Efficient Gene Expression System Using the RTP801 Promoter in the Corpus Cavernosum of High-Cholesterol Diet-Induced Erectile Dysfunction Rats for Gene Therapy

• Published in: Journal of sexual medicine Vol. 5; no. 6; pp. 1355 - 1364
• Main Authors: Lee, Minhyung, Ryu, Ji-Kan, Piao, Shuguang, Choi, Min Ji, Kim, Hyun Ah, Zhang, Lu-Wei, Shin, Hwa-Yean, Jung, Haeng In, Kim, In-Hoo, Kim, Sung Wan, Suh, Jun-Kyu
• Format: Journal Article
• Language: English
• Published: Malden, USA Elsevier Inc 01-06-2008; Blackwell Publishing Inc
• Subjects: Animals; Cholesterol, Dietary - administration & dosage; Corpus Cavernosum; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Erectile Dysfunction; Erectile Dysfunction - etiology; Erectile Dysfunction - therapy; Gene Expression; Gene Therapy; Genetic Therapy; Humans; Hypercholesterolemia; Hypercholesterolemia - complications; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Hypoxia-Inducible Factor-1α; Male; Penis - metabolism; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Repressor Proteins - genetics; Repressor Proteins - metabolism; Transfection; Up-Regulation; Vector; Erectile Dysfunction; Hypercholesterolemia; Gene Therapy; Corpus Cavernosum; Vector; Hypoxia-Inducible Factor-1α
• ISSN: 1743-6095; 1743-6109
• DOI: 10.1111/j.1743-6109.2008.00771.x

The application of gene therapy for a nonlife-threatening disease, such as erectile dysfunction (ED), requires a higher safety level and more efficacious systems for gene transfer.
To establish a novel technique for gene expression in a rat model of hypercholesterolemic ED that uses the RTP801 promoter, a hypoxia-inducible promoter.
Two-month-old male Sprague–Dawley rats were fed a diet containing 4% cholesterol and 1% cholic acid, and age-matched control animals were fed a normal diet, for 3 months.
Cavernous expression of hypoxia-inducible factor (HIF)-1α was evaluated by Western blot. After intracavernous injection of pSV-Luc or pRTP801-Luc, gene expression was evaluated by luciferase assay, and the gene expression area was evaluated by immunohistochemistry.
HIF-1α was up-regulated in the corpus cavernosum of hypercholesterolemic rats. Although pSV-Luc did not induce gene expression in either the control or the cholesterol group, pRTP801-Luc significantly induced gene expression in the cholesterol group and resulted in higher luciferase activity than did pSV-Luc up to 14 days after injection. Immunohistochemistry showed that the gene expression area was also greater in the pRTP801-Luc group than in the pSV-Luc group, but the difference was not as great as that in luciferase activity. This suggests that pRTP801-Luc exerts its effect mainly by inducing promoter activity under hypoxia, not by increasing the number of transfected cells.
The RTP801 promoter-driven gene expression system increased gene expression in the corpus cavernosum tissue of rats with cholesterol-induced ED. This may be a useful system for the development of gene therapy in vasculogenic ED. Lee M, Ryu J-K, Piao S, Choi MJ, Kim HA, Zhang L-W, Shin H-Y, Jung HI, Kim I-H, Kim SW, and Suh J-K. Efficient gene expression system using the RTP801 promoter in the corpus cavernosum of high-cholesterol diet-induced erectile dysfunction rats for gene therapy.