Expression of functional human (pro)renin receptor in silkworm (Bombyx mori) larvae using BmMNPV bacmid

The circulating RA (renin-angiotensin) system is essential for the regulation of blood pressure and electrolyte balance. Recently, plasma prorenin has been reported to significantly increase its level in diabetes and to be possibly non-proteolytically activated by binding to the PRR [(pro)renin receptor] on the cell membrane reported in several tissues during circulation. Although many pathological aspects have been researched, there is a lack of sufficient information on the biochemical structure and biological function of this hPRR (human PRR) because of the difficulty in increasing hPRR expression. In the present study, GFP(uv)-hPRR (hPRR fused with green fluorescence protein when excited with long-wave UV light) was successfully expressed by using BmMNPV (Bombyx mori multiple nucleopolyhedrovirus) bacmid DNA in silkworm (Bombyx mori) larvae. Some of the hPRR was expressed in the haemolymph of silkworm larvae and some of the hPRR was located in the fat body of silkworm larvae. The binding ability of hPRR expressed in the haemolymph and fat body with renin or prorenin was analysed by ELISA and surface plasmon resonance using a biosensor respectively. These binding assays suggest that the expressed hPRR has a functional bioactivity. hPRR preparation in silkworm larvae would, therefore, be useful for biochemical and biomedical researches related to PRR.