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Streutker EM, Devamoglu U, Vonk MC, Verdurmen WPR, Le Gac S. Fibrosis-on-Chip: A Guide to Recapitulate the Essential Features of Fibrotic Disease. Adv Healthc Mater 2024; 13:e2303991. [PMID: 38536053 DOI: 10.1002/adhm.202303991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/15/2024] [Indexed: 05/05/2024]
Abstract
Fibrosis, which is primarily marked by excessive extracellular matrix (ECM) deposition, is a pathophysiological process associated with many disorders, which ultimately leads to organ dysfunction and poor patient outcomes. Despite the high prevalence of fibrosis, currently there exist few therapeutic options, and importantly, there is a paucity of in vitro models to accurately study fibrosis. This review discusses the multifaceted nature of fibrosis from the viewpoint of developing organ-on-chip (OoC) disease models, focusing on five key features: the ECM component, inflammation, mechanical cues, hypoxia, and vascularization. The potential of OoC technology is explored for better modeling these features in the context of studying fibrotic diseases and the interplay between various key features is emphasized. This paper reviews how organ-specific fibrotic diseases are modeled in OoC platforms, which elements are included in these existing models, and the avenues for novel research directions are highlighted. Finally, this review concludes with a perspective on how to address the current gap with respect to the inclusion of multiple features to yield more sophisticated and relevant models of fibrotic diseases in an OoC format.
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Affiliation(s)
- Emma M Streutker
- Department of Medical BioSciences, Radboud University Medical Center, Geert Grooteplein 28, Nijmegen, 6525 GA, The Netherlands
| | - Utku Devamoglu
- Applied Microfluidics for BioEngineering Research, MESA+ Institute for Nanotechnoloygy and TechMed Centre, Organ-on-Chip Centre, University of Twente, Drienerlolaan 5, Enschede, 7522 NB, The Netherlands
| | - Madelon C Vonk
- Department of Rheumatology, Radboud University Medical Center, Nijmegen, PO Box 9101, Nijmegen, 6500 HB, The Netherlands
| | - Wouter P R Verdurmen
- Department of Medical BioSciences, Radboud University Medical Center, Geert Grooteplein 28, Nijmegen, 6525 GA, The Netherlands
| | - Séverine Le Gac
- Applied Microfluidics for BioEngineering Research, MESA+ Institute for Nanotechnoloygy and TechMed Centre, Organ-on-Chip Centre, University of Twente, Drienerlolaan 5, Enschede, 7522 NB, The Netherlands
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Li Y, Fan W, Link F, Wang S, Dooley S. Transforming growth factor β latency: A mechanism of cytokine storage and signalling regulation in liver homeostasis and disease. JHEP REPORTS : INNOVATION IN HEPATOLOGY 2022; 4:100397. [PMID: 35059619 PMCID: PMC8760520 DOI: 10.1016/j.jhepr.2021.100397] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 12/13/2022]
Abstract
Transforming growth factor-β (TGF-β) is a potent effector in the liver, which is involved in a plethora of processes initiated upon liver injury. TGF-β affects parenchymal, non-parenchymal, and inflammatory cells in a highly context-dependent manner. Its bioavailability is critical for a fast response to various insults. In the liver – and probably in other organs – this is made possible by the deposition of a large portion of TGF-β in the extracellular matrix as an inactivated precursor form termed latent TGF-β (L-TGF-β). Several matrisomal proteins participate in matrix deposition, latent complex stabilisation, and activation of L-TGF-β. Extracellular matrix protein 1 (ECM1) was recently identified as a critical factor in maintaining the latency of deposited L-TGF-β in the healthy liver. Indeed, its depletion causes spontaneous TGF-β signalling activation with deleterious effects on liver architecture and function. This review article presents the current knowledge on intracellular L-TGF-β complex formation, secretion, matrix deposition, and activation and describes the proteins and processes involved. Further, we emphasise the therapeutic potential of toning down L-TGF-β activation in liver fibrosis and liver cancer.
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Affiliation(s)
- Yujia Li
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Weiguo Fan
- Division of Gastroenterology and Hepatology, Stanford University, Stanford CA, USA
| | - Frederik Link
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Sai Wang
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; Tel.: 06213835595.
| | - Steven Dooley
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Corresponding authors. Addresses: Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; Tel.: 06213833768;
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Ikawa T, Ichimura Y, Miyagawa T, Fukui Y, Toyama S, Omatsu J, Awaji K, Norimatsu Y, Watanabe Y, Yoshizaki A, Sato S, Asano Y. The Contribution of LIGHT to the Development of Systemic Sclerosis by Modulating IL-6 and T Helper Type 1 Chemokine Expression in Dermal Fibroblasts. J Invest Dermatol 2021; 142:1541-1551.e3. [PMID: 34838790 DOI: 10.1016/j.jid.2021.10.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 09/28/2021] [Accepted: 10/08/2021] [Indexed: 01/24/2023]
Abstract
Systemic sclerosis (SSc) is an autoimmune and vascular disease resulting in multiple organ fibrosis, in which IL-6 and T helper (Th)2/Th17 cytokines serve as critical disease drivers. LIGHT is a proinflammatory cytokine promoting IL-6 production in lung fibroblasts and Th1 chemokine expression in dermal fibroblasts (DFs) stimulated with IFN-γ. In this study, we investigated the potential contribution of LIGHT to SSc development using clinical samples and animal models. In SSc-involved skin, LIGHT was upregulated in inflammatory cells, whereas herpesvirus entry mediator (HVEM), a receptor of LIGHT, was downregulated in DFs. Similar expression profiles of LIGHT and HVEM were reproduced in bleomycin-treated mice. Transcription factor FLI1 bound to the HVEM promoter, and FLI1 small interfering RNA suppressed HVEM expression in normal DFs. In SSc DFs, LIGHT significantly increased IL-6 production, whereas IFN-γ/LIGHT-dependent Th1 chemokine induction was decreased compared with that in normal DFs. Importantly, LIGHT small interfering RNA significantly attenuated bleomycin-induced skin fibrosis, and serum LIGHT levels were elevated in patients with diffuse cutaneous SSc and positively correlated with clinical parameters reflecting skin and pulmonary fibrosis. Taken together, these results suggest that altered response of DFs to LIGHT, namely increased IL-6 production and decreased Th1 chemokine expression, contributes to the development of skin fibrosis in SSc.
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Affiliation(s)
- Tetsuya Ikawa
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yohei Ichimura
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takuya Miyagawa
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuki Fukui
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Satoshi Toyama
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jun Omatsu
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kentaro Awaji
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuta Norimatsu
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yusuke Watanabe
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ayumi Yoshizaki
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shinichi Sato
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yoshihide Asano
- Department of Dermatology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
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Inhibition of Cancer Cell Adhesion, Migration and Proliferation by a Bispecific Antibody that Targets two Distinct Epitopes on αv Integrins. J Mol Biol 2021; 433:167090. [PMID: 34090922 DOI: 10.1016/j.jmb.2021.167090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 01/13/2023]
Abstract
Members of the αv family of integrins regulate activation of transforming growth factor beta (TGFβ) and are directly involved in pro-tumorigenic phenotypes. Thus, αv integrins may be therapeutic targets for fibrosis and cancer, yet the isolation of selective inhibitors is currently a challenge. We generated synthetic antibodies selective for αv integrins by phage display selections on cell lines that displayed integrin heterodimers. We identified antibodies that targeted two distinct epitopes on cell-surface αv integrins and partially inhibited cell adhesion mediated by interactions between integrins and the latency-associated peptide, part of the pro-form of TGFβ. Using the isolated antibody paratope sequences we engineered a bispecific antibody capable of binding to both epitopes simultaneously; this antibody potently and completely inhibited cell adhesion mediated by integrins αvβ1, αvβ3 and αvβ5. In addition, the bispecific antibody inhibited proliferation and migration of lung carcinoma lines, where the highest and lowest potencies observed correlated with integrin-αv cell surface expression levels. Taken together, our results demonstrate that phage display selections with live cells can yield high quality anti-integrin antibodies, which we used as biparatopic building blocks to construct a bispecific antibody that strongly inhibited integrin function and may be a therapeutic candidate for cancer and fibrosis.
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Fukui Y, Nakamura K, Hirabayashi M, Miyagawa T, Toyama S, Omatsu J, Awaji K, Ikawa T, Norimatsu Y, Yoshizaki A, Sato S, Asano Y. Serum vasohibin-1 levels: A potential marker of dermal and pulmonary fibrosis in systemic sclerosis. Exp Dermatol 2021; 30:951-958. [PMID: 33682189 DOI: 10.1111/exd.14321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 12/23/2022]
Abstract
Vasohibin-1 (VASH-1) is a potent anti-angiogenic factor mainly produced by endothelial cells. In addition, VASH-1 prevents TGF-β-dependent activation of renal fibroblasts. Since systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy and fibrosis of multiple organs, VASH-1 may be involved in the development of this disease. In this study, we investigated the potential role of VASH-1 in SSc by evaluating the clinical correlation between serum VASH-1 levels and the expression of VASH-1 in SSc-involved skin. Serum VASH-1 levels were higher in SSc patients, especially those with diffuse cutaneous involvement, than in healthy controls and positively correlated with skin score. Furthermore, SSc patients with interstitial lung disease had significantly elevated levels of serum VASH-1 as compared to those without. Importantly, serum VASH-1 levels correlated inversely with both the percentage of predicted vital capacity and the percentage of predicted diffusion lung capacity for carbon monoxide and positively with serum KL-6 levels, but not serum surfactant protein D levels. In SSc-involved skin, VASH1 mRNA was remarkably upregulated compared with healthy control skin, but the major source of VASH-1 was not clear. Fli1 deficiency, a predisposing factor inducing SSc-like endothelial properties, did not affect VASH-1 expression in human dermal microvascular endothelial cells. Collectively, these results suggest that VASH-1 upregulation in the skin and sera is linked to dermal and pulmonary fibrotic changes in SSc, while the contribution of VASH-1 to SSc vasculopathy seems to be limited.
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Affiliation(s)
- Yuki Fukui
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Kouki Nakamura
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Megumi Hirabayashi
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takuya Miyagawa
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Satoshi Toyama
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Jun Omatsu
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Kentaro Awaji
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Tetsuya Ikawa
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yuta Norimatsu
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Ayumi Yoshizaki
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinichi Sato
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yoshihide Asano
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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The Pathogenesis of Systemic Sclerosis: An Understanding Based on a Common Pathologic Cascade across Multiple Organs and Additional Organ-Specific Pathologies. J Clin Med 2020; 9:jcm9092687. [PMID: 32825112 PMCID: PMC7565034 DOI: 10.3390/jcm9092687] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 02/08/2023] Open
Abstract
Systemic sclerosis (SSc) is a multisystem autoimmune and vascular disease resulting in fibrosis of various organs with unknown etiology. Accumulating evidence suggests that a common pathologic cascade across multiple organs and additional organ-specific pathologies underpin SSc development. The common pathologic cascade starts with vascular injury due to autoimmune attacks and unknown environmental factors. After that, dysregulated angiogenesis and defective vasculogenesis promote vascular structural abnormalities, such as capillary loss and arteriolar stenosis, while aberrantly activated endothelial cells facilitate the infiltration of circulating immune cells into perivascular areas of various organs. Arteriolar stenosis directly causes pulmonary arterial hypertension, scleroderma renal crisis and digital ulcers. Chronic inflammation persistently activates interstitial fibroblasts, leading to the irreversible fibrosis of multiple organs. The common pathologic cascade interacts with a variety of modifying factors in each organ, such as keratinocytes and adipocytes in the skin, esophageal stratified squamous epithelia and myenteric nerve system in gastrointestinal tract, vasospasm of arterioles in the heart and kidney, and microaspiration of gastric content in the lung. To better understand SSc pathogenesis and develop new disease-modifying therapies, it is quite important to understand the complex pathogenesis of SSc from the two distinct perspectives, namely the common pathologic cascade and additional organ-specific pathologies.
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Abstract
PURPOSE OF REVIEW Systemic sclerosis (SSc) is an autoimmune connective tissue disease in which there is an activation of fibroblast to a myofibroblast that secretes huge amounts of extracellular matrix. Currently, no treatment exists that modifies the fibrosis elements and new therapeutic targets are badly needed. This review examines the current state of treatments and emerging therapeutics. RECENT FINDINGS Nintedanib was found to significantly reduce the rate of decline in SSc associated FVC, although it has no benefit on skin fibrosis. New cannabinoid receptor2 agonist has shown superb effects in phase II and results in phase III are anticipated. Other targets are currently being tested in clinical trials and new targets that are yet to be tested are increasing in the SSc literature. Nintedanib is now licenced for SSc interstitial lung disease but this does not modify the skin fibrosis. Current ongoing trials will determine the role of various targets. New targets are emerging as we gain a deeper understanding of disease pathogenesis.
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Affiliation(s)
- Monique Hinchcliff
- Section of Rheumatology and allergy, Yale School of medicine, Yale University, New Haven, CT, USA
| | - Steven O'Reilly
- Department of Biosciences, Durham University, Stockton Road, Durham, UK. steven.o'
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Khanna D, Tashkin DP, Denton CP, Lubell MW, Vazquez-Mateo C, Wax S. Ongoing clinical trials and treatment options for patients with systemic sclerosis-associated interstitial lung disease. Rheumatology (Oxford) 2020; 58:567-579. [PMID: 29893938 PMCID: PMC6434373 DOI: 10.1093/rheumatology/key151] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/24/2018] [Indexed: 01/20/2023] Open
Abstract
SSc is a rare CTD that affects multiple organ systems, resulting in substantial morbidity and mortality. Evidence of interstitial lung disease (ILD) is seen in ∼80% of patients with SSc. Currently there is no approved disease-modifying treatment for ILD and few effective treatment options are available. CYC is included in treatment guidelines, but it has limited efficacy and is associated with toxicity. MMF is becoming the most commonly used medication in clinical practice in North America and the UK, but its use is not universal. Newer agents targeting the pathogenic mechanisms underlying SSc-ILD, including fibrotic and inflammatory pathways, lymphocytes, cell-cell and cell-extracellular membrane interactions, hold promise for better treatment outcomes, including improved lung function, patient-related outcomes and quality of life. Here we review ongoing trials of established and novel agents that are currently recruiting patients with SSc-ILD.
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Affiliation(s)
- Dinesh Khanna
- Division of Rheumatology, Department of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Donald P Tashkin
- Division of Pulmonary and Critical Care Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Christopher P Denton
- Centre for Rheumatology, Division of Medicine, University College London, London, UK
| | - Martin W Lubell
- Global Clinical Development, EMD Serono Inc., Billerica, MA, USA
| | | | - Stephen Wax
- Global Clinical Development, EMD Serono Inc., Billerica, MA, USA
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Zhang Z, Wu Y, Wu B, Qi Q, Li H, Lu H, Fan C, Feng C, Zuo J, Niu L, Tang W. DZ2002 ameliorates fibrosis, inflammation, and vasculopathy in experimental systemic sclerosis models. Arthritis Res Ther 2019; 21:290. [PMID: 31842999 PMCID: PMC6916442 DOI: 10.1186/s13075-019-2074-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Systemic sclerosis is a multisystem inflammatory and vascular lesion leading to extensive tissue fibrosis. A reversible S-adenosyl-l-homocysteine hydrolase (SAHH) inhibitor, DZ2002, modulates the pathologic processes of various inflammatory diseases and autoimmune diseases. This study is designed to investigate the therapeutic potentiality of DZ2002 for experimental systemic sclerosis models. METHODS The anti-inflammatory and anti-fibrotic features of DZ2002 and its mechanisms were investigated in a bleomycin (BLM)-induced dermal fibrosis mice model. The effects of DZ2002 on expression of extracellular matrix components and TGF-β signaling in human dermal fibroblasts were analyzed. Simultaneously, the effects of DZ2002 on macrophage activation and endothelial cell adhesion molecule expression were also evaluated. RESULTS DZ2002 significantly attenuated dermal fibrosis in BLM-induced mice. Consistently, DZ2002 inhibited the expression of various molecules associated with dermal fibrosis, including transforming growth factor β1, connective tissue growth factor, tumor necrosis factor-α, interferon-γ, IL-1β, IL-4, IL-6, IL-10, IL-12p40, IL-17A, and monocyte chemotactic protein 1 in the lesional skin of BLM-induced mice. Furthermore, DZ2002 decreased the proportion of macrophages, neutrophils, and T cells (especially T helper cells) in the skin tissue of BLM-induced mice. In addition, DZ2002 attenuated both M1 macrophage and M2 macrophage differentiation in vivo and in vitro. Importantly, DZ2002 directly reversed the profibrotic phenotype of transforming growth factor-β1-treated dermal fibroblasts and suppressed ICAM-1, VCAM-1, VEGF, bFGF, and ET-1 expression in endothelial cells. Finally, our investigations showed that DZ2002 relieved systemic sclerosis by regulating fibrosis TGF-β/Smad signaling pathway. CONCLUSIONS DZ2002 prevents the development of experimental dermal fibrosis by reversing the profibrotic phenotype of various cell types and would be a potential drug for the treatment of systemic sclerosis.
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Affiliation(s)
- Zongwang Zhang
- School of Life Sciences, Shanghai University, 333 Nanchen Road, Baoshan District, Shanghai, 200444, China
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yanwei Wu
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Bing Wu
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing Qi
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Heng Li
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huimin Lu
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chen Fan
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Chunlan Feng
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Jianping Zuo
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Lili Niu
- School of Life Sciences, Shanghai University, 333 Nanchen Road, Baoshan District, Shanghai, 200444, China.
| | - Wei Tang
- Laboratory of Immunopharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Asano Y, Varga J. Rationally-based therapeutic disease modification in systemic sclerosis: Novel strategies. Semin Cell Dev Biol 2019; 101:146-160. [PMID: 31859147 DOI: 10.1016/j.semcdb.2019.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 02/07/2023]
Abstract
Systemic sclerosis (SSc) is a highly challenging chronic condition that is dominated by the pathogenetic triad of vascular damage, immune dysregulation/autoimmunity and fibrosis in multiple organs. A hallmark of SSc is the remarkable degree of molecular and phenotypic disease heterogeneity, which surpasses that of other complex rheumatic diseases. Disease trajectories in SSc are unpredictable and variable from patient to patient. Disease-modifying therapies for SSc are lacking, long-term morbidity is considerable and mortality remains unacceptably high. Currently-used empirical approaches to disease modification have modest and variable clinical efficacy and impact on survival, are expensive and frequently associated with unfavorable side effects, and none can be considered curative. However, research during the past several years is yielding significant advances with therapeutic potential. In particular, the application of unbiased omics-based discovery technologies to large and well-characterized SSc patient cohorts, coupled with hypothesis-testing experimental research using a variety of model systems is revealing new insights into SSc that allow formulation of a more nuanced appreciation of disease heterogeneity, and a deepening understanding of pathogenesis. Indeed, we are now presented with numerous novel and rationally-based strategies for targeted SSc therapy, several of which are currently, or expected to be shortly, undergoing clinical evaluation. In this review, we discuss promising novel therapeutic targets and rationally-based approaches to disease modification that have the potential to improve long-term outcomes in SSc.
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Affiliation(s)
| | - John Varga
- Northwestern Scleroderma Program, Feinberg School of Medicine, Northwestern University, Chicago, United States.
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11
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Bernhagen D, Jungbluth V, Gisbert Quilis N, Dostalek J, White PB, Jalink K, Timmerman P. High-Affinity α 5β 1-Integrin-Selective Bicyclic RGD Peptides Identified via Screening of Designed Random Libraries. ACS COMBINATORIAL SCIENCE 2019; 21:598-607. [PMID: 31269394 DOI: 10.1021/acscombsci.9b00081] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We report the identification of high-affinity and selectivity integrin α5β1-binding bicyclic peptides via "designed random libraries", that is, the screening of libraries comprising the universal integrin-binding sequence Arg-Gly-Asp (RGD) in the first loop in combination with a randomized sequence (XXX) in the second loop. Screening of first-generation libraries for α5β1-binding peptides yielded a triple-digit nanomolar bicyclic α5β1-binder (CT3RGDcT3AYGCT3, IC50 = 406 nM). Next-generation libraries were designed by partially varying the structure of the strongest first-generation lead inhibitor and screened for improved affinities and selectivities for this receptor. In this way, we identified three high-affinity α5β1-binders (CT3RGDcT3AYJCT3, J = d-Leu, IC50 = 90 nM; CT3RGDcT3AYaCT3, IC50 = 156 nM; CT3RGDcT3AWGCT3, IC50 = 173 nM), of which one even showed a higher α5β1-affinity than the 32 amino acid benchmark peptide knottin-RGD (IC50 = 114 nM). Affinity for α5β1-integrin was confirmed by SPFS analysis showing a Kd of 4.1 nM for Cy5-labeled RGD-bicycle CT3RGDcT3AYJCT3 (J = d-Leu) and a somewhat higher Kd (9.0 nM) for Cy5-labeled knottin-RGD. The α5β1-bicycles, for example, CT3RGDcT3AYJCT3 (J = d-Leu), showed excellent selectivities over αvβ5 (IC50 ratio α5β1/αvβ5 between <0.009 and 0.039) and acceptable selectivities over αvβ3 (IC50 ratios α5β1/αvβ3 between 0.090 and 0.157). In vitro staining of adipose-derived stem cells with Cy5-labeled peptides using confocal microscopy revealed strong binding of the α5β1-selective bicycle CT3RGDcT3AWGCT3 to integrins in their natural environment, illustrating the high potential of these RGD bicycles as markers for α5β1-integrin expression.
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Affiliation(s)
- Dominik Bernhagen
- Pepscan Therapeutics, Zuidersluisweg 2, 8243 RC Lelystad, the Netherlands
| | - Vanessa Jungbluth
- Biosensor Technologies, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Nestor Gisbert Quilis
- Biosensor Technologies, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Jakub Dostalek
- Biosensor Technologies, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Paul B. White
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Kees Jalink
- The Netherlands Cancer Institute, Plesmanlaan 21, 1066 CX Amsterdam, the Netherlands
| | - Peter Timmerman
- Pepscan Therapeutics, Zuidersluisweg 2, 8243 RC Lelystad, the Netherlands
- Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
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12
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Identification of regulators of the myofibroblast phenotype of primary dermal fibroblasts from early diffuse systemic sclerosis patients. Sci Rep 2019; 9:4521. [PMID: 30872777 PMCID: PMC6418101 DOI: 10.1038/s41598-019-41153-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 02/18/2019] [Indexed: 12/28/2022] Open
Abstract
Systemic sclerosis (SSc or scleroderma) is an auto-immune disease characterized by skin fibrosis. While primary cells from patients are considered as a unique resource to better understand human disease biology, the effect of in vitro culture on these cells and their evaluation as a platform to identify disease regulators remain poorly characterized. The goal of our studies was to provide insights into the utility of SSc dermal fibroblast primary cells for therapeutic target discovery. The disease phenotypes of freshly isolated and in vitro cultured SSc dermal fibroblasts were characterized using whole transcriptome profiling, alpha smooth muscle actin (ASMA) expression and cell impedance. SSc dermal fibroblasts retained most of the molecular disease phenotype upon in vitro culture for at least four cell culture passages (approximatively 10 cell doublings). We validated an RNA interference high throughput assay that successfully identified genes affecting the myofibroblast phenotype of SSc skin fibroblasts. These genes included MKL1, RHOA and LOXL2 that were previously proposed as therapeutic anti-fibrotic target, and ITGA5, that has been less studied in fibrosis biology and may be a novel potential modifier of SSc fibroblast biology. Together our results demonstrated the value of carefully-phenotyped SSc dermal fibroblasts as a platform for SSc target and drug discovery.
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Progranulin overproduction due to constitutively activated c-Abl/PKC-δ/Fli1 pathway contributes to the resistance of dermal fibroblasts to the anti-fibrotic effect of tumor necrosis factor-α in localized scleroderma. J Dermatol Sci 2018; 92:207-214. [DOI: 10.1016/j.jdermsci.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/02/2018] [Accepted: 09/11/2018] [Indexed: 11/21/2022]
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Schnittert J, Bansal R, Storm G, Prakash J. Integrins in wound healing, fibrosis and tumor stroma: High potential targets for therapeutics and drug delivery. Adv Drug Deliv Rev 2018; 129:37-53. [PMID: 29414674 DOI: 10.1016/j.addr.2018.01.020] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/16/2018] [Accepted: 01/29/2018] [Indexed: 12/20/2022]
Abstract
Wound healing is a complex process, which ultimately leads to fibrosis if not repaired well. Pathologically very similar to fibrosis is the tumor stroma, found in several solid tumors which are regarded as wounds that do not heal. Integrins are heterodimeric surface receptors which control various physiological cellular functions. Additionally, integrins also sense ECM-induced extracellular changes during pathological events, leading to cellular responses, which influence ECM remodeling. The purpose and scope of this review is to introduce integrins as key targets for therapeutics and drug delivery within the scope of wound healing, fibrosis and the tumor stroma. This review provides a general introduction to the biology of integrins including their types, ligands, means of signaling and interaction with growth factor receptors. Furthermore, we highlight integrins as key targets for therapeutics and drug delivery, based on their biological role, expression pattern within human tissues and at cellular level. Next, therapeutic approaches targeting integrins, with a focus on clinical studies, and targeted drug delivery strategies based on ligands are described.
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Asano Y. Recent advances in the treatment of skin involvement in systemic sclerosis. Inflamm Regen 2017; 37:12. [PMID: 29259711 PMCID: PMC5725888 DOI: 10.1186/s41232-017-0047-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/07/2017] [Indexed: 02/04/2023] Open
Abstract
Skin fibrosis is a devastating clinical condition commonly seen in skin-restricted and systemic disorders. The goal of skin fibrosis treatment is the restoration of abnormally activated dermal fibroblasts producing the excessive amount of extracellular matrix, which is generally a final consequence of the complex disease process including the activation of vascular and immune systems. Among various skin fibrotic conditions, the molecular mechanisms underlying dermal fibroblast activation have been mostly well studied in systemic sclerosis (SSc). SSc is a multisystem autoimmune and vascular disease resulting in extensive fibrosis of the skin and various internal organs. Since SSc pathogenesis is believed to include all the critical components regulating tissue fibrosis, the studies on anti-fibrotic drugs against SSc provide us much useful information regarding the strategy for the treatment of various skin fibrotic conditions. In the recent decade, as is the case with other autoimmune and inflammatory diseases, the molecular targeting therapy with monoclonal antibody has been clinically well examined in SSc. Promising clinical outcomes are so far reported in tocilizumab (an anti-IL-6 receptor antibody), rituximab (an anti-CD20 antibody), and fresolimumab (an anti-TGF-β antibody). The analysis of gene expression profiles in skin lesions of SSc patients treated with tocilizumab or fresolimumab revealed a critical role of monocyte-macrophage lineage cells in the development of skin fibrosis and the involvement of IL-6 and TGF-β in the activation of those cells. Considering that B cells modulate the differentiation and activation of macrophages, favorable clinical outcomes of rituximab treatment imply the central role of B cell/monocyte-macrophage lineage cell axis in the pathogenesis of SSc. This scenario may be applicable at least partly to other skin fibrotic conditions. In this review article, the currently available data on these drugs are summarized and the future directions are discussed.
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Affiliation(s)
- Yoshihide Asano
- Department of Dermatology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
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Affiliation(s)
- Yoshihide Asano
- Department of Dermatology; University of Tokyo Graduate School of Medicine; Tokyo Japan
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Lee P, Yeo GC, Weiss AS. A cell adhesive peptide from tropoelastin promotes sequential cell attachment and spreading via distinct receptors. FEBS J 2017; 284:2216-2230. [DOI: 10.1111/febs.14114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 04/30/2017] [Accepted: 05/17/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Pearl Lee
- School of Life and Environmental Sciences University of Sydney Australia
- Bosch Institute University of Sydney Australia
- Charles Perkins Centre University of Sydney Australia
| | - Giselle C. Yeo
- School of Life and Environmental Sciences University of Sydney Australia
- Charles Perkins Centre University of Sydney Australia
- Applied and Plasma Physics School of Physics University of Sydney Australia
| | - Anthony S. Weiss
- School of Life and Environmental Sciences University of Sydney Australia
- Bosch Institute University of Sydney Australia
- Charles Perkins Centre University of Sydney Australia
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Asano Y. Recent advances in animal models of systemic sclerosis. J Dermatol 2017; 43:19-28. [PMID: 26782003 DOI: 10.1111/1346-8138.13185] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 12/19/2022]
Abstract
Systemic sclerosis (SSc) is a multisystem connective tissue disease characterized by the three cardinal pathological features, comprising aberrant immune activation, vasculopathy and tissue fibrosis, with unknown etiology. Although many inducible and genetic animal models mimicking the selected aspects of SSc have been well documented, the lack of models encompassing the full clinical manifestations hindered the development and preclinical testing of therapies against this disease. Under this situation, three new genetic animal models have recently been established, such as Fra2 transgenic mice, urokinase-type plasminogen activator receptor deficient mice and Klf5(+/-) ;Fli1(+/-) mice, all of which recapitulate the pathological cascade of SSc. The former two murine models demonstrate endothelial cell apoptosis and capillary loss followed by tissue fibrosis, whereas the immune systems show no remarkable abnormality. Klf5(+/-) ;Fli1(+/-) mice develop immune activation, vasculopathy and tissue fibrosis in this sequence, eventually resulting in the development of dermal fibrosis, interstitial lung disease and pulmonary vascular involvement resembling those of SSc. Because Krueppel-like factor (KLF)5 and Friend leukemia integration 1 transcription factor (Fli1) are the transcription factors epigenetically suppressed in SSc dermal fibroblasts, the reproduction of SSc manifestations in Klf5(+/-) ;Fli1(+/-) mice supports the canonical idea that environmental influences play a central role in the development of SSc in genetically predisposed individuals. These new animal models offer important clues for the better understanding of the underlying molecular mechanisms of SSc pathology and the identification of potential molecular targets for the treatment of this incurable disease.
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Affiliation(s)
- Yoshihide Asano
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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Abstract
Systemic sclerosis is a heterogeneous condition characterized by microvascular damage, dysregulation of the immune system, and progressive fibrosis affecting skin and internal organs. Currently, there are no approved disease-modifying therapies, and management mostly involves treatment of organ-specific complications. In recent years, major advances have greatly improved our understanding of the disease process, especially the molecular mechanisms by which fibrosis becomes self-sustaining. We discuss selected aspects of these mechanisms with a focus on those relevant to ongoing efforts to develop disease-modifying therapies. We also discuss advances in identification of patient subtypes, and selected examples of potential disease-modifying therapies in clinical development.
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Conroy KP, Kitto LJ, Henderson NC. αv integrins: key regulators of tissue fibrosis. Cell Tissue Res 2016; 365:511-9. [PMID: 27139180 PMCID: PMC5010580 DOI: 10.1007/s00441-016-2407-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/08/2016] [Indexed: 01/09/2023]
Abstract
Chronic tissue injury with fibrosis results in the disruption of tissue architecture, organ dysfunction and eventual organ failure. Therefore, the development of effective anti-fibrotic therapies is urgently required. During fibrogenesis, complex interplay occurs between cellular and extracellular matrix components of the wound healing response. Integrins, a family of transmembrane cell adhesion molecules, play a key role in mediating intercellular and cell-matrix interactions. Thus, integrins provide a major node of communication between the extracellular matrix, inflammatory cells, fibroblasts and parenchymal cells and, as such, are intimately involved in the initiation, maintenance and resolution of tissue fibrosis. Modulation of members of the αv integrin family has exhibited profound effects on fibrosis in multiple organs and disease states. In this review, we discuss the current knowledge of the mechanisms of αv-integrin-mediated regulation of fibrogenesis and show that the therapeutic targeting of specific αv integrins represents a promising avenue to treat patients with a broad range of fibrotic diseases.
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Affiliation(s)
- Kylie P Conroy
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Laura J Kitto
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Neil C Henderson
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
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Ichimura Y, Asano Y, Akamata K, Noda S, Taniguchi T, Takahashi T, Toyama T, Tada Y, Sugaya M, Sato S, Kadono T. Progranulin Overproduction Due to Fli-1 Deficiency Contributes to the Resistance of Dermal Fibroblasts to Tumor Necrosis Factor in Systemic Sclerosis. Arthritis Rheumatol 2016; 67:3245-55. [PMID: 26245842 DOI: 10.1002/art.39312] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/30/2015] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Progranulin is a growth factor that is active in wound repair and is an antagonist of tumor necrosis factor (TNF) receptors, regulating fibroblast activation, angiogenesis, and inflammation. Because long-standing activation of gene programs related to wound healing is a hallmark of systemic sclerosis (SSc), we sought to investigate the role of progranulin in SSc. METHODS Progranulin expression levels in human and murine skin samples were determined by immunohistochemical analysis and quantitative reverse transcription-polymerase chain reaction. The role of progranulin in fibroblast activation was examined using a gene-silencing technique. Progranulin levels in serum obtained from 60 patients with SSc and 16 healthy control subjects were determined by enzyme-linked immunosorbent assay. RESULTS Progranulin expression was increased in SSc dermal fibroblasts compared with normal dermal fibroblasts, both in vivo and in vitro. Transcription factor Fli-1, a deficiency of which is involved in the activation of SSc dermal fibroblasts, served as a potent repressor of the progranulin gene, and Fli-1(+/-) mice and bleomycin-treated wild-type mice exhibited up-regulated expression of progranulin in dermal fibroblasts. SSc dermal fibroblasts were resistant to the antifibrotic effect of TNF, but this resistance was reversed by gene silencing of progranulin. Serum progranulin levels were elevated in patients with early diffuse cutaneous SSc (dcSSc), especially in those with inflammatory skin symptoms, and were positively correlated with the C-reactive protein level. CONCLUSION Progranulin overproduction due to Fli-1 deficiency may contribute to the constitutive activation of SSc dermal fibroblasts by antagonizing the antifibrotic effect of TNF. Progranulin may also be involved in the inflammatory process associated with progressive skin sclerosis in early dcSSc.
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Affiliation(s)
- Yohei Ichimura
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yoshihide Asano
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Kaname Akamata
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinji Noda
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | | | | | - Tetsuo Toyama
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yayoi Tada
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Makoto Sugaya
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinichi Sato
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takafumi Kadono
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
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Asano Y. [A Uuifying hypothesis for the pathogenesis of systemic sclerosis based on the deficiency of transcription factor Fli1 - the development of a new animal model of systemic sclerosis -]. ACTA ACUST UNITED AC 2015; 37:475-87. [PMID: 25748132 DOI: 10.2177/jsci.37.475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Systemic sclerosis (SSc) is a multisystem connective tissue disease featured by immune abnormalities, vasculopathy and resultant fibrosis of the skin and various internal organs. Although the pathogenesis of SSc remains incompletely elucidated, it is currently accepted that this disease is caused by the complex interplay between hereditary and environmental factors. The deficiency of transcription factor Fli1, which is epigenetically suppressed in SSc dermal fibroblasts, potentially causes SSc-like phenotypical alteration in various cell types such as fibroblasts, endothelial cells, and macrophages, suggesting that Fli1 is a predisposing factor of SSc. KLF5 is another transcription factor which is suppressed in SSc dermal fibroblasts through an epigenetic mechanism. Importantly, double heterozygous mice for Fli1 and KLF5 develop three cardinal features of SSc, including immune abnormalities, vasculopathy and fibrosis. Therefore, these two transcription factors are likely to be critical predisposing factors regulating the development of SSc. Given that potential disease modifying drugs, bosentan and imatinib, reverse the expression and transcriptional activity of Fli1, the studies on the pathological process of double heterozygous mice and the impact of these transcription factors on various cell types may provide a new clue to further understand the pathogenesis of SSc leading to the development of new therapies.
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Affiliation(s)
- Yoshihide Asano
- Department of Dermatology, University of Tokyo Graduate School of Medicine
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Altorok N, Kahaleh B. Epigenetics and systemic sclerosis. Semin Immunopathol 2015; 37:453-62. [DOI: 10.1007/s00281-015-0504-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/16/2015] [Indexed: 12/29/2022]
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Akamata K, Asano Y, Yamashita T, Noda S, Taniguchi T, Takahashi T, Ichimura Y, Toyama T, Trojanowska M, Sato S. Endothelin receptor blockade ameliorates vascular fragility in endothelial cell-specific Fli-1-knockout mice by increasing Fli-1 DNA binding ability. Arthritis Rheumatol 2015; 67:1335-44. [PMID: 25707716 DOI: 10.1002/art.39062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 02/03/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell-specific Fli-1-knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy. METHODS Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate-dextran and Evans blue dye, respectively. RESULTS In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr(312) through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels. CONCLUSION The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy.
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Affiliation(s)
- Kaname Akamata
- University of Tokyo Graduate School of Medicine, Tokyo, Japan
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25
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Rossi FW, Napolitano F, Pesapane A, Mascolo M, Staibano S, Matucci-Cerinic M, Guiducci S, Ragno P, di Spigna G, Postiglione L, Marone G, Montuori N, de Paulis A. Upregulation of the N-Formyl Peptide Receptors in Scleroderma Fibroblasts Fosters the Switch to Myofibroblasts. THE JOURNAL OF IMMUNOLOGY 2015; 194:5161-73. [DOI: 10.4049/jimmunol.1402819] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 03/30/2015] [Indexed: 01/11/2023]
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Taniguchi T, Asano Y, Akamata K, Noda S, Takahashi T, Ichimura Y, Toyama T, Trojanowska M, Sato S. Fibrosis, vascular activation, and immune abnormalities resembling systemic sclerosis in bleomycin-treated Fli-1-haploinsufficient mice. Arthritis Rheumatol 2015; 67:517-26. [PMID: 25385187 DOI: 10.1002/art.38948] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 11/04/2014] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Fli-1, a potential predisposing factor for systemic sclerosis (SSc), is constitutively down-regulated in the lesional skin of patients with SSc by an epigenetic mechanism. To investigate the impact of Fli-1 deficiency on the induction of an SSc phenotype in various cell types, we generated bleomycin-induced skin fibrosis in Fli-1(+/-) mice and investigated the molecular mechanisms underlying its phenotypic alterations. METHODS Messenger RNA (mRNA) levels and protein expression of target molecules were examined by quantitative reverse transcription-polymerase chain reaction and immunostaining. Transforming growth factor β (TGFβ) bioassay was used to evaluate the activation of latent TGFβ. The binding of Fli-1 to the target gene promoters was assessed with chromatin immunoprecipitation. RESULTS Bleomycin induced more severe dermal fibrosis in Fli-1(+/-) mice than in wild-type mice. Fli-1 haploinsufficiency activated dermal fibroblasts via the up-regulation of αvβ3 and αvβ5 integrins and activation of latent TGFβ. Dermal fibrosis in Fli-1(+/-) mice was also attributable to endothelial-to-mesenchymal transition, which is directly induced by Fli-1 deficiency and amplified by bleomycin. Th2/Th17-skewed inflammation and increased infiltration of mast cells and macrophages were seen, partly due to the altered expression of cell adhesion molecules in endothelial cells as well as the induction of the skin chemokines. Fli-1(+/-) mouse macrophages preferentially differentiated into an M2 phenotype upon stimulation with interleukin-4 (IL-4) or IL-13. CONCLUSION Our findings provide strong evidence for the fundamental role of Fli-1 deficiency in inducing SSc-like phenotypic alterations in dermal fibroblasts, endothelial cells, and macrophages in a manner consistent with human disease.
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Akamata K, Asano Y, Taniguchi T, Yamashita T, Saigusa R, Nakamura K, Noda S, Aozasa N, Toyama T, Takahashi T, Ichimura Y, Sumida H, Tada Y, Sugaya M, Kadono T, Sato S. Increased expression of chemerin in endothelial cells due to Fli1 deficiency may contribute to the development of digital ulcers in systemic sclerosis. Rheumatology (Oxford) 2014; 54:1308-16. [PMID: 25539827 DOI: 10.1093/rheumatology/keu479] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES Chemerin is a member of adipocytokines with a chemoattractant effect on plasmacytoid dendritic cells and macrophages and pro-angiogenic properties. We investigated the potential role of chemerin in the development of SSc. METHODS Chemerin expression was evaluated by immunostaining and/or real-time quantitative RT-PCR in human and murine skin. The mechanisms regulating chemerin expression in dermal fibroblasts and endothelial cells were examined using the gene silencing technique and chromatin immunoprecipitation. Serum chemerin levels were determined by ELISA in 64 SSc patients and 19 healthy subjects. RESULTS In SSc lesional skin, chemerin was up-regulated in small blood vessels, while it was down-regulated in fibroblasts surrounded with thickened collagen bundles. The decreased expression of chemerin was significantly reversed by TGF-β1 antisense oligonucleotide in cultured SSc dermal fibroblasts and chemerin expression was markedly decreased in dermal fibroblasts of bleomycin-treated mice. Gene silencing of transcription factor Fli1, which binds to the chemerin promoter, induced chemerin expression in human dermal microvascular endothelial cells and Fli1(+/-) mice exhibited elevated chemerin expression in dermal blood vessels. Serum chemerin levels inversely correlated with estimated glomerular filtration rate in SSc patients with renal dysfunction. In SSc patients with normal renal function, patients with digital ulcers had higher serum chemerin levels than those without. CONCLUSION Chemerin is down-regulated in SSc dermal fibroblasts by autocrine TGF-β, while it is up-regulated in SSc dermal blood vessels through endothelial Fli1 deficiency. Increased chemerin expression in dermal blood vessels may be associated with the development of digital ulcers in SSc.
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Affiliation(s)
- Kaname Akamata
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yoshihide Asano
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takashi Taniguchi
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takashi Yamashita
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Ryosuke Saigusa
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Kouki Nakamura
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinji Noda
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Naohiko Aozasa
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Tetsuo Toyama
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takehiro Takahashi
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yohei Ichimura
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Hayakazu Sumida
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yayoi Tada
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Makoto Sugaya
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takafumi Kadono
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinichi Sato
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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Altorok N, Tsou PS, Coit P, Khanna D, Sawalha AH. Genome-wide DNA methylation analysis in dermal fibroblasts from patients with diffuse and limited systemic sclerosis reveals common and subset-specific DNA methylation aberrancies. Ann Rheum Dis 2014; 74:1612-20. [PMID: 24812288 DOI: 10.1136/annrheumdis-2014-205303] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/13/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND The aetiology of systemic sclerosis (SSc) is not clear, but there is an emerging evidence of gene-specific epigenetic dysregulation in the pathogenesis of SSc. METHODS We performed a genome-wide DNA methylation study in dermal fibroblasts in six diffuse cutaneous SSc (dSSc) patients, six limited cutaneous SSc (lSSc) patients compared with 12 age-matched, sex-matched and ethnicity-matched healthy controls. Cytosine methylation was quantified in more than 485 000 methylation sites across the genome. Differentially methylated CpG sites between patients and controls with a fold difference ≥1.2 were identified. Quantitative real-time RT-PCR was performed to assess correlation between DNA methylation changes and gene expression levels. RESULTS We identified 2710 and 1021 differentially methylated CpG sites in dSSc and lSSc, respectively. Of the differentially methylated sites, 61% in dSSc and 90% in lSSc were hypomethylated. There were only 203 CpG sites differentially methylated in both dSSc and lSSc, representing 118 hypomethylated and 6 hypermethylated genes. Common hypomethylated genes include ITGA9, encoding an α integrin. Other relevant genes such as ADAM12, COL23A1, COL4A2 and MYO1E, and transcription factors genes RUNX1, RUNX2 and RUNX3 were also hypomethylated in both dSSc and lSSc. Pathway analysis of differentially methylated genes in both dSSc and lSSc revealed enrichment of genes involved in extracellular matrix-receptor interaction and focal adhesion. We demonstrate significant correlation between DNA methylation status and gene expression in the majority of genes evaluated. CONCLUSIONS Our data highlight common and subset-specific aberrancies in dSSc and lSSc fibroblasts at the epigenomic levels and identify novel candidate genes in SSc.
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Affiliation(s)
- Nezam Altorok
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Division of Rheumatology, Department of Internal Medicine, University of Toledo Medical Center, Toledo, Ohio, USA
| | - Pei-Suen Tsou
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA University of Michigan Scleroderma Program, Ann Arbor, Michigan, USA
| | - Patrick Coit
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Dinesh Khanna
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA University of Michigan Scleroderma Program, Ann Arbor, Michigan, USA
| | - Amr H Sawalha
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA
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Akamata K, Asano Y, Aozasa N, Noda S, Taniguchi T, Takahashi T, Ichimura Y, Toyama T, Sato S. Bosentan reverses the pro-fibrotic phenotype of systemic sclerosis dermal fibroblasts via increasing DNA binding ability of transcription factor Fli1. Arthritis Res Ther 2014; 16:R86. [PMID: 24708674 PMCID: PMC4060196 DOI: 10.1186/ar4529] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 03/21/2014] [Indexed: 02/06/2023] Open
Abstract
Introduction Although the pathogenesis of systemic sclerosis (SSc) still remains unknown, recent studies have demonstrated that endothelins are deeply involved in the developmental process of fibrosis and vasculopathy associated with SSc, and a dual endothelin receptor antagonist, bosentan, has a potential to serve as a disease modifying drug for this disorder. Importantly, endothelin-1 (ET-1) exerts a pro-fibrotic effect on normal dermal fibroblasts and bosentan reverses the pro-fibrotic phenotype of SSc dermal fibroblasts. The purpose of this study was to clarify the details of molecular mechanisms underlying the effects of ET-1 and bosentan on dermal fibroblasts, which have not been well studied. Methods The mRNA levels of target genes and the expression and phosphorylation levels of target proteins were determined by reverse transcription real-time PCR and immunoblotting, respectively. Promoter assays were performed using a sequential deletion of human α2 (I) collagen (COL1A2) promoter. DNA affinity precipitation and chromatin immunoprecipitation were employed to evaluate the DNA binding ability of Fli1. Fli1 protein levels in murine skin were evaluated by immunostaining. Results In normal fibroblasts, ET-1 activated c-Abl and protein kinase C (PKC)-δ and induced Fli1 phosphorylation at threonine 312, leading to the decreased DNA binding of Fli1, a potent repressor of the COL1A2 gene, and the increase in type I collagen expression. On the other hand, bosentan reduced the expression of c-Abl and PKC-δ, the nuclear localization of PKC-δ, and Fli1 phosphorylation, resulting in the increased DNA binding of Fli1 and the suppression of type I collagen expression in SSc fibroblasts. In bleomycin-treated mice, bosentan prevented dermal fibrosis and increased Fli1 expression in lesional dermal fibroblasts. Conclusions ET-1 exerts a potent pro-fibrotic effect on normal fibroblasts by activating “c-Abl - PKC-δ - Fli1” pathway. Bosentan reverses the pro-fibrotic phenotype of SSc fibroblasts and prevents the development of dermal fibrosis in bleomycin-treated mice by blocking this signaling pathway. Although the efficacy of bosentan for dermal and pulmonary fibrosis is limited in SSc, the present observation definitely provides us with a useful clue to further explore the potential of the upcoming new dual endothelin receptor antagonists as disease modifying drugs for SSc.
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Tamaki Z, Asano Y, Kubo M, Ihn H, Tada Y, Sugaya M, Kadono T, Sato S. Effects of the immunosuppressant rapamycin on the expression of human α2(I) collagen and matrix metalloproteinase 1 genes in scleroderma dermal fibroblasts. J Dermatol Sci 2014; 74:251-9. [PMID: 24630239 DOI: 10.1016/j.jdermsci.2014.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 11/28/2013] [Accepted: 02/03/2014] [Indexed: 01/10/2023]
Abstract
BACKGROUND Rapamycin has been shown to exert an anti-fibrotic effect on skin fibrosis in a certain subset of patients with systemic sclerosis (SSc) and in bleomycin-treated animal models. OBJECTIVES To investigate the mechanism responsible for the anti-fibrotic effect of rapamycin especially by focusing on human α2(I) collagen (COL1A2) and matrix metalloproteinase 1 (MMP1) genes in normal and systemic sclerosis (SSc) dermal fibroblasts. METHODS The expression levels of type I procollagen and MMP1 proteins were analyzed by immunoblotting and the mRNA levels of COL1A2 and MMP1 genes were evaluated by quantitative real-time RT-PCR. The activities of COL1A2 and MMP1 promoters were determined by reporter analysis. RESULTS Rapamycin significantly decreased the levels of type I procollagen protein and COL1A2 mRNA, while significantly increasing the levels of MMP1 protein and mRNA in normal dermal fibroblasts. Similar effects of rapamycin were also observed in SSc dermal fibroblasts. Importantly, the inhibitory and stimulatory effects of rapamycin on the mRNA levels of COL1A2 and MMP1 genes, respectively, were significantly greater in SSc dermal fibroblasts than in normal dermal fibroblasts. In SSc dermal fibroblasts, rapamycin affected the expression of COL1A2 gene at the post-transcriptional level. In contrast, rapamycin altered the expression of MMP1 gene at the transcriptional level through the JNK/c-Jun signaling pathway in those cells. CONCLUSION Rapamycin has a potential to directly regulate the deposition of type I collagen in extracellular matrix through inhibiting type I collagen synthesis and promoting its degradation by MMP1, suggesting that this drug is useful for the treatment of SSc.
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Affiliation(s)
- Zenshiro Tamaki
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Yoshihide Asano
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Masahide Kubo
- Department of Dermatology, Tokyo Kousei-Nenkin Hospital, Tokyo, Japan
| | - Hironobu Ihn
- Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yayoi Tada
- Department of Dermatology, Teikyo University School of Medicine, Tokyo, Japan
| | - Makoto Sugaya
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Takafumi Kadono
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Shinichi Sato
- Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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Volkert G, Jahn A, Dinkel C, Fahlbusch F, Zürn C, Hilgers KF, Rascher W, Hartner A, Marek I. Contribution of the α8 Integrin Chain to the Expression of Extracellular Matrix Components. ACTA ACUST UNITED AC 2014; 21:89-98. [DOI: 10.3109/15419061.2013.876012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Lee P, Bax DV, Bilek MMM, Weiss AS. A novel cell adhesion region in tropoelastin mediates attachment to integrin αVβ5. J Biol Chem 2013; 289:1467-77. [PMID: 24293364 DOI: 10.1074/jbc.m113.518381] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tropoelastin protein monomers assemble to form elastin. Cellular integrin αVβ3 binds RKRK at the C-terminal tail of tropoelastin. We probed cell interactions with tropoelastin by deleting the RKRK sequence to identify other cell-binding interactions within tropoelastin. We found a novel human dermal fibroblast attachment and spreading site on tropoelastin that is located centrally in the molecule. Inhibition studies demonstrated that this cell adhesion was not mediated by either elastin-binding protein or glycosaminoglycans. Cell interactions were divalent cation-dependent, indicating integrin dependence. Function-blocking monoclonal antibodies revealed that αV integrin(s) and integrin αVβ5 specifically were critical for cell adhesion to this part of tropoelastin. These data reveal a common αV integrin-binding theme for tropoelastin: αVβ3 at the C terminus and αVβ5 at the central region of tropoelastin. Each αV region contributes to fibroblast attachment and spreading, but they differ in their effects on cytoskeletal assembly.
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Affiliation(s)
- Pearl Lee
- From the School of Molecular Bioscience
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Henderson NC, Sheppard D. Integrin-mediated regulation of TGFβ in fibrosis. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1832:891-6. [PMID: 23046811 PMCID: PMC3573259 DOI: 10.1016/j.bbadis.2012.10.005] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/01/2012] [Accepted: 10/03/2012] [Indexed: 12/26/2022]
Abstract
Fibrosis is a major cause of morbidity and mortality worldwide. Currently, therapeutic options for tissue fibrosis are severely limited, and organ transplantation is the only effective treatment for end-stage fibrotic disease. However, demand for donor organs greatly outstrips supply, and so effective anti-fibrotic treatments are urgently required. In recent years, the integrin family of cell adhesion receptors has gained prominence as key regulators of chronic inflammation and fibrosis. Fibrosis models in multiple organs have demonstrated that integrins have profound effects on the fibrotic process. There is now abundant in vivo data demonstrating critical regulatory roles for integrins expressed on different cell types during tissue fibrogenesis. In this review, we will examine the ways in which integrins regulate these processes and discuss how the manipulation of integrins using function blocking antibodies and small molecule inhibitors may have clinical utility in the treatment of patients with a broad range of fibrotic diseases. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Affiliation(s)
- Neil C Henderson
- MRC Centre for Inflammation Research, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Dean Sheppard
- Lung Biology Center, Department of Medicine, University of California, San Francisco, California, USA
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Wang J, Wang L, Song G, Han B. The mechanism through which octreotide inhibits hepatic stellate cell activity. Mol Med Rep 2013; 7:1559-64. [PMID: 23525276 DOI: 10.3892/mmr.2013.1385] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 02/13/2013] [Indexed: 12/13/2022] Open
Abstract
Hepatic stellate cells (HSCs) are important in the development of liver fibrosis and in the pathogenesis of portal hypertension. Octreotide, an analogue of somatostatin, has been demonstrated to effectively treat fibrosis and portal hypertension; however, its relative mechanism in HSCs remains unknown. LX‑2, the immortalized HSC line, was used to study the mechanism whereby octreotide functions at different concentrations. Real‑time polymerase chain reaction (PCR) and western blot analysis were used to analyze the expression of fibrosis markers and transcription factors following treatment with octreotide. Soluble secreted endothelin‑1 (ET‑1), collagen I and vascular endothelial growth factor (VEGF) were assessed in the supernatants of cultured cells by enzyme-linked immunosorbent assay (ELISA). In the present study, it was shown that octreotide was able to inhibit the proliferative ability of the LX‑2 cells and decrease the expression of transforming growth factor β (TGF‑β), α‑smooth muscle actin (α‑SMA) and smad‑4a. The transcription factors, including c‑Jun and sp‑1, were downregulated in a dose‑dependent manner following treatment with octreotide. The levels of ET‑1 and collagen I in the supernatant decreased significantly in contrast with the normal levels, whereas the levels of VEGF in the LX‑2 cells and the supernatant increased at a high octreotide concentration (10‑5 nM). Octreotide may exert its effects on ET‑1 or other targeting genes in HSCs through the downregulation of c‑Jun and specificity protein 1 (sp‑1), and the increased levels of VEGF may be the reason for the side effects observed at high concentrations of octreotide.
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Affiliation(s)
- Jingjing Wang
- Clinical Test Department of Shandong Qianfoshan Hospital, and Department of Pathology,Shandong University Medical School, Jinan, Shandong 250014, PR China
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Noda S, Asano Y, Akamata K, Aozasa N, Taniguchi T, Takahashi T, Ichimura Y, Toyama T, Sumida H, Yanaba K, Tada Y, Sugaya M, Kadono T, Sato S. Constitutive activation of c-Abl/protein kinase C-δ/Fli1 pathway in dermal fibroblasts derived from patients with localized scleroderma. Br J Dermatol 2012; 167:1098-105. [PMID: 22591006 DOI: 10.1111/j.1365-2133.2012.11055.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND A noncanonical pathway of transforming growth factor-β signalling, the c-Abl/protein kinase C-δ (PKC-δ)/Friend leukemia virus integration 1 (Fli1) axis, is a powerful regulator of collagen synthesis in dermal fibroblasts. OBJECTIVES To investigate the significance of the c-Abl/PKC-δ/Fli1 pathway for the establishment of the profibrotic phenotype in lesional dermal fibroblasts from patients with localized scleroderma (LSc). METHODS The activation status of the c-Abl/PKC-δ/Fli1 pathway was evaluated by immunoblotting and chromatin immunoprecipitation using cultured dermal fibroblasts from patients with LSc and closely matched healthy controls and by immunostaining on skin sections. The effects of a platelet-derived growth factor receptor inhibitor AG1296 and gene silencing of c-Abl on the expression levels of type I collagen were evaluated by immunoblotting. RESULTS The phosphorylation levels of Fli1 at threonine 312 were increased, while the total Fli1 levels and the binding of Fli1 to the COL1A2 promoter were decreased, in cultured LSc fibroblasts compared with cultured normal fibroblasts. Furthermore, in cultured LSc fibroblasts, the expression levels of c-Abl were elevated compared with cultured normal fibroblasts and PKC-δ was preferentially localized in the nucleus. These findings were also confirmed in vivo by immunohistochemistry using skin sections. Moreover, gene silencing of c-Abl, but not AG1296, significantly suppressed the expression of type I collagen in cultured LSc fibroblasts. CONCLUSIONS Constitutive activation of the c-Abl/PKC-δ/Fli1 pathway at least partially contributes to the establishment of the profibrotic phenotype in LSc dermal fibroblasts, which provides a novel molecular basis to explain the efficacy of imatinib against skin sclerosis in a certain subset of LSc.
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Affiliation(s)
- S Noda
- Department of Dermatology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Todd NW, Luzina IG, Atamas SP. Molecular and cellular mechanisms of pulmonary fibrosis. FIBROGENESIS & TISSUE REPAIR 2012; 5:11. [PMID: 22824096 PMCID: PMC3443459 DOI: 10.1186/1755-1536-5-11] [Citation(s) in RCA: 289] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/28/2012] [Indexed: 12/22/2022]
Abstract
Pulmonary fibrosis is a chronic lung disease characterized by excessive accumulation of extracellular matrix (ECM) and remodeling of the lung architecture. Idiopathic pulmonary fibrosis is considered the most common and severe form of the disease, with a median survival of approximately three years and no proven effective therapy. Despite the fact that effective treatments are absent and the precise mechanisms that drive fibrosis in most patients remain incompletely understood, an extensive body of scientific literature regarding pulmonary fibrosis has accumulated over the past 35 years. In this review, we discuss three broad areas which have been explored that may be responsible for the combination of altered lung fibroblasts, loss of alveolar epithelial cells, and excessive accumulation of ECM: inflammation and immune mechanisms, oxidative stress and oxidative signaling, and procoagulant mechanisms. We discuss each of these processes separately to facilitate clarity, but certainly significant interplay will occur amongst these pathways in patients with this disease.
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Affiliation(s)
- Nevins W Todd
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
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Bhattacharyya S, Wei J, Varga J. Understanding fibrosis in systemic sclerosis: shifting paradigms, emerging opportunities. Nat Rev Rheumatol 2011; 8:42-54. [PMID: 22025123 PMCID: PMC3954787 DOI: 10.1038/nrrheum.2011.149] [Citation(s) in RCA: 258] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fibrosis in multiple organs is a prominent pathological finding and distinguishing hallmark of systemic sclerosis (SSc). Findings during the past 5 years have contributed to a more complete understanding of the complex cellular and molecular underpinning of fibrosis in SSc. Fibroblasts, the principal effector cells, are activated in the profibrotic cellular milieu by cytokines and growth factors, developmental pathways, endothelin 1 and thrombin. Innate immune signaling via Toll-like receptors, matrix-generated biomechanical stress signaling via integrins, hypoxia and oxidative stress seem to be implicated in perpetuating the process. Beyond chronic fibroblast activation, fibrosis represents a failure to terminate tissue repair, coupled with an expanded population of mesenchymal cells originating from bone marrow and transdifferentiation of epithelial cells, endothelial cells and pericytes. In addition, studies have identified intrinsic alterations in SSc fibroblasts resulting from epigenetic changes, as well as altered microRNA expression that might underlie the cell-autonomous, persistent activation phenotype of these cells. Precise characterization of the deregulated extracellular and intracellular signaling pathways, mediators and cellular differentiation programs that contribute to fibrosis in SSc will facilitate the development of selective, targeted therapeutic strategies. Effective antifibrotic therapy will ultimately involve novel compounds and repurposing of drugs that are already approved for other indications.
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Affiliation(s)
- Swati Bhattacharyya
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, McGaw M300, 240 East Huron Street, Chicago, IL 60611, USA
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Castelino FV, Seiders J, Bain G, Brooks SF, King CD, Swaney JS, Lorrain DS, Chun J, Luster AD, Tager AM. Amelioration of dermal fibrosis by genetic deletion or pharmacologic antagonism of lysophosphatidic acid receptor 1 in a mouse model of scleroderma. ACTA ACUST UNITED AC 2011; 63:1405-15. [PMID: 21305523 DOI: 10.1002/art.30262] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Scleroderma (systemic sclerosis [SSc]), is characterized by progressive multiorgan fibrosis. We recently implicated lysophosphatidic acid (LPA) in the pathogenesis of pulmonary fibrosis. The purpose of the present study was to investigate the roles of LPA and two of its receptors, LPA₁ and LPA₂, in dermal fibrosis in a mouse model of SSc. METHODS Wild type (WT), and LPA₁-knockout (KO) and LPA₂-KO mice were injected subcutaneously with bleomycin or phosphate buffered saline (PBS) once daily for 28 days. Dermal thickness, collagen content, and numbers of cells positive for α-smooth muscle actin (α-SMA) or phospho-Smad2 were determined in bleomycin-injected and PBS-injected skin. In separate experiments, a novel selective LPA₁ antagonist AM095 or vehicle alone was administered by oral gavage to C57BL/6 mice that were challenged with 28 daily injections of bleomycin or PBS. AM095 or vehicle treatments were initiated concurrently with, or 7 or 14 days after, the initiation of bleomycin and PBS injections and continued to the end of the experiments. Dermal thickness and collagen content were determined in injected skin. RESULTS The LPA₁ -KO mice were markedly resistant to bleomycin-induced increases in dermal thickness and collagen content, whereas the LPA₂-KO mice were as susceptible as the WT mice. Bleomycin-induced increases in dermal α-SMA+ and phospho-Smad2+ cells were abrogated in LPA₁-KO mice. Pharmacologic antagonism of LPA₁ with AM095 significantly attenuated bleomycin-induced dermal fibrosis when administered according to either a preventive regimen or two therapeutic regimens. CONCLUSION These results suggest that LPA/LPA₁ pathway inhibition has the potential to be an effective new therapeutic strategy for SSc, and that LPA₁ is an attractive pharmacologic target in dermal fibrosis.
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Affiliation(s)
- Flavia V Castelino
- Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Eldred JA, Dawes LJ, Wormstone IM. The lens as a model for fibrotic disease. Philos Trans R Soc Lond B Biol Sci 2011; 366:1301-19. [PMID: 21402588 DOI: 10.1098/rstb.2010.0341] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fibrosis affects multiple organs and is associated with hyperproliferation, cell transdifferentiation, matrix modification and contraction. It is therefore essential to discover the key drivers of fibrotic events, which in turn will facilitate the development of appropriate therapeutic strategies. The lens is an elegant experimental model to study the processes that give rise to fibrosis. The molecular and cellular organization of the lens is well defined and consequently modifications associated with fibrosis can be clearly assessed. Moreover, the avascular and non-innervated properties of the lens allow effective in vitro studies to be employed that complement in vivo systems and relate to clinical data. Using the lens as a model for fibrosis has direct relevance to millions affected by lens disorders, but also serves as a valuable experimental tool to understand fibrosis per se.
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Affiliation(s)
- J A Eldred
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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Wei J, Bhattacharyya S, Tourtellotte WG, Varga J. Fibrosis in systemic sclerosis: emerging concepts and implications for targeted therapy. Autoimmun Rev 2011; 10:267-75. [PMID: 20863909 PMCID: PMC3998379 DOI: 10.1016/j.autrev.2010.09.015] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Systemic sclerosis (SSc) is a complex and incompletely understood disease associated with fibrosis in multiple organs. Recent findings identify transforming growth factor-ß (TGF-ß), Wnt ligands, toll-like receptor-mediated signaling, hypoxia, type I interferon, type 2 immune responses and mechanical stress as extracellular cues that modulate fibroblast function and differentiation, and as potential targets for therapy. Moreover, fibrillin-1 has a major role in storing and regulating the bioavailability of TGF-ß and other cytokines, and fibrillin-1 mutations are implicated in a congenital form of scleroderma called stiff skin syndrome. Fibrosis is due not only to the activation of tissue-resident fibroblasts and their transdifferentiation into myofibroblasts, but also the differentiation of bone marrow-derived fibrocytes, and transition of endothelial and epithelial cells, pericytes and adipocytes into activated mesenchymal cells. These responses are modulated by signaling mediators and microRNAs that amplify or inhibit TGF-ß and Wnt signaling. Gain-of-function and loss-of-function abnormalities of these mediators may account for the characteristic activated phenotype of SSc fibroblasts. The nuclear orphan receptor PPAR-γ plays a particularly important role in limiting the duration and intensity of fibroblast activation and differentiation, and impaired PPAR-γ expression or function in SSc may underlie the uncontrolled progression of fibrosis. Identifying the perturbations in signaling pathways, mediators and differentiation programs that are responsible for SSc tissue damage allows their selective targeting. This in turn opens the door for therapies utilizing novel compounds, or drug repurposing by innovative uses of already-approved drugs. In view of the heterogeneous clinical presentation and unpredictable course of SSc, as well as its complex pathogenesis, only robust clinical trials incorporating the judicious application of biomarkers will be able to clarify the clinical utility of these innovative approaches.
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Affiliation(s)
- Jun Wei
- Departments of Medicine and Pathology, Feinberg School of Medicine,
Northwestern University, Chicago, IL, United States
| | - Swati Bhattacharyya
- Departments of Medicine and Pathology, Feinberg School of Medicine,
Northwestern University, Chicago, IL, United States
| | - Warren G. Tourtellotte
- Departments of Medicine and Pathology, Feinberg School of Medicine,
Northwestern University, Chicago, IL, United States
| | - John Varga
- Departments of Medicine and Pathology, Feinberg School of Medicine,
Northwestern University, Chicago, IL, United States
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Pathogenesis of systemic sclerosis. Rheumatology (Oxford) 2011. [DOI: 10.1016/b978-0-323-06551-1.00139-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Asano Y, Bujor AM, Trojanowska M. The impact of Fli1 deficiency on the pathogenesis of systemic sclerosis. J Dermatol Sci 2010; 59:153-62. [PMID: 20663647 DOI: 10.1016/j.jdermsci.2010.06.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/03/2010] [Accepted: 06/14/2010] [Indexed: 12/29/2022]
Abstract
Systemic sclerosis (SSc) is an autoimmune inflammatory disease with unknown etiology characterized by microvascular injury and fibrosis of the skin and internal organs. A growing body of evidence suggests that deficiency of the transcription factor Fli1 (Friend leukemia integration-1) has a pivotal role in the pathogenesis of SSc. Fli1 is expressed in fibroblasts, endothelial cells, and immune cells, and has important roles in the activation, differentiation, development, and survival of these cells. Previous studies demonstrated that Fli1 is downregulated in SSc fibroblasts by an epigenetic mechanism and a series of experiments with Fli1-deficient animal models revealed that Fli1 deficiency in fibroblasts and endothelial cells reproduces the histopathologic features of fibrosis and vasculopathy in SSc, respectively. In this article, we review the impact of Fli1 deficiency on the pathogenesis of SSc and discuss a new therapeutic strategy for SSc by targeting the transcription factor Fli1.
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Affiliation(s)
- Yoshihide Asano
- Department of Dermatology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Cyclic DGR-peptidomimetic containing a bicyclic reverse turn inducer as a selective alpha(v)beta (5) integrin ligand. Amino Acids 2009; 38:329-37. [PMID: 19267182 DOI: 10.1007/s00726-009-0255-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 02/02/2009] [Indexed: 11/26/2022]
Abstract
3-Aza-6,8-dioxabicyclo[3.2.1]octane-based amino acids as reverse turn inducers have been introduced into cyclic peptidomimetics containing the RGD or DGR retro-sequence, in order to achieve a stereochemical scanning of the binding capability of the resulting molecules towards alpha(v)beta(3) and alpha(v)beta(5) integrins, resulting in retro-inverso DGR peptides as micromolar ligands. A comparative analysis between the conformational preferences of 4 and of its isomer 3, having the opposite RGD sequence, was reported with respect to the binding activity, giving insight into the factors affecting the preferential binding of 4 to the alpha(v)beta(5) integrin.
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Pannu J, Asano Y, Nakerakanti S, Smith E, Jablonska S, Blaszczyk M, ten Dijke P, Trojanowska M. Smad1 pathway is activated in systemic sclerosis fibroblasts and is targeted by imatinib mesylate. ACTA ACUST UNITED AC 2008; 58:2528-37. [DOI: 10.1002/art.23698] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Renard E, Chadjichristos C, Kypriotou M, Beauchef G, Bordat P, Dompmartin A, Widom RL, Boumediene K, Pujol JP, Galéra P. Chondroitin sulphate decreases collagen synthesis in normal and scleroderma fibroblasts through a Smad-independent TGF-beta pathway--implication of C-Krox and Sp1. J Cell Mol Med 2008; 12:2836-47. [PMID: 18298657 PMCID: PMC3828896 DOI: 10.1111/j.1582-4934.2008.00287.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Despite several investigations, the transcriptional mechanisms which regulate the expression of both type I collagen genes (COL1A1 and COL1A2) in either physiological or pathological situations, such as scleroderma, are not completely known. In this study, we determined the effects of both native ichtyan chondroïtin sulphate (CS) and its derived hydrolytic fragments (CSf) on human normal (NF) and scleroderma (SF) fibroblasts. Here, we demonstrate for the first time that CS and CSf exert an inhibitory effect on type I collagen protein synthesis and decrease the corresponding mRNA steady-state levels of COL1A1 and COL1A2 in NF and SF. These glycosaminoglycan molecules repress COL1A1 gene transcription through a -112/-61 bp sequence upstream the start site of transcription and imply hc-Krox and Sp1 transcription factors. In addition, CS and CSf induced a down-regulation of TβRI expression. As a conclusion, our findings highlight a possible new role for CS and CSf as anti-fibrotic molecules and could help in elucidating the mechanisms of action by which CS and CSf exert their inhibitory effect on type I collagen synthesis.
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Affiliation(s)
- Emmanuelle Renard
- Laboratoire de Biochimie du Tissu Conjonctif, Université de Caen/Basse-Normandie, IFR 146 ICORE, Faculté de Médecine, CHU niveau 3, Caen, France
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Lygoe KA, Wall I, Stephens P, Lewis MP. Role of vitronectin and fibronectin receptors in oral mucosal and dermal myofibroblast differentiation. Biol Cell 2008; 99:601-14. [PMID: 17516912 DOI: 10.1042/bc20070008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND INFORMATION The activation of fibroblasts into myofibroblasts is a crucial event in healing that is linked to remodelling and scar formation, therefore we determined whether regulation of myofibroblast differentiation via integrins might affect wound healing responses in populations of patient-matched HOFs (human oral fibroblasts) compared with HDFs (human dermal fibroblasts). RESULTS Both the HOF and HDF cell types underwent TGF-beta1 (transforming growth factor-beta1)-induced myofibroblastic differentiation [upregulation of the expression of alpha-sma (alpha-smooth muscle actin)], although analysis of unstimulated cells indicated that HOFs contained higher basal levels of alpha-sma than HDFs (P<0.05). Functional blocking antibodies against the integrin subunits alpha 5 (fibronectin) or alpha v (vitronectin) were used to determine whether the effects of TGF-beta1 were regulated via integrin signalling pathways. alpha-sma expression in both HOFs and HDFs was down-regulated by antibodies against both alpha 5 and alpha v. Functionally, TGF-beta1 inhibited cell migration in an in vitro wound model and increased the contraction of collagen gels. Greater contraction was evident for HOFs compared with HDFs, both with and without stimulation by TGF-beta1 (P<0.05). When TGF-beta1-stimulated cells were incubated with blocking antibodies against alpha 5 and alpha v, gel contraction was decreased to that of non-stimulated cells; however, blocking alpha v or alpha 5 could not restore cellular migration in both HOFs and HDFs. CONCLUSIONS Despite intrinsic differences in their basal state, the cellular events associated with TGF-beta1-induced myofibroblastic differentiation are common to both HOFs and HDFs, and appear to require differential integrin usage; up-regulation of alpha-sma expression and increases in collagen gel contraction are vitronectin- and fibronectin-receptor-dependent processes, whereas wound re-population is not.
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Affiliation(s)
- Kate A Lygoe
- Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Grays Inn Road, London WC1X 8LD, UK
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48
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Abstract
PURPOSE OF REVIEW Systemic sclerosis is a complex disease characterized by immune/inflammatory, vascular and fibrotic processes. To date, no treatment has proven effective in modifying the course of the disease. Recent studies have begun to yield insights into the nature and interrelationship among these processes, and their cellular and molecular components. RECENT FINDINGS Novel intracellular molecular pathways have been characterized that positively or negatively regulate fibroblast responses contributing to the process of fibrosis. These include signaling mediators that specify and amplify transforming growth factor-beta responses, or inhibit collagen stimulation and block these responses in vitro and in animal models. Various gain of function or loss of function abnormalities in these mediators have been identified in systemic sclerosis, and may account for the characteristic activated phenotype of systemic sclerosis fibroblasts. SUMMARY The identification of novel signaling pathways and mediators that are altered in systemic sclerosis and contribute to tissue damage allows their selective targeting. This in turn opens the door for novel therapeutic strategies utilizing novel compounds, or innovative ways of using already-approved drugs. In light of the complex pathogenesis of systemic sclerosis, however, only carefully designed clinical trials with appropriate biomarkers and outcome measures will be able to clarify the clinical utility of these innovative approaches.
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49
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Abstract
This article reviews current understanding of the pathophysiology of fibrosis in systemic sclerosis. It highlights recent discoveries, insights, and emerging research, and potential opportunities for the development of targeted antifibrotic therapies.
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Affiliation(s)
- John A Varga
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, McGaw 2300, 240 East Huron Street, Chicago IL 60611-2909, USA.
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50
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Gu YS, Kong J, Cheema GS, Keen CL, Wick G, Gershwin ME. The immunobiology of systemic sclerosis. Semin Arthritis Rheum 2008; 38:132-60. [PMID: 18221988 DOI: 10.1016/j.semarthrit.2007.10.010] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 08/08/2007] [Accepted: 10/07/2007] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by vascular damage, autoimmunity, and excessive collagen deposition. Despite advances in disease-specific treatment of other rheumatologic diseases, disease-targeted treatment in SSc continues to be elusive. In this review, our goal was to place the contemporary immunobiology of SSc in the perspective of clinical medicine. METHODS We performed a PubMed search for the period from 1989 to 2007, using the keyword, "systemic sclerosis," resulting in a total of 9099 publications, including 1252 reviews. Articles were then selected based on their discussion of recent advances in the elusive pathogenesis of SSc. A final total of 259 articles were chosen for the review. RESULTS The SSc hallmarks of vascular damage, immunologic activation, and collagen deposition can be traced to 4 major factors: T-cells, fibroblasts, B-cells, and cytokines/chemokines. T-cells are a major component of the infiltrate in skin and lung, exhibiting increased expression of activation markers and showing signs of antigen-driven expansion. Preliminary data indicate that induction of oral tolerance with collagen, a target of SSc T-cell responses, is associated with clinical benefits. Although this suggests that T-cells participate in the pathogenesis of SSc, their precise role and antigen specificity largely remain to be elucidated. Defective numbers and functions of certain T-cell subsets, such as natural killer and gammadelta T-cells, may be involved in the failure to maintain tolerance. Other data suggest that gammadelta T-cells may themselves be effector cells in endothelial cell cytotoxicity. There are several lines of evidence for a pathogenic role of B-cells in SSc, in particular, through the production of autoantibodies. Antibody-dependent cell-mediated cytotoxicity is a primary pathogenic event in an animal model of SSc and is likely to be involved in human SSc. Nonetheless, there is as yet no convincing evidence for the pathogenicity of SSc-specific antibodies. SSc fibroblasts exhibit a specific phenotype characterized not only by excessive collagen production but also by increased responsiveness to and production of cytokines and chemokines. This phenotype is induced by a complex network of cytokines and chemokines but appears to be maintained in the absence of exogenous stimuli via the autocrine production of some of these factors by SSc fibroblasts themselves, particularly transforming growth factor, platelet-derived growth factor, monocyte chemoattractant protein 1, and interleukin-1. CONCLUSIONS Significant variations in laboratory data among patients suggest that the pathology reflects a heterogeneous disease. Nonetheless, the possibility of achieving clinical benefits by inducing oral tolerance highlights the importance of characterizing SSc T-cell antigens. It is hoped that the identification of some of the key players in the induction and maintenance of the SSc fibroblast phenotype may yield new disease-targeted treatment regimens for patients with SSc.
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Affiliation(s)
- Y Stephanie Gu
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, California 95616, USA
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