title: Involvement of receptor-bound prorenin in development of nephropathy in diabetic db/db mice.
abstract: Previous studies have demonstrated that prorenin plays a significant role in the development and progression of nephropathy in streptozotocin-induced diabetic animals, a model for type 1 diabetes, through a (pro)renin receptor-dependent mechanism. However, whether this novel mechanism also contributes to the mechanism of diabetic nephropathy in type 2 diabetes has remained undetermined. In 16-week-old db/db mice, a model for type 2 diabetes, we found a significant degree of glomerulosclerosis, enhanced immunostaining for the active site of renin (representing non-proteolytically activated prorenin), and an increased immunoreactivity to activated extracellular-signal-related protein kinase 1/2 in the kidneys. These changes were blocked by the chronic subcutaneous administration (1 mg/kg/day) of a decoy peptide with the "handle region" structure, which competitively inhibits prorenin binding to a "handle region"-specific binding protein, such as the (pro)renin receptor. The kidneys of db/db mice also contained increased angiotensin (Ang) I and II levels, eliciting significant microalbuminuria. Treatment with the "handle region" peptide significantly decreased the renal content of Ang I and II and inhibited the development of microalbuminuria. Thus prorenin also contributes to the development of nephropathy in type II diabetes, probably through a (pro)renin receptor-dependent mechanism.
authors.affiliation: Deparment of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Ichihara
authors.forename: Mariyo
authors.initials: M
authors.lastname: Sakoda
authors.forename: Asako
authors.initials: A
authors.lastname: Kurauchi-Mito
authors.forename: Akira
authors.initials: A
authors.lastname: Nishiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Itoh