Retroviral - mediated Transduction of Leptin Gene in Genetically Obese Mice / 대한내분비학회지

ABSTRACT

BACKGROUND: Leptin gene is known to be related to obesity in human and animals and complete genetic defect of the gene in ob/ob mouse has been identified. Therefore, ob/ob mouse is widely used as an animal model for the study of etiology and therapy of obesity. The main biological function of leptin was thought to involve in the regulation of food intake and weight gain, however, the regulatory mechanisms by which leptin functions in the weight reduction and lowering the blood glucose level are uncertain. In the present study, retroviral-mediated leptin gene transduction into ob/ob mouse was attempted for the correction of biochemical parameters of obesity. METHODS: Leptin cDNA was inserted into pLXSN retroviral vector (pLXSN-lep) and recombinant leptin expressing retrovirus particles (3 X10 CFU/mL) were produced in psi2 ecotropic packaging cells and subsequent transfection into PA317 amphotropic packaging cells. The leptin expressing recombinant viruses (LER) were transduced into NIH3T3 mouse fibroblasts and insertion of leptin cDNA into chromosomal DNA of PA317 and MH3T3 mouse fibroblasts was confirmed by Southern blot hybridizations. Leptin mRNA and its protein expressed in the cells were identified by Northern blot hybridization and Western blot immunodetection method, respectively. LER were injected I. P. into ob/ob mice, and body weight, food intake, serum leptin level and blood glucose level were measured. RESULTS: Expression of leptin was identified in PA317 and NIH3T3 mouse fibroblasts transduced with LER. Leptin content in sera of mice transfused with LER was drastically increased after 1 week and decreased to the almost basal level at 3 weeks after the transfusion. The body weight as well as food intake of ob/ob mouse transduced by LER decreased for the first 3 weeks and slightly increased thereafter. The reduction of both body weight and food intake in ob/ob mice transduced with LER was observed with the concomitant increase of serum leptin level, indicating that retroviral-mediated transduction of leptin gene in ob/ob mouse in vivo produced a biologically active leptin protein and released it into blood circulation. CONCLUSION: A transient expression of leptin cDNA in ob/ob mice by a retroviral-mediated transduction was performed and further studies are required for long term expression of the gene in vivo.