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Gene Transfer of TRPC6DN (Dominant Negative) Restores Erectile Function in Diabetic Rats

Authors

  • Jae Hun Jung MD,

    1. Department of Urology, Institute of Health Science, Gyeongsang National University School of Medicine, 92, Chilam-Dong, Jinju 660-751, Republic of Korea;
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  • Byung Joo Kim PhD,

    1. Pusan National University School of Oriental Medicine, Beomeo-ri, Mulgeum-eup, Yangsan, 626-770, Republic of Korea;
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  • Mee Ree Chae MA,

    1. Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Kangnam-gu, Seoul 135-710, Republic of Korea;
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  • Sung Chul Kam MD,

    1. Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Kangnam-gu, Seoul 135-710, Republic of Korea;
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  • Ju-Hong Jeon PhD,

    1. Department of Physiology and Biophysics, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Republic of Korea
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  • Insuk So MD, PhD,

    1. Department of Physiology and Biophysics, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Republic of Korea
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  • Ky Hyun Chung MD, PhD,

    1. Department of Urology, Institute of Health Science, Gyeongsang National University School of Medicine, 92, Chilam-Dong, Jinju 660-751, Republic of Korea;
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  • Sung Won Lee MD, PhD

    Corresponding author
    1. Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Kangnam-gu, Seoul 135-710, Republic of Korea;
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  • Jae Hun Jung and Byung Joo Kim contributed equally to this work.

Sung Won Lee, MD, PhD, Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine #50 Ilwon-dong Kangnan-ku, Seoul, Korea, 135-710. Tel: 82-2-3410-3552; Fax: 82-2-3410-3027; E-mail: drswlee@skku.edu

ABSTRACT

Introduction.  Transient receptor potential (TRP) channels play an important role in modulating intracellular Ca2+ ([Ca2+]i) levels.

Aim.  We examined the hypothesis that overexpression of TRPC6DN (dominant negative) may contribute to decreased [Ca2+]i levels in corporal smooth muscle (CSM). We also investigated whether gene transfer of TRPC6DN could restore erectile function in diabetic rats.

Methods.  For the in vitro study, the KCa, KATP, and TRPC6DN channel genes were transferred using cDNA, into cultured human CSM cells and human embryonic kidney cells. For the in vivo study, young adult rats were divided into three groups: normal controls; diabetic controls transfected with vector only; and a diabetic group transfected with pcDNA of the TRPC6DN gene.

Main Outcome Measures.  After gene transfer, the effects of reducing [Ca2+]i levels were assessed by Fura-2-based imaging analysis. The intracavernosal pressure (ICP) response to cavernosal nerve stimulation was assessed after intracorporal injection of TRPC6DN pcDNA. The transgene expression of the TRPC6DN was examined by reverse transcription polymerase chain reaction (RT-PCR) in rats transfected with TRPC6DN pcDNA.

Results.  Gene transfer of ion channels effectively reduced [Ca2+]i. Among these channels, transfer of the TRPC6DN gene resulted in the greatest reduction of [Ca2+]i in human CSM. The mean (±standard error of the mean) ratio of ICP to mean arterial pressure (BP) in the gene-transfer rats was 79.4 ± 2.4% (N = 8). This was significantly higher than that in control rats (55.6 ± 3.7% [N = 8]), and similar to that in the young control rats (83 ± 2.2% [N = 12]). The RT-PCR showed expression of TRPC6DN genes in the transfected rats.

Conclusion.  Gene transfer of TRPC6DN not only reduced [Ca2+]i in human CSM but also restored erectile function in diabetic rats. These results suggest that pcDNA transfer of TRPC6DN may represent a promising new form of therapy for the treatment of male erectile dysfunction in the future. Jung JH, Kim BJ, Chae MR, Kam SC, Jeon J-H, So I, Chung KH, and Lee SW. Gene transfer of TRPC6DN (dominant negative) restores erectile function in diabetic rats. J Sex Med 2010;7:1126–1138.

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