Employment of Fibroblasts for Gene Transfer: Applications for Grafting into the Central Nervous System

Abstract

Several kinds of human diseases may be characterized as a deficiency of a single-gene enzyme or single-gene reactive substance. Such genetic disorders include the absence of hypoxanthine guanine phosphoribosyl transferase in Lesch-Nyhan disease, adenosine deaminase in severe immunodeficiency disease, and factors VIII and IX in hemophilia. Our understanding of these and other disorders of the central nervous system (CNS), immune system, hematopoietic system, etc., has progressed greatly over the past two decades due to the development of molecular genetic techniques. These methods have allowed for the isolation, characterization, and cloning of genes relevant to certain disease states. Over the same period, developments in the delivery of foreign genes into target cells have advanced, such that a number of techniques are now available to introduce new DNA sequences efficiently into cultured eukaryotic cells. With these molecular genetic tools, enzymatic and protein deficiencies can be corrected through the introduction of normal and functioning genes via retroviral-mediated gene transfer into mutant or dysfunctional cells in culture (1–4). It has been proposed (5,6) that corrections of disease phenotype may also be facilitated through similar methods into the entire organism, and this approach is referred to as gene therapy. Many studies to date have employed gene transfer with subsequent grafting as a means of augmenting a deficient enzyme or protein in animal models of human disease types.