Gene Transfer to Subdermal Tissues via a New Gene Gun Design

Abstract

Although particle-mediated gene transfer technology (gene gun) has been applied for gene transfer to external tissues, the application of this technology to other tissues has met with limited success. Here we report the development of a new design of a gene gun that uses helium discharge to propel DNA-coated gold beads that are suspended in liquid. Higher discharge pressures allow for the delivery of DNA to deeper tissues. Using the new gene gun to deliver a luciferase expression plasmid resulted in higher levels of gene expression in the skin than observed with conventional guns, as well as in subdermal tissues, including subcutaneous tumors. Even when using as little as 125 ng of DNA, gene expression in skin and muscle reached its peak level at 24 hr postbombardment and remained for at least 1 week. The use of a LacZ expression plasmid showed that gene expression was distributed throughout the skin with no observable pathology. The new gene gun was used to deliver a model tumor rejection antigen (a modified human papilloma virus [HPV] E7 gene) to mice. All of the treated animals developed protective immunity against HPV-positive tumors. These results demonstrate that our new design can be used in standard gene gun applications and extends the reach of gene gun technology to tissues that were previously unavailable.

Gene therapy in wound healing: present status and future directions

“…44 Therefore, transfection rate is relatively low and ranges up to 10% of epidermis cells. However, Dileo et al 47 showed that using a modified gene gun to deliver plasmids with higher discharge pressures resulted in higher levels of gene expression in epidermis and subdermal tissues than observed with conventional guns. Gene expression in skin and muscle reached its peak level at 24 h after application and remained measurable for at least 1 week.…”

“…The tissue damage was described as insignificant. 47 Studies by the Eriksson group introduced a new method, the micro-seeding technique. 48 Micro-seeding is a method that delivers naked DNA directly into target cells by solid microneedles mounted on a modified tattooing machine.…”

Nonviral gene transfer to skeletal, smooth, and cardiac muscle in living animals

“…The only drawback to this technique is that it traditionally requires the muscle to be exposed (although a new device can penetrate multiple layers of the skin and transfect subepithelial tissues; Ref. 27) and induces some degree of trauma. Microbubble ultrasound has also been used to deliver DNA to skeletal muscle.…”

Current advances in combining stem cell and gene therapy for neurodegenerative diseases

“…Gene gun uses particle bombardment to shoot DNA-coated microscopic pellets through the cell membrane [107]. Recently a significant improvement in tissue penetration had been achieved using a newly designed gene gun, which allows longer gene expression of pDNA in subcutaneous tissues, such as muscle or tumor [109]. Liposome is a vesicular structure that is formed by the interaction and accumulation of lipids, in which pDNA is included [110].…”