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Abstract
Wound healing can be problematic in several clinical settings because of massive tissue injury (burns), wound healing deficiencies (chronic wounds), or congenital conditions and diseases. Engineered skin substitutes have been developed to address the medical need for wound coverage and tissue repair. Currently, no engineered skin substitute can replace all of the functions of intact human skin. A variety of biologic dressings and skin substitutes have however contributed to improved outcomes for patients suffering from acute and chronic wounds. These include acellular biomaterials and composite cultured skin analogs containing allogeneic or autologous cultured skin cells.
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Affiliation(s)
- Dorothy M Supp
- Research Department, Shriners Hospitals for Children, Cincinnati Burns Hospital, Cincinnati, OH 45229, USA.
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2
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Papini S, Cecchetti D, Campani D, Fitzgerald W, Grivel JC, Chen S, Margolis L, Revoltella RP. Isolation and clonal analysis of human epidermal keratinocyte stem cells in long-term culture. Stem Cells 2004; 21:481-94. [PMID: 12832701 DOI: 10.1634/stemcells.21-4-481] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We developed a procedure for growing normal epidermal keratinocyte stem cells isolated from a single punch biopsy of adult human skin in long-term culture. Primary skin epithelial cells were maintained in collagen-coated plates with irradiated human neonatal foreskin fibroblasts (line HPI.1) as a feeder for more than 120 days, approximately 115 population doublings, without signs of replicative senescence. Clonal analysis revealed the presence of holoclones, meroclones, and paraclones. Only emerging colonies with high proliferative potentials and extensive capacities for division (holoclones and meroclones) were subcultured, favoring the expansion of stem cells and progenitors capable of prolonged self-maintenance when subcloned, thus accounting for the prevailing long-term proliferation of the original culture. We found that meroclones included bipotent progenitors capable of generating both keratinocytes and mucin-producing cells. The numbers of these cells were greater after confluence, suggesting that commitment for their differentiation occurred late in the life of a single clone. On a three-dimensional gelatin matrix and on a collagen layer containing the fibroblast feeder, cells isolated from the expansion of holoclones and meroclones formed stratified cohesive layers of keratinocytes that were able to further differentiate, as in normal skin. These results indicate that our procedure will serve as a valuable tool to study expansion of epidermal stem cells as well as the growth mechanisms and cell products associated with their growth and differentiation.
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Affiliation(s)
- Sandra Papini
- Immunobiology and Cell Differentiation Unit, Institute of Biomedical Technologies, Consiglio Nazionale delle Ricerche, Pisa, Italy
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3
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Pellegrini G, Bondanza S, Guerra L, De Luca M. Cultivation of human keratinocyte stem cells: current and future clinical applications. Med Biol Eng Comput 1998; 36:778-90. [PMID: 10367472 DOI: 10.1007/bf02518885] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cultured human keratinocytes have a wide spectrum of clinical applications. Clinical results reported by several investigators are, however, contradictory. In this review, the authors discuss the biological and surgical issues which play a key role in the clinical outcome of cultured epidermal autografts used for the treatment of massive full-thickness burns. The importance of cultivation of epidermal stem cells and of their transplantation onto a wound bed prepared with donor dermis is emphasised. The paper also reviews recent data showing that: (i) cultured epidermal autografts bearing melanocytes can be used for the treatment of stable vitiligo; (ii) keratinocytes isolated from other lining epithelia, such as oral, urethral and corneal epithelia, can be cultivated and grafted onto patients suffering from disabling epithelial defects; (iii) keratinocyte stem cells can be stably transduced with retroviral vectors and are therefore attractive targets for the gene therapy of genodermatoses.
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Affiliation(s)
- G Pellegrini
- Laboratory of Tissue Engineering, I.D.C.-IRCCS, Istituto Dermopatico dell'Immacolata, Pomezia, Roma, Italy.
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4
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Dellambra E, Vailly J, Pellegrini G, Bondanza S, Golisano O, Macchia C, Zambruno G, Meneguzzi G, De Luca M. Corrective transduction of human epidermal stem cells in laminin-5-dependent junctional epidermolysis bullosa. Hum Gene Ther 1998; 9:1359-70. [PMID: 9650620 DOI: 10.1089/hum.1998.9.9-1359] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Laminin-5 is composed of three distinct polypeptides, alpha3, beta3, and gamma2, which are encoded by three different genes, LAMA3, LAMB3, and LAMC2, respectively. We have isolated epidermal keratinocytes from a patient presenting with a lethal form of junctional epidermolysis bullosa characterized by a homozygous mutation of the LAMB3 gene, which led to complete absence of the beta3 polypeptide. In vitro, beta3-null keratinocytes were unable to synthesize laminin-5 and to assemble hemidesmosomes, maintained the impairment of their adhesive properties, and displayed a decrease of their colony-forming ability. A retroviral construct expressing a human beta3 cDNA was used to transduce primary beta3-null keratinocytes. Clonogenic beta3-null keratinocytes were transduced with an efficiency of 100%. Beta3-transduced keratinocytes were able to synthesize and secrete mature heterotrimeric laminin-5. Gene correction fully restored the keratinocyte adhesion machinery, including the capacity of proper hemidesmosomal assembly, and prevented the loss of the colony-forming ability, suggesting a direct link between adhesion to laminin-5 and keratinocyte proliferative capacity. Clonal analysis demonstrated that holoclones expressed the transgene permanently, suggesting stable correction of epidermal stem cells. Because cultured keratinocytes are used routinely to make autologous grafts for patients suffering from large skin or mucosal defects, the full phenotypic reversion of primary human epidermal stem cells defective for a structural protein opens new perspectives in the long-term treatment of genodermatoses.
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Affiliation(s)
- E Dellambra
- Laboratory of Tissue Engineering, I.D.I.-IRCCS, Istituto Dermopatico dell'Immacolata, Rome, Italy
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5
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White SJ, Page SM, Margaritis P, Brownlee GG. Long-term expression of human clotting factor IX from retrovirally transduced primary human keratinocytes in vivo. Hum Gene Ther 1998; 9:1187-95. [PMID: 9625258 DOI: 10.1089/hum.1998.9.8-1187] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A persistent obstacle that has hampered gene transfer experiments is the short-term nature of transgene expression in vivo. In this article we present evidence for sustained expression from primary human keratinocytes, using the retroviral vector MFG. Primary keratinocytes were transduced in culture with the MFG retroviral vector containing the coding region from factor IX cDNA. Transduced keratinocytes, which secreted on average 830 ng of factor IX/10(6) cells/24 hr in tissue culture, were used to form a bilayered skin equivalent and grafted onto nude mice under a silicone transplantation chamber. Between 0.1 and 2.75 ng of human factor IX per milliliter was found in mouse plasma for more than 1 year, suggesting that keratinocyte stem cells were both transduced and grafted. The results show, for the first time, that long-term expression is obtainable in retrovirally transduced keratinocytes after transplantation.
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Affiliation(s)
- S J White
- Chemical Pathology Unit, Sir William Dunn School of Pathology, University of Oxford, UK
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6
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Meng X, Sawamura D, Tamai K, Hanada K, Ishida H, Hashimoto I. Keratinocyte gene therapy for systemic diseases. Circulating interleukin 10 released from gene-transferred keratinocytes inhibits contact hypersensitivity at distant areas of the skin. J Clin Invest 1998; 101:1462-7. [PMID: 9502789 PMCID: PMC508702 DOI: 10.1172/jci1031] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This study has examined the systemic effects of a circulating gene product, human interleukin 10 (IL-10), released from transduced keratinocytes. IL-10 is an anti-inflammatory cytokine which has an inhibitory effect on contact hypersensitivity (CHS). An expression vector (phIL-10) was constructed for human IL-10 and was injected into the dorsal skin of hairless rats. Local expression of IL-10 mRNA and protein was detected by reverse-transcriptase polymerase chain reaction and immunohistochemical staining, respectively. Enzyme-linked immunosorbent assay showed that the amount of IL-10 in the local keratinocytes and in the circulation increased with the dose of phIL-10 transferred. To determine whether circulating IL-10 could inhibit the effector phase of CHS at a distant area of the skin, various doses of phIL-10 were injected into the dorsal skin of sensitized rats before challenge on the ears. Our results showed that the degree of swelling of the ears of phIL-10- treated rats was significantly lower than that in the negative control animals. These results suggest that IL-10 released from transduced keratinocytes can enter the bloodstream and cause biological effects at distant areas of the skin. This study demonstrates that it may be possible to treat systemic disease using keratinocyte gene therapy.
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Affiliation(s)
- X Meng
- Department of Dermatology, Hirosaki University School of Medicine, Hirosaki 036, Japan.
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7
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Abstract
The skin represents a site for treatment of cutaneous and systemic disease and is the most accessible somatic tissue for therapeutic gene transfer in humans. Monogenic hereditary skin diseases, such as ichthyosis and epidermolysis bullosa subtypes, and disorders characterized by low levels of polypeptides in the systemic circulation, are current central foci of efforts in cutaneous-gene transfer. Additional efforts center on the treatment of wounds and malignancies. Recent developments in models of gene delivery to the skin underscore key challenges that must be met before successful treatment of human disease by cutaneous gene delivery can be achieved.
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Affiliation(s)
- P A Khavari
- Dermatology Service, V.A. Palo Alto Health Care System, CA 94304, USA.
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8
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Abstract
The skin is an accessible somatic tissue for therapeutic gene transfer and, depending on therapeutic goals, a variety of cutaneous gene delivery approaches are currently available. Recent advances in direct injection of naked DNA into intact skin have shown promise and are less labor-intensive than approaches involving grafting of genetically modified cells. We have regenerated skin from transglutaminase 1 (TGase1)-deficient patients with the genetic skin disease lamellar ichthyosis (LI) on nude mice to examine the corrective impact of direct naked plasmid injection. Regenerated LI patient skin receiving repeated in vivo injections with a TGase1 expression plasmid displayed restoration of TGase1 expression in the correct tissue location in the suprabasal epidermis. Unlike LI skin regenerated from keratinocytes, first transduced in vitro with a retroviral expression vector for TGase1 prior to grafting, however, directly injected LI skin displayed a nonuniform TGase1 gene expression pattern. In further contrast, direct injection failed to correct the central histologic and functional abnormalities of the disease. These data demonstrate that partial restoration of gene expression can be achieved via direct injection of naked DNA in human genetic skin disease tissue but underscore the need for new advances to achieve efficient and sustained plasmid-based gene delivery to the skin.
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Affiliation(s)
- K A Choate
- V.A. Palo Alto Health Care System, CA 94304, USA
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9
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Abstract
Gene therapy efforts in a variety of tissues have foundered on fundamental technologic barriers, such as difficulties in achieving high-efficiency gene transfer to diseased tissues and in sustaining delivered transgene production. The skin offers an attractive tissue for development of approaches to therapeutic gene delivery by virtue of its accessibility for regulation by topical agents, the ease of gene transfer into cutaneous tissues, and the ready ability to monitor the impact of somatic gene transfer. With the ability of the skin to deliver therapeutic polypeptides to the systemic circulation and the recent molecular characterization of monogenic skin diseases, efforts to target genes to the skin are expected to accelerate. The current status of gene therapy efforts is reviewed, with a special focus on the skin.
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Affiliation(s)
- P A Khavari
- Dermatology Service, Veterans Administration Palo Alto Health Care System, California, USA
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Mathor MB, Ferrari G, Dellambra E, Cilli M, Mavilio F, Cancedda R, De Luca M. Clonal analysis of stably transduced human epidermal stem cells in culture. Proc Natl Acad Sci U S A 1996; 93:10371-6. [PMID: 8816807 PMCID: PMC38391 DOI: 10.1073/pnas.93.19.10371] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have transduced normal human keratinocytes with retroviral constructs expressing a bacterial beta-galactosidase (beta-gal) gene or a human interleukin-6 (hIL-6) cDNA under control of a long terminal repeat. Efficiency of gene transfer averaged approximately 50% and 95% of clonogenic keratinocytes for beta-gal and hIL-6, respectively. Both genes were stably integrated and expressed for more than 150 generations. Clonal analysis showed that both holoclones and their transient amplifying progeny expressed the transgene permanently. Southern blot analysis on isolated clones showed that many keratinocyte stem cells integrated multiple proviral copies in their genome and that the synthesis of the exogenous gene product in vitro was proportional to the number of proviral integrations. When cohesive epidermal sheets prepared from stem cells transduced with hIL-6 were grafted on athymic animals, the serum levels of hIL-6 were strictly proportional to the rate of secretion in vitro and therefore to the number of proviral integrations. The possibility of specifying the level of transgene expression and its permanence in a homogeneous clone of stem cell origin opens new perspectives in the long-term treatment of genetic disorders.
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Affiliation(s)
- M B Mathor
- Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
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Yang TA, Heiser WC, Sedivy JM. Efficient in situ electroporation of mammalian cells grown on microporous membranes. Nucleic Acids Res 1995; 23:2803-10. [PMID: 7659501 PMCID: PMC307114 DOI: 10.1093/nar/23.15.2803] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Electroporation is a common technique for the introduction of DNA molecules into living cells. The method is currently limited by the necessity of applying the electrical discharge to cells in suspension. Adherent cells must therefore be removed from their substratum, which can induce unwanted physiological effects. We report here a new procedure for in situ electroporation of cells grown on microporous membranes of polyethylene terephthalate (PET) or polyester (PE). We demonstrate that this method of in situ electroporation employs only readily available materials and standard electroporation devices without any modifications, is as efficient as conventional electroporation of cells in suspension, and is applicable to a wide range of cell types. Efficient electroporation can be achieved under conditions of minimal cell killing, and can be performed with quiescent cells as well as with confluent epithelial sheets. The method is a useful extension of electroporation technology, and will allow the application of electroporation to a wider spectrum of biological systems.
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Affiliation(s)
- T A Yang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
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