51
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Trappmann B, Gautrot JE, Connelly JT, Strange DGT, Li Y, Oyen ML, Cohen Stuart MA, Boehm H, Li B, Vogel V, Spatz JP, Watt FM, Huck WTS. Extracellular-matrix tethering regulates stem-cell fate. NATURE MATERIALS 2012; 11:642-9. [PMID: 22635042 DOI: 10.1038/nmat3339] [Citation(s) in RCA: 1093] [Impact Index Per Article: 91.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 04/20/2012] [Indexed: 05/20/2023]
Abstract
To investigate how substrate properties influence stem-cell fate, we cultured single human epidermal stem cells on polydimethylsiloxane (PDMS) and polyacrylamide (PAAm) hydrogel surfaces, 0.1 kPa-2.3 MPa in stiffness, with a covalently attached collagen coating. Cell spreading and differentiation were unaffected by polydimethylsiloxane stiffness. However, cells on polyacrylamide of low elastic modulus (0.5 kPa) could not form stable focal adhesions and differentiated as a result of decreased activation of the extracellular-signal-related kinase (ERK)/mitogen-activated protein kinase (MAPK) signalling pathway. The differentiation of human mesenchymal stem cells was also unaffected by PDMS stiffness but regulated by the elastic modulus of PAAm. Dextran penetration measurements indicated that polyacrylamide substrates of low elastic modulus were more porous than stiff substrates, suggesting that the collagen anchoring points would be further apart. We then changed collagen crosslink concentration and used hydrogel-nanoparticle substrates to vary anchoring distance at constant substrate stiffness. Lower collagen anchoring density resulted in increased differentiation. We conclude that stem cells exert a mechanical force on collagen fibres and gauge the feedback to make cell-fate decisions.
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Affiliation(s)
- Britta Trappmann
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Kyriakakis E, Maslova K, Philippova M, Pfaff D, Joshi MB, Buechner SA, Erne P, Resink TJ. T-Cadherin is an auxiliary negative regulator of EGFR pathway activity in cutaneous squamous cell carcinoma: impact on cell motility. J Invest Dermatol 2012; 132:2275-85. [PMID: 22592160 DOI: 10.1038/jid.2012.131] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Genetic and epigenetic studies in different cancers, including cutaneous carcinomas, have implicated T-cadherin (T-cad) as a tumor suppressor. Immunohistochemical and in vitro studies have suggested that T-cad loss promotes incipient invasiveness in cutaneous squamous cell carcinoma (SCC). Molecular mechanisms are unknown. This study found that the main consequence of T-cad silencing in SCC is facilitation of ligand-dependent EGFR activation, whereas T-cad overexpression impedes EGFR activation. Gain- and loss-of-function studies in A431 SCC cells demonstrate T-cad-controlled responsiveness to EGF with respect to pharmacological inhibition of EGFR and to diverse signaling and functional events of the EGFR activation cascade (EGFR phosphorylation, internalization, nuclear translocation, cell retraction/de-adhesion, motility, invasion, integrin β1, and Rho small GTPases such as RhoA, Rac1, and Cdc42 activation). Further, T-cad modulates the EGFR pathway activity by influencing membrane compartmentalization of EGFR; T-cad upregulation promotes retention of EGFR in lipid rafts, whereas T-cad silencing releases EGFR from this compartment, rendering EGFR more accessible to ligand stimulation. This study reveals a mechanism for fine-tuning of EGFR activity in SCC, whereby T-cad represents an auxiliary "negative" regulator of the EGFR pathway, which impacts invasion-associated behavioral responses of SCC to EGF. This action of T-cad in SCC may serve as a paradigm explaining other malignancies displaying concomitant T-cad loss and enhanced EGFR activity.
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Affiliation(s)
- Emmanouil Kyriakakis
- Laboratory for Signal Transduction, Department of Biomedicine, Basel University Hospital, Basel, Switzerland
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53
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Sun Y, Villa-Diaz LG, Lam RHW, Chen W, Krebsbach PH, Fu J. Mechanics regulates fate decisions of human embryonic stem cells. PLoS One 2012; 7:e37178. [PMID: 22615930 PMCID: PMC3353896 DOI: 10.1371/journal.pone.0037178] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 04/18/2012] [Indexed: 01/10/2023] Open
Abstract
Research on human embryonic stem cells (hESCs) has attracted much attention given their great potential for tissue regenerative therapy and fundamental developmental biology studies. Yet, there is still limited understanding of how mechanical signals in the local cellular microenvironment of hESCs regulate their fate decisions. Here, we applied a microfabricated micromechanical platform to investigate the mechanoresponsive behaviors of hESCs. We demonstrated that hESCs are mechanosensitive, and they could increase their cytoskeleton contractility with matrix rigidity. Furthermore, rigid substrates supported maintenance of pluripotency of hESCs. Matrix mechanics-mediated cytoskeleton contractility might be functionally correlated with E-cadherin expressions in cell-cell contacts and thus involved in fate decisions of hESCs. Our results highlighted the important functional link between matrix rigidity, cellular mechanics, and pluripotency of hESCs and provided a novel approach to characterize and understand mechanotransduction and its involvement in hESC function.
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Affiliation(s)
- Yubing Sun
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Luis G. Villa-Diaz
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Raymond H. W. Lam
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Weiqiang Chen
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Paul H. Krebsbach
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jianping Fu
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Boehnke K, Falkowska-Hansen B, Stark HJ, Boukamp P. Stem cells of the human epidermis and their niche: composition and function in epidermal regeneration and carcinogenesis. Carcinogenesis 2012; 33:1247-58. [PMID: 22461521 DOI: 10.1093/carcin/bgs136] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Skin, as the largest organ, has long been subject of excellent and pioneering studies on stem cells and their role in tissue regulation and tumor formation. In particular, intensive research on mouse skin, and here especially the hair follicle, has largely extended our knowledge. Surprisingly, human skin, although the most easily accessible tissue in man, is far less conceived with regard to its stem cells and their specific environment (the niche). In consequence, these features are as yet only insufficiently defined and it still has to be elucidated how insights in cutaneous stem cell biology gained in mice can be extrapolated to humans. In the last few years, human model systems such as humanized mice or in vitro organotypic cultures that support maintenance or reconstruction of human skin and long-term epidermal regeneration have been developed. These models allow lineage tracing experiments and can be modified by adopting genetically manipulated cell types. Accordingly, they represent proper tools for human stem cell research and will clearly help to improve our still incomplete understanding. Like normal skin, the non-melanoma skin cancers and their respective tumors have gained considerable interest in basic as well as in clinical research. Being the most frequent human tumors globally, basal cell carcinomas and cutaneous squamous cell carcinomas (SCCs) continue to increase in incidence and specifically SCCs predominate in immunosuppressed transplant recipients. This review intends to compile the present knowledge on keratinocyte stem cells and their niches in normal skin and skin carcinomas with a special focus on the human situation. In particular, the role of the microenvironment, the niche, is emphasized, promoting our view of the decisive importance of the niche as a key regulatory element for controlling position, fate and regenerative potential of the stem cell population both in healthy skin and in carcinomas.
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Affiliation(s)
- Karsten Boehnke
- Division of Genetics of Skin Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Sun Y, Chen CS, Fu J. Forcing stem cells to behave: a biophysical perspective of the cellular microenvironment. Annu Rev Biophys 2012; 41:519-42. [PMID: 22404680 DOI: 10.1146/annurev-biophys-042910-155306] [Citation(s) in RCA: 297] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Physical factors in the local cellular microenvironment, including cell shape and geometry, matrix mechanics, external mechanical forces, and nanotopographical features of the extracellular matrix, can all have strong influences on regulating stem cell fate. Stem cells sense and respond to these insoluble biophysical signals through integrin-mediated adhesions and the force balance between intracellular cytoskeletal contractility and the resistant forces originated from the extracellular matrix. Importantly, these mechanotransduction processes can couple with many other potent growth-factor-mediated signaling pathways to regulate stem cell fate. Different bioengineering tools and microscale/nanoscale devices have been successfully developed to engineer the physical aspects of the cellular microenvironment for stem cells, and these tools and devices have proven extremely powerful for identifying the extrinsic physical factors and their downstream intracellular signaling pathways that control stem cell functions.
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Affiliation(s)
- Yubing Sun
- Integrated Biosystems and Biomechanics Laboratory, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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56
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He H, Li MW, Niu CS. The pathological characteristics of glioma stem cell niches. J Clin Neurosci 2011; 19:121-7. [PMID: 22178090 DOI: 10.1016/j.jocn.2011.07.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 01/10/2023]
Abstract
Brain tumor stem cells (BTSC) are predicted to be critical drivers of tumor progression due to their self-renewal capacity and limitless proliferative potential. Recent studies suggest that stem cells are controlled by a particular microenvironment known as a "niche". We therefore analysed human glioma tissues and found that the CD133(+) and nestin(+) niches are perivascularly localized in all glioma tissues. Furthermore, there is a positive correlation between the CD133(+) niches and CD133(+) blood vessels, which is similar to the correlation between the nestin(+) niches and nestin(+) blood vessels. We demonstrate that both CD133(+) blood vessels and nestin(+) blood vessels have an important role in maintaining the structure of the glioma stem cell niche. Moreover, the abundance of CD133(+) niches and nestin(+) niches increases significantly as tumor grade increases. These findings provide a new insight into the biology of BTSC and open a new perspective for targeted therapy against the brain tumors.
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Affiliation(s)
- Hu He
- Department of Neurosurgery, Anhui Provincial Hospital Affiliated to Anhui Medical University, 17 Lujiang Road, Hefei, Anhui Province 230001, China
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Connelly JT, Mishra A, Gautrot JE, Watt FM. Shape-induced terminal differentiation of human epidermal stem cells requires p38 and is regulated by histone acetylation. PLoS One 2011; 6:e27259. [PMID: 22073300 PMCID: PMC3206954 DOI: 10.1371/journal.pone.0027259] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 10/12/2011] [Indexed: 11/19/2022] Open
Abstract
Engineered model substrates are powerful tools for examining interactions between stem cells and their microenvironment. Using this approach, we have previously shown that restricted cell adhesion promotes terminal differentiation of human epidermal stem cells via activation of serum response factor (SRF) and transcription of AP-1 genes. Here we investigate the roles of p38 MAPK and histone acetylation. Inhibition of p38 activity impaired SRF transcriptional activity and shape-induced terminal differentiation of human keratinocytes. In addition, inhibiting p38 reduced histone H3 acetylation at the promoters of SRF target genes, FOS and JUNB. Although histone acetylation correlated with SRF transcriptional activity and target gene expression, treatment with the histone de-acetylase inhibitor, trichostatin A (TSA) blocked terminal differentiation on micro-patterned substrates and in suspension. TSA treatment simultaneously maintained expression of LRIG1, TP63, and ITGB1. Therefore, global histone de-acetylation represses stem cell maintenance genes independent of SRF. Our studies establish a novel role for extrinsic physical cues in the regulation of chromatin remodeling, transcription, and differentiation of human epidermal stem cells.
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Affiliation(s)
- John T Connelly
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
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58
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Reiisi S, Esmaeili F, Shirazi A. Isolation, culture and identification of epidermal stem cells from newborn mouse skin. In Vitro Cell Dev Biol Anim 2011; 46:54-9. [PMID: 19915936 DOI: 10.1007/s11626-009-9245-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 09/30/2009] [Indexed: 12/23/2022]
Abstract
In healthy individuals, skin integrity is maintained by epidermal stem cells which self-renew and generate daughter cells that undergo terminal differentiation. Epidermal stem cells represent a promising source of stem cells, and their culture has great potential in scientific research and clinical application. However, no single method has been universally adopted for identifying and isolating epidermal stem cells. Here, we reported the isolation and characterization of putative epidermal stem cells from newborn mouse skin. The keratinocytes were separated enzymatically. Putative epidermal stem cells were selected by rapid adherence on a composite matrix made of type I collagen and fibronectin. Unattached cells were discarded after 10 min, and the attached cells were cultured in a defined culture medium. The isolated cells showed the typical epidermal stem cell morphology. Immunofluorescence indicated that the cells were strongly stained for β1 integrin family of extracellular matrix receptors. In conclusion, mouse putative epidermal stem cells were successfully isolated from newborn mouse epidermis on the basis of high rapid adhesion to extracellular matrix proteins and cultured in vitro.
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Affiliation(s)
- Somayeh Reiisi
- Department of Biology, Faculty of Basic Sciences, University of Shahrekord, Shahrekord, Iran
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59
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Abstract
There is worldwide enthusiasm for the prospect of some kind of cellular transplant therapy for repair of failing organs. The olfactory mucosa of a patient's nose is easily biopsied to provide a ready source of multipotent cells. In this article we address practical issues pertinent to using olfactory neural stem cells for tissue repair. These cells are emerging as potentially most significant candidates for human tissue repair strategies. Previously we have shown that stem cells from olfactory mucosa are multipotent. As well, we have recently published three potential clinical applications. Their expression of dopaminergic markers in vitro and in a Parkinson's rat transplant model has been demonstrated. Their conversion to chondrogenic phenotype in vitro and in vivo has also been described, as has their transplant into a rat model of cardiac infarction. Here we examine in detail the biology of the olfactory neural stem cell using the rat as our animal model cell source. We establish its presence by examining self-renewal capacity and for phenotypic acquisition in inductive circumstances. We determine its frequency within the cell population and show that our culture system selects for this putative stem cell. Our studies demonstrate that adult olfactory stem cells, when transplanted into an environmental niche different from that of their origin, are able to demonstrate multipotency by acquiring the phenotype of the resident cells. We investigate how immediate the instruction need be. We test the hypothesis that olfactory neurospheres contain stem cells whose capacity for differentiation is triggered by signals of the immediate environmental niche. Significantly, of importance to any tissue regeneration endeavor, stem cell numbers were shown to be enriched by our culture methods. This was confirmed whether measured by sphere-forming capacity or differentiation response rate.
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Affiliation(s)
- Andrew Wetzig
- Eskitis Institute for Cell and Molecular Therapies, National Centre for Adult Stem Cell Research, Griffith University, Nathan, Queensland, Australia
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60
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Watt FM, Fujiwara H. Cell-extracellular matrix interactions in normal and diseased skin. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a005124. [PMID: 21441589 DOI: 10.1101/cshperspect.a005124] [Citation(s) in RCA: 236] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mammalian skin comprises a multi-layered epithelium, the epidermis, and an underlying connective tissue, the dermis. The epidermal extracellular matrix is a basement membrane, whereas the dermal ECM comprises fibrillar collagens and associated proteins. There is considerable heterogeneity in ECM composition within both epidermis and dermis. The functional significance of this extends beyond cell adhesion to a range of cell autonomous and nonautonomous processes, including control of epidermal stem cell fate. In skin, cell-ECM interactions influence normal homeostasis, aging, wound healing, and disease. Disturbed integrin and ECM signaling contributes to both tumor formation and fibrosis. Strategies for manipulating cell-ECM interactions to repair skin defects and intervene in a variety of skin diseases hold promise for the future.
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Affiliation(s)
- Fiona M Watt
- Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Cambridge, United Kingdom.
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Epidermal FABP (FABP5) Regulates Keratinocyte Differentiation by 13(S)-HODE-Mediated Activation of the NF-κB Signaling Pathway. J Invest Dermatol 2011; 131:604-12. [DOI: 10.1038/jid.2010.342] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Lyssiotis CA, Lairson LL, Boitano AE, Wurdak H, Zhu S, Schultz PG. Chemical Control of Stem Cell Fate and Developmental Potential. Angew Chem Int Ed Engl 2010; 50:200-42. [DOI: 10.1002/anie.201004284] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Costas A. Lyssiotis
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Luke L. Lairson
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 (USA)
| | - Anthony E. Boitano
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 (USA)
| | - Heiko Wurdak
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Shoutian Zhu
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Peter G. Schultz
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
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Lyssiotis CA, Lairson LL, Boitano AE, Wurdak H, Zhu S, Schultz PG. Chemische Kontrolle des Schicksals und Entwicklungspotenzials von Stammzellen. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004284] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Costas A. Lyssiotis
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Luke L. Lairson
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 (USA)
| | - Anthony E. Boitano
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 (USA)
| | - Heiko Wurdak
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Shoutian Zhu
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
| | - Peter G. Schultz
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA), Fax: (+1) 858‐784‐9440
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Flow cytometry-based characterization of label-retaining stem cells following transplacental BrdU labelling. Cell Biol Int 2010. [DOI: 10.1042/cb20100335] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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65
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Senescence as a modulator of oral squamous cell carcinoma development. Oral Oncol 2010; 46:840-53. [DOI: 10.1016/j.oraloncology.2009.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 09/24/2009] [Accepted: 09/24/2009] [Indexed: 12/25/2022]
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The lytic activation of KSHV during keratinocyte differentiation is dependent upon a suprabasal position, the loss of integrin engagement, and calcium, but not the interaction of cadherins. Virology 2010; 410:17-29. [PMID: 21084105 DOI: 10.1016/j.virol.2010.10.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/04/2010] [Accepted: 10/13/2010] [Indexed: 12/15/2022]
Abstract
We previously found that KSHV (HHV-8) lytic activation occurs during differentiation of oral keratinocytes in organotypic raft cultures. To further investigate the spatial and temporal aspects of KSHV lytic activation and the roles of integrins, cadherins, and calcium, we used rKSHV.219-infected primary oral keratinocytes in submerged, suspension, and direct suprabasal plating, models of differentiation. We found that early keratinocyte differentiation did not activate lytic KSHV in cells attached to a substratum, with activation only occurring in suprabasal cells. Temporally, KSHV lytic expression occurred between the expression of early and late differentiation markers. Keratinocytes differentiated in suspension culture, which mimics substratum loss that occurs with stratification, activated lytic KSHV. This lytic activation was inhibited by integrin engagement, showing that integrins are a control point for KSHV reactivation. A role for cadherins was not found. Elevated extracellular calcium was necessary, but not sufficient, for lytic activation.
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Gemenetzidis E, Elena Costea D, Parkinson EK, Waseem A, Wan H, Teh MT. Induction of human epithelial stem/progenitor expansion by FOXM1. Cancer Res 2010; 70:9515-26. [PMID: 21062979 PMCID: PMC3044465 DOI: 10.1158/0008-5472.can-10-2173] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Stem cells are permanent residents of tissues and thought to be targets of cancer initiation. The frequent, and often early, upregulation of the FOXM1 transcription factor in the majority of human cancers suggests that it may participate in the initiation of human tumorigenesis. However, this hypothesis has not been tested. Herein, we show that targeting the ectopic expression of FOXM1 to the highly clonogenic cells of primary human keratinocytes with stem/progenitor cell properties, but not to differentiating cells, caused clonal expansion in vitro. We show, using a functional three-dimensional organotypic epithelial tissue regeneration system, that ectopic FOXM1 expression perturbed epithelial differentiation generating a hyperproliferative phenotype reminiscent of that seen in human epithelial hyperplasia. Furthermore, transcriptional expression analysis of a panel of 28 epithelial differentiation-specific genes reveals a role for FOXM1 in the suppression of epithelial differentiation. This study provides the first evidence that FOXM1 participates in an early oncogenic pathway that predisposes cells to tumorigenesis by expanding the stem/progenitor compartment and deregulating subsequent keratinocyte terminal differentiation. This finding reveals an important window of susceptibility to oncogenic signals in epithelial stem/progenitor cells prior to differentiation, and may provide a significant benefit to the design of cancer therapeutic interventions that target oncogenesis at its earliest incipient stage.
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Affiliation(s)
- Emilios Gemenetzidis
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Turner Street, London E1 2AD, England, United Kingdom
| | - Daniela Elena Costea
- Section of Pathology, The Gade Institute, Faculty of Medicine and Odontology, University of Bergen, Norway
| | - Eric K. Parkinson
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Turner Street, London E1 2AD, England, United Kingdom
| | - Ahmad Waseem
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Turner Street, London E1 2AD, England, United Kingdom
| | - Hong Wan
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Turner Street, London E1 2AD, England, United Kingdom
| | - Muy-Teck Teh
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Turner Street, London E1 2AD, England, United Kingdom
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Georgopoulos NT, Kirkwood LA, Walker DC, Southgate J. Differential regulation of growth-promoting signalling pathways by E-cadherin. PLoS One 2010; 5:e13621. [PMID: 21049033 PMCID: PMC2964323 DOI: 10.1371/journal.pone.0013621] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/13/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Despite the well-documented association between loss of E-cadherin and carcinogenesis, as well as the link between restoration of its expression and suppression of proliferation in carcinoma cells, the ability of E-cadherin to modulate growth-promoting cell signalling in normal epithelial cells is less well understood and frequently contradictory. The potential for E-cadherin to co-ordinate different proliferation-associated signalling pathways has yet to be fully explored. METHODOLOGY/PRINCIPAL FINDINGS Using a normal human urothelial (NHU) cell culture system and following a calcium-switch approach, we demonstrate that the stability of NHU cell-cell contacts differentially regulates the Epidermal Growth Factor Receptor (EGFR)/Extracellular Signal-Regulated Kinase (ERK) and Phosphatidylinositol 3-Kinase (PI3-K)/AKT pathways. We show that stable cell contacts down-modulate the EGFR/ERK pathway, whilst inducing PI3-K/AKT activity, which transiently enhances cell growth at low density. Functional inactivation of E-cadherin interferes with the capacity of NHU cells to form stable calcium-mediated contacts, attenuates E-cadherin-mediated PI3-K/AKT induction and enhances NHU cell proliferation by allowing de-repression of the EGFR/ERK pathway and constitutive activation of β-catenin-TCF signalling. CONCLUSIONS/SIGNIFICANCE Our findings provide evidence that E-cadherin can differentially and concurrently regulate specific growth-related signalling pathways in a context-specific fashion, with direct, functional consequences for cell proliferation and population growth. Our observations not only reveal a novel, complex role for E-cadherin in normal epithelial cell homeostasis and tissue regeneration, but also provide the basis for a more complete understanding of the consequences of E-cadherin loss on malignant transformation.
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Affiliation(s)
- Nikolaos T. Georgopoulos
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York, United Kingdom
| | - Lisa A. Kirkwood
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York, United Kingdom
| | - Dawn C. Walker
- Department of Computer Science, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
| | - Jennifer Southgate
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York, United Kingdom
- * E-mail:
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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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70
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Richard V, Pillai MR. The stem cell code in oral epithelial tumorigenesis: 'the cancer stem cell shift hypothesis'. Biochim Biophys Acta Rev Cancer 2010; 1806:146-62. [PMID: 20599480 DOI: 10.1016/j.bbcan.2010.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/21/2010] [Accepted: 06/27/2010] [Indexed: 12/21/2022]
Abstract
Tumors of the oral cavity provide an ideal model to study various stages of epithelial tumor progression. A group of cancer cells termed cancer stem cells (CSCs) eludes therapy, persists and initiates recurrence augmenting malignant spread of the disease. Hitherto, accurate identification and separation of such minimal residual cells have proven futile due to lack of identifiable traits to single out these cells from the heterogeneous tumor bulk. In this review we have compiled comprehensive evidence from comparative phenotypic and genotypic studies on normal oral mucosa as well as tumors of different grades to elucidate that differential expression patterns of putative stem cells markers may identify 'minimal residual disease' in oral squamous cell carcinoma. We propose the "cancer stem cell shift hypothesis" to explain the exact identity and switch-over, tumor-promoting mechanisms adapted by putative CSCs with correlation to tumor staging.
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Affiliation(s)
- Vinitha Richard
- Integrated Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
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71
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Actin and serum response factor transduce physical cues from the microenvironment to regulate epidermal stem cell fate decisions. Nat Cell Biol 2010; 12:711-8. [PMID: 20581838 DOI: 10.1038/ncb2074] [Citation(s) in RCA: 335] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 05/13/2010] [Indexed: 12/15/2022]
Abstract
Epidermal homeostasis depends on a balance between stem cell renewal and differentiation and is regulated by extrinsic signals from the extracellular matrix (ECM). A powerful approach to analysing the pathways involved is to engineer single-cell microenvironments in which individual variables are precisely and quantitatively controlled. Here, we employ micropatterned surfaces to identify the signalling pathways by which restricted ECM contact triggers human epidermal stem cells to initiate terminal differentiation. On small (20 microm diameter) circular islands, keratinocytes remained rounded, and differentiated at higher frequency than cells that could spread on large (50 microm diameter) islands. Differentiation did not depend on ECM composition or density. Rather, the actin cytoskeleton mediated shape-induced differentiation by regulating serum response factor (SRF) transcriptional activity. Knockdown of SRF or its co-factor MAL inhibited differentiation, whereas overexpression of MAL stimulated SRF activity and involucrin expression. SRF target genes FOS and JUNB were also required for differentiation: c-Fos mediated serum responsiveness, whereas JunB was regulated by actin and MAL. Our findings demonstrate how biophysical cues are transduced into transcriptional responses that determine epidermal cell fate.
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72
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Bombardelli L, Carpenter ES, Wu AP, Alston N, DelGiorno KE, Crawford HC. Pancreas-specific ablation of beta1 integrin induces tissue degeneration by disrupting acinar cell polarity. Gastroenterology 2010; 138:2531-40, 2540.e1-4. [PMID: 20188101 PMCID: PMC2883624 DOI: 10.1053/j.gastro.2010.02.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 02/01/2010] [Accepted: 02/11/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Integrin contact with basement membrane is a major determinant of epithelial cell polarity. beta1 integrin heterodimers are the primary receptors for basement membrane in pancreatic acinar cells, which function to synthesize and directionally secrete digestive enzymes into a central lumen. Aberrant acinar secretion and exposure of the parenchyma to digestive enzyme activity lead to organ damage and pancreatitis. METHODS beta1 integrin conditional knockout mice were crossed to Ptf1a-Cre mice to ablate beta1 integrin in the pancreas. Histopathology of aged and cerulein-treated mice were assessed by histology and immunocytochemistry. Directional secretion was determined in vitro by FM1-43 loading with cerulein stimulation. RESULTS Pancreas-specific ablation of beta1 integrin led to progressive organ degeneration, associated with focal acinar cell necrosis and ductal metaplasia along with widespread inflammation and collagen deposition. beta1 Integrin-null pancreata were highly susceptible to cerulein-induced acute pancreatitis, displaying an enhanced level of damage with no loss in regeneration. Degenerating beta1 integrin-null pancreata were marked by disruption of acinar cell polarity. Protein kinase C epsilon, normally localized apically, was found in the cytoplasm where it can lead to intracellular digestive enzyme activation. beta1 Integrin-null acinar cells displayed indiscriminate secretion to all membrane surfaces, consistent with an observed loss of basolateral membrane localization of Munc18c, which normally prevents basal secretion of digestive enzymes. CONCLUSIONS Ablation of beta1 integrin induces organ atrophy by disrupting acinar cell polarity and exposing the pancreatic parenchyma to digestive enzymes.
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Affiliation(s)
| | | | | | | | | | - Howard C. Crawford
- Correspondence: Howard C. Crawford, Ph.D., Stony Brook University, Department of Pharmacology, 1 Circle Road, BST 8-140, Stony Brook, NY 11794-8651, Phone: (631) 444-3085, Fax: (631) 444-9749,
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73
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Differential expression of stem cell markers in human follicular bulge and interfollicular epidermal compartments. Histochem Cell Biol 2010; 133:455-65. [PMID: 20229054 DOI: 10.1007/s00418-010-0684-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2010] [Indexed: 12/17/2022]
Abstract
Although skin contains a number of stem cell repositories, their characterization has been hindered by a lack of specific markers and an unclear in vivo localization. In this study, we whole mounted single human scalp hair follicles and examined their profiles using in situ immunohistochemistry and multicolor immunofluorescence in search of markers to distinguish between stem cells residing in the interfollicular epidermis (IFE) and bulge. Our study revealed that expression of several biomarkers localized uniquely to the basal IFE (CD34 and CD117), bulge region (CD200), or both (CK15, CD49f, and CD29). In addition, we found that both basal IFE and bulge stem cells did not express CD71 or CD24 suggesting their potential utility as negative selection markers. Dermal papilla but not basal IFE or bulge stem cells expressed CD90, making it a potential positive selection marker for dermal hair follicle stem cells. The markers tested in this study may enable pursuit of cell sorting and purification strategies aimed at determining each stem cell population's unique molecular signature.
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74
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Stochastic fate of p53-mutant epidermal progenitor cells is tilted toward proliferation by UV B during preneoplasia. Proc Natl Acad Sci U S A 2009; 107:270-5. [PMID: 20018764 DOI: 10.1073/pnas.0909738107] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UV B (UVB) radiation induces clones of cells mutant for the p53 tumor suppressor gene in human and murine epidermis. Here we reanalyze large datasets that report the fate of clones in mice subjected to a course of UVB radiation, to uncover how p53 mutation affects epidermal progenitor cell behavior. We show that p53 mutation leads to exponential growth of clones in UV-irradiated epidermis; this finding is also consistent with the size distribution of p53 mutant clones in human epidermis. Analysis of the tail of the size distribution further reveals that the fate of individual mutant cells is stochastic. Finally, the data suggest that ending UVB exposure results in the p53 mutant cells adopting the balanced fate of wild-type cells: the loss of mutant cells is balanced by proliferation so that the population of preneoplastic cells remains constant. We conclude that preneoplastic clones do not derive from long-lived, self-renewing mutant stem cells but rather from mutant progenitors with random cell fate. It follows that ongoing, low-intensity UVB radiation will increase the number of precancerous cells dramatically compared with sporadic, higher-intensity exposure at the same cumulative dose, which may explain why nonmelanoma skin cancer incidence depends more strongly on age than on radiation dosage. Our approach may be applied to determine cell growth rates in clonally labeled material from a wide range of tissues including human samples.
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75
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Engineering integrin signaling for promoting embryonic stem cell self-renewal in a precisely defined niche. Biomaterials 2009; 31:1219-26. [PMID: 19926127 DOI: 10.1016/j.biomaterials.2009.10.054] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 10/25/2009] [Indexed: 11/22/2022]
Abstract
We present development and use of a 3D synthetic extracellular matrix (ECM) analog with integrin-specific adhesion ligands to characterize the microenvironmental influences in embryonic stem cell (ESC) self-renewal. Transcriptional analysis of 24 integrin subunits followed by confirmation at the translational and functional levels suggested that integrins alpha(5)beta(1), alpha(v)beta(5), alpha(6)beta(1) and alpha(9)beta(1) play important roles in maintenance of stemness in undifferentiated mouse ESCs. Using the well-defined matrix as a tool to activate integrins alpha(5)beta(1) plus alpha(v)beta(5), alpha(6)beta(1) and alpha(9)beta(1), individually and in combination, differential integrin activation was demonstrated to exert exquisite control over ESC fate decisions. Simultaneous ligation of these four integrin heterodimers promoted self-renewal, as evidence by prolonged SSEA-1, Oct4 and Nanog expression, and induced Akt1 kinase signaling along with translational regulation of other stemness-related genes. The biofunctional network we have designed based on this knowledge may be useful as a defined niche for regulating ESC pluripotency through selective cell-matrix interactions, and the method we present may be more generally useful for probing matrix interactions in stem cell self-renewal and differentiation.
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76
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Lutolf MP, Blau HM. Artificial stem cell niches. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2009; 21:3255-68. [PMID: 20882496 PMCID: PMC3099745 DOI: 10.1002/adma.200802582] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Stem cells are characterized by their dual ability to reproduce themselves (self-renew) and specialize (differentiate), yielding a plethora of daughter cells that maintain and regenerate tissues. In contrast to their embryonic counterparts, adult stem cells retain their unique functions only if they are in intimate contact with an instructive microenvironment, termed stem cell niche. In these niches, stem cells integrate a complex array of molecular signals that, in concert with induced cell-intrinsic regulatory networks, control their function and balance their numbers in response to physiologic demands. This progress report provides a perspective on how advanced materials technologies could be used (i) to engineer and systematically analyze specific aspects of functional stem cells niches in a controlled fashion in vitro and (ii) to target stem cell niches in vivo. Such "artificial niches" constitute potent tools for elucidating stem cell regulatory mechanisms with the capacity to directly impact the development of novel therapeutic strategies for tissue regeneration.
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Affiliation(s)
- Matthias P. Lutolf
- Prof. M. P. Lutolf, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland), , Prof. H. M. Blau, Baxter Laboratory in Genetic Pharmacology, Stanford University School of Medicine, Stanford, CA (USA),
| | - Helen M. Blau
- Prof. M. P. Lutolf, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland), , Prof. H. M. Blau, Baxter Laboratory in Genetic Pharmacology, Stanford University School of Medicine, Stanford, CA (USA),
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77
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Abstract
Stem cells have been isolated from embryonic, foetal and adult sources. Embryonic stem cells, derived from the pre-implantation embryo, can be expanded indefinitely in vitro. When reintroduced into the blastocyst they contribute to all lineages in vivo. In vitro, differentiated derivatives of embryonic stem cells are obtained by manipulating culture conditions. Embryonic germ cells, derived from the primordial germ cells, display the same degree of pluripotential differentiation. Adult stem cells that repopulate the tissue of origin throughout life possess the ability to differentiate into phenotypes not restricted to the tissue and, in some cases, to the germ layer from which they derive. Although the pluripotential differentiation capability of these stem-cell populations is supported by an increasing amount of evidence, a better understanding of the mechanisms that control differentiation is required for their exploitation in the treatment of human diseases.
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78
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Sun T, Smallwood R, MacNeil S. Development of a mini 3D cell culture system using well defined nickel grids for the investigation of cell scaffold interactions. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:1483-1493. [PMID: 19225869 DOI: 10.1007/s10856-009-3703-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 01/26/2009] [Indexed: 05/27/2023]
Abstract
A bioreactor system was developed using a series of fine mesh nickel grids as free standing scaffolds to investigate the behaviours of fibroblasts and keratinocytes in tissue culture. It was found that the mesh size of the suspended grids, but not of the grids that attached to tissue culture surface, had significant influences on cell behaviour and there was a maximum size for fibroblast to span within the defined culture period. Time lapse video microscopy demonstrated fibroblasts cultured on these grids initially migrated onto the struts but then worked together to fill in the voids between struts with a membranous sheet of tissue. In contrast keratinocytes barely migrated from the initial site of cell deposition and when they moved (to a modest extent) it was as an integrated sheet of cells. Similar results were observed when both types of cells were co-cultured in the system.
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Affiliation(s)
- Tao Sun
- Department of Engineering Materials, Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S37HQ, UK.
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79
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Larouche D, Lavoie A, Proulx S, Paquet C, Carrier P, Beauparlant A, Auger F, Germain L. La médecine régénératrice : les cellules souches, les interactions cellulaires et matricielles dans la reconstruction cutanée et cornéenne par génie tissulaire. ACTA ACUST UNITED AC 2009; 57:299-308. [DOI: 10.1016/j.patbio.2008.04.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 04/16/2008] [Indexed: 12/22/2022]
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80
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Janes SM, Ofstad TA, Campbell DH, Eddaoudi A, Warnes G, Davies D, Watt FM. PI3-kinase-dependent activation of apoptotic machinery occurs on commitment of epidermal keratinocytes to terminal differentiation. Cell Res 2009; 19:328-39. [PMID: 18766172 DOI: 10.1038/cr.2008.281] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We have investigated the earliest events in commitment of human epidermal keratinocytes to terminal differentiation. Phosphorylated Akt and caspase activation were detected in cells exiting the basal layer of the epidermis. Activation of Akt by retroviral transduction of primary cultures of human keratinocytes resulted in an increase in abortive clones founded by transit amplifying cells, while inhibition of the upstream kinase, PI3-kinase, inhibited suspension-induced terminal differentiation. Caspase inhibition also blocked differentiation, the primary mediator being caspase 8. Caspase activation was initiated by 2 h in suspension, preceding the onset of expression of the terminal differentiation marker involucrin by several hours. Incubation of suspended cells with fibronectin or inhibition of PI3-kinase prevented caspase induction. At 2 h in suspension, keratinocytes that had become committed to terminal differentiation had increased side scatter, were 7-aminoactinomycin D (7-AAD) positive and annexin V negative; they exhibited loss of mitochondrial membrane potential and increased cardiolipin oxidation, but with no increase in reactive oxygen species. These properties indicate that the onset of terminal differentiation, while regulated by PI3-kinase and caspases, is not a classical apoptotic process.
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Affiliation(s)
- Sam M Janes
- Centre for Respiratory Research, Rayne Institute, University College London, 5 University Street, London, UK
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81
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Ferreira M, Fujiwara H, Morita K, Watt FM. An activating beta1 integrin mutation increases the conversion of benign to malignant skin tumors. Cancer Res 2009; 69:1334-42. [PMID: 19190332 DOI: 10.1158/0008-5472.can-08-3051] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Identifying the physiologic relevance of cancer-associated genetic polymorphisms is a major challenge. Several changes in the coding sequence of beta integrin subunits have now been described in human tumors. One of these, T188Ibeta1, was identified as a heterozygous mutation in a poorly differentiated squamous cell carcinoma (SCC) and shown to activate extracellular matrix adhesion and inhibit keratinocyte differentiation in vitro. To study its contribution to tumor development, we overexpressed the mutant or wild-type (WT) human beta1 subunit in the basal layer of mouse epidermis using the keratin 14 promoter. The transgenic integrins were expressed at the cell surface and were functional, with the T188Ibeta1 subunit promoting cell spreading to a greater extent than WTbeta1. Epidermal proliferation and differentiation were unaffected and no expansion of the stem cell compartment was detected. During chemical carcinogenesis, both transgenes increased papilloma formation, but only the T188Ibeta1 transgene stimulated the conversion of papillomas to SCCs. Papillomas bearing the mutation showed increased Erk activity and reduced differentiation. SCCs expressing T188Ibeta1 were less well-differentiated than those expressing WTbeta1. These observations establish that the expression of a genetic variant in the I-like domain of beta1 integrins does not affect normal epidermal homeostasis, but increases tumor susceptibility and influences tumor type.
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Affiliation(s)
- Manuela Ferreira
- Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
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82
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Two distinct roles of mitogen-activated protein kinases in platelets and a novel Rac1-MAPK-dependent integrin outside-in retractile signaling pathway. Blood 2008; 113:893-901. [PMID: 18957688 DOI: 10.1182/blood-2008-05-155978] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitogen-activated protein kinases (MAPK), p38, and extracellular stimuli-responsive kinase (ERK), are acutely but transiently activated in platelets by platelet agonists, and the agonist-induced platelet MAPK activation is inhibited by ligand binding to the integrin alpha(IIb)beta(3). Here we show that, although the activation of MAPK, as indicated by MAPK phosphorylation, is initially inhibited after ligand binding to integrin alpha(IIb)beta(3), integrin outside-insignaling results in a late but sustained activation of MAPKs in platelets. Furthermore, we show that the early agonist-induced MAPK activation and the late integrin-mediated MAPK activation play distinct roles in different stages of platelet activation. Agonist-induced MAPK activation primarily plays an important role in stimulating secretion of platelet granules, while integrin-mediated MAPK activation is important in facilitating clot retraction. The stimulatory role of MAPK in clot retraction is mediated by stimulating myosin light chain (MLC) phosphorylation. Importantly, integrin-dependent MAPK activation, MAPK-dependent MLC phosphorylation, and clot retraction are inhibited by a Rac1 inhibitor and in Rac1 knockout platelets, indicating that integrin-induced activation of MAPK and MLC and subsequent clot retraction is Rac1-dependent. Thus, our results reveal 2 different activation mechanisms of MAPKs that are involved in distinct aspects of platelet function and a novel Rac1-MAPK-dependent cell retractile signaling pathway.
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83
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Liebig T, Erasmus J, Kalaji R, Davies D, Loirand G, Ridley A, Braga VMM. RhoE Is required for keratinocyte differentiation and stratification. Mol Biol Cell 2008; 20:452-63. [PMID: 18923151 DOI: 10.1091/mbc.e07-11-1197] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The molecular mechanism via which keratinocyte differentiation assembles multiple layers of cells (stratification) is poorly understood. We describe here a novel function of the Rho family member RhoE as a regulator of epidermal morphogenesis. RhoE protein levels are specifically and transiently up-regulated upon keratinocyte differentiation. RhoE up-regulation requires the activity of Rho kinase (ROCK) I, suggesting that both RhoE and ROCKI are important during keratinocyte differentiation. RhoE overexpression results in a striking enlargement of cell size and the number of stratified cells. In contrast, RhoE depletion induces hyperproliferation and delays initiation of keratinocyte differentiation. Interestingly, up-regulation of RhoE protein is seen primarily in basal, undifferentiated cells, in which commitment to differentiation and stratification takes place. RhoE activation in basal cells negatively modulates integrin adhesion, thereby facilitating detachment from the substratum and migration to form suprabasal layers. Thus, RhoE integrates two processes essential for keratinocyte differentiation and stratification: regulation of proliferative status and integrin adhesion.
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Affiliation(s)
- Timo Liebig
- Molecular Medicine, National Heart and Lung Institute, Imperial College London., United Kingdom
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84
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Potten CS, Barthel D, Li YQ, Ohlrich R, Matthé B, Loeffler M. Proliferation in murine epidermis after minor mechanical stimulation. Part 1. Sustained increase in keratinocyte production and migration. Cell Prolif 2008; 33:231-46. [PMID: 11041204 PMCID: PMC6496670 DOI: 10.1046/j.1365-2184.2000.00178.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It was our objective to obtain an insight into the details and dynamics of the cell proliferative changes following minor barrier disruption, the mechanisms of recovery, and their regulation. Hair of the dorsal area of DBA2-mice was removed and the epidermis was tape stripped. Tritiated thymidine was injected into groups of mice at daily intervals thereafter. Labelling and nuclear densities were measured at several time intervals later in the various epidermal strata to characterize cell production and cell fluxes through the tissue. A dramatic proliferative response was observed at 24 h when the labelling density increased more than sixfold in the basal layer. Labelled cells rapidly appeared in suprabasal layers within a few hours in large quantities while this process took over 2 days in normal skin. Some cycling cells were also found in the suprabasal layer (pulse labelling at 24 h) in contrast with the controls. The cellular flux through the suprabasal layers was drastically (20-fold) increased and the transit time was shortened. Although the nuclear density in the basal layer showed only moderate changes it increased four-fold in the suprabasal layer within 5 days. A kinetic model analysis suggested that the cell cycle time of proliferative cells dropped from a normal value of about 200 h to less than 12 h post tape strip. After 7 days, the proliferative activation still persisted, even though at 3 days post tape strip the stratum corneum had been re-established. Hence, a mild mechanical alteration with removal of some parts of the cornified layer in mouse backskin epidermis triggers a huge proliferative response with massive overproduction of cells that lasts at least 7 days. Our findings suggest that the re-establishment of the cornified layer does not immediately shut down cell proliferation and that more complex, slower (long-term) regulatory processes are involved.
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Affiliation(s)
- C S Potten
- CRC Epithelial Biology Group, Paterson Institute for Cancer Research, Christie Hospital, Manchester, UK
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85
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Inoue-Narita T, Hamada K, Sasaki T, Hatakeyama S, Fujita S, Kawahara K, Sasaki M, Kishimoto H, Eguchi S, Kojima I, Beermann F, Kimura T, Osawa M, Itami S, Mak TW, Nakano T, Manabe M, Suzuki A. Pten deficiency in melanocytes results in resistance to hair graying and susceptibility to carcinogen-induced melanomagenesis. Cancer Res 2008; 68:5760-8. [PMID: 18632629 DOI: 10.1158/0008-5472.can-08-0889] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphate and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor gene inactivated in numerous sporadic cancers, including melanomas. To analyze Pten functions in melanocytes, we used the Cre-loxP system to delete Pten specifically in murine pigment-producing cells and generated DctCrePten(flox/flox) mice. Half of DctCrePten(flox/flox) mice died shortly after birth with enlargements of the cerebral cortex and hippocampus. Melanocytes were increased in the dermis of perinatal DctCrePten(flox/flox) mice. When the mutants were subjected to repeated depilations, melanocyte stem cells in the bulge of the hair follicle resisted exhaustion and the mice were protected against hair graying. Although spontaneous melanomas did not form in DctCrePten(flox/flox) mice, large nevi and melanomas developed after carcinogen exposure. DctCrePten(flox/flox) melanocytes were increased in size and exhibited heightened activation of Akt and extracellular signal-regulated kinases, increased expression of Bcl-2, and decreased expression of p27(Kip1). Our results show that Pten is important for the maintenance of melanocyte stem cells and the suppression of melanomagenesis.
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Affiliation(s)
- Tae Inoue-Narita
- Department of Dermatology, Akita University School of Medicine, Akita, Japan
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86
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Kirkland SC, Ying H. Alpha2beta1 integrin regulates lineage commitment in multipotent human colorectal cancer cells. J Biol Chem 2008; 283:27612-27619. [PMID: 18664572 PMCID: PMC2562061 DOI: 10.1074/jbc.m802932200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The human colorectal epithelium is maintained by multipotent stem cells
that give rise to absorptive, mucous, and endocrine lineages. Recent evidence
suggests that human colorectal cancers are likewise maintained by a minority
population of so-called cancer stem cells. We have previously established a
human colorectal cancer cell line with multipotent characteristics (HRA-19)
and developed a serum-free medium that induces endocrine, mucous and
absorptive lineage commitment by HRA-19 cells in vitro. In this
study, we investigate the role of the β1 integrin family of cell surface
extracellular matrix receptors in multilineage differentiation by these
multipotent human colorectal cancer cells. We show that endocrine and mucous
lineage commitment is blocked in the presence of function-blocking antibodies
to β1 integrin. Function-blocking antibodies to α2 integrin also
blocked both HRA-19 endocrine lineage commitment and enterocytic
differentiation by Caco-2 human colon cancer cells; both effects being
abrogated by the MEK inhibitor, PD98059, suggesting a role for ERK signaling
in α2-mediated regulation of colorectal cancer cell differentiation. To
further explore the role of α2 integrin in multilineage differentiation,
we established multipotent cells expressing high levels of wild-type α2
integrin or a non-signaling chimeric α2 integrin. Overexpression of
wild-type α2 integrin in HRA-19 cells significantly enhanced endocrine
and mucous lineage commitment, while cells expressing the non-signaling
chimeric α2 integrin had negligible ability for either endocrine or
mucous lineage commitment. This study indicates that the collagen receptor
α2β1 integrin is a regulator of cell fate in human multipotent
colorectal cancer cells.
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Affiliation(s)
- Susan C Kirkland
- Department of Histopathology, Faculty of Medicine, Imperial College London, London W12 ONN, United Kingdom.
| | - Huijun Ying
- Department of Histopathology, Faculty of Medicine, Imperial College London, London W12 ONN, United Kingdom
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87
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Commo S, Gaillard O, Bernard B. The human hair follicle contains two distinct K19 positive compartments in the outer root sheath: a unifying hypothesis for stem cell reservoir? Differentiation 2008. [DOI: 10.1111/j.1432-0436.2000.660401.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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88
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Temporal and spatial regulation of integrins during development. Curr Opin Cell Biol 2008; 20:520-4. [PMID: 18603422 DOI: 10.1016/j.ceb.2008.05.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 05/13/2008] [Accepted: 05/19/2008] [Indexed: 11/21/2022]
Abstract
Integrin receptors for extracellular matrix (ECM) are critical determinants of biological processes. Regulation of integrin expression is one way for cells to respond to changes in the ECM, to integrate intracellular signals, and to obtain appropriate adhesion for cell motility, proliferation, and differentiation. Transcriptional and post-translational mechanisms for changing the integrin repertoire at the cell surface have recently been described. These mechanisms work through transcriptional regulation that alters the proportions of one integrin relative to another, referred to as integrin switching, or through localized regulation of integrin-ECM interactions, thus providing exquisite control over cell rearrangements during tissue morphogenesis and remodeling. These integrin regulatory pathways may also be important targets in such emerging fields as tissue engineering and regenerative medicine.
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90
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Deshayes N, Rathman-Josserand M. Origines & sélection de progéniteurs et cellules souches épidermiques : Un défi pour l'ingénierie tissulaire. ACTA ACUST UNITED AC 2008; 202:43-54. [DOI: 10.1051/jbio:2008006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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91
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Daley WP, Peters SB, Larsen M. Extracellular matrix dynamics in development and regenerative medicine. J Cell Sci 2008; 121:255-64. [PMID: 18216330 DOI: 10.1242/jcs.006064] [Citation(s) in RCA: 675] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix (ECM) regulates cell behavior by influencing cell proliferation, survival, shape, migration and differentiation. Far from being a static structure, the ECM is constantly undergoing remodeling--i.e. assembly and degradation--particularly during the normal processes of development, differentiation and wound repair. When misregulated, this can contribute to disease. ECM assembly is regulated by the 3D environment and the cellular tension that is transmitted through integrins. Degradation is controlled by complex proteolytic cascades, and misregulation of these results in ECM damage that is a common component of many diseases. Tissue engineering strives to replace damaged tissues with stem cells seeded on synthetic structures designed to mimic the ECM and thus restore the normal control of cell function. Stem cell self-renewal and differentiation is influenced by the 3D environment within the stem cell niche. For tissue-engineering strategies to be successful, the intimate dynamic relationship between cells and the ECM must be understood to ensure appropriate cell behavior.
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Affiliation(s)
- William P Daley
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA
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92
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Three-dimensional extracellular matrix-directed cardioprogenitor differentiation: systematic modulation of a synthetic cell-responsive PEG-hydrogel. Biomaterials 2008; 29:2757-66. [PMID: 18396331 DOI: 10.1016/j.biomaterials.2008.03.016] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 03/16/2008] [Indexed: 12/31/2022]
Abstract
We show that synthetic three-dimensional (3D) matrix metalloproteinase (MMP)-sensitive poly(ethylene glycol) (PEG)-based hydrogels can direct differentiation of pluripotent cardioprogenitors, using P19 embryonal carcinoma (EC) cells as a model, along a cardiac lineage in vitro. In order to systematically probe 3D matrix effects on P19 EC differentiation, matrix elasticity, MMP-sensitivity and the concentration of a matrix-bound RGDSP peptide were modulated. Soft matrices (E=322+/-64.2 Pa, stoichiometric ratio: 0.8), mimicking the elasticity of embryonic cardiac tissue, increased the fraction of cells expressing the early cardiac transcription factor Nkx2.5 around 2-fold compared to embryoid bodies (EB) in suspension. In contrast, stiffer matrices (E=4,036+/-419.6 Pa, stoichiometric ratio: 1.2) decreased the number of Nkx2.5-positive cells significantly. Further indicators of cardiac maturation were promoted by ligation of integrins relevant in early cardiac development (alpha(5)beta(1,) alpha(v)beta(3)) by the RGDSP ligand in combination with the MMP-sensitivity of the matrix, with a 6-fold increased amount of myosin heavy chain (MHC)-positive cells as compared to EB in suspension. This precisely controlled 3D culture system thus may serve as a potential alternative to natural matrices for engineering cardiac tissue structures for cell culture and potentially therapeutic applications.
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93
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Sun T, McMinn P, Coakley S, Holcombe M, Smallwood R, MacNeil S. An integrated systems biology approach to understanding the rules of keratinocyte colony formation. J R Soc Interface 2008; 4:1077-92. [PMID: 17374590 PMCID: PMC2396345 DOI: 10.1098/rsif.2007.0227] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Closely coupled in vitro and in virtuo models have been used to explore the self-organization of normal human keratinocytes (NHK). Although it can be observed experimentally, we lack the tools to explore many biological rules that govern NHK self-organization. An agent-based computational model was developed, based on rules derived from literature, which predicts the dynamic multicellular morphogenesis of NHK and of a keratinocyte cell line (HaCat cells) under varying extracellular Ca++ concentrations. The model enables in virtuo exploration of the relative importance of biological rules and was used to test hypotheses in virtuo which were subsequently examined in vitro. Results indicated that cell-cell and cell-substrate adhesions were critically important to NHK self-organization. In contrast, cell cycle length and the number of divisions that transit-amplifying cells could undergo proved non-critical to the final organization. Two further hypotheses, to explain the growth behaviour of HaCat cells, were explored in virtuo-an inability to differentiate and a differing sensitivity to extracellular calcium. In vitro experimentation provided some support for both hypotheses. For NHKs, the prediction was made that the position of stem cells would influence the pattern of cell migration post-wounding. This was then confirmed experimentally using a scratch wound model.
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Affiliation(s)
- Tao Sun
- Department of Engineering Materials, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
| | - Phil McMinn
- Department of Computer Science, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
| | - Simon Coakley
- Department of Computer Science, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
| | - Mike Holcombe
- Department of Computer Science, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
| | - Rod Smallwood
- Department of Computer Science, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
| | - Sheila MacNeil
- Department of Engineering Materials, University of SheffieldKroto Research Institute, Broad Lane, Sheffield S3 7HQ, UK
- Author for correspondence ()
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94
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Wodarz D. Stem cell regulation and the development of blast crisis in chronic myeloid leukemia: Implications for the outcome of Imatinib treatment and discontinuation. Med Hypotheses 2008; 70:128-36. [PMID: 17566666 DOI: 10.1016/j.mehy.2007.03.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Accepted: 03/02/2007] [Indexed: 11/22/2022]
Abstract
Chronic myeloid leukemia (CML) is a cancer of the hematopoietic system that is initiated by a single genetic alteration (the BCR-ABL fusion gene or Philadelphia chromosome) and progresses in several phases: during the chronic phase the number of cells grows slowly and the fraction of immature cells is low. During the accelerated phase and blast crisis, the population of CML cells and the fraction of immature cells rises sharply. The mechanisms that drive the transition from the chronic phase to blast crisis are not understood, and the requirement of genetic instability and further mutations has been suggested. Using mathematical models, I describe a theory that can account for the transition from the chronic phase to blast crisis without the need to invoke further mutations. The transition to blast crisis can be explained solely by feedback mechanisms that regulate the patterns of stem cell division, in particular the occurrence of symmetric versus asymmetric cell division. The model also has implications for the outcome of Imatinib treatment. According to the model, treatment can lead to the low level persistence of CML stem cells without assuming that these cells are less susceptible to drug-mediated activity, and this might explain why disease tends to relapse after treatment discontinuation even in the absence of acquired drug resistance. Further, the model defines conditions when Imatinib treatment might lead to the eradication of CML, which is relevant in the context of recent data that show absence of relapse as long as two years after treatment cessation.
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Affiliation(s)
- Dominik Wodarz
- Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, CA 92697, USA.
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95
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Doyle KL, Karl T, Hort Y, Duffy L, Shine J, Herzog H. Y1 receptors are critical for the proliferation of adult mouse precursor cells in the olfactory neuroepithelium. J Neurochem 2007; 105:641-52. [PMID: 18088353 DOI: 10.1111/j.1471-4159.2007.05188.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While the regenerative capacity of the olfactory neuroepithelium has been well studied less is known about the molecular events controlling precursor cell activity. Neuropeptide Y (NPY) is expressed at high levels in the olfactory system, and NPY has been shown to play a role in neuroregeneration of the brain. In this study, we show that the numbers of olfactory neurospheres derived from NPY, NPY/peptide YY, and Y1 receptor knockout mice are decreased compared with wild type (WT) controls. Furthermore, flow cytometric analysis of isolated horizontal basal cells, globose basal cells, and glandular cells showed that only glandular cells derived from WT mice, but not from NPY and Y1 receptor knockout mice, formed secondary neurospheres suggesting a critical role for NPY signaling in this process. Interestingly, olfactory function tests revealed that olfaction in Y1 knockout mice is impaired compared with those of WT mice, probably because of the reduced number of olfactory neurons formed. Together these results indicate that NPY and the Y1 receptor are required for the normal proliferation of adult olfactory precursors and olfactory function.
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Affiliation(s)
- Kharen L Doyle
- Neuroscience Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
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96
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Jones PH, Simons BD, Watt FM. Sic Transit Gloria: Farewell to the Epidermal Transit Amplifying Cell? Cell Stem Cell 2007; 1:371-81. [DOI: 10.1016/j.stem.2007.09.014] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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97
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Panchal H, Wansbury O, Parry S, Ashworth A, Howard B. Neuregulin3 alters cell fate in the epidermis and mammary gland. BMC DEVELOPMENTAL BIOLOGY 2007; 7:105. [PMID: 17880691 PMCID: PMC2110892 DOI: 10.1186/1471-213x-7-105] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Accepted: 09/19/2007] [Indexed: 01/22/2023]
Abstract
BACKGROUND The Neuregulin family of ligands and their receptors, the Erbb tyrosine kinases, have important roles in epidermal and mammary gland development as well as during carcinogenesis. Previously, we demonstrated that Neuregulin3 (Nrg3) is a specification signal for mammary placode formation in mice. Nrg3 is a growth factor, which binds and activates Erbb4, a receptor tyrosine kinase that regulates cell proliferation and differentiation. To understand the role of Neuregulin3 in epidermal morphogenesis, we have developed a transgenic mouse model that expresses Nrg3 throughout the basal layer (progenitor/stem cell compartment) of mouse epidermis and the outer root sheath of developing hair follicles. RESULTS Transgenic females formed supernumerary nipples and mammary glands along and adjacent to the mammary line providing strong evidence that Nrg3 has a role in the initiation of mammary placodes along the body axis. In addition, alterations in morphogenesis and differentiation of other epidermal appendages were observed, including the hair follicles. The transgenic epidermis is hyperplastic with excessive sebaceous differentiation and shows striking similarities to mouse models in which c-Myc is activated in the basal layer including decreased expression levels of the adhesion receptors, alpha6-integrin and beta1-integrin. CONCLUSION These results indicate that the epidermis is sensitive to Nrg3 signaling, and that this growth factor can regulate cell fate of pluripotent epidermal cell populations including that of the mammary gland. Nrg3 appears to act, in part, by inducing c-Myc, altering the proliferation and adhesion properties of the basal epidermis, and may promote exit from the stem cell compartment. The results we describe provide significant insight into how growth factors, such as Nrg3, regulate epidermal homeostasis by influencing the balance between stem cell renewal, lineage selection and differentiation.
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Affiliation(s)
- Heena Panchal
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research 237 Fulham Road, London SW3 6JB, UK
| | - Olivia Wansbury
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research 237 Fulham Road, London SW3 6JB, UK
| | - Suzanne Parry
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research 237 Fulham Road, London SW3 6JB, UK
| | - Alan Ashworth
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research 237 Fulham Road, London SW3 6JB, UK
| | - Beatrice Howard
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research 237 Fulham Road, London SW3 6JB, UK
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98
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Hsu GP, Mathy JA, Wang Z, Xia W, Sakamoto G, Kundu R, Longaker MT, Quertermous T, Yang GP. Increased rate of hair regrowth in mice with constitutive overexpression of Del1. J Surg Res 2007; 146:73-80. [PMID: 17764695 DOI: 10.1016/j.jss.2007.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 01/23/2007] [Accepted: 02/13/2007] [Indexed: 12/18/2022]
Abstract
BACKGROUND Developmental endothelial locus (Del)1 is a secreted extracellular matrix-associated protein that stimulates angiogenesis through integrin binding and is implicated in vasculogenesis. We hypothesized that increased expression of an angiogenic factor would lead to enhanced wound healing. MATERIALS AND METHODS Transgenic mice had Del1 cloned behind a keratin 14 promoter (K14-Del1) to drive constitutive expression in basal keratinocytes. Transgenic animals and wild-type litter mates underwent excisional wounding or depilation, and tissues were harvested at various time points. Wound healing and hair regrowth were assessed by photography, histology, and immunohistochemistry. For injection experiments, purified Del1 protein was injected in the flanks of wild-type mice with carrier on the contralateral flank as a control. Del1 expression during hair development was performed using transgenic mice with a LacZ cassette introduced downstream from the native promoter. RESULTS K14-Del1 animals appeared normal and healed excisional wounds normally but demonstrated an increased rate of hair regrowth after wound healing. Using depilation experiments to specifically address hair follicle growth, we found increased hair regrowth was independent of wounding. This was confirmed by injection of purified Del1 protein. During normal hair anagenesis, Del1 is expressed in the root of the hair follicle. CONCLUSIONS Constitutive expression of Del1 in skin does not affect skin vascularity or improve wound healing. Surprisingly, we found the primary effect of constitutive Del1 expression in the basal keratinocytes was increased hair growth following induction of anagenesis. During normal hair anagenesis, we see expression of Del1 in the root of the hair follicle suggesting it may function there to stimulate hair growth.
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Affiliation(s)
- Gloria P Hsu
- Department of Surgery, Stanford University School of Medicine, Stanford, California 94305, USA
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99
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Hayashi Y, Furue MK, Okamoto T, Ohnuma K, Myoishi Y, Fukuhara Y, Abe T, Sato JD, Hata RI, Asashima M. Integrins regulate mouse embryonic stem cell self-renewal. Stem Cells 2007; 25:3005-15. [PMID: 17717067 DOI: 10.1634/stemcells.2007-0103] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Extracellular matrix (ECM) components regulate stem-cell behavior, although the exact effects elicited in embryonic stem (ES) cells are poorly understood. We previously developed a simple, defined, serum-free culture medium that contains leukemia inhibitory factor (LIF) for propagating pluripotent mouse embryonic stem (mES) cells in the absence of feeder cells. In this study, we determined the effects of ECM components as culture substrata on mES cell self-renewal in this culture medium, comparing conventional culture conditions that contain serum and LIF with gelatin as a culture substratum. mES cells remained undifferentiated when cultured on type I and type IV collagen or poly-D-lysine. However, they differentiated when cultured on laminin or fibronectin as indicated by altered morphologies, the activity of alkaline phosphatase decreased, Fgf5 expression increased, and Nanog and stage-specific embryonic antigen 1 expression decreased. Under these conditions, the activity of signal transducer and activator of transcription (STAT)3 and Akt/protein kinase B (PKB), which maintain cell self-renewal, decreased. In contrast, the extracellular signal-regulated kinase (ERK)1/2 activity, which negatively controls cell self-renewal, increased. In the defined conditions, mES cells did not express collagen-binding integrin subunits, but they expressed laminin- and fibronectin-binding integrin subunits. The expression of some collagen-binding integrin subunits was downregulated in an LIF concentration-dependent manner. Blocking the interactions between ECM and integrins inhibited this differentiation. Conversely, the stimulation of ECM-integrin interactions by overexpressing collagen-binding integrin subunits induced differentiation of mES cells cultured on type I collagen. The results of the study indicated that inactivation of the integrin signaling is crucial in promoting mouse embryonic stem cell self-renewal. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Yohei Hayashi
- Department of Life Sciences (Biology), Graduate School of Arts and Sciences, Kanagawa Dental College, 82 Inaoka-cho, Yokosuka, 238-8580 Japan
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100
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Growth activity of epidermal cells from different parts of human body. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200708020-00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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