| Before 1980, obesity was a negligible factor for human health due to its low prevalence. However, it has dramatically increased due to changes in eating habits and reductions in physical activity, and has surged to be one of the most serious causes of death worldwide, because it contributes to many severe diseases, such as type 2 diabetes. Numerous therapeutic approaches including drugs, surgery, and hormone treatments have been tried, but all have failed to stem the tide of rising obesity rates and obesity-related deaths. Because single therapeutic agents have produced disappointing weight loss results, combinatorial therapies based on peptide administration to manage obesity have been intensively investigated. However, they require high and frequent doses, leading to low patient compliance. On the other hand, combinatorial anti-obesity genes assembled in one plasmid to treat obesity may allow for low and infrequent doses. In addition, nonviral gene carriers are promising delivery system due to their safety and high gene-packaging capacity. The goal of this work is to develop a plasmid containing dual genes (bicistronic plasmid system) for the exogenic regulation of obesity using a nonviral gene carrier. The genes inserted into the plasmids were selected from appetite-suppressing or heat-producing hormone genes that can mitigate obesity development effectively.;To this end, two bicistronic plasmids were designed, developed, and evaluated in vitro and in vivo. My working hypothesis is that a higher efficacy of obesity treatment can be achieved by combining genes into a single plasmid. Self-cleaving peptide gene sequences between each selected gene were introduced to allow co-expression of the hormone proteins independently.;The newly created plasmids were administered using a nonviral gene carrier, linear polyethylenimine (lPEI), into diet-induced obese (DIO) mice to validate their efficacy. The outcomes demonstrated that their weekly treatments reduced the body weight, adiposity, and obesity-related metabolic variables, and ramped up the energy metabolism in DIO mice. Hence, I have concluded that nonviral gene carrier-based combinatorial anti-obesity gene delivery is therapeutically attractive to treat obesity. |
