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Gramignoli R, Hofmann N, Agudo-Barriuso M, Antica M, Flores AI, Girandon L, Kerdjoudj H, Navakauskiene R, Schiavi J, Scholz H, Shablii V, Lafarge X, Nicolás FJ, Gindraux F. Expert Revision of Key Elements for Clinical-Grade Production and Qualification of Perinatal Derivatives. Stem Cells Transl Med 2024; 13:14-29. [PMID: 38071447 PMCID: PMC10785218 DOI: 10.1093/stcltm/szad068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/13/2023] [Indexed: 01/13/2024] Open
Abstract
Perinatal derivatives have been proposed as adjunct therapeutic strategies or innovative treatments. Undoubtedly, perinatal derivatives can offer the opportunity and source material to isolate multipotent stem cells, but both maternal- and fetal-derived tissues can be processed and transformed into engineered tissues or advanced biomedical devices, whose potential remains to be fully elucidated. Promising preclinical and clinical results collected so far clearly foresee an escalation of such novel treatments. Market forecasts predict exponential growth in such advanced medicinal products during the next decade, with a pragmatic innovation for medicine into a more advanced biomedical version, enlarging the portfolio for treating a wide range of congenital and acute conditions. However, all these promising and fascinating therapeutic possibilities cannot gain a solid and recognized role in established medical practice without rigid and harmonized manufacturing strategies. The implementation of strategies according to guidelines and directives compiled by Regulatory Agencies, in conformity to (European) Pharmacopoeia and for Good Manufacturing Practice -conforming production of such products, represent critical steps required to translate perinatal technologies into effective therapeutic approaches. During the past 5 years, a panel of European experts and developers, gathered under the umbrella of the COST Sprint Action, supported by the European Cooperation in Science and Technology action, had the opportunity to revise and summarize experience and recommendations for a fruitful and proficient generation of perinatal biomedical products. In order to facilitate the creation and potential commercialization of perinatal bioengineered and advanced pharmaceutical products and technologies, such a collection of data and recommendations is described and discussed here.
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Affiliation(s)
- Roberto Gramignoli
- Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet, Stockholm, Sweden
- Department of Pathology and Cancer Diagnostics, Karolinska University Hospital, Stockholm, Sweden
| | - Nicola Hofmann
- German Society for Tissue Transplantation (DGFG) gGmbH, Hannover, Germany
| | - Marta Agudo-Barriuso
- Experimental Ophthalmology Group, University of Murcia and Instituto Murciano de Investigación Biosanitaria (IMIB), Campus Ciencias de la Salud, Murcia, Spain
| | | | - Ana I Flores
- Regenerative Medicine Group, Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | | | - Halima Kerdjoudj
- University of Reims Champagne Ardenne, EA 4691 BIOS, Reims, France
| | - Ruta Navakauskiene
- Department of Molecular Cell Biology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania
| | - Jessica Schiavi
- Department of Bioprocesses Biomolecules, University of Lorraine, CNRS, LRGP, Nancy, France
| | - Hanne Scholz
- Department of Transplant Medicine, Department of Cellular Therapy, University of Oslo, Oslo, Norway
| | - Volodymyr Shablii
- Laboratory of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, Department of Functional Genomics, National Academy of Science, Kyiv, Ukraine
- Placenta Stem Cell Laboratory, Cryobank, Institute of Cell Therapy, Kyiv, Ukraine
| | - Xavier Lafarge
- Etablissement Français du Sang Nouvelle-Aquitaine, Laboratoire d’ingénierie tissulaire et cellulaire, Bordeaux, France
- INSERM U1211 « Maladies Rares: Génétique et Métabolisme », Université de Bordeaux, France
| | - Francisco J Nicolás
- Lab. Regeneración, Oncología Molecular y TGFß. IMIB-Pascual Parrilla, El Palmar, Murcia, Spain
| | - Florelle Gindraux
- CHU Besançon, Service de Chirurgie Maxillo-Faciale, Stomatologie et Odontologie Hospitalière, F-25000 Besançon, France
- Université de Franche-Comté, LNIT (Laboratoire de Nanomédecine, Imagerie, Thérapeutique EA 4662), F-25000 Besançon, France
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Hofmann N, Lafarge X, Antica M, Ferry N, Girandon L, Gramignoli R, Jurga M, Kerdjoudj H, Navakauskiene R, Schiavi J, Shablii V, Nicolás FJ, Gindraux F. Expert Consideration on Regulatory Aspects for Perinatal Derivatives in Clinical Settings. Stem Cells Transl Med 2023; 12:258-265. [PMID: 37027834 PMCID: PMC10184691 DOI: 10.1093/stcltm/szad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/10/2023] [Indexed: 04/09/2023] Open
Abstract
Perinatal derivatives (PnD) are drawing growing interest among the scientific community as an unrestricted source of multipotent stem cells, secretome, and biological matrices. They are useful for the treatment of diseases that currently have limited or no effective therapeutic options, but they require the development of regenerative approaches. With this development, the question of regulation of donation, processing, and distribution has therefore become more important. Within the European Cooperation in Science and Technology (COST) community, we compiled a group of international experts on PnD technologies, who revised and compared existing EU national regulations. Notably, despite clear European directives, each EU Country has developed their own implementation and standard levels for cell- and tissue-based therapies. To enable extended applications of PnD treatments within the EU community and worldwide, harmonization is highly recommended. This paper aims to provide an overview of the various options available to introduce PnD into clinical practice. For this purpose, the different aspects resulting from (1) the type of PnD, (2) the amount of available data, (3) the degree of manipulation, and (4) the intended application and the process toward a possible commercialization will be presented. In the future, it will be important to find a balance between regulatory requirements and the best medical quality of the PnD product.
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Affiliation(s)
- Nicola Hofmann
- German Society for Tissue Transplantation (DGFG) gGmbH, Hannover, Germany
| | - Xavier Lafarge
- Etablissement Français du Sang Nouvelle-Aquitaine Laboratoire d'ingénierie tissulaire et cellulaire, Bordeaux, France
- INSERM U1211 « Maladies Rares: Génétique et Métabolisme, Bordeaux, France
| | | | - Nicolas Ferry
- INSERM, Department of health technology, Île-de-France, Paris, France
| | | | - Roberto Gramignoli
- Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet, Stockholm, Sweden
- Medicinsk Cancerdiagnostik, Karolinska University Hospital, Stockholm, Sweden
| | | | - Halima Kerdjoudj
- Université de Reims Champagne Ardenne, Odontology, EA4691-BIOS, Reims, France
| | - Ruta Navakauskiene
- Department of Molecular Cell Biology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania
| | - Jessica Schiavi
- CNRS, LRGP, Department of Biomolecules Bioprocess, University of Lorraine, Nancy, France
| | - Volodymyr Shablii
- Laboratory of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, Department of Functional Genomics, National Academy of Science, Kyiv, Ukraine
- Placenta Stem Cell Laboratory, Cryobank, Institute of Cell Therapy, Kyiv, Ukraine
| | - Francisco J Nicolás
- Lab. Regeneración, Oncología Molecular y TGFß. IMIB-Pascual Parrilla. El Palmar, Murcia, Spain
| | - Florelle Gindraux
- Service de Chirurgie Maxillo-Faciale, Stomatologie et Odontologie Hospitalière, CHU Besancon, Besancon, France
- Université de Franche-Comté, Laboratoire de Nanomédecine, Imagerie, Thérapeutique EA 4662 (LNIT), Besançon, France
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Liarte S, Bernabé-García Á, Rodríguez-Valiente M, Moraleda JM, Castellanos G, Nicolás FJ. Amniotic Membrane Restores Chronic Wound Features to Normal in a Keratinocyte TGF-β-Chronified Cell Model. Int J Mol Sci 2023; 24:ijms24076210. [PMID: 37047181 PMCID: PMC10094701 DOI: 10.3390/ijms24076210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/22/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Unsuccessful wound closure in chronic wounds can be linked to altered keratinocyte activation and their inability to re-epithelize. Suggested mechanisms driving this impairment involve unbalanced cytokine signaling. However, the molecular events leading to these aberrant responses are poorly understood. Among cytokines affecting keratinocyte responses, Transforming Growth Factor-β (TFG-β) is thought to have a great impact. In this study, we have used a previously characterized skin epidermal in vitro model, HaCaT cells continuously exposed to TGF-β1, to study the wound recovery capabilities of chronified/senescent keratinocytes. In this setting, chronified keratinocytes show decreased migration and reduced activation in response to injury. Amniotic membrane (AM) has been used successfully to manage unresponsive complicated wounds. In our in vitro setting, AM treatment of chronified keratinocytes re-enabled migration in the early stages of wound healing, also promoting proliferation at later stages. Interestingly, when checking the gene expression of markers known to be altered in TGF-β chronified cells and involved in cell cycle regulation, early migratory responses, senescence, and chronic inflammation, we discovered that AM treatment seemed to reset back to keratinocyte status. The analysis of the evolution of both the levels of keratinocyte activation marker cytokeratin 17 and the spatial-temporal expression pattern of the proliferation marker Ki-67 in human in vivo biopsy samples suggests that responses to AM recorded in TGF-β chronified HaCaT cells would be homologous to those of resident keratinocytes in chronic wounds. All these results provide further evidence that sustained TGF-β might play a key role in wound chronification and postulate the validity of our TGF-β chronified HaCaT in vitro model for the study of chronic wound physiology.
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Gindraux F, Hofmann N, Agudo-Barriuso M, Antica M, Couto PS, Dubus M, Forostyak S, Girandon L, Gramignoli R, Jurga M, Liarte S, Navakauskiene R, Shablii V, Lafarge X, Nicolás FJ. Perinatal derivatives application: Identifying possibilities for clinical use. Front Bioeng Biotechnol 2022; 10:977590. [PMID: 36304904 PMCID: PMC9595339 DOI: 10.3389/fbioe.2022.977590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/04/2022] [Indexed: 11/13/2022] Open
Abstract
Perinatal derivatives are drawing growing interest among the scientific community as an unrestricted source of multipotent stromal cells, stem cells, cellular soluble mediators, and biological matrices. They are useful for the treatment of diseases that currently have limited or no effective therapeutic options by means of developing regenerative approaches. In this paper, to generate a complete view of the state of the art, a comprehensive 10-years compilation of clinical-trial data with the common denominator of PnD usage has been discussed, including commercialized products. A set of criteria was delineated to challenge the 10-years compilation of clinical trials data. We focused our attention on several aspects including, but not limited to, treated disorders, minimal or substantial manipulation, route of administration, dosage, and frequency of application. Interestingly, a clear correlation of PnD products was observed within conditions, way of administration or dosage, suggesting there is a consolidated clinical practice approach for the use of PnD in medicine. No regulatory aspects could be read from the database since this information is not mandatory for registration. The database will be publicly available for consultation. In summary, the main aims of this position paper are to show possibilities for clinical application of PnD and propose an approach for clinical trial preparation and registration in a uniform and standardized way. For this purpose, a questionnaire was created compiling different sections that are relevant when starting a new clinical trial using PnD. More importantly, we want to bring the attention of the medical community to the perinatal products as a consolidated and efficient alternative for their use as a new standard of care in the clinical practice.
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Liarte S, Bernabé-García Á, Nicolás FJ. Human Skin Keratinocytes on Sustained TGF-β Stimulation Reveal Partial EMT Features and Weaken Growth Arrest Responses. Cells 2020; 9:cells9010255. [PMID: 31968599 PMCID: PMC7017124 DOI: 10.3390/cells9010255] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/03/2020] [Accepted: 01/09/2020] [Indexed: 12/22/2022] Open
Abstract
Defects in wound closure can be related to the failure of keratinocytes to re-epithelize. Potential mechanisms driving this impairment comprise unbalanced cytokine signaling, including Transforming Growth Factor-β (TFG-β). Although the etiologies of chronic wound development are known, the relevant molecular events are poorly understood. This lack of insight is a consequence of ethical issues, which limit the available evidence to humans. In this work, we have used an in vitro model validated for the study of epidermal physiology and function, the HaCaT cells to provide a description of the impact of sustained exposure to TGF-β. Long term TGF-β1 treatment led to evident changes, HaCaT cells became spindle-shaped and increased in size. This phenotype change involved conformational re-arrangements for actin filaments and E-Cadherin cell-adhesion structures. Surprisingly, the signs of consolidated epithelial-to-mesenchymal transition were absent. At the molecular level, modified gene expression and altered protein contents were found. Non-canonical TGF-β pathway elements did not show relevant changes. However, R-Smads experienced alterations best characterized by decreased Smad3 levels. Functionally, HaCaT cells exposed to TGF-β1 for long periods showed cell-cycle arrest. Yet, the strength of this restraint weakens the longer the treatment, as revealed when challenged by pro-mitogenic factors. The proposed setting might offer a useful framework for future research on the mechanisms driving wound chronification.
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Valiente MR, Nicolás FJ, García-Hernández AM, Fuente Mora C, Blanquer M, Alcaraz PJ, Almansa S, Merino GR, Lucas MDL, Algueró MC, Insausti CL, Piñero A, Moraleda JM, Castellanos G. Cryopreserved amniotic membrane in the treatment of diabetic foot ulcers: a case series. J Wound Care 2019; 27:806-815. [PMID: 30557111 DOI: 10.12968/jowc.2018.27.12.806] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The amniotic membrane (AM) is a tissue with low immunogenity and high therapeutic potential due to its anti-inflammatory, anti-fibrotic and antimicrobial effects. This paper describes the use of cryopreserved amniotic membrane allografts to treat diabetic foot ulcers (DFUs) in patients with diabetes. METHOD In this case series, AM was processed to obtain a final medicinal product: cryopreserved amniotic membrane. cryopreserved AM was applied every 7-10 days until total epithelialisation of the DFUs. RESULTS A total of 14 patients with DFUs (median size: 12.30cm, (range: 0.52-42.5cm2) were treated and followed up until complete closure (median time: 20 weeks, range: 7-56 weeks). Patients received 4-40 AM applications. All patients in this study achieved complete epithelialisation of the wound. No adverse events were observed. CONCLUSION AM is a feasible and safe treatment in complex DFUs. Furthermore, the treatment is successful in achieving epithelialisation of long-evolution, unhealed wounds resistant to conventional therapies.
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Affiliation(s)
- Mónica Rodríguez Valiente
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain; and Department of General Surgery, Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Francisco J Nicolás
- Molecular Oncology and TGFß, Research Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca)
| | - Ana M García-Hernández
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Cristina Fuente Mora
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Miguel Blanquer
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Patricio J Alcaraz
- Department of General Surgery, Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Sonia Almansa
- Department of General Surgery, Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Guadalupe Ruiz Merino
- FFIS de la Región de Murcia, Support Research Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Ma Dolores López Lucas
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - María C Algueró
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Carmen L Insausti
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Antonio Piñero
- Department of General Surgery, Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - José M Moraleda
- Cell Therapy Unit at Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
| | - Gregorio Castellanos
- Department of General Surgery, Hospital Clínico Universitario Virgen de la Arrixaca. Biomedical Research Institute of Murcia (Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca). El Palmar, Spain
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Bernabé-García Á, Liarte S, Moraleda JM, Castellanos G, Nicolás FJ. Amniotic membrane promotes focal adhesion remodeling to stimulate cell migration. Sci Rep 2017; 7:15262. [PMID: 29127427 PMCID: PMC5681678 DOI: 10.1038/s41598-017-15509-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/26/2017] [Indexed: 02/04/2023] Open
Abstract
During wound healing, the migration of keratinocytes onto newly restored extracellular matrix aims to reestablish continuity of the epidermis. The application of amniotic membrane (AM) to chronic, deep traumatic, non-healing wounds has proven successful at stimulating re-epithelialization. When applied on epithelial cell cultures, AM activates extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinases 1/2 (JNK1/2), with the overexpression and phosphorylation of c-Jun along the wound edge. The effect of AM on the migration of cells was investigated by studying critical proteins involved in the focal adhesions turn-over: Focal Adhesion Kinase (FAK), Paxillin and Vinculin. In Mv1Lu and HaCaT cells, validated models for cell migration and wound healing, AM affected the expression and activation of Paxillin, but did not affect Vinculin expression, both factors which integrate into focal adhesions. Moreover, AM regulation also affected FAK activity through phosphorylation. Finally, we have determined that AM regulation of focal adhesions involves both JNK and MEK MAP kinase signaling pathways. This data provides a molecular background to understand how AM regulates critical cell and molecular aspects of cell migration, organizing and directing the movement of cells by the continuous formation, maturation, and turnover of focal adhesion structures at the migration leading edge.
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Affiliation(s)
- Ángel Bernabé-García
- Laboratorio de Oncología Molecular y TGF-ß, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Sergio Liarte
- Laboratorio de Oncología Molecular y TGF-ß, IMIB-Arrixaca, El Palmar, Murcia, Spain
| | - Jose M Moraleda
- Unidad de Trasplante y Terapia Celular, Servicio Hematología, Hospital Clínico Universitario Virgen de la Arrixaca, Universidad de Murcia, Murcia, Spain
| | - Gregorio Castellanos
- Servicio de Cirugía General y del Aparato Digestivo, Hospital Clínico Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Francisco J Nicolás
- Laboratorio de Oncología Molecular y TGF-ß, IMIB-Arrixaca, El Palmar, Murcia, Spain.
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Castellanos G, Bernabé-García Á, Moraleda JM, Nicolás FJ. Amniotic membrane application for the healing of chronic wounds and ulcers. Placenta 2017; 59:146-153. [PMID: 28413063 DOI: 10.1016/j.placenta.2017.04.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/05/2017] [Accepted: 04/07/2017] [Indexed: 12/12/2022]
Abstract
Wound healing usually follows a predictable sequence and prognosis of events. Its evolutionary process is the result of a complicated interaction between patient-related factors, the wound, the treatment used and the skills and knowledge of the professionals who treat them. Only through a meticulous initial assessment of the wound is it possible to identify the factors that contribute to its complexity. The challenge for professionals will be to implement efficient therapies at the right time and in the most cost-efficient way in order to reduce associated problems, treat the symptoms and expectations of the patients and achieve adequate wound healing whenever possible. This is particularly evident in big chronic wounds with considerable tissue loss, which become senescent in the process of inflammation or proliferation losing the ability to epithelialize. Generally, chronic wounds do not respond to current treatments, therefore they need special interventions. AM is a tissue of particular interest as a biological dressing and it has well-documented reepithelialization effects which are in part related to its capacity to synthesize and release biological active factors. Our studies have demonstrated that amniotic membrane (AM) is able to induce epithelialization in chronic wounds that were unable to epithelialize. AM induces several signaling pathways that are involved in cell migration and/or proliferation. Additionally, AM is able to selectively antagonize the anti-proliferative effect of transforming growth factor-ß (TGF-β) by modifying the genetic program that TGF-β induces on keratinocytes. The combined effect of AM on keratinocytes, promoting cell proliferation/migration and antagonizing the effect of TGF-β is the perfect combination, allowing chronic wounds to move out of their non-healing state and progress into epithelialization.
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Affiliation(s)
- Gregorio Castellanos
- Surgery Service, Virgen de La Arrixaca University Clinical Hospital, El Palmar, Murcia, Spain
| | - Ángel Bernabé-García
- Molecular Oncology and TGF-ß, Research Unit, Virgen de La Arrixaca University Hospital, El Palmar, Murcia, Spain
| | - José M Moraleda
- Cell Therapy Unit, Virgen de La Arrixaca University Clinical Hospital, El Palmar, Murcia, Spain
| | - Francisco J Nicolás
- Molecular Oncology and TGF-ß, Research Unit, Virgen de La Arrixaca University Hospital, El Palmar, Murcia, Spain.
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Alcaraz A, Mrowiec A, Insausti CL, García-Vizcaíno EM, Ruiz-Canada C, López-Martínez MC, Moraleda JM, Nicolás FJ. Autocrine TGF-β induces epithelial to mesenchymal transition in human amniotic epithelial cells. Cell Transplant 2012; 22:1351-67. [PMID: 23031712 DOI: 10.3727/096368912x657387] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human amniotic epithelial cells (hAECs) have been the object of intense research due to their potential therapeutic use. In this paper, we present molecular evidence of a bona fide epithelial to mesenchymal transition (EMT) undergone by hAECs. Amniotic membrane (AM)-derived hAECs showed the presence of typical epithelial markers such as E-cadherin and cytokeratins. hAECs in culture, however, underwent morphological changes acquiring a mesenchymal shape. Epithelial cell markers were lost and typical mesenchymal markers, such as vimentin and α-SMA, appeared. Several genes associated with EMT, such as SNAI1, MMP9, PAI1, or ACTA2, increased their expression. The expression of the transcription activators KLF4 or MTA3 was consistent with the downregulation of CDH1. We have shown that hAECs undergo EMT due to the autocrine production of TGF-β. Furthermore, the addition of the TGF-β receptor I (ALK5) inhibitor SB-431542 or TGF-β neutralizing antibody to hAECs prevented EMT and preserved the hAECs' epithelial phenotype. Altogether, these results suggest that cultured hAECs undergo EMT through the autocrine production of TGF-β.
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Affiliation(s)
- Antonia Alcaraz
- Oncología Molecular y TGF-β, Unidad de Investigación, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
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10
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Insausti CL, Blanquer Blanquer M, Meseguer Olmo L, López-Martínez MC, Férez Ruiz X, Rodríguez Lozano FJ, Cabañas Perianes V, Funes C, Nicolás FJ, Majado MJ, Moraleda Jiménez JM. Isolation and Characterization of Mesenchymal Stem Cells from the Fat Layer on the Density Gradient Separated Bone Marrow. Stem Cells Dev 2012; 21:260-72. [DOI: 10.1089/scd.2010.0572] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Carmen L. Insausti
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Miguel Blanquer Blanquer
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Luis Meseguer Olmo
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - María C. López-Martínez
- Laboratorio de Oncología Molecular and TGFß, Unidad de Investigación, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Xavier Férez Ruiz
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Francisco J. Rodríguez Lozano
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Valentín Cabañas Perianes
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Consuelo Funes
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Francisco J. Nicolás
- Laboratorio de Oncología Molecular and TGFß, Unidad de Investigación, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - María J. Majado
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - José M. Moraleda Jiménez
- Unidad de Terapia Celular, Servicio de Hematología, Hospital Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
- Universidad de Murcia, Murcia, Spain
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11
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Insausti CL, Alcaraz A, García-Vizcaíno EM, Mrowiec A, López-Martínez MC, Blanquer M, Piñero A, Majado MJ, Moraleda JM, Castellanos G, Nicolás FJ. Amniotic membrane induces epithelialization in massive posttraumatic wounds. Wound Repair Regen 2010; 18:368-77. [DOI: 10.1111/j.1524-475x.2010.00604.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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Abstract
Transforming growth factor β (TGF-β) signalling leads to phosphorylation and activation of receptor-regulated Smad2 and Smad3, which form complexes with Smad4 and accumulate in the nucleus. The Smads, however, do not seem to reside statically in the cytoplasm in the absence of signalling or in the nucleus upon TGF-β stimulation, but have been suggested to shuttle continuously between these cellular compartments in both the absence and presence of TGF-β. Here we investigate this nucleocytoplasmic shuttling in detail in living cells using fusions of Smad2 and Smad4 with enhanced GFP. We first establish that the GFPSmad fusions behave like wild-type Smads in a variety of cellular assays. We go on to demonstrate directly, using photobleaching experiments, that Smad2 and Smad4 shuttle between the cytoplasm and nucleus in both TGF-β-induced cells and in uninduced cells. In uninduced cells, GFPSmad2 is less mobile in the cytoplasm than is GFPSmad4, suggesting that it may be tethered there. In addition, we show that both GFPSmad2 and GFPSmad4 undergo a substantial decrease in mobility in the nucleus upon TGF-β stimulation, suggesting that active complexes of Smads are tethered in the nucleus, whereas unactivated Smads are more freely diffusible. We propose that regulated cytoplasmic and nuclear retention may play a role in determining the distribution of Smads between the cytoplasm and the nucleus in both uninduced cells and upon TGF-β induction.
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Affiliation(s)
- Francisco J Nicolás
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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13
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De Bosscher K, Hill CS, Nicolás FJ. Molecular and functional consequences of Smad4 C-terminal missense mutations in colorectal tumour cells. Biochem J 2004; 379:209-16. [PMID: 14715079 PMCID: PMC1224058 DOI: 10.1042/bj20031886] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Accepted: 01/09/2004] [Indexed: 01/07/2023]
Abstract
Smad4 is an essential signal transducer of the transforming growth factor beta (TGF-beta) signalling pathway and has been identified as a tumour suppressor, being mutated in approx. 50% of pancreatic cancers and approx. 15% of colorectal cancers. Two missense mutations in the C-terminal domain of Smad4, D351H (Asp351-->His) and D537Y (Asp537-->Tyr), have been described recently in the human colorectal cancer cell lines CACO-2 and SW948 respectively [Woodford-Richens, Rowan, Gorman, Halford, Bicknell, Wasan, Roylance, Bodmer and Tomlinson (2001) Proc. Natl. Acad. Sci. U.S.A. 98, 9719-9723]. Previous work in vitro suggested that only Asp-351 was required for interaction with Smad2 [Wu, Fairman, Penry and Shi (2001) J. Biol. Chem. 276, 20688-20694]. In the present study, we investigate the functional consequences of these point mutations in vivo. We demonstrate that neither of these colorectal cancer cells undergo growth arrest in response to TGF-beta, which can be explained, at least in part, by their inability to up-regulate cyclin-dependent kinase inhibitors p21 (CIP1 ) or p15 ( INK4b) after TGF-beta stimulation. Although the point-mutated Smad4s are expressed at normal levels in these colorectal cancer cells, they cannot interact with either TGF-beta-induced phosphorylated Smad2 or Smad3. As a result, these Smad4 mutants do not accumulate in the nucleus after TGF-beta stimulation, are not recruited to DNA by relevant Smad-binding transcription factors and cannot generate transcriptionally active DNA-bound complexes. Therefore both these colorectal tumour cells completely lack functional Smad4 activity owing to the missense mutations. Given the location of these mutations in the three-dimensional structure of the Smad4 C-terminal domain, the results also give us significant insights into Smad complex formation.
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Affiliation(s)
- Karolien De Bosscher
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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14
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Nicolás FJ, Hill CS. Attenuation of the TGF-beta-Smad signaling pathway in pancreatic tumor cells confers resistance to TGF-beta-induced growth arrest. Oncogene 2003; 22:3698-711. [PMID: 12802277 DOI: 10.1038/sj.onc.1206420] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have investigated the mechanism whereby tumor cells become resistant to the antiproliferative effects of transforming growth factor (TGF)-beta, while maintaining other responses that can lead to increased malignancy and invasiveness. TGF-beta signaling results in nuclear accumulation of active Smad complexes which regulate transcription of target genes. Here we show that in two pancreatic carcinoma cell lines, PT45 and Panc-1, that are resistant to TGF-beta-induced growth arrest, the TGF-beta-Smad signaling pathway is attenuated compared with epithelial cells that are sensitive to the antiproliferative effects of TGF-beta (HaCaT and Colo-357). In PT45 and Panc-1 cells, active Smad complexes remain nuclear for only 1-2 h compared with more than 6 h in HaCaT and Colo-357 cells. The attenuated pathway in PT45 and Panc-1 cells correlates with low levels of TGF-beta type I receptor and results in an altered expression profile of TGF-beta-inducible genes required for cell cycle arrest. Most significantly, expression of the CDK inhibitor, p21(Cip1/WAF1), which is required for TGF-beta-induced growth arrest in these cells, is not maintained. Moreover, we show that artificially attenuating the TGF-beta-Smad signaling pathway in HaCaT cells is sufficient to prevent TGF-beta-induced growth arrest. Our results demonstrate that the duration of TGF-beta-Smad signaling is a critical determinant of the specificity of the TGF-beta response.
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Affiliation(s)
- Francisco J Nicolás
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, UK
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15
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Nicolás FJ, Lehmann K, Warne PH, Hill CS, Downward J. Epithelial to mesenchymal transition in Madin-Darby canine kidney cells is accompanied by down-regulation of Smad3 expression, leading to resistance to transforming growth factor-beta-induced growth arrest. J Biol Chem 2003; 278:3251-6. [PMID: 12435725 DOI: 10.1074/jbc.m209019200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In normal epithelial cells, transforming growth factor-beta (TGF-beta) typically causes growth arrest in the G(1) phase of the cell cycle and may eventually lead to apoptosis. However, transformed cells lose these inhibitory responses and often instead show an increase in malignant character following TGF-beta treatment. In the canine kidney-derived epithelial cell line, MDCK, synergism between activation of the Raf/MAPK pathway and the resulting autocrine production of TGF-beta triggers transition from an epithelial to a mesenchymal phenotype. During this process, these cells become refractive to TGF-beta-induced cell cycle arrest and apoptosis. TGF-beta signals are primarily transduced to the nucleus through complexes of receptor-regulated Smads, Smad2 and Smad3 with the common mediator Smad, Smad4. Here we show that the transition from an epithelial to mesenchymal phenotype is accompanied by gradual down-regulation of expression of Smad3. Restoration of Smad3 to previous levels of expression restores the cell cycle arrest induced by TGF-beta without reverting the cells to an epithelial phenotype or impacting on the MAPK pathway. Regulation of apoptosis is not affected by Smad3 levels. These data attribute to Smad3 a critical role in the control of cell proliferation by TGF-beta, which is lost following an epithelial to mesenchymal transition.
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Affiliation(s)
- Francisco J Nicolás
- Developmental Signalling Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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16
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Abstract
Transforming growth factor (TGF)-beta stimulation leads to phosphorylation and activation of Smad2 and Smad3, which form complexes with Smad4 that accumulate in the nucleus and regulate transcription of target genes. Here we demonstrate that, following TGF-beta stimulation of epithelial cells, receptors remain active for at least 3-4 hr, and continuous receptor activity is required to maintain active Smads in the nucleus and for TGF-beta-induced transcription. We show that continuous nucleocytoplasmic shuttling of the Smads during active TGF-beta signaling provides the mechanism whereby the intracellular transducers of the signal continuously monitor receptor activity. Our data therefore explain how, at all times, the concentration of active Smads in the nucleus is directly dictated by the levels of activated receptors in the cytoplasm.
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Affiliation(s)
- Gareth J Inman
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, United Kingdom
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Inman GJ, Nicolás FJ, Callahan JF, Harling JD, Gaster LM, Reith AD, Laping NJ, Hill CS. SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5, and ALK7. Mol Pharmacol 2002; 62:65-74. [PMID: 12065756 DOI: 10.1124/mol.62.1.65] [Citation(s) in RCA: 1307] [Impact Index Per Article: 59.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Small molecule inhibitors have proven extremely useful for investigating signal transduction pathways and have the potential for development into therapeutics for inhibiting signal transduction pathways whose activities contribute to human diseases. Transforming growth factor beta (TGF-beta) is a member of a large family of pleiotropic cytokines that are involved in many biological processes, including growth control, differentiation, migration, cell survival, adhesion, and specification of developmental fate, in both normal and diseased states. TGF-beta superfamily members signal through a receptor complex comprising a type II and type I receptor, both serine/threonine kinases. Here, we characterize a small molecule inhibitor (SB-431542) that was identified as an inhibitor of activin receptor-like kinase (ALK)5 (the TGF-beta type I receptor). We demonstrate that it inhibits ALK5 and also the activin type I receptor ALK4 and the nodal type I receptor ALK7, which are very highly related to ALK5 in their kinase domains. It has no effect on the other, more divergent ALK family members that recognize bone morphogenetic proteins (BMPs). Consistent with this, we demonstrate that SB-431542 is a selective inhibitor of endogenous activin and TGF-beta signaling but has no effect on BMP signaling. To demonstrate the specificity of SB-431542, we tested its effect on several other signal transduction pathways whose activities depend on the concerted activation of multiple kinases. SB-431542 has no effect on components of the ERK, JNK, or p38 MAP kinase pathways or on components of the signaling pathways activated in response to serum.
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Affiliation(s)
- Gareth J Inman
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London, UK
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Nicolás FJ, Moore WJ, Zhang C, Clarke PR. XMog1, a nuclear Ran-binding protein in Xenopus, is a functional homologue of Schizosaccharomyces pombe Mog1p that co-operates with RanBP1 to control generation of Ran-GTP. J Cell Sci 2001; 114:3013-23. [PMID: 11686304 DOI: 10.1242/jcs.114.16.3013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ran is a multifunctional small GTPase of the Ras superfamily that plays roles in nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. By screening a Xenopus oocyte cDNA library for Ran-GTP-binding proteins using the two-hybrid system of co-expression in yeast, we identified XMog1, a 20.4 kDa polypeptide related to Mog1p in Saccharomyces cerevisiae and similar gene products in Schizosaccharomyces pombe, Arabidopsis and mammals. We show that cDNAs encoding XMog1 and S. cerevisiae Mog1p rescue the growth defect of S. pombe cells lacking mog1, demonstrating conservation of their functions. In Xenopus somatic cells and transfected mammalian cells, XMog1 is localised to the nucleus. XMog1 alone does not stimulate Ran GTPase activity or nucleotide exchange, but causes nucleotide release from Ran-GTP and forms a complex with nucleotide-free Ran. However, in combination with Ran-binding protein 1 (RanBP1), XMog1 promotes the release of GDP and the selective binding of GTP to Ran. XMog1 and RanBP1 also promote selective GTP loading onto Ran catalysed by the nuclear guanine nucleotide exchange factor, RCC1. We propose that Mog1-related proteins, together with RanBP1, facilitate the generation of Ran-GTP from Ran-GDP in the nucleus.
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Affiliation(s)
- F J Nicolás
- Biomedical Research Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK
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19
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Abstract
Smad4 plays a pivotal role in all transforming growth factor beta (TGF-beta) signaling pathways. Here we describe six widely expressed alternatively spliced variants of human Smad4 with deletions of different exons in the linker, the region of Smad4 that separates the two well-conserved MH1 and MH2 domains. All these Smad4 variants form complexes with activated Smad2 and Smad3 and are incorporated into DNA-binding complexes with the transcription factor Fast-1, regardless of the amount of linker they contain. However, sequences encoded by exons 5 to 7 in the linker are essential for transcriptional activation. Most importantly, our observation that different Smad4 isoforms have different subcellular localizations has led us to the identification of a functional CRM1-dependent nuclear export signal in the Smad4 linker and a constitutively active nuclear localization signal in the N-terminal MH1 domain. In the absence of TGF-beta signaling, we conclude that Smad4 is rapidly and continuously shuttling between the nucleus and the cytoplasm, the distribution of Smad4 between the nucleus and the cytoplasm being dictated by the relative strengths of the nuclear import and export signals. We demonstrate that inhibition of CRM1-mediated nuclear export by treatment of cells with leptomycin B results in endogenous Smad4 accumulating very rapidly in the nucleus. Endogenous Smad2 and Smad3 are completely unaffected by leptomycin B treatment, indicating that the nucleocytoplasmic shuttling is specific for Smad4. We propose that, upon TGF-beta signaling, complex formation between Smad4 and activated Smad2 or -3 leads to nuclear accumulation of Smad4 through inhibition of its nuclear export. We demonstrate that after prolonged TGF-beta signaling Smad2 becomes dephosphorylated and Smad2 and Smad4 accumulate back in the cytoplasm.
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Affiliation(s)
- C E Pierreux
- Laboratory of Developmental Signalling, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
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Vives M, Porcel JM, Nicolás FJ, Rubio M. [Pleuro-pulmonary infection by Clostridium perfringens]. Enferm Infecc Microbiol Clin 1999; 17:196-7. [PMID: 10365519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Nicolás FJ, Zhang C, Hughes M, Goldberg MW, Watton SJ, Clarke PR. Xenopus Ran-binding protein 1: molecular interactions and effects on nuclear assembly in Xenopus egg extracts. J Cell Sci 1997; 110 ( Pt 24):3019-30. [PMID: 9365272 DOI: 10.1242/jcs.110.24.3019] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ran is a nuclear GTPase implicated in nucleocytoplasmic transport, the maintenance of nuclear structure, mRNA processing, and cell cycle regulation. By two-hybrid interaction in yeast, we have identified a Xenopus homologue of Ran-binding protein 1 (RanBP1). Xenopus RanBP1 interacts specifically with the GTP-bound form of Ran and forms complexes in Xenopus egg extracts with Ran, importin-beta/karyopherin-beta and importin-alpha/karyopherin-alpha, but not p10, p120/RanBP7, RanBP2 or other nucleoporins. These complexes may play roles in the recycling of Ran and importins/karyopherins during nucleocytoplasmic transport. Increased concentrations of RanBP1 stabilise an interaction between Ran and RCC1 in egg extracts, inhibiting the exchange activity of RCC1 towards Ran. Under these conditions, the assembly of nuclei from chromatin is dramatically affected: the nuclei do not assemble a lamina and become very small with homogeneously condensed chromatin. They fail to actively import proteins and do not undergo DNA replication. By field emission in-lens scanning electron microscopy, we show that these nuclei have an intact nuclear envelope containing pore complexes, but the envelope is highly convoluted. However, RanBP1 does not directly inhibit nuclear protein import in assembled nuclei. These results suggest that RCC1 and/or Ran have a function early in nuclear assembly that is disrupted by RanBP1.
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Affiliation(s)
- F J Nicolás
- Zeneca Laboratory of Molecular and Cellular Biology, School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK
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Abstract
The Gram-negative bacterium Myxococcus xanthus responds to blue light by producing carotenoid pigments (Car+ phenotype). Genes for carotenoid synthesis lie at two unlinked chromosomal sites, the carC and the carBA operon, but are integrated in a single "light regulon" by the action of common trans-acting regulatory elements. Three known regulatory genes are grouped together at the (light-inducible) carQRS operon. By screening the Car phenotype of a large collection of transposon-induced mutants, we have identified a new car locus that has been named carD (carD1 for the mutant allele). The carD gene product plays a critical role in the light regulon, as it is required for activation of the carQRS and carC promoters by blue light. The carD1 mutant is impaired in the (starvation-induced) developmental process that allows M. xanthus cells both to form multicellular fruiting bodies and to sporulate. Our results indicate that the carD gene product is also required for the expression of a particular set of development-specific genes that are normally activated through the action of intercellular signals.
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Affiliation(s)
- F J Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Spain
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