Human Growth Factor Expressed in Transgenic Insect

The application of sterile Lucilia sericata (green bottle fly) larvae to wounds is a cost-effective treatment for diabetic foot ulcers and other medical conditions. The advent of genetic engineering has allowed for expression and secretion of human growth factors and other proteins in transgenic insects. Rebecca J. Linger of North Carolina State University presented a concept in MDT technology that combines the benefits of MDT and genetic engineering to promote healing.

The team developed strains of transgenic Lucilia sericata that secrete PDGF-BB, a growth factor that promotes wound healing, at detectable levels in adult hemolymph, whole larval lysate, and maggot excretions/secretions (ES), with potential for clinical use in wound healing.

The team used two techniques in expressing the gene in the maggot. First, they used a heat-inducible promoter. Upon heat shock, the PDGF-BB protein was detectable in transgenic larval lysates and adult hemolymph but not in maggot ES. In an alternate technique, a tetracycline-repressible expression of pdgf-b was used. Using this technique, the PDGF-BB protein was readily detected in whole larval lysate as well as larval ES.

The study showed inducible expression and production of human PDGF-BB protein from two conditional expression systems in transgenic L. sericata larvae. The tetracycline-repressible system appears to be the most promising as PDGF-BB protein was detectable in larval ES following induction. This system could potentially be used to deliver a variety of growth factors and anti-microbial peptides to the wound environment with the aim of enhancing wound healing.

For more information, read the article on BMC Biotechnology.