Bone morphogenetic protein-7 (BMP-7) antagonizes
transforming growth factor-β (TGF-β), which is critically involved in liver fibrogenesis. Here, we designed a
micelle formulation consisting of a
protein transduction domain (PTD) fused
BMP-7 polypeptide (mPTD-BMP-7) to enhance endocytic delivery, and investigated its ability to ameliorate
liver fibrosis. The mPTD-BMP-7 formulation was efficiently delivered into cells via endocytosis, where it inhibited TGF-β mediated epithelial-mesenchymal transition. After successfully demonstrating delivery of fluorescently labeled mPTD-BMP-7 into the murine liver in vivo, we tested the mPTD-BMP-7 formulation in a murine
liver fibrosis model, developed by repeated
intraperitoneal injection of hepatotoxic
carbon tetrachloride, twice weekly from 4 to 16 weeks. mPTD-BMP-7 effects were tested by injecting the mPTD-BMP-7 formulation (or vehicle control) into the lateral tail at a dose of 50 (n=8) or 500 μg/kg (n=10), also twice per week from 4 to 16 weeks. Vehicle-treated control mice developed fibrous septa surrounding the liver parenchyma and marked portal-to-portal bridging with occasional nodules, whereas mice treated with mPTD-BMP-7 showed only fibrous expansion of some portal areas, with or without short fibrous septa. Using the Ishak scoring system, we found that the fibrotic burden was significantly lower in mPTD-BMP-7 treated mice than in control mice (all P<0.001). Treatment with mPTD-BMP-7 protected tight junctions between hepatocytes and reduced
extracellular matrix protein levels. It also significantly decreased
mRNA levels of
collagen 1A, smooth muscle α-actin, and
connective tissue growth factor compared with that in control mice (all P<0.001). Collectively, out results indicate that mPTD-BMP-7, a
prodrug formulation of
BMP-7, ameliorates
liver fibrosis by suppressing the TGF-β signaling pathway in a murine
liver fibrosis model.