Electroporation-Based Non-Viral Gene Delivery to Adipose Tissue in Mice

Abstract

Adipose tissue is distributed throughout the body as fat depots. The amount of adipose tissue increases with age. In mice, epididymal fat depots in males and gonadal fat depots in females are associated with the reproductive system. Regarding fat depots in females, the adipose tissue under the skin can be easily exposed via surgery when the ovary, oviduct, and uterus are pulled out and exposed. As handling adipose tissue is relatively easy, adipocytes might be good targets for genetic manipulation (including gene delivery to the adipose cells). To examine this possibility, we injected 1 μL of dye (e.g., trypan blue or India ink) into the gonadal fat depots of female mice using a breath-controlled micropipette under a dissecting microscope. The injected dye remained at the injection site for at least one day. The injection of piggyBac (PB) transposons containing an enhanced green fluorescent protein (EGFP)-expressing unit and subsequent in vivo electroporation (EP) at the injection site resulted in the successful transfection of adipocytes. The introduction of the PB transposons caused chromosomal integration of the gene of interest. The introduction of a vector containing an octamer-binding transcription factor-3/4 promoter-directed EGFP cDNA expression unit helped to identify stem-like cells. These results supported the feasibility of our EP-based non-viral gene delivery system to transfect murine adipocytes in vivo. Using this approach, several applications such as the local production of therapeutically useful proteins, plasmid-based vaccinations, and the acquisition of immortalized adipose-derived stem cells might be possible.