Nonviral gene delivery to the lateral ventricles in rat brain: Initial evidence for widespread distribution and expression in the central nervous system

The use of DNA for nonviral gene expression depends on several factors. The se include (i) delivery and accessibility to the targeted tissue, (ii) prot ection from extracellular degradation, (iii) sufficient uptake by cells of interest, and (iv) protection from intracellular degradation to allow trans lation of adequate levels of intracellular or secreted proteins. As an init ial step in demonstrating the feasibility of nonviral, cationic lipid-media ted gene therapy, we present evidence for the successful delivery and expre ssion of heat shock protein Hsp70 and reporter gene enzymes in the central nervous system (CNS) of the rat after injection into the lateral ventricle. Gene delivery is accomplished using optimized formulations of plasmid DNA, which have been complexed with the cationic lipid MLRI. Results from DNA v ectors encoding for green fluorescent protein (GFP), luciferase, and Hsp70 are reported. Standard immunofluorescent methods were used to demonstrate w idespread expression of the reporter proteins and of Hsp70. Stereology anal ysis has been completed on three coronal sections, which illustrates the di stribution of expression along the longitudinal axis. These initial finding s support the further development of nonviral, lipid-mediated gene delivery technology for transient expression of protective, intracellular proteins and represent an important step leading to in vivo studies to identify pote ntial clinical benefits.