Keratinocyte gene therapy for adenosine deaminase deficiency: a model approach for inherited metabolic disorders.
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.
Fenjves
E S
ES
Department of Oral Biology and Pathology, State University of New York at Stony Brook 11794, USA.
Schwartz
P M
PM
Blaese
R M
RM
Taichman
L B
LB
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
D000243:Adenosine Deaminase