HSP47 siRNA conjugated with cationized gelatin microspheres suppresses peritoneal fibrosis in mice

Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is essential for the biosynthesis and secretion of collagen and is expressed in the fibrotic peritoneum. In the present study, we evaluated the efficacy of HSP47 small interfering RNA (siRNA) to suppress the development of peritoneal fibrosis induced by chlorhexidine gluconate in mice. We initially confirmed that biodegradable cationized gelatin microspheres (CGMs) containing HSP47 siRNA could continuously release siRNA over 21 days as a result of microsphere degradation. We then determined that a single injection of CGMs incorporating HSP47 siRNA suppressed collagen expression and macrophage infiltration, thereby preventing peritoneal fibrosis. Therefore, we suggest that this controlled-release technology using HSP47 siRNA is a potential treatment for peritoneal fibrosis. Additionally, RNA interference combined with CGMs as a drug-delivery system may lead to new strategies for knocking down specific genes in vivo.