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Valencia-Expósito A, Gómez-Lamarca MJ, Widmann TJ, Martín-Bermudo MD. Integrins Cooperate With the EGFR/Ras Pathway to Preserve Epithelia Survival and Architecture in Development and Oncogenesis. Front Cell Dev Biol 2022; 10:892691. [PMID: 35769262 PMCID: PMC9234701 DOI: 10.3389/fcell.2022.892691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Adhesion to the extracellular matrix (ECM) is required for normal epithelial cell survival. Disruption of this interaction leads to a specific type of apoptosis known as anoikis. Yet, there are physiological and pathological situations in which cells not connected to the ECM are protected from anoikis, such as during cell migration or metastasis. The main receptors transmitting signals from the ECM are members of the integrin family. However, although integrin-mediated cell-ECM anchorage has been long recognized as crucial for epithelial cell survival, the in vivo significance of this interaction remains to be weighed. In this work, we have used the Drosophila wing imaginal disc epithelium to analyze the importance of integrins as survival factors during epithelia morphogenesis. We show that reducing integrin expression in the wing disc induces caspase-dependent cell death and basal extrusion of the dead cells. In this case, anoikis is mediated by the activation of the JNK pathway, which in turn triggers expression of the proapoptotic protein Hid. In addition, our results strongly suggest that, during wing disc morphogenesis, the EGFR pathway protects cells undergoing cell shape changes upon ECM detachment from anoikis. Furthermore, we show that oncogenic activation of the EGFR/Ras pathway in integrin mutant cells rescues them from apoptosis while promoting their extrusion from the epithelium. Altogether, our results support the idea that integrins promote cell survival during normal tissue morphogenesis and prevent the extrusion of transformed cells.
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Affiliation(s)
| | - M. Jesús Gómez-Lamarca
- Centro Andaluz de Biología del Desarrollo CSIC-Universidad Pablo de Olavide, Sevilla, Spain
- Departamento de Biología Celular, Universidad de Sevilla, Sevilla, Spain
| | | | - María D. Martín-Bermudo
- Centro Andaluz de Biología del Desarrollo CSIC-Universidad Pablo de Olavide, Sevilla, Spain
- *Correspondence: María D. Martín-Bermudo,
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Tayem R, Niemann C, Pesch M, Morgner J, Niessen CM, Wickström SA, Aumailley M. Laminin 332 Is Indispensable for Homeostatic Epidermal Differentiation Programs. J Invest Dermatol 2021; 141:2602-2610.e3. [PMID: 33965403 DOI: 10.1016/j.jid.2021.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/24/2021] [Accepted: 04/13/2021] [Indexed: 12/16/2022]
Abstract
The skin epidermis is attached to the underlying dermis by a laminin 332 (Lm332)-rich basement membrane. Consequently, loss of Lm332 leads to the severe blistering disorder epidermolysis bullosa junctionalis in humans and animals. Owing to the indispensable role of Lm332 in keratinocyte adhesion in vivo, the severity of the disease has limited research into other functions of the protein. We have conditionally disrupted Lm332 expression in basal keratinocytes of adult mice. Although blisters develop along the interfollicular epidermis, hair follicle basal cells provide sufficient anchorage of the epidermis to the dermis, making inducible deletion of the Lama3 gene compatible with life. Loss of Lm332 promoted the thickening of the epidermis and exaggerated desquamation. Global RNA expression analysis revealed major changes in the expression of keratins, cornified envelope proteins, and cellular stress markers. These modifications of the keratinocyte genetic program are accompanied by changes in cell shape and disorganization of the actin cytoskeleton. These data indicate that loss of Lm332-mediated progenitor cell adhesion alters cell fate and disturbs epidermal homeostasis.
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Affiliation(s)
- Raneem Tayem
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Catherin Niemann
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Monika Pesch
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Jessica Morgner
- Paul Gerson Unna Group 'Skin Homeostasis and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany; Division of Molecular Pathology, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Carien M Niessen
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Medical Faculty, Department of Cell Biology of the Skin, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sara A Wickström
- Paul Gerson Unna Group 'Skin Homeostasis and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland; Wihuri Research Institute, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Monique Aumailley
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany.
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Abstract
Integrins are heterodimeric cell surface receptors ensuring the mechanical connection between cells and the extracellular matrix. In addition to the anchorage of cells to the extracellular matrix, these receptors have critical functions in intracellular signaling, but are also taking center stage in many physiological and pathological conditions. In this review, we provide some historical, structural, and physiological notes so that the diverse functions of these receptors can be appreciated and put into the context of the emerging field of mechanobiology. We propose that the exciting journey of the exploration of these receptors will continue for at least another new generation of researchers.
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Affiliation(s)
- Michael Bachmann
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Sampo Kukkurainen
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Vesa P Hytönen
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
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4
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Joint features and complementarities of Tspan8 and CD151 revealed in knockdown and knockout models. Biochem Soc Trans 2017; 45:437-447. [PMID: 28408484 DOI: 10.1042/bst20160298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 02/04/2017] [Accepted: 02/13/2017] [Indexed: 02/06/2023]
Abstract
Tetraspanins are highly conserved 4-transmembrane proteins which form molecular clusters with a large variety of transmembrane and cytosolic proteins. By these associations tetraspanins are engaged in a multitude of biological processes. Furthermore, tetraspanin complexes are located in specialized microdomains, called tetraspanin-enriched microdomains (TEMs). TEMs provide a signaling platform and are poised for invagination and vesicle formation. These vesicles can be released as exosomes (Exo) and are important in cell contact-independent intercellular communication. Here, we summarize emphasizing knockdown and knockout models' pathophysiological joint and selective activities of CD151 and Tspan8, and discuss the TEM-related engagement of CD151 and Tspan8 in Exo activities.
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5
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Has C, He Y. Renal-skin syndromes. Cell Tissue Res 2017; 369:63-73. [DOI: 10.1007/s00441-017-2623-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/03/2017] [Indexed: 12/16/2022]
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6
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Azzariti A, Mancarella S, Porcelli L, Quatrale AE, Caligiuri A, Lupo L, Dituri F, Giannelli G. Hepatic stellate cells induce hepatocellular carcinoma cell resistance to sorafenib through the laminin-332/α3 integrin axis recovery of focal adhesion kinase ubiquitination. Hepatology 2016; 64:2103-2117. [PMID: 27639064 DOI: 10.1002/hep.28835] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/04/2016] [Accepted: 08/17/2016] [Indexed: 12/19/2022]
Abstract
UNLABELLED In patients with hepatocellular carcinoma (HCC) receiving sorafenib, drug resistance is common. HCC develops in a microenvironment enriched with extracellular matrix proteins including laminin (Ln)-332, produced by hepatic stellate cells (HSCs). Ln-332 is the ligand of α3β1 and α6β4 integrins, differently expressed on the HCC cell surface, that deliver intracellular pathways. The aim of this study was to investigate the effect of Ln-332 on sorafenib's effectiveness. HCC cells were challenged with sorafenib in the presence of Ln-332 and of HSC conditioned medium (CM). Sorafenib impaired HCC cell proliferation and induced apoptosis. HSC-CM or Ln-332 inhibited sorafenib's effectiveness in HCC cells expressing both α3β1 and α6β4. Inhibiting α3 but not α6 integrin subunit using blocking antibodies or small interfering RNA abrogated the protection induced by Ln-332 and HSC-CM. Hep3B cells expressing α6β4 but lacking the α3 integrin were insensitive to Ln-332 and HSC-CM protective effects. Hep3B α3-positive, but not wild-type and scramble transfected, cells acquired protection by sorafenib when plated on Ln-332-CM or HSCs. Sorafenib dephosphorylated focal adhesion kinase (FAK) and extracellular signal-regulated kinases 1/2, whereas Ln-332 and HSC-CM partially restored the pathways. Silencing FAK, but not extracellular signal-regulated kinases 1/2, abrogated the protection induced by Ln-332 and HSC-CM, suggesting a specific role for FAK. Sorafenib down-regulated total FAK, inducing its proteasomal degradation, while Ln-332 and HSC-CM promoted the escape of FAK from ubiquitination, probably inducing a preferential membrane localization. CONCLUSION This study unveils a novel mechanism of sorafenib resistance depending on the α3β1/Ln-332 axis and requiring FAK ubiquitination, providing new insights into personalizing therapy for patients with HCC. (Hepatology 2016;64:2103-2117).
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Affiliation(s)
- Amalia Azzariti
- National Cancer Institute, Istituto Tumori G. Paolo II, Bari, Italy
| | - Serena Mancarella
- National Institute of Gastroenterology, IRCCS "S. De Bellis", Castellana Grotte Bari, Italy
| | - Letizia Porcelli
- National Cancer Institute, Istituto Tumori G. Paolo II, Bari, Italy
| | | | | | - Luigi Lupo
- University of Bari Medical School, Bari, Italy
| | - Francesco Dituri
- National Institute of Gastroenterology, IRCCS "S. De Bellis", Castellana Grotte Bari, Italy
| | - Gianluigi Giannelli
- National Institute of Gastroenterology, IRCCS "S. De Bellis", Castellana Grotte Bari, Italy
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7
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Iwanabe Y, Masaki C, Tamura A, Tsuka S, Mukaibo T, Kondo Y, Hosokawa R. The effect of low-intensity pulsed ultrasound on wound healing using scratch assay in epithelial cells. J Prosthodont Res 2016; 60:308-314. [DOI: 10.1016/j.jpor.2016.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/07/2016] [Accepted: 03/15/2016] [Indexed: 10/22/2022]
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8
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Integrin-mediated regulation of epidermal wound functions. Cell Tissue Res 2016; 365:467-82. [PMID: 27351421 DOI: 10.1007/s00441-016-2446-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/02/2016] [Indexed: 01/14/2023]
Abstract
During cutaneous wound healing, keratinocyte proliferation and migration are critical for re-epithelialization. In addition the epidermis secretes growth factors, cytokines, proteases, and matricellular proteins into the wound microenvironment that modify the extracellular matrix and stimulate other wound cells that control the inflammatory response, promote angiogenesis and facilitate tissue contraction and remodeling. Wound keratinocytes express at least seven different integrins-the major cell adhesion receptors for the extracellular matrix-that collectively control essential cell-autonomous functions to ensure proper re-epithelialization, including migration, proliferation, survival and basement membrane assembly. Moreover, it has become evident in recent years that some integrins can regulate paracrine signals from wound epidermis that stimulate other wound cells involved in angiogenesis, contraction and inflammation. Importantly, it is likely that abnormal integrin expression or function in the epidermis contributes to wound pathologies such as over-exuberant healing (e.g., hypertrophic scar formation) or diminished healing (e.g., chronic wounds). In this review, we discuss current knowledge of integrin function in the epidermis, which implicates them as attractive therapeutic targets to promote wound healing or treat wound pathologies. We also discuss challenges that arise from the complex roles that multiple integrins play in wound epidermis, which may be regulated through extracellular matrix remodeling that determines ligand availability. Indeed, understanding how different integrin functions are temporally coordinated in wound epidermis and which integrin functions go awry in pathological wounds, will be important to determine how best to target them clinically to achieve maximum therapeutic benefit. Graphical abstract In addition to their well-characterized roles in keratinocyte adhesion, migration and wound re-epithelialization, epidermal integrins play important roles in modifying the wound microenvironment by regulating the expression and secretion of growth factors, extracellular proteases, and matricellular proteins that stimulate other wound cells, including vascular endothelial cells and fibroblasts/myofibroblasts.
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9
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Wegner J, Loser K, Apsite G, Nischt R, Eckes B, Krieg T, Werner S, Sorokin L. Laminin α5 in the keratinocyte basement membrane is required for epidermal-dermal intercommunication. Matrix Biol 2016; 56:24-41. [PMID: 27234307 DOI: 10.1016/j.matbio.2016.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/04/2016] [Accepted: 05/08/2016] [Indexed: 12/22/2022]
Abstract
Laminin α5 is broadly expressed in the epidermal basement membrane (BM) of mature mice and its elimination at this site (Lama5Ker5 mouse) results in hyperproliferation of basal keratinocytes and a delay in hair follicle development, which correlated with upregulation of the dermally-derived laminin α2 and laminin α4 chains in the epidermal BM and of tenascin-C subjacent to the BM. In vitro studies revealed laminin 511 to be strongly adhesive for primary keratinocytes and that loss of laminin α5 does not result in cell autonomous defects in proliferation. Flow cytometry reveals that the loss of laminin α5 resulted in increased numbers of CD45+, CD4+ and CD11b+ immune cells in the skin, which temporo-spatial analyses revealed were detectable only subsequent to the loss of laminin α5 and the appearance of the hyperproliferative keratinocyte phenotype. These findings indicate that immune cell changes are the consequence and not the cause of keratinocyte hyperproliferation. Loss of laminin α5 in the epidermal BM was also associated with changes in the expression of several dermally-derived growth factors involved in keratinocyte proliferation and hair follicle development in adult but not new born Lama5Ker5 skin, including KGF, EGF and KGF-2. In situ binding of FGF-receptor-2α (IIIb)-Fc chimera (FGFR2IIIb) to mouse skin sections revealed decoration of several BMs, including the epidermal BM, which was absent in Lama5Ker5 skin. This indicates reduced levels of FGFR2IIIb ligands, which include KGF and KGF-2, in the epidermal BM of adult Lama5Ker5 skin. Our data suggest an initial inhibitory effect of laminin α5 on basal keratinocyte proliferation and migration, which is exacerbated by subsequent changes in growth factor expression by epidermal and dermal cells, implicating laminin α5 in epidermal-dermal intercommunication.
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Affiliation(s)
- Jeannine Wegner
- Institute of Physiological Chemistry and Pathobiochemistry, University of Muenster, Germany; Cells-in-Motion Cluster of Excellence, University of Muenster, Germany
| | - Karin Loser
- Cells-in-Motion Cluster of Excellence, University of Muenster, Germany; Department of Dermatology, University of Muenster, Germany
| | - Gunita Apsite
- Institute of Physiological Chemistry and Pathobiochemistry, University of Muenster, Germany; Cells-in-Motion Cluster of Excellence, University of Muenster, Germany
| | | | - Beate Eckes
- Department of Dermatology, University of Cologne, Germany
| | - Thomas Krieg
- Department of Dermatology, University of Cologne, Germany
| | - Sabine Werner
- Department of Biology, Institute of Molecular Health Sciences, ETH Zurich, Switzerland
| | - Lydia Sorokin
- Institute of Physiological Chemistry and Pathobiochemistry, University of Muenster, Germany; Cells-in-Motion Cluster of Excellence, University of Muenster, Germany.
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10
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Duperret EK, Dahal A, Ridky TW. Focal-adhesion-independent integrin-αv regulation of FAK and c-Myc is necessary for 3D skin formation and tumor invasion. J Cell Sci 2015; 128:3997-4013. [PMID: 26359297 DOI: 10.1242/jcs.175539] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/08/2015] [Indexed: 12/25/2022] Open
Abstract
Integrins play crucial roles in epithelial adhesion, proliferation, wound healing and cancer. In the epidermis, the roles of many integrin subunits are incompletely defined and mechanistic details regarding their functions are lacking. We performed a multiplexed small hairpin (sh)RNA screen to define roles for each subunit in human organotypic skin. We show that integrin-αv (also known as ITGAV) heterodimers are essential for epidermal generation, with integrin-αv loss driving a keratinocyte G1-S cell cycle block. Surprisingly, integrin αv is not localized within keratinocyte focal adhesions, and instead maintains proliferation by controlling cellular (c)-Myc translation through FAK, p38β and p90RSK1. These phenotypes depend only on the binding partners of integrin-αv--integrin β5 and integrin β6 (also known as ITGB5 and ITGB6, respectively). Through inducible depletion of integrin αv in both normal organotypic epidermis and Ras-driven invasive neoplasia, we show that integrin αv is required for de novo tissue generation and neoplastic invasion but that it is dispensable for epidermal maintenance. Heterodimers of integrin αv with integrin β5 (integrin αvβ5) or integrin β6 (integrin αvβ6) are required to similar extents for neoplastic invasion, thus identifying integrin αvβ5 and integrin αvβ6 heterodimers as potential therapeutic targets for epidermal squamous cell carcinoma.
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Affiliation(s)
- Elizabeth K Duperret
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, BRB 1010, 421 Curie Blvd, Philadelphia, PA 19104, USA
| | - Ankit Dahal
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, BRB 1010, 421 Curie Blvd, Philadelphia, PA 19104, USA
| | - Todd W Ridky
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, BRB 1010, 421 Curie Blvd, Philadelphia, PA 19104, USA
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11
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Has C, Nyström A. Epidermal Basement Membrane in Health and Disease. CURRENT TOPICS IN MEMBRANES 2015; 76:117-70. [PMID: 26610913 DOI: 10.1016/bs.ctm.2015.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Skin, as the organ protecting the individual from environmental aggressions, constantly meets external insults and is dependent on mechanical toughness for its preserved function. Accordingly, the epidermal basement membrane (BM) zone has adapted to enforce tissue integrity. It harbors anchoring structures created through unique organization of common BM components and expression of proteins exclusive to the epidermal BM zone. Evidence for the importance of its correct assembly and the nonredundancy of its components for skin integrity is apparent from the multiple skin blistering disorders caused by mutations in genes coding for proteins associated with the epidermal BM and from autoimmune disorders in which autoantibodies target these molecules. However, it has become clear that these proteins not only provide mechanical support but are also critically involved in tissue homeostasis, repair, and regeneration. In this chapter, we provide an overview of the unique organization and components of the epidermal BM. A special focus will be given to its function during regeneration, and in inherited and acquired diseases.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
| | - Alexander Nyström
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
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12
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Yalcin EG, He Y, Orhan D, Pazzagli C, Emiralioglu N, Has C. Crucial role of posttranslational modifications of integrin α3 in interstitial lung disease and nephrotic syndrome. Hum Mol Genet 2015; 24:3679-88. [PMID: 25810266 DOI: 10.1093/hmg/ddv111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/23/2015] [Indexed: 01/06/2023] Open
Abstract
Interstitial lung disease, nephrotic syndrome and junctional epidermolysis bullosa is an autosomal recessive multiorgan disorder caused by mutations in the gene for the integrin α3 subunit (ITGA3). The full spectrum of manifestations and genotype-phenotype correlations is still poorly characterized. Here, we uncovered the disease-causing role and the molecular mechanisms underlying a homozygous ITGA3 mutation leading to the single amino acid substitution, p.R463W. The patient suffered from respiratory distress and episodes of cyanosis with onset in the first week of life and had a nephrotic syndrome. Although there was no clinical evidence for cutaneous fragility, the analysis of a skin sample and of skin epithelial cells enabled the direct assessment of the authentic mutant protein. We show that the mutation altered the conformation of the extracellular β-propeller domain of the integrin α3 subunit preventing correct processing of N-linked oligosaccharides, heterodimerization with β1 integrin and maturation through cleavage into heavy and light chains in the Golgi. Confocal microscopy demonstrated that the mutant protein accumulated intracellularly, but it was not present in focal adhesions or on the cell membrane as shown by flow cytometry. These findings highlight that single amino acid changes in the integrin α3 subunit may crucially alter the structure and complex processing of this integrin, completely preventing its functionality. The present report also underscores that ITGA3 mutations may account for atypical cases solely with early onset respiratory and renal involvement.
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Affiliation(s)
| | - Yinghong He
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and
| | - Diclehan Orhan
- Department of Pediatric Pathology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Chiara Pazzagli
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany
| | | | - Cristina Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and
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13
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Integrin-mediated adhesion and mechano-sensing in cutaneous wound healing. Cell Tissue Res 2014; 360:571-82. [DOI: 10.1007/s00441-014-2064-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/11/2014] [Indexed: 12/30/2022]
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14
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Aggarwal A, Al-Rohil RN, Batra A, Feustel PJ, Jones DM, DiPersio CM. Expression of integrin α3β1 and cyclooxygenase-2 (COX2) are positively correlated in human breast cancer. BMC Cancer 2014; 14:459. [PMID: 24950714 PMCID: PMC4069347 DOI: 10.1186/1471-2407-14-459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 06/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Expression of integrin α3β1 is associated with tumor progression, metastasis, and poor prognosis in several cancers, including breast cancer. Moreover, preclinical studies have revealed important pro-tumorigenic and pro-metastatic functions for this integrin, including tumor growth, survival, invasion, and paracrine induction of angiogenesis. Our previously published work in a preclinical breast cancer model showed that integrin α3β1 promotes expression of cyclooxygenase-2 (COX2/PTGS2), a known driver of breast cancer progression. However, the clinical significance of this regulation was unknown. The objective of the current study was to assess the clinical relevance of the relationship between integrin α3β1 and COX2 by testing for their correlated expression among various forms of human breast cancer. METHODS Immunohistochemistry was performed to assess co-expression of α3 and COX2 in specimens of human invasive ductal carcinoma (IDC), either on a commercial tissue microarray (n = 59 samples) or obtained from Albany Medical Center archives (n = 68 samples). Immunostaining intensity for the integrin α3 subunit or COX2 was scored, and Spearman's rank correlation coefficient analysis was performed to assess their co-expression across and within different tumor subtypes or clinicopathologic criteria. RESULTS Although expression of integrin α3 or COX2 varied among clinical IDC samples, a statistically significant, positive correlation was detected between α3 and COX2 in both tissue microarrays (r(s) = 0.49, p < 0.001, n = 59) and archived samples (r(s) = 0.59, p < 0.0001, n = 68). In both sample sets, this correlation was independent of hormone receptor status, histological grade, or disease stage. CONCLUSIONS COX2 and α3 are correlated in IDC independently of hormone receptor status or other clinicopathologic features, supporting the hypothesis that integrin α3β1 is a determinant of COX2 expression in human breast cancer. These results support the clinical relevance of α3β1-dependent COX2 gene expression that we reported previously in breast cancer cells. The findings also suggest that COX2-positive breast carcinomas of various subtypes might be vulnerable to therapeutic strategies that target α3β1, and that α3 expression might serve as an independent prognostic biomarker.
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Affiliation(s)
- Anshu Aggarwal
- Center for Cell Biology & Cancer Research, Albany Medical College, Mail Code 165, Room MS-420, 47 New Scotland Avenue, Albany, NY 12208-3479, USA
| | - Rami N Al-Rohil
- Department of Pathology, Albany Medical Center, Albany, NY 12208, USA
| | - Anupam Batra
- Department of Internal Medicine, Albany Medical Center, Albany, NY 12208, USA
| | - Paul J Feustel
- Center for Neuropharmacology and Neurosciences, Albany Medical College, Albany, NY 12208, USA
| | - David M Jones
- Department of Pathology, Albany Medical Center, Albany, NY 12208, USA
| | - C Michael DiPersio
- Center for Cell Biology & Cancer Research, Albany Medical College, Mail Code 165, Room MS-420, 47 New Scotland Avenue, Albany, NY 12208-3479, USA
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15
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Longmate WM, Monichan R, Chu ML, Tsuda T, Mahoney MG, DiPersio CM. Reduced fibulin-2 contributes to loss of basement membrane integrity and skin blistering in mice lacking integrin α3β1 in the epidermis. J Invest Dermatol 2014; 134:1609-1617. [PMID: 24390135 PMCID: PMC4020984 DOI: 10.1038/jid.2014.10] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 10/23/2013] [Accepted: 11/04/2013] [Indexed: 11/20/2022]
Abstract
Deficient epidermal adhesion is a hallmark of blistering skin disorders and chronic wounds, implicating integrins as potential therapeutic targets. Integrin α3β1, a major receptor in the epidermis for adhesion to laminin-332 (LN-332), has critical roles in basement membrane (BM) organization during skin development. In the current study we identify a role for α3β1 in promoting stability of nascent epidermal BMs through induction of fibulin-2, a matrix-associated protein that binds LN-332. We demonstrate that mice lacking α3β1 in the epidermis display ruptured BM beneath neo-epidermis of wounds, characterized by extensive blistering. This junctional blistering phenocopies defects reported in newborn α3-null mice, as well as in human patients with α3 gene mutations, indicating that the developmental role of α3β1 in BM organization is recapitulated during wound healing. Mice lacking epidermal α3β1 also have reduced fibulin-2 expression, and fibulin-2-null mice display perinatal skin blisters similar to those in α3β1-deficient mice. Interestingly, α3-null wound epidermis or keratinocytes also show impaired processing of the LN-332 γ2 chain, although this defect was independent of reduced fibulin-2 and did not appear to cause blistering. Our findings indicate a role for integrin α3β1 in BM stability through fibulin-2 induction, both in neonatal skin and in adult wounds.
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Affiliation(s)
- Whitney M Longmate
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York, USA
| | - Ruby Monichan
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York, USA
| | - Mon-Li Chu
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Takeshi Tsuda
- Nemours Biomedical Research and Nemours Cardiac Center, Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - My G Mahoney
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - C Michael DiPersio
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York, USA.
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16
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Longmate WM, DiPersio CM. Integrin Regulation of Epidermal Functions in Wounds. Adv Wound Care (New Rochelle) 2014; 3:229-246. [PMID: 24669359 DOI: 10.1089/wound.2013.0516] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/13/2014] [Indexed: 12/12/2022] Open
Abstract
Significance: Integrins are bidirectional signaling receptors for extracellular matrix that regulate both inside-out signaling that controls keratinocyte-mediated changes to the wound microenvironment and outside-in signaling that controls keratinocyte responses to microenvironmental changes. As such, integrins represent attractive therapeutic targets for treatment of chronic wounds or general promotion of wound healing. Advances in wound management are particularly important as the elderly and diabetic populations within the United States continue to grow. Recent Advances: Although integrins are best known for mediating cell adhesion and migration, integrins in wound epidermis also control cell survival, proliferation, matrix remodeling, and paracrine crosstalk to other cellular compartments of the wound. Importantly, the concept of targeting integrins in the clinic has been established for treatment of certain cancers and other diseases, laying the groundwork for similar exploitation of integrins as targets to treat chronic wounds. Critical Issues: Despite their attractiveness as therapeutic targets, integrins have complex roles in wound healing that are impacted by both their own expression and a highly dynamic wound microenvironment that determines ligand availability. Therefore, identifying relevant integrin ligands in the wound and understanding both distinct and overlapping functions that different integrins play in the epidermis will be critical to determine their precise roles in wound healing. Future Directions: Future research should focus on gaining a thorough understanding of the highly coordinated functions of different integrins in wound epidermis, and on determining which of these functions go awry in pathological wounds. This focus should facilitate development of integrin-targeting therapeutics for treating chronic wounds.
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Affiliation(s)
- Whitney M. Longmate
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - C. Michael DiPersio
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
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17
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Duperret EK, Ridky TW. Focal adhesion complex proteins in epidermis and squamous cell carcinoma. Cell Cycle 2013; 12:3272-85. [PMID: 24036537 DOI: 10.4161/cc.26385] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Focal adhesions (FAs) are large, integrin-containing, multi-protein assemblies spanning the plasma membrane that link the cellular cytoskeleton to surrounding extracellular matrix. They play critical roles in adhesion and cell signaling and are major regulators of epithelial homeostasis, tissue response to injury, and tumorigenesis. Most integrin subunits and their associated FA proteins are expressed in skin, and murine genetic models have provided insight into the functional roles of FAs in normal and neoplastic epidermis. Here, we discuss the roles of these proteins in normal epidermal proliferation, adhesion, wound healing, and cancer. While many downstream signaling mechanisms remain unclear, the critically important roles of FAs are highlighted by the development of therapeutics targeting FAs for human cancer.
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18
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BPAG1-e restricts keratinocyte migration through control of adhesion stability. J Invest Dermatol 2013; 134:773-782. [PMID: 24025550 DOI: 10.1038/jid.2013.382] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/12/2013] [Accepted: 08/27/2013] [Indexed: 02/08/2023]
Abstract
Bullous pemphigoid antigen 1 (BPAG1-e, also known as BP230) is a member of the plakin family of hemidesmosome cytoskeletal linker proteins that is encoded by an isoform of the dystonin (DST) gene. Recently, we reported two unrelated families with homozygous nonsense mutations in this DST isoform that led to ultrastructural loss of hemidesmosomal inner plaques and clinical features of trauma-induced skin fragility. We now demonstrate that keratinocytes isolated from these individuals have significant defects in adhesion, as well as increased cell spreading and migration. These mutant keratinocytes also display reduced levels of β4 integrins at the cell surface but increased total protein levels of keratin-14 and β1 integrins. These alterations in cell behavior and protein expression were not seen in control keratinocytes in which BPAG1-e expression had been silenced by stable expression of short hairpin RNA to target DST. The failure of knockdown approaches to recapitulate the changes in morphology, adhesion, and migration seen in patient cells therefore suggests such approaches are not appropriate to study loss of this protein in vivo. The contrasting findings in keratinocytes harboring naturally occurring mutations, however, demonstrate a previously unappreciated key role for BPAG1-e in regulating keratinocyte adhesion and migration and suggest a requirement for this protein in controlling functional switching between integrin types in epithelial cells.
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19
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BB0172, a Borrelia burgdorferi outer membrane protein that binds integrin α3β1. J Bacteriol 2013; 195:3320-30. [PMID: 23687274 DOI: 10.1128/jb.00187-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lyme disease is a multisystemic disorder caused by Borrelia burgdorferi infection. Upon infection, some B. burgdorferi genes are upregulated, including members of the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) protein family, which facilitate B. burgdorferi adherence to extracellular matrix components of the host. Comparative genome analysis has revealed a new family of B. burgdorferi proteins containing the von Willebrand factor A (vWFA) domain. In the present study, we characterized the expression and membrane association of the vWFA domain-containing protein BB0172 by using in vitro transcription/translation systems in the presence of microsomal membranes and with detergent phase separation assays. Our results showed evidence of BB0172 localization in the outer membrane, the orientation of the vWFA domain to the extracellular environment, and its function as a metal ion-dependent integrin-binding protein. This is the first report of a borrelial adhesin with a metal ion-dependent adhesion site (MIDAS) motif that is similar to those observed in eukaryotic integrins and has a similar function.
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20
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Martins-Green M. The Yin and Yang of Integrin Function in Re-Epithelialization During Wound Healing. Adv Wound Care (New Rochelle) 2013; 2:75-80. [PMID: 24527329 DOI: 10.1089/wound.2011.0342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Integrins are transmembrane proteins that are present in the plasma membrane of basal ketatinocytes and connect them to the underlying basement membrane and to the dermis. There are primarily two types of interactions between the epidermis and the dermis-via focal adhesion plaques and hemidesmosomes. It is critical that these interactions form properly to confer the skin strong mechanical properties. Integrins are also critical during wound healing, particularly in closure of the wound. THE PROBLEM Margadant et al. (2009) address proper closure of cutaneous wounds. They developed a conditional knockout mouse for integrin α3 and showed that the absence of the α3 integrin resulted in faster migration of the keratinocytes during wound healing. However, its absence also led to inflammation, hair loss, basement membrane duplication, and loss of dermal epidermal interactions with blister formation. The latter has important consequences for the ability of the skin to withstand mechanical challenges. BASIC/CLINICAL SCIENCE ADVANCES Models such as the conditional model developed by Margadant et al. (2009) will provide the opportunity for making major advances in understanding the complex function of integrins during healing. CLINICAL CARE RELEVANCE The model and the findings provide an opportunity to decipher mechanisms of disease and for potential development of treatments for human skin disorders and impaired healing, including chronic ulcers. CONCLUSION This work provides knowledge that leads to the understanding of delayed re-epithelialization during wound healing and dermal epidermal defects, blistering, and chronic skin diseases, hence providing the opportunity to understand the basic cellular and molecular mechanisms involved in these situations.
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Affiliation(s)
- Manuela Martins-Green
- Department of Cell Biology and Neuroscience, University of California, Riverside, California
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21
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Abstract
The key role of extracellular matrices in alveolar epithelial cell (AEC) biology is highlighted by the phenotypes of primary AECs cultured on a soft laminin gel contrasted with that on a stiff, fibronectin matrix. On laminin, AECs maintain an epithelial phenotype, and progenitor cells within this population proliferate. In contrast, on fibronectin, AECs rapidly lose surfactant expression and spread extensively, changes that depend on activation of latent TGF-β1 by engagement of fibronectin-binding integrins. The progenitor subpopulation responding to TGF-β1 undergoes epithelial mesenchymal transition (EMT). Although it remains uncertain to what degree EMT contributes directly to collagen 1 production, signaling pathways critical to EMT are important for repair and fibrosis, implying that EMT is part of the general program of lung repair. EMT reprogramming requires not only Smad signaling but also pY654-β-catenin. Generation of pY654-β-catenin requires assembly of complexes of the integrin α3β1, E-cadherin, and TGF-β1 receptors, and such assembly is a function of cell-cell and cell-matrix contacts. Sequestration of α3β1 or E-cadherin in such contacts prevents complex assembly, TGF-β1 induced pY654-β-catenin generation and EMT. Disruption of these contacts is a signal for the cells to initiate repair. Critical remaining questions center around better definition of direct versus indirect effects of EMT on collagen deposition and the nature of AEC progenitors differentiating during fibrogenesis. Elucidation of specific inhibitors of EMT should further test the question of whether the process is important to fibrosis in vivo and a viable therapeutic target.
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22
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Kligys KR, Wu Y, Hopkinson SB, Kaur S, Platanias LC, Jones JCR. α6β4 integrin, a master regulator of expression of integrins in human keratinocytes. J Biol Chem 2012; 287:17975-84. [PMID: 22493440 DOI: 10.1074/jbc.m111.310458] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three major laminin and collagen-binding integrins in skin (α6β4, α3β1, and α2β1) are involved in keratinocyte adhesion to the dermis and dissemination of skin cells during wound healing and/or tumorigenesis. Knockdown of α6 integrin in keratinocytes not only results in motility defects but also leads to decreased surface expression of the α2, α3, and β4 integrin subunits. Whereas α2 integrin mRNA levels are decreased in α6 integrin knockdown cells, α3 and β4 integrin mRNAs levels are unaffected. Expression of either α6 or α3 integrin in α6 integrin knockdown cells restores α2 integrin mRNA levels. Moreover, re-expression of α6 integrin increases β4 integrin protein at the cell surface, which results in an increase in α3 integrin expression via activation of initiation factor 4E-binding protein 1. Our data indicate that the α6β4 integrin is a master regulator of transcription and translation of other integrin subunits and underscore its pivotal role in wound healing and cancer.
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Affiliation(s)
- Kristina R Kligys
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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23
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Greciano PG, Moyano JV, Buschmann MM, Tang J, Lu Y, Rudnicki J, Manninen A, Matlin KS. Laminin 511 partners with laminin 332 to mediate directional migration of Madin-Darby canine kidney epithelial cells. Mol Biol Cell 2011; 23:121-36. [PMID: 22031290 PMCID: PMC3248892 DOI: 10.1091/mbc.e11-08-0718] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Sustained directional migration of epithelial cells is essential for regeneration of injured epithelia. Front-rear polarity of migrating cells is determined by local activation of a signaling network involving Cdc42 and other factors in response to spatial cues from the environment, the nature of which are obscure. We examined the roles of laminin (LM)-511 and LM-332, two structurally different laminin isoforms, in the migration of Madin-Darby canine kidney cells by suppressing expression of their α subunits using RNA interference. We determined that knockdown of LM-511 inhibits directional migration and destabilizes cell-cell contacts, in part by disturbing the localization and activity of the polarization machinery. Suppression of integrin α3, a laminin receptor subunit, in cells synthesizing normal amounts of both laminins has a similar effect as knockdown of LM-511. Surprisingly, simultaneous suppression of both laminin α5 and laminin α3 restores directional migration and cell-cell contact stability, suggesting that cells recognize a haptotactic gradient formed by a combination of laminins.
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Affiliation(s)
- Patricia G Greciano
- Department of Surgery and Committee on Molecular Medicine, University of Chicago, Chicago, IL 60637, USA.
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24
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Deconstructing the skin: cytoarchitectural determinants of epidermal morphogenesis. Nat Rev Mol Cell Biol 2011; 12:565-80. [PMID: 21860392 DOI: 10.1038/nrm3175] [Citation(s) in RCA: 318] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
To provide a stable environmental barrier, the epidermis requires an integrated network of cytoskeletal elements and cellular junctions. Nevertheless, the epidermis ranks among the body's most dynamic tissues, continually regenerating itself and responding to cutaneous insults. As keratinocytes journey from the basal compartment towards the cornified layers, they completely reorganize their adhesive junctions and cytoskeleton. These architectural components are more than just rivets and scaffolds - they are active participants in epidermal morphogenesis that regulate epidermal polarization, signalling and barrier formation.
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25
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Chung H, Suh EK, Han IO, Oh ES. Keratinocyte-derived laminin-332 promotes adhesion and migration in melanocytes and melanoma. J Biol Chem 2011; 286:13438-47. [PMID: 21349841 PMCID: PMC3075690 DOI: 10.1074/jbc.m110.166751] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 02/11/2011] [Indexed: 02/02/2023] Open
Abstract
Melanocytes are highly motile cells that play an integral role in basic skin physiological processes such as wound healing and proper skin pigmentation. It has been postulated that surrounding keratinocytes contribute to melanocyte migration, but underlying mechanisms remain rather vague so far. In this study, we set out to analyze the specific potential contribution of keratinocyte components to melanocytes and melanoma cell migration-related processes. Our studies revealed that A375 human melanoma cell attachment, spreading, and migration are interestingly better supported by HaCaT keratinocyte extracellular matrix (ECM) than by self-derived A375 ECM. Moreover, HaCaT ECM caused increased integrin α6 expression, adhesion-mediated focal adhesion kinase phosphorylation, and focal adhesion formations. Similar effects were confirmed in human melanocytes. Furthermore, we found that keratinocyte-derived soluble factors did not appear to significantly contribute to these processes. Specific extrinsic factors that promoted melanoma migration were attributed to keratinocyte-derived laminin-332, whereas alternative ECM component such as laminin-111 and fibronectin functions appeared to have insignificant contributions. Taken together, these studies implicate extrinsic laminin-332 in promoting the high mobility property and perhaps invasiveness inherently characteristic of, and that are the menace of, melanocytes and melanomas, respectively.
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Affiliation(s)
- Heesung Chung
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
| | - Eun-Kyung Suh
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
| | - Inn-Oc Han
- the Department of Physiology and Biophysics, College of Medicine, Inha University, Incheon 402-751, Korea
| | - Eok-Soo Oh
- From the Division of Life and Pharmaceutical Sciences, Department of Life Sciences, and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea and
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26
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Abstract
Integrins are adhesive proteins that have evolved to mediate cell-cell and cell-matrix communication that is indispensable for development and postnatal physiology. Despite their widespread expression, the genetic deletion of specific integrin family members in lower organisms as well as mammals leads to relatively distinct abnormalities. Many of the processes in which integrins participate have a requirement for strong adhesion coincident with times of mechanical stress. In Drosophila, the absence of specific integrins leads to detachment of muscle from the gut and body wall and separation of the two epithelial layers in the wing. In mice and humans, a deletion of either subunit of the laminin-binding integrin, α6β4 leads to severe skin blistering and defects in other epithelial layers. In addition, integrins have also evolved to serve more subspecialized roles ranging from the establishment of a stem cell niche in Drosophila and mammals, to the regulation of pathogenic tumor vascularization, platelet adhesion, and leukocyte transmigration in mammalian systems. However, some cells seem to function normally in the absence of all integrins, as revealed by the very surprising finding that deletion of all the major integrin types on dendritic cells of mice has no effect on the ability of these cells to migrate within the interstitium of the skin and enter into lymphatics. In addition to serving as transmembrane mechanical links, integrins in vertebrates synergize with a number of receptors including growth factor receptors, to enhance responses. This leads to the activation of a large signaling network that affects cell proliferation and differentiation, as well as cell shape and migration. In vivo studies, in lower organisms, knockout mouse models as well as in inherited human diseases together have provided important insights into how this major, primordial family of adhesion receptors have remained true to their name "integrins" as their diverse functions have in common the ability to integrate extracellular stimuli into intracellular signals that affect cell behavior.
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27
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Hotta A, Kawakatsu T, Nakatani T, Sato T, Matsui C, Sukezane T, Akagi T, Hamaji T, Grigoriev I, Akhmanova A, Takai Y, Mimori-Kiyosue Y. Laminin-based cell adhesion anchors microtubule plus ends to the epithelial cell basal cortex through LL5alpha/beta. ACTA ACUST UNITED AC 2010; 189:901-17. [PMID: 20513769 PMCID: PMC2878951 DOI: 10.1083/jcb.200910095] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A newly discovered interaction between LL5s, laminins, and integrins reveals how the extracellular matrix directs microtubule polarity in epithelial tissues. LL5β has been identified as a microtubule-anchoring factor that attaches EB1/CLIP-associating protein (CLASP)–bound microtubule plus ends to the cell cortex. In this study, we show that LL5β and its homologue LL5α (LL5s) colocalize with autocrine laminin-5 and its receptors, integrins α3β1 and α6β4, at the basal side of fully polarized epithelial sheets. Depletion of both laminin receptor integrins abolishes the cortical localization of LL5s, whereas LL5 depletion reduces the amount of integrin α3 at the basal cell cortex. Activation of integrin α3 is sufficient to initiate LL5 accumulation at the cell cortex. LL5s form a complex with the cytoplasmic tails of these integrins, but their interaction might be indirect. Analysis of the three-dimensional distribution of microtubule growth by visualizing EB1-GFP in epithelial sheets in combination with RNA interference reveals that LL5s are required to maintain the density of growing microtubules selectively at the basal cortex. These findings reveal that signaling from laminin–integrin associations attaches microtubule plus ends to the epithelial basal cell cortex.
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Affiliation(s)
- Azusa Hotta
- KAN Research Institute, Inc., Chuo-ku, Kobe 650-0047, Japan
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28
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Margadant C, Charafeddine RA, Sonnenberg A. Unique and redundant functions of integrins in the epidermis. FASEB J 2010; 24:4133-52. [DOI: 10.1096/fj.09-151449] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Coert Margadant
- Division of Cell BiologyThe Netherlands Cancer Institute Amsterdam The Netherlands
| | | | - Arnoud Sonnenberg
- Division of Cell BiologyThe Netherlands Cancer Institute Amsterdam The Netherlands
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29
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Wen T, Zhang Z, Yu Y, Qu H, Koch M, Aumailley M. Integrin alpha3 subunit regulates events linked to epithelial repair, including keratinocyte migration and protein expression. Wound Repair Regen 2010; 18:325-34. [PMID: 20412552 DOI: 10.1111/j.1524-475x.2010.00590.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two integrins, alpha3beta1 and alpha6beta4, are high-affinity receptors for laminin 332, the major laminin isoform of the dermal-epidermal junction, although they are thought to have different functions. Biological and genetic studies have firmly established that the alpha6beta4 integrin is indispensable for the stable anchorage of the epidermis to the underlying dermis. In contrast, the alpha3beta1 integrin is thought to be important for cell migration, although the issue is controversial, and both positive and negative effects have been reported. To address the function of alpha3beta1 integrin, we used small interfering RNA to down-regulate the alpha3 subunit in human keratinocytes. The resulting phenotype indicates that lack of alpha3beta1 integrin compromises intercellular adhesion and collective migration, while it enhances single cell migration with a concomitant increase of both focal adhesion kinase and extracellular signal-regulated kinase. In addition, down-regulation of integrin alpha3 subunit results in an increased expression of fibronectin and precursor laminin 332, two extracellular matrix proteins known to be up-regulated during wound healing. Thus, down-regulation of alpha3beta1 integrin recapitulates crucial events governing keratinocyte migration associated with wound healing and tissue repair.
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30
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Ko MS, Marinkovich MP. Role of dermal-epidermal basement membrane zone in skin, cancer, and developmental disorders. Dermatol Clin 2010; 28:1-16. [PMID: 19945611 DOI: 10.1016/j.det.2009.10.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The dermal-epidermal basement membrane zone is an important epithelial and stromal interface, consisting of an intricately organized collection of intracellular, transmembrane, and extracellular matrix proteins. The basement membrane zone has several main functions including acting as a permeability barrier, forming an adhesive interface between epithelial cells and the underlying matrix, and controlling cellular organization and differentiation. This article identifies key molecular players of the dermal-epidermal membrane zone, and highlights recent research studies that have identified structural and functional roles of these components in the context of various blistering, neoplastic, and developmental syndromes.
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Affiliation(s)
- Myung S Ko
- Program in Epithelial Biology, Stanford University School of Medicine, 269 Campus Drive, Stanford, CA 94305, USA
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31
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Daehn IS, Varelias A, Rayner TE. T-lymphocyte-induced, Fas-mediated apoptosis is associated with early keratinocyte differentiation. Exp Dermatol 2009; 19:372-80. [PMID: 19645855 DOI: 10.1111/j.1600-0625.2009.00917.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The development of eczematous lesions is thought to be due in part to a breakdown in skin barrier function as a result of T lymphocytes (T cells) invading the skin causing epidermal keratinocyte apoptosis. In this study, we investigated the interaction of T cells and keratinocytes on apoptosis and terminal differentiation using an in vitro co-culture system. Experiments were performed using the HaCaT keratinocyte cell line or normal human epidermal keratinocytes. Activated human peripheral blood-derived T cells were found to induce Fas-dependent keratinocyte apoptosis by up to sixfold. Increased Fas was associated with increased IFN-gamma. The T-cell apoptotic signal was found to target preferentially keratinocytes in the very early stages of terminal differentiation, such as those with low levels of alpha 6-integrin expression, and result in subsequent increased caspase 3 activity. This observation was accompanied by a marked increase in keratinocyte ICAM-1 expression and its ligand LFA-1 on T cells. Our data suggest that T cells may initiate the onset of keratinocyte terminal differentiation making them more susceptible to Fas-dependent cell death signals delivered by the T cells.
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Affiliation(s)
- Ilse S Daehn
- Women's & Children's Health Research Institute, Women's and Children's Hospital, North Adelaide, SA, Australia.
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32
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Mitchell K, Szekeres C, Milano V, Svenson KB, Nilsen-Hamilton M, Kreidberg JA, DiPersio CM. Alpha3beta1 integrin in epidermis promotes wound angiogenesis and keratinocyte-to-endothelial-cell crosstalk through the induction of MRP3. J Cell Sci 2009; 122:1778-87. [PMID: 19435806 DOI: 10.1242/jcs.040956] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
During cutaneous wound healing, epidermal keratinocytes play essential roles in the secretion of factors that promote angiogenesis. However, specific cues in the wound microenvironment that trigger the production of pro-angiogenic factors by keratinocytes, and the cellular receptors that mediate this response, remain unclear. In this study, we exploited a model of conditional integrin knockout to demonstrate impaired wound angiogenesis in mice that lack alpha3beta1 integrin in epidermis. In addition, we used genetic and shRNA approaches to determine that alpha3beta1-integrin deficiency in keratinocytes leads to reduced mRNA and protein expression of the pro-angiogenic factor mitogen-regulated protein 3 (MRP3; also known as PRL2C4), and to demonstrate that this regulation provides a mechanism of keratinocyte-to-endothelial-cell crosstalk that promotes endothelial-cell migration. Finally, we showed that the impaired wound angiogenesis in epidermis-specific alpha3-integrin-knockout mice is correlated with reduced expression of MRP3 in wounded epidermis. These findings identify a novel role for alpha3beta1 integrin in promoting wound angiogenesis through a mechanism of crosstalk from epidermal to endothelial cells, and they implicate MRP3 in this integrin-dependent crosstalk. Such a mechanism represents a novel paradigm for integrin-mediated regulation of wound angiogenesis that extends beyond traditional roles for integrins in cell adhesion and migration.
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Affiliation(s)
- Kara Mitchell
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, NY 12208, USA
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D'Alessio S, Gerasi L, Blasi F. uPAR-deficient mouse keratinocytes fail to produce EGFR-dependent laminin-5, affecting migration in vivo and in vitro. J Cell Sci 2008; 121:3922-32. [PMID: 19001498 DOI: 10.1242/jcs.037549] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The urokinase receptor (uPAR) is involved in a series of pathological processes, from inflammation to cancer. We have analyzed in detail the role of uPAR and the mechanisms involved in keratinocyte behavior during wound healing by exploiting uPAR-knockout (KO) mice. In vivo, uPAR-KO mice showed delayed wound healing, with abnormal keratinocyte migration and proliferation. In vitro, unlike wild-type cells, primary uPAR-KO keratinocytes did not proliferate in response to epidermal growth factor (EGF), their growth and migration were not inhibited by EGF-receptor (EGFR) inhibitors, and they did not adhere to uncoated surfaces. Whereas EGFR levels in uPAR-KO keratinocytes were normal, there was no tyrosine phosphorylation upon addition of EGF, and its downstream targets, extracellular-signal-regulated kinases 1 and 2 (ERK1/2), were not activated. Re-introduction of mouse uPAR rescued all phenotypes. In vitro adhesion and migration defects were associated with the failure of uPAR-KO keratinocytes to normally produce and secrete laminin-5 (LN5), an event that requires EGFR signaling. These results were confirmed in vivo, with LN5 being upregulated during wound healing in wild-type but not in uPAR-KO epidermis.
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Affiliation(s)
- Silvia D'Alessio
- Università Vita Salute San Raffaele and Istituto Scientifico H San Raffaele, via Olgettina 60, 20132 Milano, Italy
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34
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Beta1 integrin expression by podocytes is required to maintain glomerular structural integrity. Dev Biol 2008; 316:288-301. [PMID: 18328474 DOI: 10.1016/j.ydbio.2008.01.022] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 01/09/2008] [Accepted: 01/15/2008] [Indexed: 11/22/2022]
Abstract
Integrins are transmembrane heteromeric receptors that mediate interactions between cells and extracellular matrix (ECM). beta1, the most abundantly expressed integrin subunit, binds at least 12 alpha subunits. beta1 containing integrins are highly expressed in the glomerulus of the kidney; however their role in glomerular morphogenesis and maintenance of glomerular filtration barrier integrity is poorly understood. To study these questions we selectively deleted beta1 integrin in the podocyte by crossing beta1(flox/flox) mice with podocyte specific podocin-cre mice (pod-Cre), which express cre at the time of glomerular capillary formation. We demonstrate that podocyte abnormalities are visualized during glomerulogenesis of the pod-Cre;beta1(flox/flox) mice and proteinuria is present at birth, despite a grossly normal glomerular basement membrane. Following the advent of glomerular filtration there is progressive podocyte loss and the mice develop capillary loop and mesangium degeneration with little evidence of glomerulosclerosis. By 3 weeks of age the mice develop severe end stage renal failure characterized by both tubulointerstitial and glomerular pathology. Thus, expression of beta1 containing integrins by the podocyte is critical for maintaining the structural integrity of the glomerulus.
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35
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Ackerl R, Walko G, Fuchs P, Fischer I, Schmuth M, Wiche G. Conditional targeting of plectin in prenatal and adult mouse stratified epithelia causes keratinocyte fragility and lesional epidermal barrier defects. J Cell Sci 2007; 120:2435-43. [PMID: 17606998 DOI: 10.1242/jcs.004481] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plectin, a widespread intermediate filament-based cytolinker protein capable of interacting with a variety of cytoskeletal structures and plasma membrane-bound junctional complexes, serves essential functions in maintenance of cell and tissue cytoarchitecture. We have generated a mouse line bearing floxed plectin alleles and conditionally deleted plectin in stratified epithelia. This strategy enabled us to study the consequences of plectin deficiency in this particular type of tissues in the context of the whole organism without plectin loss affecting other tissues. Conditional knockout mice died early after birth, showing signs of starvation and growth retardation. Blistering was observed on their extremities and on the oral epithelium after initial nursing, impairing food uptake. Knockout epidermis was very fragile and showed focal epidermal barrier defects caused by the presence of small skin lesions. Stratification, proliferation and differentiation of knockout skin seemed unaffected by epidermis-restricted plectin deficiency. In an additionally generated mouse model, tamoxifen-induced Cre-ER(T)-mediated recombination led to mice with a mosaic plectin deletion pattern in adult epidermis, combined with microblister formation and epidermal barrier defects. Our study explains the early lethality of plectin-deficient mice and provides a model to ablate plectin in adult animals which could be used for developing gene or pharmacological therapies.
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Affiliation(s)
- Reinhard Ackerl
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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36
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Rodius S, Indra G, Thibault C, Pfister V, Georges-Labouesse E. Loss of alpha6 integrins in keratinocytes leads to an increase in TGFbeta and AP1 signaling and in expression of differentiation genes. J Cell Physiol 2007; 212:439-49. [PMID: 17474077 DOI: 10.1002/jcp.21040] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mice lacking the alpha6 integrin chain die at birth with severe skin blistering. To further study the function of alpha6 integrin in skin, we generated conditionally immortalized cell lines from the epidermis of wild-type and alpha6 deficient mouse embryos. Mutant cells presented a decreased adhesion on laminin 5, the major component of the basement membrane in the skin, and on laminins 10/11 and 2. A DNA array analysis revealed alterations in the expression of extracellular matrix (ECM) components including laminin 5, cytoskeletal elements, but also membrane receptors like the hemidesmosomal components integrin beta4 and collagen XVII, or growth factors and signaling molecules of the TGFbeta, EGF, and Wnt pathways. Finally, an increase of several epidermal differentiation markers was observed in cells and tissue at the protein level. Further examination of the mutant tissue revealed alterations in the filaggrin signal. These differences may be linked to an upregulation of the TGFbeta and the Jun/Fos pathways in mutant keratinocytes. These results are in favor of a role for integrin alpha6beta4 in the maintenance of basal keratinocyte properties and epidermal homeostasis.
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Affiliation(s)
- Sophie Rodius
- Department of Developmental Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
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37
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Edick MJ, Tesfay L, Lamb LE, Knudsen BS, Miranti CK. Inhibition of integrin-mediated crosstalk with epidermal growth factor receptor/Erk or Src signaling pathways in autophagic prostate epithelial cells induces caspase-independent death. Mol Biol Cell 2007; 18:2481-90. [PMID: 17475774 PMCID: PMC1924805 DOI: 10.1091/mbc.e06-04-0261] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 04/20/2007] [Accepted: 04/24/2007] [Indexed: 01/13/2023] Open
Abstract
In vivo in the prostate gland, basal epithelial cells adhere to laminin 5 (LM5) via alpha3beta1 and alpha6beta4 integrins. When placed in culture primary prostate basal epithelial cells secrete and adhere to their own LM5-rich matrix. Adhesion to LM5 is required for cell survival that is dependent on integrin-mediated, ligand-independent activation of the epidermal growth factor receptor (EGFR) and the cytoplasmic tyrosine kinase Src, but not PI-3K. Integrin-mediated adhesion via alpha3beta1, but not alpha6beta4 integrin, supports cell survival through EGFR by signaling downstream to Erk. PC3 cells, which do not activate EGFR or Erk on LM5-rich matrices, are not dependent on this pathway for survival. PC3 cells are dependent on PI-3K for survival and undergo caspase-dependent death when PI-3K is inhibited. The death induced by inhibition of EGFR or Src in normal primary prostate cells is not mediated through or dependent on caspase activation, but depends on the induction of reactive oxygen species. In addition the presence of an autophagic pathway, maintained by adhesion to matrix through alpha3beta1 and alpha6beta4, prevents the induction of caspases when EGFR or Src is inhibited. Suppression of autophagy is sufficient to induce caspase activation and apoptosis in LM5-adherent primary prostate epithelial cells.
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Affiliation(s)
- Mathew J. Edick
- *Laboratory of Integrin Signaling, Van Andel Research Institute, Grand Rapids, MI 49503; and
| | - Lia Tesfay
- *Laboratory of Integrin Signaling, Van Andel Research Institute, Grand Rapids, MI 49503; and
| | - Laura E. Lamb
- *Laboratory of Integrin Signaling, Van Andel Research Institute, Grand Rapids, MI 49503; and
| | - Beatrice S. Knudsen
- Division of Public Health Sciences, Program in Cancer Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Cindy K. Miranti
- *Laboratory of Integrin Signaling, Van Andel Research Institute, Grand Rapids, MI 49503; and
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38
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Tsai SH, Liu YW, Tang WC, Zhou ZW, Hwang CY, Hwang GY, Ou BR, Hu CP, Yang VC, Chen JK. Characterization of porcine arterial endothelial cells cultured on amniotic membrane, a potential matrix for vascular tissue engineering. Biochem Biophys Res Commun 2007; 357:984-90. [PMID: 17459341 DOI: 10.1016/j.bbrc.2007.04.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 04/10/2007] [Indexed: 01/02/2023]
Abstract
The existing of basement membrane improves the development of endothelium while constructing blood vessel equivalent. The amniotic membrane (AM) provides a natural basement membrane and has been used in ocular surface reconstruction. This study evaluated the molecular and cellular characteristics of porcine vascular endothelial cells (ECs) cultured on AM. ECs cultured on AM expressed the endothelial marker vWF and exhibited normal endothelial morphology. Here, we demonstrated that AM enhanced the expression of intercellular molecules, platelet-endothelial cell adhesion molecule-1 (PECAM-1), and adhesion molecule VE-cadherin at the intercellular junctions. The expression level of integrin was markedly higher in ECs cultured on AM than on plastic dish. Furthermore, the AM downregulated the expression of E-selectin and P-selectin in both LPS-activated and non-activated ECs. Consistently, adhesion of leukocytes to both activated and non-activated cells was decreased in ECs cultured on AM. Our results suggest that AM is an ideal matrix to develop a functional endothelium in blood vessel equivalent construction.
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Affiliation(s)
- Shu-Huai Tsai
- Department of Life Science, Tunghai University, Taichung, Taiwan
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39
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Choma DP, Milano V, Pumiglia KM, DiPersio CM. Integrin alpha3beta1-dependent activation of FAK/Src regulates Rac1-mediated keratinocyte polarization on laminin-5. J Invest Dermatol 2007; 127:31-40. [PMID: 16917494 DOI: 10.1038/sj.jid.5700505] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Upon epidermal wounding, keratinocytes at the wound edge become activated, deposit newly synthesized laminin-5 into the extracellular matrix, and migrate into the wound bed. The interaction between integrin alpha3beta1 and laminin-5 is essential for establishment of a stable, leading lamellipodium and persistent keratinocyte migration. We previously showed that integrin alpha3beta1 activates the Rho family GTPase Rac1 and regulates Rac1-dependent formation of polarized, leading lamellipodia in migrating keratinocytes. In the present study, we explored the role of focal adhesion kinase (FAK) and src signaling in this process. We show that overexpression of the FAK inhibitor FAK-related non-kinase or of the FAK(Y397F) auto-phosphorylation mutant, induced abnormal, non-polarized spreading of keratinocytes on laminin-5. Integrin alpha3beta1 was required for full FAK auto-phosphorylation at Y397, and subsequent src kinase-dependent phosphorylation of FAK at residues Y861 and Y925, sites responsible for promoting signal transduction downstream of FAK, indicating that alpha3beta1 regulates the coordination of FAK/src signal transduction. Inhibiting either src kinase activity or FAK signaling interfered with alpha3beta1-mediated Rac1 activation and polarized cell spreading. These findings reveal a novel pathway in migratory keratinocytes wherein alpha3beta1-laminin-5 interactions regulate src kinase signaling through FAK, promoting Rac1 activation and polarized lamellipodium extension.
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Affiliation(s)
- David P Choma
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York 12208-3479, USA
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40
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Knudsen BS, Miranti CK. The impact of cell adhesion changes on proliferation and survival during prostate cancer development and progression. J Cell Biochem 2006; 99:345-61. [PMID: 16676354 DOI: 10.1002/jcb.20934] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the normal prostate epithelium, androgen receptor (AR) negative basal epithelial cells adhere to the substratum, while AR expressing secretory cells lose substratum adhesion. In contrast, prostate cancer cells both express AR and adhere to a tumor basement membrane. In this review, we describe the differential expression of integrins, growth factor receptors (GFRs), and AR in normal and cancerous epithelium. In addition, we discuss how signals from integrins, GFRs, and AR are integrated to regulate the proliferation and survival of normal and malignant prostate epithelial cells. While cell adhesion is likely of great importance when considering therapeutic approaches for treatment of metastatic prostate cancer, no data on integrin expression are available from tissues of prostate cancer metastasis. However, several drug targets that are upregulated after androgen ablative therapy regulate cell adhesion and thus novel targeted therapies indirectly interfere with cell adhesion mechanisms in prostate cancer cells.
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Affiliation(s)
- Beatrice S Knudsen
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
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41
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Wu X, Quondamatteo F, Brakebusch C. Cdc42 expression in keratinocytes is required for the maintenance of the basement membrane in skin. Matrix Biol 2006; 25:466-74. [PMID: 17049825 DOI: 10.1016/j.matbio.2006.09.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 08/01/2006] [Accepted: 09/06/2006] [Indexed: 01/16/2023]
Abstract
Cdc42 is a small GTPase, which acts as a molecular switch to regulate a wide variety of cellular functions, such as actin cytoskeleton organization, cell proliferation, apoptosis, cell migration and in particular, cell polarity. Formation and maintenance of the basement membrane is a polarized process, which requires directed secretion, deposition and organization of basement membrane components at the basal side of epithelial cells. In the current study, we analyzed the maintenance of skin basement membrane in mice with a keratinocyte-restricted deletion of the Cdc42 gene. In the absence of Cdc42, basement membrane components became aberrantly deposited and the processing of laminin 5 was impaired in parts of the dermal-epidermal junction. These impairments became more severe with age and corresponded to local defects of the basement membrane in 4.5-month-old mutant mice. However, both, structure and number of hemidesomosomes were not significantly changed in the Cdc42 mutant skin compared with the control mice and no blister formation was observed in mutant skin. These data indicate that Cdc42 in keratinocytes is important for maintenance of the basement membrane of skin.
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Affiliation(s)
- Xunwei Wu
- University of Copenhagen, Institute of Molecular Pathology, Fredrik V's Vej 11, 2100 Copenhagen, Denmark
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42
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Turner FE, Broad S, Khanim FL, Jeanes A, Talma S, Hughes S, Tselepis C, Hotchin NA. Slug regulates integrin expression and cell proliferation in human epidermal keratinocytes. J Biol Chem 2006; 281:21321-21331. [PMID: 16707493 DOI: 10.1074/jbc.m509731200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The human epidermis is a self-renewing epithelial tissue composed of several layers of keratinocytes. Within the epidermis there exists a complex array of cell adhesion structures, and many of the cellular events within the epidermis (differentiation, proliferation, and migration) require that these adhesion structures be remodeled. The link between cell adhesion, proliferation, and differentiation within the epidermis is well established, and in particular, there is strong evidence to link the process of terminal differentiation to integrin adhesion molecule expression and function. In this paper, we have analyzed the role of a transcriptional repressor called Slug in the regulation of adhesion molecule expression and function in epidermal keratinocytes. We report that activation of Slug, which is expressed predominantly in the basal layer of the epidermis, results in down-regulation of a number of cell adhesion molecules, including E-cadherin, and several integrins, including alpha3, beta1, and beta4. We demonstrate that Slug binds to the alpha3 promoter and that repression of alpha3 transcription by Slug is dependent on an E-box sequence within the promoter. This reduction in integrin expression is reflected in decreased cell adhesion to fibronectin and laminin-5. Despite the reduction in integrin expression and function, we do not observe any increase in differentiation. We do, however, find that activation of Slug results in a significant reduction in keratinocyte proliferation.
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Affiliation(s)
- Frances E Turner
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Simon Broad
- Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
| | - Farhat L Khanim
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Alexa Jeanes
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Sonia Talma
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Sharon Hughes
- School of Medicine, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Chris Tselepis
- School of Medicine, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Neil A Hotchin
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
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43
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Wilhelmsen K, Litjens SHM, Sonnenberg A. Multiple functions of the integrin alpha6beta4 in epidermal homeostasis and tumorigenesis. Mol Cell Biol 2006; 26:2877-86. [PMID: 16581764 PMCID: PMC1446957 DOI: 10.1128/mcb.26.8.2877-2886.2006] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Kevin Wilhelmsen
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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44
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López-Rovira T, Silva-Vargas V, Watt FM. Different consequences of beta1 integrin deletion in neonatal and adult mouse epidermis reveal a context-dependent role of integrins in regulating proliferation, differentiation, and intercellular communication. J Invest Dermatol 2006; 125:1215-27. [PMID: 16354192 DOI: 10.1111/j.0022-202x.2005.23956.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There are conflicting reports of the consequences of deleting beta1 integrins from the epidermis of transgenic mice. Epidermal thinning with normal differentiation and lack of inflammation has been observed; conversely, epidermal thickening, abnormal differentiation, and dermal fibrosis can occur. beta1 integrin deletion results in decreased epidermal proliferation, yet on wounding the proliferative defect is overcome. To distinguish primary from secondary consequences of beta1 integrin loss, we compared epidermal beta1 deletion at E14.5 via K5Cre and 4-hydroxy-tamoxifen induced deletion in adulthood via K14CreER. As reported previously, there was dermo-epidermal splitting, inflammation, reduced proliferation, and hair follicle and sebaceous gland loss in 30-d-old K5Cre beta1-null mice. These changes were not observed 30 d after beta1 integrin deletion in adult epidermis, however, and there were no changes in the hair follicle stem cell compartment. Deletion in adult epidermis revealed a previously unreported correlation between the level of beta1 integrins and proliferation in the interfollicular epidermis that was remarkably consistent with human epidermis. In addition, the number of melanocytes in interfollicular epidermis was greatly increased. Our results highlight the context-dependent effects of beta1 integrin deletion and suggest that inflammation may be responsible for some of the K5Cre beta1-null phenotype.
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Affiliation(s)
- Teresa López-Rovira
- Keratinocyte Laboratory, Cancer Research UK London Research Institute, London, UK
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45
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Hamelers IHL, Olivo C, Mertens AEE, Pegtel DM, van der Kammen RA, Sonnenberg A, Collard JG. The Rac activator Tiam1 is required for (alpha)3(beta)1-mediated laminin-5 deposition, cell spreading, and cell migration. J Cell Biol 2005; 171:871-81. [PMID: 16330714 PMCID: PMC2171282 DOI: 10.1083/jcb.200509172] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 10/31/2005] [Indexed: 01/10/2023] Open
Abstract
The Rho-like guanosine triphosphatase Rac1 regulates various signaling pathways, including integrin-mediated adhesion and migration of cells. However, the mechanisms by which integrins signal toward Rac are poorly understood. We show that the Rac-specific guanine nucleotide exchange factor Tiam1 (T-lymphoma invasion and metastasis 1) is required for the integrin-mediated laminin (LN)-5 deposition, spreading, and migration of keratinocytes. In contrast to wild-type keratinocytes, Tiam1-deficient (Tiam1-/-) keratinocytes are unable to adhere to and spread on a glass substrate because they are unable to deposit their own LN5 substrate. Both Tiam1 and V12Rac1 can rescue the defects of Tiam1-/- keratinocytes, indicating that these deficiencies are caused by impaired Tiam1-mediated Rac activation. Tiam1-/- cells are unable to activate Rac upon alpha3beta1-mediated adhesion to an exogenous LN5 substrate. Moreover, Tiam1 deficiency impairs keratinocyte migration in vitro and reepithelialization of excision wounds in mouse skin. Our studies indicate that Tiam1 is a key molecule in alpha3beta1-mediated activation of Rac, which is essential for proper production and secretion of LN5, a requirement for the spreading and migration of keratinocytes.
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Affiliation(s)
- Irene H L Hamelers
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
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46
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Lipscomb EA, Mercurio AM. Mobilization and activation of a signaling competent α6β4integrin underlies its contribution to carcinoma progression. Cancer Metastasis Rev 2005; 24:413-23. [PMID: 16258729 DOI: 10.1007/s10555-005-5133-4] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This review examines the hypothesis that the function of the alpha 6beta 4 integrin is altered substantially as normal epithelia undergo malignant transformation and progress to invasive carcinoma and that the functions of this integrin contribute to the behavior of aggressive carcinoma cells. Specifically, alpha 6beta 4 functions primarily as an adhesion receptor in normal epithelia, often as a component of hemidesmosomes and associated with intermediate filaments. Factors in the host-tumor microenvironment have the potential to mobilize alpha 6beta 4 from hemidesmosomes and promote its association with F-actin in lamellae and filopodia, a process that is mediated by PKC-dependent phosphorylation of the beta 4 cytoplasmic domain. Importantly, this altered localization of alpha 6beta 4 appears to be coupled to an activation of its signaling potential, which may occur through its association with growth factor receptors or lipid rafts, possibilities that are not mutually exclusive. The primal signaling event triggered by alpha 6beta 4 appears to be activation of PI3-K and this activation has profound consequences on the migration, invasion and survival of carcinoma cells. Arguably, the ability of alpha 6beta 4 to stimulate the PI3-K-dependent translation of VEGF and possibly other growth factors may be the most significant contribution of this integrin to carcinoma because of the potential autocrine and paracrine effects of these factors.
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Affiliation(s)
- Elizabeth A Lipscomb
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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47
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Nikolopoulos SN, Blaikie P, Yoshioka T, Guo W, Puri C, Tacchetti C, Giancotti FG. Targeted deletion of the integrin beta4 signaling domain suppresses laminin-5-dependent nuclear entry of mitogen-activated protein kinases and NF-kappaB, causing defects in epidermal growth and migration. Mol Cell Biol 2005; 25:6090-102. [PMID: 15988021 PMCID: PMC1168825 DOI: 10.1128/mcb.25.14.6090-6102.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 12/20/2004] [Accepted: 04/28/2005] [Indexed: 01/15/2023] Open
Abstract
The alpha6beta4 integrin-a laminin-5 receptor-mediates assembly of hemidesmosomes and recruitment of Shc and phosphoinositide 3-kinase through the unique cytoplasmic extension of beta4. Mice carrying a targeted deletion of the signaling domain of beta4 develop normally and do not display signs of skin fragility. The epidermis of these mice contains well-structured hemidesmosomes and adheres stably to the basement membrane. However, it is hypoplastic due to reduced proliferation of basal keratinocytes and undergoes wound repair at a reduced rate. Keratinocytes from beta4 mutant mice undergo extensive spreading but fail to proliferate and migrate in response to epidermal growth factor (EGF) on laminin-5. EGF causes significant phosphorylation of extracellular signal-regulated kinase (ERK) and Jun N-terminal protein kinase (JNK) and phosphorylation and degradation of IkappaB in beta4 mutant cells adhering to laminin-5. Unexpectedly, however, ERK, JNK, and NF-kappaB remain in the cytoplasm in beta4 mutant cells on laminin-5, whereas they enter effectively into the nucleus in the same cells on fibronectin or in wild-type cells on both matrix proteins. Inhibitor studies indicate that alpha6beta4 promotes keratinocyte proliferation and migration through its effect on NF-kappaB and P-JNK. These findings provide evidence that beta4 signaling promotes epidermal growth and wound healing through a previously unrecognized effect on nuclear translocation of NF-kappaB and mitogen-activated protein kinases.
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Affiliation(s)
- Sotiris N Nikolopoulos
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, Box 216, 1275 York Avenue, New York, New York 10021, USA
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48
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Morasso MI, Tomic-Canic M. Epidermal stem cells: the cradle of epidermal determination, differentiation and wound healing. Biol Cell 2005; 97:173-83. [PMID: 15715523 PMCID: PMC1283090 DOI: 10.1042/bc20040098] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The field of epidermal stem cells has dramatically advanced in the last decade, leading to a better understanding of the molecular factors, signalling pathways and cellular events that identify and characterize stem cells, thus revealing their immense potential for therapeutic use. Furthermore, multipotent epidermal stem cells present the major advantage of easy accessibility with the discovery of their specific location within the bulge of the hair follicle. This review focuses on the most recent findings on epidermal stem cells, and their potential role in initial epidermal commitment, differentiation and wound healing processes in the skin.
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Affiliation(s)
- Maria I Morasso
- Developmental Skin Biology Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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49
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Raymond K, Kreft M, Janssen H, Calafat J, Sonnenberg A. Keratinocytes display normal proliferation, survival and differentiation in conditional β4-integrin knockout mice. J Cell Sci 2005; 118:1045-60. [PMID: 15731010 DOI: 10.1242/jcs.01689] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The α6β4 integrin is located at the basal surface of keratinocytes, in hemidesmosomal structures that mediate stable adhesion of epidermal cells to the underlying basement membrane component laminin-5. The absence of α6β4 integrin causes junctional epidermolysis bullosa, a severe blistering disease of the skin leading to perinatal death, confirming its essential role in mediating strong keratinocyte adhesion. Several studies have suggested that α6β4 integrin can also regulate signaling cascades that control cell proliferation, survival and migration through a mechanism independent of its adhesive function. We have generated a conditional knockout mouse strain, in which the gene encoding the β4 integrin subunit (Itgb4) was inactivated only in small stretches of the skin. These mice were viable and permitted an accurate analysis of the consequences of the loss of β4 on various biological processes by comparing β4-positive and -negative parts of the skin in the same animal. Despite the complete loss of hemidesmosomes in regions lacking α6β4 integrin, the distribution of a range of adhesion receptors and basement membrane proteins was unaltered. Moreover, loss of α6β4 did not affect squamous differentiation, proliferation or survival, except for areas in which keratinocytes had detached from the basement membrane. These in vivo observations were confirmed in vitro by using immortalized keratinocytes – derived from β4-subunit conditional knockout mice – from which the gene encoding β4 had been deleted by Cre-mediated recombination. Consistent with the established role of α6β4 in adhesion strengthening, its loss from cells was found to increase their motility. Our findings clearly demonstrate that, after birth, epidermal differentiation, proliferation and survival all proceed normally in the absence of α6β4, provided that cell adhesion is not compromised.
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Affiliation(s)
- Karine Raymond
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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50
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Abstract
Extracellular matrix (ECM) molecules and growth factors have a crucial role in the signalling that controls cell behaviour during development. Integrins, which are cell-surface receptors for ECM molecules, and growth factor receptors cooperate with each other to regulate this signalling by several mechanisms. In particular, direct interactions between the integrin and growth factor receptors themselves, which often occur within a single macromolecular complex, amplify signalling by mechanisms that include posttranslational modifications and integrin shape changes that are related to activation. As a result, growth factor concentrations in the physiological range, which are too low to initiate signalling alone, do so in the presence of the ECM, enabling integrins to control the time and space of growth factor signalling.
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Affiliation(s)
- Charles ffrench-Constant
- Departments of Pathology and Medical Genetics, and Cambridge Centre for Brain Repair, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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