Ex vivo and in vivo gene transfer to the skin using replication-deficient recombinant adenovirus vectors

Abstract

The skin has the potential for a variety of gene therapy applications. In addition to local delivery, it is the largest organ of the body, and highly vascular, and thus is an ideal site for systemic delivery of gene products. To evaluate the potential for adenovirus-mediated skin gene transfer, the replicationdeficient recombinant adenovirus vectors Ad.RSVβgal (coding for Escherichia coli β-galactosidase) and Adα1AT (coding for human α1-antitrypsin) were used in both ex vivo and in vivo approaches. Following in vitro infection with Ad.RSVβgal, murine keratinocytes expressed β-galactosidase. Parallel in vitro studies with Adα1AT documented de novo synthesis and secretion of human α1AT as shown by [35s]methionine labeling and immunoprecipitation. Quantification of human α1AT in the culture supernatants demonstrated 0.1 - 0.3 μg human α1 AT secreted/ml-24 h. Evaluation of the serum of mice receiving transplants (105 cells/ mouse) of Adα1AT-infected syngeneic keratinocytes demonstrated human α1AT for at least 14 d with maximum levels of 41 ng/ml. To demonstrate the feasibility of direct adenovirus-mediated in vivo transfer of genes to the skin, Ad.RSVβgal or Adα1AT were administered subcutaneously to mice. Histologic evaluation after 4 demonstrated expression of β-galactosidase in various types of skin cells. Quantification of human α1 AT in serum of animals infected subcutaneously with Adα1AT showed levels of 53 ng/ml at day 4, with human α1AT detectable for at least 14 d. These observations support the feasibility of ex vivo and in vivo gene transfer to the skin mediated by replication-deficient adenovirus vectors. © 1994.