Although viral carriers in gene therapy have shown promising results, potential immunogenicity and host chromosomal integration still remain, which causes a drawback in human application. We propose a new polymer carrier, polyamido ethylenimine containing multiple disulfide bonds (SS-PAEI). This well characterized polymer presented higher level of reporter gene expression with a significantly lower cellular toxicity than conventional high molecular weight polyethylenimine. It has been reported that glucagon-like peptide 1 (GLP-1) administration completely normalized blood glucose in type 2 diabetic patients. However, plasma half life is too short and continuous infusion of multiple injections is required for therapeutic use of GLP-1. In this application, construction of GLP-1 plasmid and its delivery with SS-PAEI are proposed for the treatment of type 2 diabetes. GLP-1 plasmid will be delivered by non-viral SS-PAEI carrier for prolonged time of GLP-1 production by gene delivery. This SS-PAEI carrier improves transfection efficiency, non-immunogenic and less difficult to use. Its high transfection is due to cytosomal destabilization and fast degradation to release DNA in the cells. In this application, we will develop an effective GLP-1 plasmid by selecting the optimal promoter/enhancer and transcription factor binding sites. GLP-1 plasmid will be constructed with strong promoter/enhancer. To increase nuclear import, the nuclear factor kappa B (NFkB) binding sites will be incorporated into plasmid. Since this nuclear import is mainly presented in cytoplasm and has nuclear localization signal, it will enhance nuclear import of DNA. In addition, two step transcriptional amplification (TSTA) will be employed to enhance transcriptional activity. The effectiveness of the designed delivery system will be evaluated by both in vitro transfection and in vivo experiment with type 2 diabetic animal model. ? ? ?
