biochem Biophys Res Commun 2005; 338:1711-8. [PMID: 16289037 DOI: 10.1016/j.bbrc.2005.10.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 10/22/2005] [Indexed: 12/16/2022]
Abstract
Oxidative stress is important in the pathogenesis of liver fibrosis through its induction of hepatic stellate cell (HSC) proliferation and enhancement of collagen synthesis. Reactive oxygen species have been found to be essential second messengers in the signaling of both major fibrotic growth factors, platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta), in cultured HSC and liver fibrosis. The non-toxic aminothiol N-acetyl-L-cysteine (NAC) inhibits cellular activation and attenuates experimental fibrosis in liver. Prior reports show that NAC is capable of reducing the effects of TGF-beta in biological systems, in cultured endothelial cells, and HSC through its direct reducing activity upon TGF-beta molecules. We here analyzed the effects of NAC on PDGF integrity, receptor binding, and downstream signaling in culture-activated HSC. We found that NAC dose-dependently induces disintegration of PDGF in vitro. However, even high doses (>20mM) were not sufficient to prevent the phosphorylation of the PDGF receptor type beta, extracellular signal-regulated kinase, or protein kinase B (PKB/Akt). Therefore, we conclude that the PDGF monomer is still active. The described antifibrotic effects are therefore mainly attributable to the structural impairment of TGF-beta signaling components reported previously.
Collapse
|
32
|
Kim DI, Lee TK, Jang TH, Kim CH. The inhibitory effect of a Korean herbal medicine, Zedoariae rhizoma, on growth of cultured human hepatic myofibroblast cells. Life Sci 2005; 77:890-906. [PMID: 15964308 DOI: 10.1016/j.lfs.2005.01.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Accepted: 01/05/2005] [Indexed: 11/20/2022]
Abstract
The aim of this study was to assess the effect of ZR on the growth of cultured human hepatic myofibroblast cells (hMF). The zedoary (Zedoariae Rhizoma) made from the dried rhizome of Curcuma zedoaria Roscoe is an herbal drug used as an aromatic stomachic. The plant is a perennial herb which is natively distributed throughout Korea and is a traditional Korean herbal medicine. Zedoariae rhizoma is a bioactive traditional medicine with anti-tumor, anti-atherosclerosis, anti-inflammation, and growth-regulating properties. During the course of liver fibrogenesis, hMF, mostly derived from hepatic stellate cells, proliferate and synthesize excessive amounts of extracellular matrix components. To evaluate the antiproliferative effect of a traditional herbal medicine, Zedoariae rhizoma water extracts (ZR) was examined on the growth inhibition of hMF since proliferation of hMF is known to be central for the development of fibrosis during liver injury, and factors that may limit their growth are potential antifibrotic agents. The aim of this study was to test the effects of ZR on the proliferation in cultured hMF. hMF were obtained by outgrowth from human liver explants. ZR markedly reduced serum driven cell proliferation, as assessed by nuclear autoradiography experiments and measurement of actual cell growth. Growth inhibition was totally reversed after removal of the ZR. ZR potently inhibited hMF growth (IC50 = 8.5 microg/ml), in a pertussis toxin-insensitive manner. Analysis of the mechanisms involved in growth inhibition revealed that ZR rapidly increased prostaglandin E2 production and in turn cAMP, which inhibited hMF proliferation, did not affect cAMP levels. Production of cAMP by ZR was abolished by NS-398, a selective inhibitor of cycloxygenase (COX)-2. Also, ZR potently induced COX-2 protein expression. Blocking COX-2 by NS-398 blunted the antiproliferative effect of ZR. We conclude that ZR inhibits proliferation of hMF, probably via an intracellular mechanism, through early COX-2-dependent release of prostaglandin E2 and cAMP, and delayed COX-2 induction. Our results indicated a novel role for ZR as a growth inhibitory mediator and pointed out its potential involvement in the negative regulation of liver fibrogenesis. The results that ZR exhibits potent antiproliferative and antifibrogenic effects toward hMF, indicated that ZR might have therapeutic implications in chronic liver disease.
Collapse
Affiliation(s)
- Dong-Il Kim
- Department of Biochemistry, Molecular Biology and Gynecology, Dongguk University College of Oriental Medicine, and National Research Laboratory for Glycobiology, Kyungju, Kyungbuk 780-714, Korea
| | | | | | | |
Collapse
|
33
|
Borkham-Kamphorst E, Stoll D, Gressner AM, Weiskirchen R. Antisense strategy against PDGF B-chain proves effective in preventing experimental liver fibrogenesis. Biochem Biophys Res Commun 2004; 321:413-23. [PMID: 15358192 DOI: 10.1016/j.bbrc.2004.06.153] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Indexed: 01/18/2023]
Abstract
Hepatic stellate cells (HSCs) and transdifferentiated myofibroblasts are the principal producers of excessive extracellular matrix in liver fibrosis and cirrhosis. Activation of HSC is regulated by several cytokines and growth factors, including platelet-derived growth factor B-chain (PDGF-B), a potent mitogen for HSC, and overexpressed during hepatic fibrogenesis. Previous studies showed that MAPK and phosphatidylinositol 3' kinase are key signaling pathways involved in PDGF-induced stimulation of HSC. Based on the involvement of PDGF-B in fibrogenesis, reducing ligand stimulation of proliferative cytokine- or growth factor receptors interfering with receptor signaling therefore presents an interesting strategy for hepatic fibrosis prevention or interruption. We therefore generated an adenoviral vector serotype 5 (Ad5) expressing an antisense mRNA of the PDGF B-chain (Ad5-CMV-asPDGF) for application in an experimentally induced liver fibrogenesis model. The transgene clearly showed the ability to down-regulate endogenous PDGF B-chain and PDGFRbeta mRNA in culture-activated HSC and rat livers. The asPDGF mRNA also attenuates experimental liver fibrogenesis indicated by reduced levels of alpha-SMA and collagen type I expression.
Collapse
|