title: Keratinocyte gene therapy for adenosine deaminase deficiency: a model approach for inherited metabolic disorders.
abstract: Disorders in which there is toxic buildup of circulating substrate may be treated by furnishing an enzyme reservoir capable of metabolically processing the excess substrate. The epidermal keratinocyte is a potential site for such a reservoir. In this study, we explore the capacity of genetically modified keratinocytes to metabolize extracellular substrate in a culture model that resembles in vivo epidermal architecture. Keratinocytes from adenosine deaminase (ADA)-deficient patients were transduced with a retroviral vector encoding the human ADA gene and the capacity of this tissue to deaminate deoxyadenosine (dAdo) in vitro was measured. The results show that at a substrate concentration of 10 microM, ADA-corrected keratinocytes deaminate dAdo at a rate of 0.38 nmol/min.10(6) cells. These results indicate that keratinocytes process extracellular substrate at rates that suggest complete substrate conversion in a single pass. This study provides a strong indication that the epidermis, the largest and most accessible tissue of the body, is a valuable site for designing clinically relevant gene therapies.
authors.affiliation: Department of Oral Biology and Pathology, State University of New York at Stony Brook 11794, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Fenjves
authors.forename: P M
authors.initials: PM
authors.lastname: Schwartz
authors.forename: R M
authors.initials: RM
authors.lastname: Blaese
authors.forename: L B
authors.initials: LB
authors.lastname: Taichman
mesh_terms: D000243:Adenosine Deaminase / Q000172:deficiency*; D002478:Cells, Cultured; D002648:Child; D015316:Genetic Therapy; D006801:Humans; D015603:Keratinocytes / Q000502:physiology*; D008659:Metabolic Diseases / Q000235:genetics / Q000628:therapy*; D012190:Retroviridae / Q000235:genetics; D014161:Transduction, Genetic
chemical_list: D000243:Adenosine Deaminase