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He W, Zhang J, Wen S, Li Y, Shen L, Zhou T, Wen Q, Fan Y. Epigenetic identification of LTBP4 as a putative tumor suppressor in breast cancer. Epigenomics 2024; 16:999-1012. [PMID: 39193795 PMCID: PMC11404579 DOI: 10.1080/17501911.2024.2388017] [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: 04/06/2024] [Accepted: 07/31/2024] [Indexed: 08/29/2024] Open
Abstract
Aim: To explore the LTBP4's expression, prognostic significance and molecular mechanism of action in breast cancer (BC).Methods: On the basis of omics datasets and experiments, we conducted a synthetical analysis of LTBP4 in BC.Results & conclusion: LTBP4 was downregulated in BC with high promoter methylation and low genetic alteration. DNA methylation was negatively associated with LTBP4 mRNA expression. Higher LTBP4 associated with better survival. LTBP4 was enrichment in extracellular matrix receptor interactions, cell adhesion molecules, cell cycle and MAPK pathway. LTBP4 expression and methylation were positively and negatively associated with tumor infiltrating immune cells, respectively. In conclusion, LTBP4 is a putative tumor suppressor in BC, which expression is regulated by DNA methylation and relates with prognosis.
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Affiliation(s)
- Wenfeng He
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, 646000, Luzhou, PR China
| | - Jingheng Zhang
- Department of Oncology, The People's Hospital of Luzhou, 646000, Luzhou, PR China
| | - Siyuan Wen
- Faculty of Clinical Medicine, Southwest Medical University, 646000, Luzhou, PR China
| | - Ying Li
- Faculty of Clinical Medicine, Southwest Medical University, 646000, Luzhou, PR China
| | - Lin Shen
- Faculty of Clinical Medicine, Southwest Medical University, 646000, Luzhou, PR China
| | - Tiejun Zhou
- Department of Pathology, The Affiliated Hospital of Southwest Medical University, 646000, Luzhou, PR China
| | - Qinglian Wen
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, 646000, Luzhou, PR China
| | - Yu Fan
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, 646000, Luzhou, PR China
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2
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Chen Z, Yu H, Chen X, Chen W, Song W, Li Z. Mutual regulation between glycosylation and transforming growth factor-β isoforms signaling pathway. Int J Biol Macromol 2023; 236:123818. [PMID: 36858092 DOI: 10.1016/j.ijbiomac.2023.123818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/18/2023] [Accepted: 02/19/2023] [Indexed: 03/02/2023]
Abstract
Transforming growth factor-beta (TGF-β) superfamily members orchestrate a wide breadth of biological processes. Through Sma and Mad (Smad)-related dependent or noncanonical pathways, TGF-β members involve in the occurrence and development of many diseases such as cancers, fibrosis, autoimmune diseases, cardiovascular diseases and brain diseases. Glycosylation is one kind of the most common posttranslational modifications on proteins or lipids. Abnormal protein glycosylation can lead to protein malfunction and biological process disorder, thereby causing serious diseases. Previously, researchers commonly make comprehensive systematic overviews on the roles of TGF-β signaling in a specific disease or biological process. In recent years, more and more evidences associate glycosylation modification with TGF-β signaling pathway, and we can no longer disengage and ignore the roles of glycosylation from TGF-β signaling to make investigation. In this review, we provide an overview of current findings involved in glycosylation within TGF-βs and theirs receptors, and the interaction effects between glycosylation and TGF-β subfamily signaling, concluding that there is an intricate mutual regulation between glycosylation and TGF-β signaling, hoping to present the glycosylation regulatory patterns that concealed in TGF-βs signaling pathways.
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Affiliation(s)
- Zhuo Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Hanjie Yu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Xiangqin Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Wentian Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Wanghua Song
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Zheng Li
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China.
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3
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Dysregulation of hexosamine biosynthetic pathway wiring metabolic signaling circuits in cancer. Biochim Biophys Acta Gen Subj 2023; 1867:130250. [PMID: 36228878 DOI: 10.1016/j.bbagen.2022.130250] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022]
Abstract
Metabolite sensing, a fundamental biological process, plays a key role in metabolic signaling circuit rewiring. Hexosamine biosynthetic pathway (HBP) is a glucose metabolic pathway essential for the synthesis of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), which senses key nutrients and integrally maintains cellular homeostasis. UDP-GlcNAc dynamically regulates protein N-glycosylation and O-linked-N-acetylglucosamine modification (O-GlcNAcylation). Dysregulated HBP flux leads to abnormal protein glycosylation, and contributes to cancer development and progression by affecting protein function and cellular signaling. Furthermore, O-GlcNAcylation regulates cellular signaling pathways, and its alteration is linked to various cancer characteristics. Additionally, recent findings have suggested a close association between HBP stimulation and cancer stemness; an elevated HBP flux promotes cancer cell conversion to cancer stem cells and enhances chemotherapy resistance via downstream signal activation. In this review, we highlight the prominent roles of HBP in metabolic signaling and summarize the recent advances in HBP and its downstream signaling, relevant to cancer.
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4
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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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5
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A Rare Case of Brachyolmia with Amelogenesis Imperfecta Caused by a New Pathogenic Splicing Variant in LTBP3. Genes (Basel) 2021; 12:genes12091406. [PMID: 34573388 PMCID: PMC8470690 DOI: 10.3390/genes12091406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 12/13/2022] Open
Abstract
In recent years, a rare form of autosomal recessive brachyolmia associated with amelogenesis imperfecta (AI) has been described as a novel nosologic entity. This disorder is characterized by skeletal dysplasia (e.g., platyspondyly, short trunk, scoliosis, broad ilia, elongated femoral necks with coxa valga) and severe enamel and dental anomalies. Pathogenic variants in the latent transforming growth factor-β binding protein 3 (LTBP3) gene have been found implicated in the pathogenesis of this disorder. So far, biallelic pathogenic LTBP3 variants have been identified in less than 10 families. We here report a young boy born from consanguineous parents with a complex phenotype including skeletal dysplasia associated with aortic stenosis, hypertrophic cardiomyopathy, hypodontia and amelogenesis imperfecta caused by a previously unreported homozygous LTBP3 splice site variant. We also compare the genotypes and phenotypes of patients reported to date. This work provides further evidence that brachyolmia with amelogenesis imperfecta is a distinct nosologic entity and that variations in LTBP3 are involved in its pathogenesis.
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6
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Zhang J, Ten Dijke P, Wuhrer M, Zhang T. Role of glycosylation in TGF-β signaling and epithelial-to-mesenchymal transition in cancer. Protein Cell 2021; 12:89-106. [PMID: 32583064 PMCID: PMC7862465 DOI: 10.1007/s13238-020-00741-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/29/2020] [Indexed: 12/14/2022] Open
Abstract
Glycosylation is a common posttranslational modification on membrane-associated and secreted proteins that is of pivotal importance for regulating cell functions. Aberrant glycosylation can lead to uncontrolled cell proliferation, cell-matrix interactions, migration and differentiation, and has been shown to be involved in cancer and other diseases. The epithelial-to-mesenchymal transition is a key step in the metastatic process by which cancer cells gain the ability to invade tissues and extravasate into the bloodstream. This cellular transformation process, which is associated by morphological change, loss of epithelial traits and gain of mesenchymal markers, is triggered by the secreted cytokine transforming growth factor-β (TGF-β). TGF-β bioactivity is carefully regulated, and its effects on cells are mediated by its receptors on the cell surface. In this review, we first provide a brief overview of major types of glycans, namely, N-glycans, O-glycans, glycosphingolipids and glycosaminoglycans that are involved in cancer progression. Thereafter, we summarize studies on how the glycosylation of TGF-β signaling components regulates TGF-β secretion, bioavailability and TGF-β receptor function. Then, we review glycosylation changes associated with TGF-β-induced epithelial-to-mesenchymal transition in cancer. Identifying and understanding the mechanisms by which glycosylation affects TGF-β signaling and downstream biological responses will facilitate the identification of glycans as biomarkers and enable novel therapeutic approaches.
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Affiliation(s)
- Jing Zhang
- Oncode Institute and Cell Chemical Biology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Peter Ten Dijke
- Oncode Institute and Cell Chemical Biology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands.
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tao Zhang
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
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7
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Barnes JW, Aarnio-Peterson M, Norris J, Haskins M, Flanagan-Steet H, Steet R. Upregulation of Sortilin, a Lysosomal Sorting Receptor, Corresponds with Reduced Bioavailability of Latent TGFβ in Mucolipidosis II Cells. Biomolecules 2020; 10:biom10050670. [PMID: 32357547 PMCID: PMC7277838 DOI: 10.3390/biom10050670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Mucolipidosis II (ML-II) is a lysosomal disease caused by defects in the carbohydrate-dependent sorting of soluble hydrolases to lysosomes. Altered growth factor signaling has been identified as a contributor to the phenotypes associated with ML-II and other lysosomal disorders but an understanding of how these signaling pathways are affected is still emerging. Here, we investigated transforming growth factor beta 1 (TGFβ1) signaling in the context of ML-II patient fibroblasts, observing decreased TGFβ1 signaling that was accompanied by impaired TGFβ1-dependent wound closure. We found increased intracellular latent TGFβ1 complexes, caused by reduced secretion and stable localization in detergent-resistant lysosomes. Sortilin, a sorting receptor for hydrolases and TGFβ-related cytokines, was upregulated in ML-II fibroblasts as well as GNPTAB-null HeLa cells, suggesting a mechanism for inappropriate lysosomal targeting of TGFβ. Co-expression of sortilin and TGFβ in HeLa cells resulted in reduced TGFβ1 secretion. Elevated sortilin levels correlated with normal levels of cathepsin D in ML-II cells, consistent with a compensatory role for this receptor in lysosomal hydrolase targeting. Collectively, these data support a model whereby sortilin upregulation in cells with lysosomal storage maintains hydrolase sorting but suppresses TGFβ1 secretion through increased lysosomal delivery. These findings highlight an unexpected link between impaired lysosomal sorting and altered growth factor bioavailability.
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Affiliation(s)
- Jarrod W Barnes
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | - Joy Norris
- Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Mark Haskins
- Emeritus Professor, Pathology and Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6051, USA
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8
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Stachowski TR, Snell ME, Snell EH. Structural insights into conformational switching in latency-associated peptide between transforming growth factor β-1 bound and unbound states. IUCRJ 2020; 7:238-252. [PMID: 32148852 PMCID: PMC7055372 DOI: 10.1107/s205225251901707x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Transforming growth factor β-1 (TGFβ-1) is a secreted signalling protein that directs many cellular processes and is an attractive target for the treatment of several diseases. The primary endogenous activity regulatory mechanism for TGFβ-1 is sequestration by its pro-peptide, latency-associated peptide (LAP), which sterically prohibits receptor binding by caging TGFβ-1. As such, recombinant LAP is promising as a protein-based therapeutic for modulating TGFβ-1 activity; however, the mechanism of binding is incompletely understood. Comparison of the crystal structure of unbound LAP (solved here to 3.5 Å resolution) with that of the bound complex shows that LAP is in a more open and extended conformation when unbound to TGFβ-1. Analysis suggests a mechanism of binding TGFβ-1 through a large-scale conformational change that includes contraction of the inter-monomer interface and caging by the 'straight-jacket' domain that may occur in partnership through a loop-to-helix transition in the core jelly-roll fold. This conformational change does not appear to include a repositioning of the integrin-binding motif as previously proposed. X-ray scattering-based modelling supports this mechanism and reveals possible orientations and ensembles in solution. Although native LAP is heavily glycosylated, solution scattering experiments show that the overall folding and flexibility of unbound LAP are not influenced by glycan modification. The combination of crystallography, solution scattering and biochemical experiments reported here provide insight into the mechanism of LAP sequestration of TGFβ-1 that is of fundamental importance for therapeutic development.
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Affiliation(s)
- Timothy R. Stachowski
- Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
- Cell Stress Biology, Roswell Park Comprehensive Cancer Center, 665 Elm Street, Buffalo, NY 14203, USA
| | - Mary E. Snell
- Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
| | - Edward H. Snell
- Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
- Materials Design and Innovation, State University of New York at Buffalo, 700 Ellicott Street, Buffalo, NY 14203, USA
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9
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Mamedov T, Musayeva I, Acsora R, Gun N, Gulec B, Mammadova G, Cicek K, Hasanova G. Engineering, and production of functionally active human Furin in N. benthamiana plant: In vivo post-translational processing of target proteins by Furin in plants. PLoS One 2019; 14:e0213438. [PMID: 30861020 PMCID: PMC6413912 DOI: 10.1371/journal.pone.0213438] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 02/21/2019] [Indexed: 11/19/2022] Open
Abstract
A plant expression platform with eukaryotic post-translational modification (PTM) machinery has many advantages compared to other protein expression systems. This promising technology is useful for the production of a variety of recombinant proteins including, therapeutic proteins, vaccine antigens, native additives, and industrial enzymes. However, plants lack some of the important PTMs, including furin processing, which limits this system for the production of certain mammalian complex proteins of therapeutic value. Furin is a ubiquitous proprotein convertase that is involved in the processing (activation) of a wide variety of precursor proteins, including blood coagulation factors, cell surface receptors, hormones and growth factors, viral envelope glycoproteins, etc. and plays a critical regulatory role in a wide variety of cellular events. In this study, we engineered the human furin gene for expression in plants and demonstrated the production of a functional active recombinant truncated human furin in N. benthamiana plant. We demonstrate that plant produced human furin is highly active both in vivo and in vitro and specifically cleaved the tested target proteins, Factor IX (FIX) and Protective Antigen (PA83). We also demonstrate that both, enzymatic deglycosylation and proteolytic processing of target proteins can be achieved in vivo by co-expression of deglycosylating and furin cleavage enzymes in a single cell to produce deglycosylated and furin processed target proteins. It is highly expected that this strategy will have many potential applications in pharmaceutical industry and can be used to produce safe and affordable therapeutic proteins, antibodies, and vaccines using a plant expression system.
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Affiliation(s)
- Tarlan Mamedov
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
- Azerbaijan National Academy of Science, Department of Biology and Medical Science, Baku, Azerbaijan
| | - Ilaha Musayeva
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Rabia Acsora
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Nilufer Gun
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Burcu Gulec
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Gulshan Mammadova
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Kader Cicek
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Gulnara Hasanova
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
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10
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Mamedov T, Cicek K, Gulec B, Ungor R, Hasanova G. In vivo production of non-glycosylated recombinant proteins in Nicotiana benthamiana plants by co-expression with Endo-β-N-acetylglucosaminidase H (Endo H) of Streptomyces plicatus. PLoS One 2017; 12:e0183589. [PMID: 28827815 PMCID: PMC5565186 DOI: 10.1371/journal.pone.0183589] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 08/07/2017] [Indexed: 11/29/2022] Open
Abstract
A plant transient expression system, with eukaryotic post-translational modification machinery, offers superior efficiency, scalability, safety, and lower cost over other expression systems. However, due to aberrant N-glycosylation, this expression system may not be a suitable expression platform for proteins not carrying N-linked glycans in the native hosts. Therefore, it is crucial to develop a strategy to produce target proteins in a non-glycosylated form while preserving their native sequence, conformation and biological activity. Previously, we developed a strategy for enzymatic deglycosylation of proteins in planta by co-expressing bacterial peptide-N-glycosidase F (PNGase F). Though PNGase F removes oligosaccharides from glycosylated proteins, in so doing it causes an amino acid change due to the deamidation of asparagine to aspartate in the N-X-S/T site. Endo-β-N-acetylglucosaminidase (EC3.2.1.96, Endo H), another deglycosylating enzyme, catalyzes cleavage between two N-Acetyl-D-glucosamine residues of the chitobiose core of N-linked glycans, leaving a single N-Acetyl-D-glucosamine residue without the concomitant deamidation of asparagine. In this study, a method for in vivo deglycosylation of recombinant proteins in plants by transient co-expression with bacterial Endo H is described for the first time. Endo H was fully active in vivo. and successfully cleaved N-linked glycans from glycoproteins were tested. In addition, unlike the glycosylated form, in vivo Endo H deglycosylated Pfs48/45 was recognized by conformational specific Pfs48/45 monoclonal antibody, in a manner similar to its PNGase F deglycosylated counterpart. Furthermore, the deglycosylated PA83 molecule produced by Endo H showed better stability than a PNGase F deglycosylated counterpart. Thus, an Endo H in vivo deglycosylation approach provides another opportunity to develop vaccine antigens, therapeutic proteins, antibodies, and industrial enzymes.
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Affiliation(s)
- Tarlan Mamedov
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Kader Cicek
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Burcu Gulec
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Rifat Ungor
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
| | - Gulnara Hasanova
- Akdeniz University, Department of Agricultural Biotechnology, Antalya, Turkey
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11
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Wilbers RHP, Westerhof LB, van Raaij DR, van Adrichem M, Prakasa AD, Lozano-Torres JL, Bakker J, Smant G, Schots A. Co-expression of the protease furin in Nicotiana benthamiana leads to efficient processing of latent transforming growth factor-β1 into a biologically active protein. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:1695-704. [PMID: 26834022 PMCID: PMC5067602 DOI: 10.1111/pbi.12530] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/16/2015] [Accepted: 10/19/2015] [Indexed: 05/21/2023]
Abstract
Transforming growth factor beta (TGF-β) is a signalling molecule that plays a key role in developmental and immunological processes in mammals. Three TGF-β isoforms exist in humans, and each isoform has unique therapeutic potential. Plants offer a platform for the production of recombinant proteins, which is cheap and easy to scale up and has a low risk of contamination with human pathogens. TGF-β3 has been produced in plants before using a chloroplast expression system. However, this strategy requires chemical refolding to obtain a biologically active protein. In this study, we investigated the possibility to transiently express active human TGF-β1 in Nicotiana benthamiana plants. We successfully expressed mature TGF-β1 in the absence of the latency-associated peptide (LAP) using different strategies, but the obtained proteins were inactive. Upon expression of LAP-TGF-β1, we were able to show that processing of the latent complex by a furin-like protease does not occur in planta. The use of a chitinase signal peptide enhanced the expression and secretion of LAP-TGF-β1, and co-expression of human furin enabled the proteolytic processing of latent TGF-β1. Engineering the plant post-translational machinery by co-expressing human furin also enhanced the accumulation of biologically active TGF-β1. This engineering step is quite remarkable, as furin requires multiple processing steps and correct localization within the secretory pathway to become active. Our data demonstrate that plants can be a suitable platform for the production of complex proteins that rely on specific proteolytic processing.
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Affiliation(s)
- Ruud H P Wilbers
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Lotte B Westerhof
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Debbie R van Raaij
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Marloes van Adrichem
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Andreas D Prakasa
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Jose L Lozano-Torres
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Jaap Bakker
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Geert Smant
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Arjen Schots
- Laboratory of Nematology, Plant Sciences Department, Wageningen University and Research Centre, Wageningen, The Netherlands
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12
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Kim WK, Yun S, Park CK, Bauer S, Kim J, Lee MG, Kim H. Sustained Mutant KIT Activation in the Golgi Complex Is Mediated by PKC-θ in Gastrointestinal Stromal Tumors. Clin Cancer Res 2016; 23:845-856. [PMID: 27440273 DOI: 10.1158/1078-0432.ccr-16-0521] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/18/2016] [Accepted: 07/11/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Tumorigenesis of gastrointestinal stromal tumors (GIST) is driven by gain-of-function mutations in the KIT gene, which result in overexpression of activated mutant KIT proteins (MT-KIT). However, the mechanism of MT-KIT overexpression is poorly understood. EXPERIMENTAL DESIGN By protein expression analysis and immunofluorescent microscopic analysis, we determine the stability and localization of MT-KIT in four GIST cell lines with different mutations and HeLa cells transfected with mutant KIT model vectors. We also used 154 human GIST tissues to analyze the relationship between the expression of PKC-θ and MT-KITs, and correlations between PKC-θ overexpression and clinicopathological parameters. RESULTS We report that four different MT-KIT proteins are intrinsically less stable than wild-type KIT due to proteasome-mediated degradation and abnormally localized to the endoplasmic reticulum (ER) or the Golgi complex. By screening a MT-KIT-stabilizing factor, we find that PKC-θ is strongly and exclusively expressed in GISTs and interacts with intracellular MT-KIT to promote its stabilization by increased retention in the Golgi complex. In addition, Western blotting analysis using 50 GIST samples shows strong correlation between PKC-θ and MT-KIT expression (correlation coefficient = 0.682, P < 0.000001). Immunohistochemical analysis using 154 GISTs further demonstrates that PKC-θ overexpression significantly correlates with several clinicopathological parameters such as high tumor grade, frequent recurrence/metastasis, and poor patient survival. CONCLUSIONS Our findings suggest that sustained MT-KIT overexpression through PKC-θ-mediated stabilization in the Golgi contributes to GIST progression and provides a rationale for anti-PKC-θ therapy in GISTs. Clin Cancer Res; 23(3); 845-56. ©2016 AACR.
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Affiliation(s)
- Won Kyu Kim
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - SeongJu Yun
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Cheol Keun Park
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sebastian Bauer
- Sarcoma Center, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, Essen, Germany and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Jiyoon Kim
- Department of Pharmacology, Pharmacogenomic Research Center for Membrane Transporters, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology, Pharmacogenomic Research Center for Membrane Transporters, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hoguen Kim
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
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Transforming growth factor Beta family: insight into the role of growth factors in regulation of fracture healing biology and potential clinical applications. Mediators Inflamm 2015; 2015:137823. [PMID: 25709154 PMCID: PMC4325469 DOI: 10.1155/2015/137823] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/09/2014] [Indexed: 01/15/2023] Open
Abstract
The transforming growth factor beta (TGF-β) family forms a group of three isoforms, TGF-β1, TGF-β2, and TGF-β3, with their structure formed by interrelated dimeric polypeptide chains. Pleiotropic and redundant functions of the TGF-β family concern control of numerous aspects and effects of cell functions, including proliferation, differentiation, and migration, in all tissues of the human body. Amongst many cytokines and growth factors, the TGF-β family is considered a group playing one of numerous key roles in control of physiological phenomena concerning maintenance of metabolic homeostasis in the bone tissue. By breaking the continuity of bone tissue, a spread-over-time and complex bone healing process is initiated, considered a recapitulation of embryonic intracartilaginous ossification. This process is a cascade of local and systemic phenomena spread over time, involving whole cell lineages and various cytokines and growth factors. Numerous in vivo and in vitro studies in various models analysing cytokines and growth factors' involvement have shown that TGF-β has a leading role in the fracture healing process. This paper sums up current knowledge on the basis of available literature concerning the role of the TGF-β family in the fracture healing process.
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Expression, Purification, and Characterization of Endo-β-N-Acetylglucosaminidase H Using Baculovirus-Mediated Silkworm Protein Expression System. Appl Biochem Biotechnol 2014; 172:3978-88. [DOI: 10.1007/s12010-014-0814-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
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15
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Constam DB. Regulation of TGFβ and related signals by precursor processing. Semin Cell Dev Biol 2014; 32:85-97. [PMID: 24508081 DOI: 10.1016/j.semcdb.2014.01.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
Abstract
Secreted cytokines of the TGFβ family are found in all multicellular organisms and implicated in regulating fundamental cell behaviors such as proliferation, differentiation, migration and survival. Signal transduction involves complexes of specific type I and II receptor kinases that induce the nuclear translocation of Smad transcription factors to regulate target genes. Ligands of the BMP and Nodal subgroups act at a distance to specify distinct cell fates in a concentration-dependent manner. These signaling gradients are shaped by multiple factors, including proteases of the proprotein convertase (PC) family that hydrolyze one or several peptide bonds between an N-terminal prodomain and the C-terminal domain that forms the mature ligand. This review summarizes information on the proteolytic processing of TGFβ and related precursors, and its spatiotemporal regulation by PCs during development and various diseases, including cancer. Available evidence suggests that the unmasking of receptor binding epitopes of TGFβ is only one (and in some cases a non-essential) function of precursor processing. Future studies should consider the impact of proteolytic maturation on protein localization, trafficking and turnover in cells and in the extracellular space.
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Affiliation(s)
- Daniel B Constam
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Bâtiment SV ISREC, Station 19, CH-1015 Lausanne, Switzerland.
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16
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Maurya VK, Jha RK, Kumar V, Joshi A, Chadchan S, Mohan JJ, Laloraya M. Transforming growth factor-beta 1 (TGF-B1) liberation from its latent complex during embryo implantation and its regulation by estradiol in mouse. Biol Reprod 2013; 89:84. [PMID: 23926286 DOI: 10.1095/biolreprod.112.106542] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Transforming growth factor-beta (TGF-B) plays an important role in embryo implantation; however, TGF-B requires liberation from its inactive latent forms (i.e., large latent TGF-B complex [LLC] and small latent TGF-B complex [SLC]) to its biologically active (i.e., monomer or dimer) forms in order to act on its receptors (TGF-BRs), which in turn activate SMAD2/3. Activation of TGF-B1 from its latent complexes in the uterus is not yet deciphered. We investigated uterine latent TGF-B1 complex and its biologically active form during implantation, decidualization, and delayed implantation. Our study, utilizing nonreducing SDS-PAGE followed by Western blotting and immunoblotting with TGF-B1, LTBP1, and latency-associated peptide, showed the presence of LLC and SLC in the uterine extracellular matrix and plasma membranous protein fraction during stages of the implantation period. A biologically active form of TGF-B1 (~17-kDa monomer) was highly elevated in the uterine plasma membranous compartment at the peri-implantation stage (implantation and nonimplantation sites). Administration of hydroxychloroquine (an inhibitor of pro-TGF-B processing) at the preimplantation stage was able to block the liberation of biologically active TGF-B1 from its latent complex at the postimplantation stage; as a consequence, the number of implantation sites was reduced at Day 5 (1000 h), as was the number of fetuses at Day 13. The inhibition of TGF-B1 showed reduced levels of phosphorylated SMAD3. Further, the delayed-implantation mouse model showed progesterone and estradiol coordination to release the active TGF-B1 form from its latent complex in the receptive endometrium. This study demonstrates the importance of liberation of biologically active TGF-B1 during the implantation period and its regulation by estradiol.
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Affiliation(s)
- Vineet Kumar Maurya
- Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow, India
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17
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Ceco E, McNally EM. Modifying muscular dystrophy through transforming growth factor-β. FEBS J 2013; 280:4198-209. [PMID: 23551962 PMCID: PMC3731412 DOI: 10.1111/febs.12266] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 03/11/2013] [Accepted: 03/20/2013] [Indexed: 12/31/2022]
Abstract
Muscular dystrophy arises from ongoing muscle degeneration and insufficient regeneration. This imbalance leads to loss of muscle, with replacement by scar or fibrotic tissue, resulting in muscle weakness and, eventually, loss of muscle function. Human muscular dystrophy is characterized by a wide range of disease severity, even when the same genetic mutation is present. This variability implies that other factors, both genetic and environmental, modify the disease outcome. There has been an ongoing effort to define the genetic and molecular bases that influence muscular dystrophy onset and progression. Modifier genes for muscle disease have been identified through both candidate gene approaches and genome-wide surveys. Multiple lines of experimental evidence have now converged on the transforming growth factor-β (TGF-β) pathway as a modifier for muscular dystrophy. TGF-β signaling is upregulated in dystrophic muscle as a result of a destabilized plasma membrane and/or an altered extracellular matrix. Given the important biological role of the TGF-β pathway, and its role beyond muscle homeostasis, we review modifier genes that alter the TGF-β pathway and approaches to modulate TGF-β activity to ameliorate muscle disease.
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Affiliation(s)
- Ermelinda Ceco
- Committee on Cell Physiology, University of Chicago, IL 60637, USA
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18
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E-selectin ligand 1 regulates bone remodeling by limiting bioactive TGF-β in the bone microenvironment. Proc Natl Acad Sci U S A 2013; 110:7336-41. [PMID: 23589896 DOI: 10.1073/pnas.1219748110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
TGF-β is abundantly produced in the skeletal system and plays a crucial role in skeletal homeostasis. E-selectin ligand-1 (ESL-1), a Golgi apparatus-localized protein, acts as a negative regulator of TGF-β bioavailability by attenuating maturation of pro-TGF-β during cartilage homeostasis. However, whether regulation of intracellular TGF-β maturation by ESL-1 is also crucial during bone homeostasis has not been well defined. Here, we show that Esl-1(-/-) mice exhibit a severe osteopenia with elevated bone resorption and decreased bone mineralization. In primary culture, Esl-1(-/-) osteoclast progenitors show no difference in osteoclastogenesis. However, Esl-1(-/-) osteoblasts show delayed differentiation and mineralization and stimulate osteoclastogenesis more potently in the osteoblast-osteoclast coculture, suggesting that ESL-1 primarily acts in osteoblasts to regulate bone homeostasis. In addition, Esl-1(-/-) calvaria exhibit an elevated mature TGF-β/pro-TGF-β ratio, with increased expression of TGF-β downstream targets (plasminogen activator inhibitor-1, parathyroid hormone-related peptide, connective tissue growth factor, and matrix metallopeptidase 13, etc.) and a key regulator of osteoclastogenesis (receptor activator of nuclear factor κB ligand). Moreover, in vivo treatment with 1D11, a pan-TGF-β antibody, significantly improved the low bone mass of Esl-1(-/-) mice, suggesting that elevated TGF-β signaling is the major cause of osteopenia in Esl-1(-/-) mice. In summary, our study identifies ESL-1 as an important regulator of bone remodeling and demonstrates that the modulation of TGF-β maturation is pivotal in the maintenance of a homeostatic bone microenvironment and for proper osteoblast-osteoclast coupling.
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Wottawa M, Leisering P, Ahlen MV, Schnelle M, Vogel S, Malz C, Bordoli MR, Camenisch G, Hesse A, Napp J, Alves F, Kristiansen G, Farhat K, Katschinski DM. Knockdown of prolyl-4-hydroxylase domain 2 inhibits tumor growth of human breast cancer MDA-MB-231 cells by affecting TGF-β1 processing. Int J Cancer 2012; 132:2787-98. [PMID: 23225569 DOI: 10.1002/ijc.27982] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 11/21/2012] [Indexed: 12/26/2022]
Abstract
The prolyl-4-hydroxylase domain 1-3 (PHD1-3) enzymes are regulating the protein stability of the α-subunit of the hypoxia-inducible factor-1 (HIF-1), which mediates oxygen-dependent gene expression. PHD2 is the main isoform regulating HIF-1α hydroxylation and thus stability in normoxia. In human cancers, HIF-1α is overexpressed as a result of intratumoral hypoxia which in turn promotes tumor progression. The role of PHD2 for tumor progression is in contrast far from being thoroughly understood. Therefore, we established PHD2 knockdown clones of MDA-MB-231 breast cancer cells and analyzed their tumor-forming potential in a SCID mouse model. Tumor progression was significantly impaired in the PHD2 knockdown MDA-MB-231 cells, which could be partially rescued by re-establishing PHD2 expression. In a RNA profile screen, we identified the secreted phosphoprotein 1 (SPP1) as one target, which is differentially regulated as a consequence of the PHD2 knockdown. Knockdown of PHD2 drastically reduced the SPP1 expression in MDA-MB-231 cells. A correlation of SPP1 and PHD2 expression was additionally verified in 294 invasive breast cancer biopsies. In subsequent analyses, we identified that PHD2 alters the processing of transforming growth factor (TGF)-β1, which is highly involved in SPP1 expression. The altered processing capacity was associated with a dislocation of the pro-protein convertase furin. Thus, our data demonstrate that in MDA-MB-231 cells PHD2 might affect tumor-relevant TGF-β1 target gene expression by altering the TGF-β1 processing capacity.
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Affiliation(s)
- Marieke Wottawa
- Department of Cardiovascular Physiology, University Medical Center, Georg-August University of Göttingen, D-37073 Göttingen, Germany
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20
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Barnes J, Warejcka D, Simpliciano J, Twining S, Steet R. Latency-associated peptide of transforming growth factor-β1 is not subject to physiological mannose phosphorylation. J Biol Chem 2012; 287:7526-34. [PMID: 22262853 DOI: 10.1074/jbc.m111.308825] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Latent TGF-β1 was one of the first non-lysosomal glycoproteins reported to bear mannose 6-phosphate (Man-6-P) residues on its N-glycans. Prior studies have suggested that this sugar modification regulates the activation of latent TGF-β1 by allowing it to bind cell surface-localized Man-6-P receptors. Man-6-P has also been proposed as an anti-scarring therapy based on its ability to directly block the activation of latent TGF-β1. A complete understanding of the physiological relevance of latent TGF-β1 mannose phosphorylation, however, is still lacking. Here we investigate the degree of mannose phosphorylation on secreted latent TGF-β1 and examine its Man-6-P-dependent activation in primary human corneal stromal fibroblasts. Contrary to earlier reports, minimal to no Man-6-P modification was found on secreted and cell-associated latent TGF-β1 produced from multiple primary and transformed cell types. Results showed that the inability to detect Man-6-P residues was not due to masking by the latent TGF-β1-binding protein (LTBP). Moreover, the efficient processing of glycans on latent TGF-β1 to complex type structures was consistent with the lack of mannose phosphorylation during biosynthesis. We further demonstrated that the conversion of corneal stromal fibroblast to myofibroblasts, a well known TGF-β1-dependent process, was not altered by Man-6-P addition when latent forms of this growth factor were present. Collectively, these findings indicate that Man-6-P-dependent effects on latent TGF-β1 activation are not mediated by direct modification of its latency-associated peptide.
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Affiliation(s)
- Jarrod Barnes
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
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21
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Ueland T, Lekva T, Otterdal K, Dahl TB, Olarescu NC, Jørgensen AP, Fougner KJ, Brixen K, Aukrust P, Bollerslev J. Increased serum and bone matrix levels of transforming growth factor {beta}1 in patients with GH deficiency in response to GH treatment. Eur J Endocrinol 2011; 165:393-400. [PMID: 21653735 DOI: 10.1530/eje-11-0442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Patients with adult onset GH deficiency (aoGHD) have secondary osteoporosis, which is reversed by long-term GH substitution. Transforming growth factor β1 (TGFβ1 or TGFB1) is abundant in bone tissue and could mediate some effects of GH/IGFs on bone. We investigated its regulation by GH/IGF1 in vivo and in vitro. DESIGN AND METHODS The effects of GH substitution (9-12 months, placebo controlled) on circulating and cortical bone matrix contents of TGFβ1 were investigated in patients with aoGHD. The effects of GH/IGF1 on TGFβ1 secretion in osteoblasts (hFOB), adipocytes, and THP-1 macrophages as well as the effects on release from platelets were investigated in vitro. RESULTS In vivo GH substitution increased TGFβ1 protein levels in cortical bone and serum. In vitro, GH/IGF1 stimulation induced a significant increase in TGFβ1 secretion in hFOB. In contrast, no major effect of GH/IGF1 on TGFβ1 was found in adipocytes and THP-1 macrophages. Finally, a minor modifying effect on SFLLRN-stimulated platelet release of TGFβ1 was observed in the presence of IGF1. CONCLUSION GH substitution increases TGFβ1 in vivo and in vitro, and this effect could contribute to improved bone metabolism during such therapy, potentially reflecting direct effect of GH/IGF1 on bone cells.
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Affiliation(s)
- Thor Ueland
- Research Institute for Internal Medicine Department of Endocrinology Section of Clinical Immunology and Infectious Faculty of Medicine, Oslo University Hospital Rikshospitalet, University of Oslo, Oslo, Norway.
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22
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Chandramouli A, Simundza J, Pinderhughes A, Cowin P. Choreographing metastasis to the tune of LTBP. J Mammary Gland Biol Neoplasia 2011; 16:67-80. [PMID: 21494784 PMCID: PMC3747963 DOI: 10.1007/s10911-011-9215-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 03/20/2011] [Indexed: 12/20/2022] Open
Abstract
Latent Transforming Growth Factor beta (TGFβ) Binding Proteins (LTBPs) are chaperones and determinants of TGFβ isoform-specific secretion. They belong to the LTBP/Fibrillin family and form integral components of the fibronectin and microfibrillar extracellular matrix (ECM). LTBPs serve as master regulators of TGFβ bioavailability, functioning to incorporate and spatially pattern latent TGFβ at regular intervals within the ECM, and actively participate in integrin-mediated stretch activation of TGFβ in vivo. In so doing they create a highly patterned sensory system where local changes in ECM tension can be detected and transduced into focal signals. The physiological role of LTBPs in the mammary gland remains largely unstudied, however both loss and gain of LTBP expression is found in breast cancers and breast cancer cell lines. Importantly, elevated LTBP1 levels appear in two gene signatures predictive of enhanced metastatic behavior. LTBP may promote metastasis by providing the bridge between structural and signaling components of the epithelial to mesenchymal transition (EMT).
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Affiliation(s)
- Anupama Chandramouli
- Department of Dermatology, New York University School of Medicine, New York, NY, USA
| | - Julia Simundza
- Department of Cell Biology, MSB 621, New York University School of Medicine, 550 First Ave, New York, NY 10016, USA
| | - Alicia Pinderhughes
- Department of Cell Biology, MSB 621, New York University School of Medicine, 550 First Ave, New York, NY 10016, USA
| | - Pamela Cowin
- Department of Dermatology, New York University School of Medicine, New York, NY, USA
- Department of Cell Biology, MSB 621, New York University School of Medicine, 550 First Ave, New York, NY 10016, USA
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23
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Latent transforming growth factor binding protein 4 (LTBP4) is downregulated in mouse and human DCIS and mammary carcinomas. Cell Oncol (Dordr) 2011; 34:419-34. [PMID: 21468687 PMCID: PMC3219867 DOI: 10.1007/s13402-011-0023-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2011] [Indexed: 12/03/2022] Open
Abstract
Background Transforming growth factor beta (TGF-ß) is able to inhibit the proliferation of epithelial cells and is involved in the carcinogenesis of mammary tumors. Three latent transforming growth factor-ß binding proteins (LTBPs) are known to modulate TGF-ß functions. Methods The current study analyses the expression profiles of LTBP4, its isoforms LTBP1 and LTBP3, and TGF-ß1, TGF-ß2, TGF-ß3, and SMAD2, SMAD3 and SMAD4 in human and murine (WAP-TNP8) DCIS compared to invasive mammary tumors. Additionally mammary malignant (MCF7, Hs578T, MDA-MB361) and non malignant cell lines (Hs578BsT) were analysed. Microarray, q-PCR, immunoblot, immunohistochemistry and immunofluorescence were used. Results In comparison to non-malignant tissues (n = 5), LTBP4 was downregulated in all human and mouse DCIS (n = 9) and invasive mammary adenocarcinomas (n = 5) that were investigated. We also found decreased expression of bone morphogenic protein 4 (BMP4) and increased expression of its inhibitor gremlin (GREM1). Treatment of the mammary tumor cell line (Hs578T) with recombinant TGF-ß1 rescued BMP4 and GREM1 expression. Conclusion We conclude that the lack of LTBP4-mediated targeting in malignant mammary tumor tissues may lead to a possible modification of TGF-ß1 and BMP bioavailability and function. Electronic supplementary material The online version of this article (doi:10.1007/s13402-011-0023-y) contains supplementary material, which is available to authorized users.
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Öklü R, Hesketh R, Wicky S, Metcalfe JC. Localization of Latent Transforming Growth Factor-.BETA. Binding Protein-1 in Human Coronary Atherosclerotic Plaques. Circ J 2011; 75:196-200. [DOI: 10.1253/circj.cj-10-0334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rahmi Öklü
- Harvard Medical School, Massachusetts General Hospital, Vascular Imaging and Interventions
| | - Robin Hesketh
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge
| | - Stephan Wicky
- Harvard Medical School, Massachusetts General Hospital, Vascular Imaging and Interventions
| | - James C. Metcalfe
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge
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25
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Oida T, Weiner HL. Overexpression of TGF-ß 1 gene induces cell surface localized glucose-regulated protein 78-associated latency-associated peptide/TGF-ß. THE JOURNAL OF IMMUNOLOGY 2010; 185:3529-35. [PMID: 20720212 DOI: 10.4049/jimmunol.0904121] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TGF-beta plays a crucial role in immune regulation. It has been reported that pro-TGF-beta, latency-associated peptide (LAP), latent TGF-beta and/or active TGF-beta (LAP/TGF-beta) is localized on the cell surface of Foxp3(+) regulatory T cells. However, the molecular mechanism(s) of how LAP/TGF-beta is anchored on the cell membrane is unknown. In this study, we show that forced expression of human TGF-beta(1) gene by retrovirus transduction into P3U1 mouse myeloma cells, and other cell types including murine CD4(+)CD25(-) T cells, makes these cells surface LAP/TGF-beta-positive. The surface LAP/TGF-beta contains high-glycosylated, furin-processed latent TGF-beta, which is different from the low-glycosylated, furin-unprocessed intracellular form or the high-glycosylated, furin-unprocessed secreted form. Furthermore, surface LAP/TGF-beta forms a complex with the molecular chaperone glucose-regulated protein 78 (GRP78, also known as BiP), and knockdown of GRP78 reduced the expression levels of surface LAP/TGF-beta. GRP78, however, is not involved in GARP-mediated surface LAP/TGF-beta. Our results suggest that GRP78 provides an additional surface localization mechanism for LAP/TGF-beta, which may play an important role in controlling TGF-beta activity.
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Affiliation(s)
- Takatoku Oida
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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26
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Yang T, Mendoza-Londono R, Lu H, Tao J, Li K, Keller B, Jiang MM, Shah R, Chen Y, Bertin TK, Engin F, Dabovic B, Rifkin DB, Hicks J, Jamrich M, Beaudet AL, Lee B. E-selectin ligand-1 regulates growth plate homeostasis in mice by inhibiting the intracellular processing and secretion of mature TGF-beta. J Clin Invest 2010; 120:2474-85. [PMID: 20530870 DOI: 10.1172/jci42150] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/28/2010] [Indexed: 02/02/2023] Open
Abstract
The majority of human skeletal dysplasias are caused by dysregulation of growth plate homeostasis. As TGF-beta signaling is a critical determinant of growth plate homeostasis, skeletal dysplasias are often associated with dysregulation of this pathway. The context-dependent action of TFG-beta signaling is tightly controlled by numerous mechanisms at the extracellular level and downstream of ligand-receptor interactions. However, TGF-beta is synthesized as an inactive precursor that is cleaved to become mature in the Golgi apparatus, and the regulation of this posttranslational intracellular processing and trafficking is much less defined. Here, we report that a cysteine-rich protein, E-selectin ligand-1 (ESL-1), acts as a negative regulator of TGF-beta production by binding TGF-beta precursors in the Golgi apparatus in a cell-autonomous fashion, inhibiting their maturation. Furthermore, ESL-1 inhibited the processing of proTGF-beta by a furin-like protease, leading to reduced secretion of mature TGF-beta by primary mouse chondrocytes and HEK293 cells. In vivo loss of Esl1 in mice led to increased TGF-beta/SMAD signaling in the growth plate that was associated with reduced chondrocyte proliferation and delayed terminal differentiation. Gain-of-function and rescue studies of the Xenopus ESL-1 ortholog in the context of early embryogenesis showed that this regulation of TGF-beta/Nodal signaling was evolutionarily conserved. This study identifies what we believe to be a novel intracellular mechanism for regulating TGF-beta during skeletal development and homeostasis.
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Affiliation(s)
- Tao Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Klopfleisch R, Klose P, Gruber AD. The Combined Expression Pattern of BMP2, LTBP4, and DERL1 Discriminates Malignant From Benign Canine Mammary Tumors. Vet Pathol 2010; 47:446-54. [DOI: 10.1177/0300985810363904] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Several markers of malignancy have been proposed for canine mammary tumors on the mRNA and protein levels. However, their association with tumor malignancy applies only for mean values of large groups of tumors, but no single marker identified to date can be used to reliably predict malignancy for individual tumors. A quantitative real-time reverse transcription polymerase chain reaction array was established to quantify the expression levels of 49 genes relevant to carcinogenesis in laser-microdissected tumor cells of 10 benign and 13 metastatic canine mammary tumors. Analysis of variance and discriminant analysis were used to identify relevant gene expression patterns that differentiate adenomas from metastatic carcinomas and their lymph node metastases. Seventeen genes with significant ( P < .05) differences in gene expression levels between benign and malignant tumors were identified—including ERBB1, SLIT2, progesterone receptor, MIG6, SATB1, and SMAD6—but correct classification of each tumor as benign or malignant was impossible on the basis of any of these genes alone. However, the combined expression patterns of BMP2, LTBP4, and DERL1 (Derlin-1) correctly classified each individual tumor as benign or malignant. This pilot study identified a complex mRNA expression pattern of 3 genes that was able to identify malignancy in laser-microdissected tumor cells for each individual tumor, instead of group means as used in previous studies.
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Affiliation(s)
- R. Klopfleisch
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | - P. Klose
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | - A. D. Gruber
- Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
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28
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Mauel S, Kruse B, Etschmann B, von der Schulenburg AG, Schaerig M, Stövesand K, Wilcken B, Sterner-Kock A. Latent transforming growth factor binding protein 4 (LTBP-4) is downregulated in human mammary adenocarcinomas in vitro and in vivo. APMIS 2007; 115:687-700. [PMID: 17550376 DOI: 10.1111/j.1600-0463.2007.apm_453.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transforming growth factor beta (TGF-ss) is able to inhibit proliferation of epithelial cells and is involved in the carcinogenesis of human mammary tumours. Three latent transforming growth factor-beta binding proteins (LTBP-1, -3 and -4) are involved in TGF-beta function. The aim of the study was to analyze the expression profiles of TGF-beta 1 and 2 and LTBP-4 in human mammary carcinoma cell lines as well as in human mammary tumours. Expression analysis was performed at the transcription and protein level under in vivo and in vitro conditions. LTBP-4 expression was quantitatively analysed in human carcinomas of the mammary gland and in healthy mammary tissues of the same patients. Downregulation of LTBP-4 in all investigated human mammary tumours compared to normal tissues could be demonstrated. Results also revealed that protein levels of TGF-beta 1 are downregulated and of TGF-beta 2 are upregulated in human mammary carcinoma cell lines compared to primary (normal) human mammary epithelial cells. LTBP-4 reduction in neoplasms leads to a possible decrease of TGF-beta 1 extracellular deposition with reduced TGF-beta 1 bioavailability. TGF-beta 2 was upregulated, which indicates a possible compensatory mechanism. This study demonstrated a possible functional role of LTBP-4 for TGF-beta bioavailability with respect to carcinogenesis of human mammary tumours in vivo and in vitro.
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Affiliation(s)
- Susanne Mauel
- Institute of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
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29
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Hu Z, Zeng L, Xie L, Lu W, Zhang J, Li T, Wang X. Morphological alteration of Golgi apparatus and subcellular compartmentalization of TGF-beta1 in Golgi apparatus in gerbils following transient forebrain ischemia. Neurochem Res 2007; 32:1927-31. [PMID: 17564835 DOI: 10.1007/s11064-007-9382-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 05/08/2007] [Indexed: 10/23/2022]
Abstract
Golgi apparatus (GA) is a very important organelle involved in the metabolism of numerous proteins. TGF-beta1 plays an important role in supporting neuronal survival after ischemic insults. Little is known, however, about the morphological alteration of GA and subcellular compartmentalization of TGF-beta1 in brain after ischemia. Therefore, our present study was designed to check for GA morphological alterations and TGF-beta1 subcellular localization. GA immunoreactivities were examined in the somatosensory cortex of gerbils after 10 min transient forebrain ischemia. Confocal Immunofluorographs of TGF-beta1 and TGN38 were also taken. Results indicated that no fragmentation of GA was found in gerbils of norm, shams and 6, 24 and 72 h postocclusion, but some of the cortical cells showed fragmentation of GA in gerbils 7 days postocclusion. TGF-beta1 was colocalized with TGN38, a marker molecule for the GA. We conclude that there was morphological alterations of GA and TGF-beta1 was present in GA in the somatosensory cortex after 10 min ischemia.
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Affiliation(s)
- Zhiping Hu
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
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30
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Higashi T, Kyo S, Inoue M, Tanii H, Saijoh K. Novel functional single nucleotide polymorphisms in the latent transforming growth factor-beta binding protein-1L promoter: effect on latent transforming growth factor-beta binding protein-1L expression level and possible prognostic significance in ovarian cancer. J Mol Diagn 2006; 8:342-50. [PMID: 16825507 PMCID: PMC1867604 DOI: 10.2353/jmoldx.2006.050133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Latent transforming growth factor (TGF)-beta binding proteins (LTBPs) play important roles in the secretion and activation of TGF-beta. We previously reported that LTBP-1L is overexpressed in some patients with ovarian cancer. To clarify the molecular mechanism of LTBP-1L regulation, we analyzed DNA sequences in the promoter region of LTBP-1L and identified two novel single nucleotide polymorphisms, -202G/C and +20A/C. While the alleles with -202C and +20C were initially reported, our data demonstrated that -202G and +20A are common in both ovarian cancer patients and healthy patients in the Japanese population. Luciferase reporter assays revealed that the G-A haplotype induced transcriptional activation in a Sp1-dependent manner. Electrophoretic mobility shift assays showed that increased binding affinity of Sp1 to the promoter with -202G and +20A. Interestingly, ovarian cancer patients (n = 42) with G-A/G-A homozygous genotype had increased expression of LTBP-1 and apparently poorer survival than those with other genotypes (P = 0.02). These findings suggest that the single nucleotide polymorphisms -202G/C and +20A/C on the LTBP-1L promoter may affect the clinical outcome of ovarian cancer patients, probably via up-regulating protein expression. Further studies using a larger number of samples will definitively determine the correlation between LTBP-1 haplotype and clinical behavior of ovarian cancer.
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Affiliation(s)
- Tomomi Higashi
- Department of Hygiene, Kanazawa University Graduate School of Medical Science, 13-1 Takaramachi, Ishikawa 920-8640, Japan.
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31
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McFarlane C, Langley B, Thomas M, Hennebry A, Plummer E, Nicholas G, McMahon C, Sharma M, Kambadur R. Proteolytic processing of myostatin is auto-regulated during myogenesis. Dev Biol 2005; 283:58-69. [PMID: 15975431 DOI: 10.1016/j.ydbio.2005.03.039] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 03/19/2005] [Accepted: 03/23/2005] [Indexed: 11/17/2022]
Abstract
Myostatin, a potent negative regulator of myogenesis, is proteolytically processed by furin proteases into active mature myostatin before secretion from myoblasts. Here, we show that mature myostatin auto-regulates its processing during myogenesis. In a cell culture model of myogenesis, Northern blot analysis revealed no appreciable change in myostatin mRNA levels between proliferating myoblasts and differentiated myotubes. However, Western blot analysis confirmed a relative reduction in myostatin processing and secretion by differentiated myotubes as compared to proliferating myoblasts. Furthermore, in vivo results demonstrate a lower level of myostatin processing during fetal muscle development when compared to postnatal adult muscle. Consequently, high levels of circulatory mature myostatin were detected in postnatal serum, while fetal circulatory myostatin levels were undetectable. Since Furin proteases are important for proteolytically processing members of the TGF-beta superfamily, we therefore investigated the ability of myostatin to control the transcription of furin and auto-regulate the extent of its processing. Transfection experiments indicate that mature myostatin indeed regulates furin protease promoter activity. Based on these results, we propose a mechanism whereby myostatin negatively regulates its proteolytic processing during fetal development, ultimately facilitating the differentiation of myoblasts by controlling both furin protease gene expression and subsequent active concentrations of mature myostatin peptide.
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32
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Mazzieri R, Jurukovski V, Obata H, Sung J, Platt A, Annes E, Karaman-Jurukovska N, Gleizes PE, Rifkin DB. Expression of truncated latent TGF-beta-binding protein modulates TGF-beta signaling. J Cell Sci 2005; 118:2177-87. [PMID: 15870109 DOI: 10.1242/jcs.02352] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Transforming growth factor-beta is released from most cells as an inactive complex consisting of transforming growth factor-beta, the transforming growth factor-beta propeptide and the latent transforming growth factor-beta-binding protein. We studied the role of latent transforming growth factor-beta-binding protein in modulating transforming growth factor-beta availability by generating transgenic mice that express a truncated form of latent transforming growth factor-beta-binding protein-1 that binds to transforming growth factor-beta but is missing the known N- and C-terminal matrix-binding sequences. As transforming growth factor-beta is an inhibitor of keratinocyte proliferation and is involved in the control of hair cycling, we over-expressed the mutated form of latent transforming growth factor-beta-binding protein under the control of the keratin 14-promoter. Transgenic animals displayed a hair phenotype due to a reduction in keratinocyte proliferation, an abbreviated growth phase and an early initiation of the involution (catagen) phase of the hair cycle. This phenotype appears to result from excess active transforming growth factor-beta, as enhanced numbers of pSmad2/3-positive nuclei are observed in transgenic animal skin. These data suggest that the truncated form of latent transforming growth factor-beta-binding protein-1 competes with wild-type latent transforming growth factor-beta-binding protein for binding to latent transforming growth factor-beta, resulting in latent transforming growth factor-beta complexes that fail to be targeted correctly in the extracellular matrix. The mis-localization of the transforming growth factor-beta results in inappropriate activation and premature initiation of catagen, thereby illustrating the significance of latent transforming growth factor-beta-binding protein interaction with transforming growth factor-beta in the targeting and activation of latent transforming growth factor-beta in addition to previously reported effects on small latent complex secretion.
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Affiliation(s)
- Roberta Mazzieri
- Department of Cell Biology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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33
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Wallace SE, Lachman RS, Mekikian PB, Bui KK, Wilcox WR. Marked phenotypic variability in progressive diaphyseal dysplasia (Camurati-Engelmann disease): report of a four-generation pedigree, identification of a mutation in TGFB1, and review. Am J Med Genet A 2005; 129A:235-47. [PMID: 15326622 DOI: 10.1002/ajmg.a.30148] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Progressive diaphyseal dysplasia (PDD) (Camurati-Engelmann disease) is an autosomal dominant craniotubular dysplasia characterized by hyperostosis and sclerosis of the diaphyses of the long bones and the skull. Mutations in transforming growth factor beta-1 (TGFB1) were recently found in patients with PDD. We report on a four-generation pedigree with seven individuals affected by PDD, linkage and mutational analysis results, and review the literature. This pedigree demonstrates the autosomal dominant inheritance pattern, remarkable variation in expressivity, and reduced penetrance. The most severely affected individual had progression of mild skull hyperostosis to severe skull thickening and cranial nerve compression over 30 years. His carrier father remained asymptomatic into his ninth decade and had no radiographic hyperostosis or sclerosis of the bones. Symptomatic relatives presented with lower limb pain and weakness. They were initially diagnosed with a variety of other conditions. Two of the symptomatic individuals were treated successfully with prednisone. We genotyped 7 markers from chromosome region 19q13.1-13.3 in 15 relatives and confirmed linkage to this region in this family. We screened the TGFB1 gene for mutations and identified a missense mutation resulting in an R218H substitution in the affected individuals, the asymptomatic obligate carrier, and another unaffected relative. We genotyped the family for seven known TGFB1 polymorphisms and a novel TAAA tetranucleotide repeat in intron 1. These polymorphisms did not appear to account for the variability in disease severity in this family. Our review illustrates how the disorder can significantly compromise health. Cranial involvement, which occurs in 61% of patients, can be severe, entrapping cranial nerves or causing increased intracranial pressure. Therapy with corticosteroids should be attempted in all symptomatic patients.
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Affiliation(s)
- Stephanie E Wallace
- Medical Genetics Institute, Steven Spielberg Pediatric Research Center, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
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34
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Mair GR, Niciu MJ, Stewart MT, Brennan G, Omar H, Halton DW, Mains R, Eipper BA, Maule AG, Day TA. A functionally atypical amidating enzyme from the human parasite Schistosoma mansoni. FASEB J 2004; 18:114-21. [PMID: 14718392 DOI: 10.1096/fj.03-0429com] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Many neuropeptide transmitters require the presence of a carboxy-terminal alpha-amide group for biological activity. Amidation requires conversion of a glycine-extended peptide intermediate into a C-terminally amidated product. This post-translational modification depends on the sequential action of two enzymes (peptidylglycine alpha-hydroxylating monooxygenase or PHM, and peptidyl-alpha-hydroxyglycine alpha-amidating lyase or PAL) that in most eukaryotes are expressed as separate domains of a single protein (peptidylglycine alpha-amidating monooxygenase or PAM). We identified a cDNA encoding PHM in the human parasite Schistosoma mansoni. Transient expression of schistosome PHM (smPHM) revealed functional properties that are different from other PHM proteins; smPHM displays a lower pH-optimum and, when expressed in mammalian cells, is heavily N-glycosylated. In adult worms, PHM is found in the trans-Golgi network and secretory vesicles of both central and peripheral nerves. The widespread occurrence of PHM in the nervous system confirms the important role of amidated neuropeptides in these parasitic flatworms. The differences between schistosome and mammalian PHM suggest that it could be a target for new chemotherapeutics.
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Affiliation(s)
- Gunnar R Mair
- Parasitology Research Group, School of Biology and Biochemistry, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
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35
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Santiago-Josefat B, Mulero-Navarro S, Dallas SL, Fernandez-Salguero PM. Overexpression of latent transforming growth factor-beta binding protein 1 (LTBP-1) in dioxin receptor-null mouse embryo fibroblasts. J Cell Sci 2004; 117:849-59. [PMID: 14762110 DOI: 10.1242/jcs.00932] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a transcriptional regulator of genes involved in xenobiotic metabolism. Increasingly clear is also the role of the AhR in the control of cell growth and proliferation. By analyzing differential patterns of gene expression between wild-type (AhR+/+) and null (AhR-/-) mouse embryo fibroblasts (MEF), we have identified latent transforming growth factor-beta binding protein 1 (LTBP-1) as a negatively AhR-regulated gene in the absence of xenobiotics. Ltbp-1 mRNA and protein expression were markedly increased in AhR-/- MEF. Furthermore, secreted LTBP-1 was elevated in the culture medium and the extracellular matrix of AhR-null MEF. Actinomycin D inhibited Ltbp-1 mRNA overexpression, suggesting regulation at the transcriptional level. AhR activation by dioxin (TCDD) downregulated Ltbp-1, again suggesting an AhR-regulated mechanism. Treatment of AhR+/+ MEF with transforming growth factor-beta(TGF-beta) downregulated AhR and, simultaneously, increased Ltbp-1, further supporting the role of this receptor in LTBP-1 expression. AhR-/- conditioned medium had higher levels of active and total TGF-beta activity, suggesting a role for LTBP-1 in maintaining extracellular TGF-beta concentrations. TGF-beta did not appear to directly regulate Ltbp-1 given that addition of TGFbeta neutralizing antibody or TGFbeta protein to AhR-/- MEF had no effect on Ltbp-1 expression. AhR-/- MEF had lower levels of matrix metalloproteinase 2 (MMP-2) activity, which could not be attributable to MMP-2 mRNA downregulation or MMP-inhibitors Timp-1 and Timp-2 overexpression. These data identify LTBP-1 as one of the few AhR-regulated genes not involved in xenobiotic metabolism and also support the implication of the AhR in controlling TGFbeta activity and cell proliferation.
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Affiliation(s)
- Belen Santiago-Josefat
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
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36
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Hsiao YW, Liao KW, Hung SW, Chu RM. Tumor-Infiltrating Lymphocyte Secretion of IL-6 Antagonizes Tumor-Derived TGF-β1 and Restores the Lymphokine-Activated Killing Activity. THE JOURNAL OF IMMUNOLOGY 2004; 172:1508-14. [PMID: 14734728 DOI: 10.4049/jimmunol.172.3.1508] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
IL-6 is a multifunctional cytokine that regulates cell growth, differentiation, and cell survival. Many tumor cells produce TGF-beta1, which allows them to evade CTL-mediated immune responses. IL-6 antagonizes TGF-beta1 inhibition of CD3 cell activation. However, whether IL-6 restores NK activity, which also is suppressed by TGF-beta1, is not known. We used canine transmissible venereal tumor (CTVT), which produces TGF-beta1, as a model to determine whether IL-6 restores lymphokine-activated killer (LAK) activity. During the progression phase, CTVT cells stop expressing MHC molecules. During the regression phase, the number of surface MHC molecules increases dramatically on about one-third of tumor cells. Tumor cells that stop expressing MHC should be targeted by NK cells. In this study, we found that TGF-beta1 secreted by CTVT cells suppressed LAK cytotoxicity. Interestingly, tumor-infiltrating lymphocytes (TIL) isolated from regressing CTVT secrete high concentrations of IL-6 and antagonize the anti-LAK activity of tumor cell TGF-beta1. TIL also produce IL-6 during progression phase, but the concentration is too low to block the anti-LAK activity of TGF-beta1. There is probably a threshold concentration of IL-6 needed to reverse TGF-beta1-inhibited LAK activity. In addition, in the absence of TGF-beta1, IL-6 derived from TIL does not promote the activity of LAK. This new mechanism, in which TIL manufacture high concentrations of IL-6 to block tumor TGF-beta1 anti-LAK activity, has potential applications in cancer immunotherapy and tumor prognosis.
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MESH Headings
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/physiology
- Animals
- Cell-Free System/immunology
- Cell-Free System/metabolism
- Coculture Techniques
- Cytotoxicity, Immunologic/immunology
- Disease Progression
- Dogs
- Female
- Interleukin-6/biosynthesis
- Interleukin-6/metabolism
- Interleukin-6/pharmacology
- Interleukin-6/physiology
- Intracellular Fluid/immunology
- Intracellular Fluid/metabolism
- Killer Cells, Lymphokine-Activated/immunology
- Killer Cells, Lymphokine-Activated/metabolism
- Lymphocyte Subsets/pathology
- Lymphocytes, Tumor-Infiltrating/immunology
- Lymphocytes, Tumor-Infiltrating/metabolism
- Lymphocytes, Tumor-Infiltrating/pathology
- Male
- Monocytes/pathology
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Regression, Spontaneous/immunology
- RNA, Messenger/biosynthesis
- Suppressor Factors, Immunologic/antagonists & inhibitors
- Suppressor Factors, Immunologic/metabolism
- Suppressor Factors, Immunologic/physiology
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/biosynthesis
- Transforming Growth Factor beta/genetics
- Transforming Growth Factor beta/physiology
- Transforming Growth Factor beta1
- Tumor Cells, Cultured
- Venereal Tumors, Veterinary/immunology
- Venereal Tumors, Veterinary/metabolism
- Venereal Tumors, Veterinary/therapy
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Affiliation(s)
- Ya-Wen Hsiao
- Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
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37
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Specht H, Peterziel H, Bajohrs M, Gerdes HH, Krieglstein K, Unsicker K. Transforming growth factor beta2 is released from PC12 cells via the regulated pathway of secretion. Mol Cell Neurosci 2003; 22:75-86. [PMID: 12595240 DOI: 10.1016/s1044-7431(02)00023-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Transforming growth factor beta2 (TGF-beta2), a prototypic member of a large superfamily of multifunctional cytokines, is expressed by neurons and glial cells. Its subcellular compartmentalization and release from neurons, however, are largely unknown. Here we show that TGF-beta2 colocalizes with the trans-Golgi network marker TGN38 and a marker molecule for secretory granules, chromogranin B (CgB), in PC12 cells. Similarly, primary hippocampal neurons show colocalization of TGN38 and TGF-beta2. A substantial amount of endogenous as well as transfected TGF-beta2 in PC12 cells comigrates with CgB on an equilibrium gradient, suggesting costorage in secretory granules. TGF-beta biological activity peaks in identical fractions. Depolarization of PC12 cells with high potassium triggers colocalization of CgB and TGF-beta2 at the cell surface, suggesting their regulated corelease from secretory granules. High potassium also liberates biologically active TGF-beta from PC12 cells and primary neurons. Our results indicate that a substantial portion of TGF-beta2 is secreted by the regulated secretory pathway in PC12 cells and hippocampal neurons.
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Affiliation(s)
- Heike Specht
- Neuroanatomy and Center for Neurosciences (IZN), University of Heidelberg, Im Neuenheimer Feld 307, 2.OG, D-69120 Heidelberg, Germany
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38
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Huang C, Kim Y, Caramori MLA, Fish AJ, Rich SS, Miller ME, Russell GB, Mauer M. Cellular basis of diabetic nephropathy: II. The transforming growth factor-beta system and diabetic nephropathy lesions in type 1 diabetes. Diabetes 2002; 51:3577-81. [PMID: 12453917 DOI: 10.2337/diabetes.51.12.3577] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Transforming growth factor-beta (TGF-beta) may be critical in the development of diabetic nephropathy (DN), and genetic predisposition is an important determinant of DN risk. We evaluated mRNA expression levels of TGF-beta system components in cultured skin fibroblasts (SFs) from type 1 diabetic patients with fast versus slow development of DN. A total of 125 long-standing type 1 diabetic patients were ranked by renal mesangial expansion score (MES) based on renal biopsy findings and diabetes duration. Patients in the highest quintile of MES who were also microalbuminuric or proteinuric (n = 16) were classified as "fast-track" for DN, while those in the lowest quintile who were also normoalbuminuric (n = 23) were classsified as "slow-track" for DN. Twenty-five normal subjects served as control subjects. SFs were cultured in medium with 25 mmol/l glucose for 36 h. SF mRNA expression levels for TGF-beta1, TGF-beta type II receptor (TGF-beta RII), thrombospondin-1, and latent TGF-beta binding protein-1 (LTBP-1) were measured by real-time RT-PCR. LTBP-1 mRNA expression was reduced in slow-track (0.99 +/- 0.38) versus fast-track patients (1.65 +/- 0.52, P = 0.001) and control subjects (1.41 +/- 0.7, P = 0.025). mRNA levels for TGF-beta1, TGF-beta RII, and thrombospondin-1 were similar in the three groups. Reduced LTBP-1 mRNA expression in SFs from slow-track patients may reflect genetically determined DN protection and suggests that LTBP-1 may be involved in the pathogenesis of DN through the regulation of TGF-beta activity.
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Affiliation(s)
- Chunmei Huang
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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39
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Penttinen C, Saharinen J, Weikkolainen K, Hyytiäinen M, Keski-Oja J. Secretion of human latent TGF-β-binding protein-3 (LTBP-3) is dependent on co-expression of TGF-β. J Cell Sci 2002; 115:3457-68. [PMID: 12154076 DOI: 10.1242/jcs.115.17.3457] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Latent TGF-β-binding proteins (LTBPs) were initially identified through their binding to the growth factor. Three of the four known LTBPs are able to associate covalently with the small latent forms of TGF-β and mediate their efficient secretion. LTBPs have subsequently been found to associate with the extracellular matrix. We report here the cDNA cloning and characterization of the human LTBP-3 protein, which is the smallest LTBP. The hLTBP-3 gene consists of 28 exons, including one alternatively spliced exon. The splice variant contains an additional epidermal-growth-factor-like repeat in the C-terminus. The gene is transcribed to produce a ∼4.6 kb mRNA, which is expressed at high levels in human heart, skeletal muscle, prostate and ovaries and in certain osteosarcoma and fibroblastic cell lines. Antibodies were generated against recombinant fragment of hLTBP-3 and used to detect the protein and its secretion from cultured COS-7 and osteosarcoma cells. Immunoblotting analysis indicated that efficient secretion of overexpressed hLTBP-3 from COS-7 cells required co-expression of TGF-β1, which resulted in the secretion of high molecular weight complexes of ∼240 kDa. hLTBP-3 protein was secreted from cultured osteosarcoma cells as high molecular weight complexes rather than in the free form. Similar complexes were recognized with antibodies specific toβ1•LAP. These findings indicate that human LTBP-3 has an essential role in the secretion and targeting of TGF-β1.
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Affiliation(s)
- Carita Penttinen
- Departments of Virology and Pathology, Haartman Institute and Biomedicum Helsinki, University of Helsinki and Helsinki University Hospital, FIN-00014 Helsinki, Finland
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40
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Jiang J, McCool BA, Parrish AR. Cadmium- and mercury-induced intercellular adhesion molecule-1 expression in immortalized proximal tubule cells: evidence for a role of decreased transforming growth factor-beta1. Toxicol Appl Pharmacol 2002; 179:13-20. [PMID: 11884233 DOI: 10.1006/taap.2001.9345] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A definitive association between the aberrant expression of cytokines and adhesion molecules in renal failure has been established. In this regard a relationship between cytokine and adhesion molecule expression is suggested but has not been shown in models of proximal tubular cell injury. To investigate the impact of acute injury on the relationship between transforming growth factor-beta 1 (TGF-beta1) and intercellular adhesion molecule-1 (ICAM-1) expression, two immortalized mouse proximal tubular epithelial cell lines were exposed to cadmium chloride or mercuric chloride (0-50 microM) for 0-8 h. ELISA and Western blot measured expression of secreted and intercellular TGF-beta1, respectively. Direct cellular ELISA or Western blot was used to assess ICAM-1 expression. Challenge with cadmium caused a greater loss of cell viability than did mercury. Interestingly, cadmium significantly decreased the amount of TGF-beta1 in the conditioned media. Although a similar trend was seen in mercury-challenged cells, no significant differences were observed. The decrease in TGF-beta1 in the culture media was not due to decreased expression of this cytokine, as intercellular levels were not affected by metal-induced injury. Significant increases in ICAM-1 protein expression were observed following cadmium and mercury challenge. The increase in ICAM-1 appears to be due to increased mRNA, as Northern blot analysis demonstrated increased message expression following a 4-h cadmium or mercury challenge. Supplementation of the culture media with exogenous TGF-beta1 decreased basal ICAM-1 expression and attenuated the cadmium-induced increase. These data suggest that metal-induced injury is associated with increased ICAM-1 expression. The mechanism of this induction may involve the decreased TGF-beta1 in the conditioned media following metal challenge. Taken together, these studies suggest a link between cytokine and adhesion molecule expression in renal injury.
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Affiliation(s)
- Jing Jiang
- Department of Medical Pharmacology and Toxicology, Texas A&M University System Health Science Center, College Station, Texas 77843-1114, USA
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41
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Zhu HJ, Burgess AW. Regulation of transforming growth factor-beta signaling. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 2001; 4:321-30. [PMID: 11703090 DOI: 10.1006/mcbr.2001.0301] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Members of transforming growth factor beta (TGF-beta) family are potent regulators of multiple cellular functions, including cell proliferation, differentiation, migration, organization, and death. Yet the signaling pathways underpinning a wide array of biological activities of TGF-beta appear to be deceptively simple. At every step from TGF-beta secretion to activation of its target genes, the activity of TGF-beta is regulated tightly, both positively and negatively. Biologically active TGF-beta is cleaved from a precursor protein (latent form) and multiple process factors control the levels of active TGF-beta. The efficient secretion, correct folding and deposition to the extracellular matrices require the cosecretion of latent TGF-beta binding proteins (LTBPs). Once activated, TGF-beta ligand signals through a heteromeric receptor complex of two distinct type I and type II serine/threonine kinase receptors TbetaRI and TbetaRII. Many factors appear to influence the formation of the active ligand-receptor complex. The relative orientation of TbetaRI and TbetaRII in the ligand-receptor complex is critical for activation: through TbetaRI, the activated ligand-receptor complex directly binds and phosphorylates downstream intracellular substrates, called Smads. Inhibitory Smads, Smad6 and 7, can antagonize this process. The phosphorylation of Smads leads to the formation of complexes which translocate to the nucleus. Other signaling systems can modulate the activity of the Smads: e.g., ras activity can prevent Smad complexes from entering the nucleus and specific ubiquitin ligases can target Smad for degradation. In the nucleus, the Smad complexes associate with other transcription activators or suppressors to regulate gene expression, either positively or negatively. The combined effects of the positive and/or negative TGF-beta controlled gene expression together with the endogenous protein set of the target cell are responsible for the multiplicity of biological functions.
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Affiliation(s)
- H J Zhu
- Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
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42
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Koli K, Saharinen J, Kärkkäinen M, Keski-Oja J. Novel non-TGF-β-binding splice variant of LTBP-4 in human cells and tissues provides means to decrease TGF-β deposition. J Cell Sci 2001; 114:2869-78. [PMID: 11683420 DOI: 10.1242/jcs.114.15.2869] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small latent TGF-β consists of latency associated peptide (LAP) bound to the 25 kDa TGF-β by noncovalent interactions. Small latent TGF-β is secreted from cells and deposited into the extracellular matrix as covalent complexes with its binding proteins, LTBPs. Four LTBPs have been molecularly cloned and their structures contain repetitive sequences. The 3rd 8-Cys repeats of LTBP-1, -3 and -4 are able to associate with small latent TGF-β. We analyzed by RT-PCR the expression of LTBPs 1-4 in a panel of cultured human cell lines including fibroblasts of different origin, endothelial cells and immortalized keratinocytes. LTBPs were expressed in an overlapping manner, but differences in their expression levels were detected. SV-40 transformed human embryonic lung fibroblasts contained less of the mRNAs for the LTBPs, suggesting that malignant transformation leads to decrease in LTBP expression. A novel alternatively spliced form of LTBP-4 lacking the 3rd 8-Cys repeat (LTBP-4Δ8-Cys3rd) was identified. LTBP-4Δ8-Cys3rd does not bind TGF-β and it was found to be expressed in the same tissues as the full length LTBP-4. The exon-intron structure of LTBP-4 around the 3rd 8-Cys repeat was similar to those of LTBP-2 and -3. LTBP-4Δ8-Cys3rd was produced by alternative splicing over two exons. In addition, HL-60 promyelocytic leukemia cells expressed a splice variant lacking only one exon of this region. The expression of the non-TGF-β-binding variant of LTBP-4 may be important for the regulation of TGF-β deposition in tissues. Since LTBPs are a part of the extracellular matrix microfibrils, the LTBP-4Δ8-Cys3rd protein may also be involved in various structural functions not related to TGF-β signaling.
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Affiliation(s)
- K Koli
- Department of Virology, Haartman Institute and Biomedicum Helsinki, University of Helsinki and Helsinki University Hospital, Finland.
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Abstract
The TGF-beta superfamily of growth factors consists of an increasing number of different polypeptide modulators of cell growth, differentiation, and morphogenesis. Three mammalian isoforms have been molecularly cloned. Numerous ways to regulate the expression of the TGF-beta genes have been identified. TGF-betas are, for example, subject to regulation by retinoids, steroid hormones, and vitamin D. A characteristic feature in the biology of TGF-betas is that they are usually secreted from cells in latent forms. The large latent complex consists of the small latent complex (TGF-beta and its propeptide) and a high molecular weight protease resistant binding protein, latent TGF-beta binding protein (LTBP). LTBPs are required for the proper folding and secretion of TGF-beta. TGF-beta is not just secreted from cultured cells but is deposited via LTBPs to the pericellular space, namely to the extracellular matrix. Release of these complexes and activation by proteases is under tight regulation and provides a means to rapidly increase local concentrations of TGF-beta. Biological events, where enhanced or focal proteolysis and activation of latent TGF-beta takes place, include cell invasion, tissue remodeling, and wound healing.
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Affiliation(s)
- K Koli
- Department of Virology, Haartman Institute, University of Helsinki, FIN-00014 Helsinki, Finland.
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Dubois CM, Blanchette F, Laprise MH, Leduc R, Grondin F, Seidah NG. Evidence that furin is an authentic transforming growth factor-beta1-converting enzyme. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 158:305-16. [PMID: 11141505 PMCID: PMC1850265 DOI: 10.1016/s0002-9440(10)63970-3] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Transforming growth factor (TGF)-beta1 plays an essential role in cell growth and differentiation. It is also considered as a gatekeeper of immune homeostasis with gene disruption leading to autoimmune and inflammatory diseases. TGF-beta1 is produced as an inactive precursor polypeptide that can be efficiently secreted but correct proteolytic cleavage is an essential step for its activation. Assessment of the cleavage site has revealed a unique R-H-R-R sequence reminiscent of proprotein convertase (PC) recognition motifs and has previously demonstrated that this PC-like cleavage site is correctly cleaved by furin, a member of the PC family. Here we report that among PC members, furin more closely satisfies the requirements needed to fulfill the role of a genuine TGF-beta1 convertase. Even though six members of the PC family have the ability to cleave TGF-beta1, ectopic expression of alpha(1)-antitrypsin Portland (alpha(1)-AT-PDX), a potent furin inhibitor, blocked 80% of TGF-beta1 processing mediated by endogenous enzymes as demonstrated in an in vitro digestion assay. Genetic complementation of a furin-deficient LoVo cell line with the wild-type gene restores the production of mature and bioactivable TGF-beta1. Moreover, both furin and TGF-beta are coordinately expressed and regulated in vitro and in vivo in the hematopoietic and immune system, an important tissue target. These results demonstrate for the first time that furin is an authentic and adaptive TGF-beta1-converting enzyme whereas other members of the PC family might substitute or supplement furin activity. Our study advances our comprehension of the complexity of the TGF-beta system and should facilitate the development of therapeutically useful TGF-beta inhibitors.
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Affiliation(s)
- C M Dubois
- Immunology Division and Department of Pharmacology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Canada.
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Saharinen J, Keski-Oja J. Specific sequence motif of 8-Cys repeats of TGF-beta binding proteins, LTBPs, creates a hydrophobic interaction surface for binding of small latent TGF-beta. Mol Biol Cell 2000; 11:2691-704. [PMID: 10930463 PMCID: PMC14949 DOI: 10.1091/mbc.11.8.2691] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Transforming growth factor (TGF)-betas are secreted in large latent complexes consisting of TGF-beta, its N-terminal latency-associated peptide (LAP) propeptide, and latent TGF-beta binding protein (LTBP). LTBPs are required for secretion and subsequent deposition of TGF-beta into the extracellular matrix. TGF-beta1 associates with the 3(rd) 8-Cys repeat of LTBP-1 by LAP. All LTBPs, as well as fibrillins, contain multiple 8-Cys repeats. We analyzed the abilities of fibrillins and LTBPs to bind latent TGF-beta by their 8-Cys repeats. 8-Cys repeat was found to interact with TGF-beta1*LAP by direct cysteine bridging. LTBP-1 and LTBP-3 bound efficiently all TGF-beta isoforms, LTBP-4 had a much weaker binding capacity, whereas LTBP-2 as well as fibrillins -1 and -2 were negative. A short, specific TGF-beta binding motif was identified in the TGF-beta binding 8-Cys repeats. Deletion of this motif in the 3(rd) 8-Cys repeat of LTBP-1 resulted in loss of TGF-beta*LAP binding ability, while its inclusion in non-TGF-beta binding 3(rd) 8-Cys repeat of LTBP-2 resulted in TGF-beta binding. Molecular modeling of the 8-Cys repeats revealed a hydrophobic interaction surface and lack of three stabilizing hydrogen bonds introduced by the TGF-beta binding motif necessary for the formation of the TGF-beta*LAP - 8-Cys repeat complex inside the cells.
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Affiliation(s)
- J Saharinen
- Departments of Virology and Pathology, The Haartman Institute, University of Helsinki, Finland
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Koishi K, Dalzell KG, McLennan IS. The expression and structure of TGF-beta2 transcripts in rat muscles. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1492:311-9. [PMID: 10899565 DOI: 10.1016/s0304-419x(00)00012-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The transforming growth factor-beta2 (TGF-beta2) transcripts expressed in various tissues of rat were characterised by RT-PCR and the nucleotide sequence of the cDNAs determined. A transcript with an 84-nucleotide insert in the latency-associated peptide region, the long form, was found. The long form of TGF-beta2 was detected in the aorta, primary bronchus, uterus, heart, skeletal muscle, sciatic nerve and spinal cord but not in the intestine. The 3' untranslated region of TGF-beta2 contained several putative AU-rich elements and multiple polyadenylation sites, indicating post-transcriptional regulation of TGF-beta2 synthesis. The levels of TGF-beta2 transcripts were estimated using semi-quantitative RT-PCR. They were down-regulated during muscle development and up-regulated after denervation. The long form constituted approximately 6% of the total TGF-beta2 messages in skeletal muscle.
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Affiliation(s)
- K Koishi
- Department of Anatomy and Structural Biology, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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Köhl R, Antoine M, Olwin BB, Dickson C, Kiefer P. Cysteine-rich fibroblast growth factor receptor alters secretion and intracellular routing of fibroblast growth factor 3. J Biol Chem 2000; 275:15741-8. [PMID: 10748074 DOI: 10.1074/jbc.m903271199] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of the cysteine-rich fibroblast growth factor (FGF) receptor (CFR) in COS-1 cells strongly inhibits the secretion of co-expressed FGF3. By using a column retention assay and affinity chromatography, we demonstrate that at physiological salt concentrations FGF3 binds with strong affinity to CFR in vivo and in vitro. Furthermore, to show that FGF3 binds to CFR in vivo, truncation mutants of CFR with changed subcellular distributions were shown to cause a similar redistribution of FGF3. Although CFR is a 150-kDa integral membrane glycoprotein that is primarily located in the Golgi apparatus, we show here that in COS-1 cells a substantial proportion of CFR is secreted. This is due to a carboxyl-terminal proteolytic cleavage that releases the intraluminal portion of the protein for secretion. However, the apparent size of the integral membrane and secreted CFR appears similar, since the loss of protein mass is balanced by a gain of complex carbohydrates. The released CFR is associated with the extracellular matrix through its affinity for glycosaminoglycans. These findings show that CFR can modulate the secretion of FGF3 and may control its biological activity by regulating its secretion.
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Affiliation(s)
- R Köhl
- Ruhr-Universität Bochum, Medizinische Fakultät, Abteilung für Virologie, Universitätsstrasse 150, Gebäuole MA 6/130, D-44780 Bochum, Germany
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Marmorstein AD, Csaky KG, Baffi J, Lam L, Rahaal F, Rodriguez-Boulan E. Saturation of, and competition for entry into, the apical secretory pathway. Proc Natl Acad Sci U S A 2000; 97:3248-53. [PMID: 10725401 PMCID: PMC16224 DOI: 10.1073/pnas.97.7.3248] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To investigate mechanisms of apical sorting in the secretory pathway of epithelial cells, we expressed varying amounts of the 165 amino acid isoform of vascular endothelial growth factor (VEGF(165)) and transforming growth factor beta1 (TGF-beta1) via replication defective adenoviruses. Apical sorting of both proteins was efficient at low expression levels but saturated or was reversed at high expression levels. High expression levels of TGF-beta1 were effective at competing VEGF(165) out of the apical pathway; however, VEGF(165) did not compete out TGF-beta1. Tunicamycin inhibition experiments showed that the apical polarity of VEGF(165) was independent of N-glycosylation. We conclude that the apical sorting of these two molecules is a saturable, signal-mediated process, involving competition for apical sorting receptors. The sorting of the two proteins does not appear to involve N-glycans as sorting signals, or lectin sorters. The observations are particularly relevant to gene therapy because they demonstrate that overexpression of a transgene can result in undesirable missorting of the encoded protein.
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Affiliation(s)
- A D Marmorstein
- Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Cornell University Medical College, 1300 York Avenue, New York, NY 10021, USA
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Koski C, Saharinen J, Keski-Oja J. Independent promoters regulate the expression of two amino terminally distinct forms of latent transforming growth factor-beta binding protein-1 (LTBP-1) in a cell type-specific manner. J Biol Chem 1999; 274:32619-30. [PMID: 10551816 DOI: 10.1074/jbc.274.46.32619] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Latent transforming growth factor-beta (TGF-beta)-binding proteins (LTBPs) are components of the extracellular matrix and large latent TGF-beta complexes are secreted by various cells. Human LTBP-1 is known to exist in different forms. LTBP-1L (long) has an amino-terminal extension, which is not found in the smaller LTBP-1S isoform. To study the formation and transcriptional regulation of LTBP-1S and LTBP-1L isoforms, we determined the nucleotide sequences of their 5'-flanking regions. The upstream regions of both isoforms are devoid of TATA boxes but contain other putative binding sites for several transcription factors. Genomic sequencing revealed that LTBP-1L transcript is alternatively spliced to an internal splice acceptor inside exon 1 of LTBP-1S and thus defined the genomic organization of the isoforms. Reporter gene analysis of upstream regions indicated the presence of independent, functional promoters, which regulate the transcription of the isoforms by cell-specific manner. Deletion analyses of the promoter regions revealed specific elements modulating their basal and cell type-specific expression. In SV-40 virus-transformed WI-38 lung fibroblasts a regulatory element repressed the transcription of LTBP-1S by a cell-specific manner. In amniotic epithelial cells, transcription of the LTBP-1S reporter gene construct was down-regulated by a distal upstream element. mRNA levels of the isoforms of LTBP-1 were stimulated in response to TGF-beta1 in WI-38 cells. However, since TGF-beta1 failed to stimulate the transcription of LTBP-1 reporter gene constructs, TGF-beta1 may mediate the induction of the isoforms by post-transcriptional mechanisms. Chromosomal localization of the LTBP-1 gene was refined to 2p22-24.
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Affiliation(s)
- C Koski
- Department of Virology, The Haartman Institute, University of Helsinki, FIN-00014 Helsinki, Finland
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50
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Saharinen J, Hyytiäinen M, Taipale J, Keski-Oja J. Latent transforming growth factor-beta binding proteins (LTBPs)--structural extracellular matrix proteins for targeting TGF-beta action. Cytokine Growth Factor Rev 1999; 10:99-117. [PMID: 10743502 DOI: 10.1016/s1359-6101(99)00010-6] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Growth factors of the transforming growth factor-beta family are potent regulators of the extracellular matrix formation, in addition to their immunomodulatory and regulatory roles for cell growth. TGF-beta s are secreted from cells as latent complexes containing TGF-beta and its propeptide, LAP (latency-associated peptide). In most cells LAP is covalently linked to an additional protein, latent TGF-beta binding protein (LTBP), forming the large latent complex. LTBPs are required for efficient secretion and correct folding of TGF-beta s. The secreted large latent complexes associate covalently with the extracellular matrix via the N-termini of the LTBPs. LTBPs belong to the fibrillin-LTBP family of extracellular matrix proteins, which have a typical repeated domain structure consisting mostly of epidermal growth factor (EGF)-like repeats and characteristic eight cysteine (8-Cys) repeats. Currently four different LTBPs and two fibrillins have been identified. LTBPs contain multiple proteinase sensitive sites, providing means to solubilize the large latent complex from the extracellular matrix structures. LTBPs are now known to exist both as soluble molecules and in association with the extracellular matrix. An important consequence of this is LTBP-mediated deposition and targeting of latent, activatable TGF-beta into extracellular matrices and connective tissues. LTBPs have a dual function, they are required both for the secretion of the small latent TGF-beta complex as well as directing bound latent TGF-beta to extracellular matrix microfibrils. However, it is not known at present whether LTBPs are capable of forming microfibrils independently, or whether they are a part of the fibrillin-containing fibrils. Most LTBPs possess RGD-sequences, which may have a role in their interactions with the cell surface. At least LTBP-1 is chemotactic to smooth muscle cells, and is involved in vascular remodelling. Analyses of the expressed LTBPs have revealed considerable variations throughout the molecules, generated both by alternative splicing and utilization of multiple promoter regions. The significance of this structural diversity is mostly unclear at present.
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Affiliation(s)
- J Saharinen
- Department of Virology, Haartman Institute, University of Helsinki, Finland
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