Small activating RNA-guided iNOS up-regulation improves erectile function of diabetic rats

Abstract

Purpose

Promoter-targeted small activating RNAs (saRNAs) have been shown to mediate sequence-specific up-regulation of gene expression. We aimed to explore the therapeutic effect of RNAa-mediated activation of inducible nitric oxide synthase (iNOS) gene on improving erectile function in a rat model of diabetes mellitus.

Materials and Methods

An optimal saRNA sequence specific for iNOS promoter was cloned into an adenoviral vector (AdU6/shiNOS and AdU6/shControl). The corresponding viruses were used to transduce cultured rat cavernous smooth muscle cells ( CSMCs). Streptozotocin (STZ)-induced diabetes models were established in rats and used to test the effects of intracavenosal delivery of iNOS saRNA viruses on erectile function. iNOS expression in CSMCs or in penile tissue of treated rats was assessed by RT-PCR and Western blotting. Cyclic guanosine monophosphate (cGMP) was analyzed by ELISA. Intracavernous pressure (ICP) in response to cavernosal nerve stimulation (CNS) was measured using a data acquisition system on day 1, 3, 5, 7, 10 and 14 post-injection.

Results

Adenovirus-mediated expression of the iNOS saRNA caused sustained up-regulation of iNOS in CSMCs. Intracavernosal injection of AdU6/shiNOS activated iNOS expression in vivo and significantly increased peak intracavernous pressure in STZ-induced diabetic rats through activating nitric oxide (NO)/intracellular cGMP.

Conclusions

The results demonstrate that saRNA-mediated iNOS overexpression in penis can restore erectile function of STZ-diabetic rats through the NO-cGMP pathway.

http://www.jurology.com/article/S0022-5347(13)03690-2/abstract