Non-viral gene delivery in skeletal muscle: a protein factory

Abstract

Ever since the publication of the first reports in 1990 using skeletal muscle as a direct target for expressing foreign transgenes, an avalanche of papers has identified a variety of proteins that can be synthesized and correctly processed by skeletal muscle. The impetus to the development of such applications is not only amelioration of muscle diseases, but also a range of therapeutic applications, from immunization to delivery of therapeutic proteins, such as clotting factors and hormones. Although the most efficient way of introducing transgenes into muscle fibres has been by a variety of recombinant viral vectors, there are potential benefits in the use of non-viral vectors. In this review we assess the recent advances in construction and delivery of naked plasmid DNA to skeletal muscle and highlight the options available for further improvements to raise efficiency to therapeutic levels.

Molecular signature of the immune and tissue response to non-coding plasmid DNA in skeletal muscle after electrotransfer

“…2 Skeletal muscle has several features that make it more readily amenable to this technique, including accessibility, the ability to stably retain episomal gene cassettes due to its non-dividing nature and its potential to secrete molecules into the circulation. 3 Extensive investigation by many groups over the past decade has enabled vast improvements in the technology and transduction efficiency, 2 such that it has now been successfully used in pre-clinical and clinical trials for the delivery of therapeutic plasmids 4 and DNA vaccines. 5,6 However, two unresolved aspects of ET are the underlying nature of any tissue response to the ET process as a measure of safety and/or any immunological response induced by the procedure and/or nucleic acid itself.…”

Suppression of tumor growth by intra-muscular transfer of naked DNA encoding adrenomedullin antagonist

“…Several factors make skeletal muscle an attractive route for gene therapy: (1) the tissue is abundant, making up about 40% of the body weight of an average adult; (2) skeletal muscle can be used for most of the delivery systems currently used for gene transfer and; (3) there is no significant replacement in skeletal muscle tissue, so that transgene expression can thus persist for relatively long periods. 5 While viral vectors are commonly used for gene transfer into skeletal muscle, naked DNA is now receiving considerable attention for gene transfer into muscle tissue, owing to its safety, simplicity and reliability. 4,6,7,13 However, as the transfection efficiency of naked DNA by intra-muscular injection is relatively low, this method would not suffice for the treatment of systemic diseases.…”

“…[4][5][6] As gene therapy using viral delivery systems has several aspects, which still need to be resolved, like the evasion from helper virus contamination and avoidance of immunogenicity of the viral particle itself, gene therapy using non-viral delivery systems is now being anticipated. 7 However, the non-viral delivery systems, regrettably, also have several controversial features, such as low efficiency in gene delivery and low immunogenicity of naked DNA.…”

Microwave irradiation enhances gene and oligonucleotide delivery and induces effective exon skipping in myoblasts

“…Non-viral biochemical vectors, such as cationic liposomes, polymers and microbubbles, are relatively safe and easy to manufacture, but with limited efficacy, particularly in vivo. 2 The main physical methods are electroporation and sonoporation. Electroporation has been shown to provide efficient gene delivery both in cultured cells and in tissues in vivo locally.…”