Mouse Type-I Interferon-Mannosylated Albumin Fusion Protein for the Treatment of Chronic Hepatitis.

Although a lot of effort has been put into creating drugs and combination therapies against chronic hepatitis, no effective treatment has been established. Type-I interferon is a promising therapeutic for chronic hepatitis due to its excellent anti-inflammatory effects through interferon receptors on hepatic macrophages. To develop a type-I IFN equipped with the ability to target hepatic macrophages through the macrophage mannose receptor, the present study designed a mouse type-I interferon-mannosylated albumin fusion protein using site-specific mutagenesis and albumin fusion technology. This fusion protein exhibited the induction of anti-inflammatory molecules, such as IL-10, IL-1Ra, and PD-1, in RAW264.7 cells, or hepatoprotective effects on carbon tetrachloride-induced chronic hepatitis mice. As expected, such biological and hepatoprotective actions were significantly superior to those of human fusion proteins. Furthermore, the repeated administration of mouse fusion protein to carbon tetrachloride-induced chronic hepatitis mice clearly suppressed the area of liver fibrosis and hepatic hydroxyproline contents, not only with a reduction in the levels of inflammatory cytokine (TNF-α) and fibrosis-related genes (TGF-ß, Fibronectin, Snail, and Collagen 1α2), but also with a shift in the hepatic macrophage phenotype from inflammatory to anti-inflammatory. Therefore, type-I interferon-mannosylated albumin fusion protein has the potential as a new therapeutic agent for chronic hepatitis.

Therapeutic Effects of Albumin-Fused BMP7 on 2 Experimental Models of Liver Fibrosis.

Despite the fact that liver fibrosis is an intractable disease with a poor prognosis, effective therapeutic agents are not available. In this study, we focused on bone morphogenetic factor 7 (BMP7) that inhibits transforming growth factor (TGF)-ß signaling, which is involved in liver fibrosis. We prepared an albumin-fused BMP7 (HSA-BMP7) that is retained in the blood and evaluated its inhibitory effect on liver fibrosis. Bile duct ligated mice were used as an acute liver fibrosis model, and carbon tetrachloride-induced liver fibrosis mice were used as a chronic model. All mice were administered HSA-BMP7 once per week. In the mice with bile duct ligation, the administration of HSA-BMP7 significantly suppressed the infiltration of inflammatory cells, the area of fibrosis around the bile duct, and decreased in the level of hydroxyproline as compared with saline administration. The mRNA expression of TGF-ß and its downstream fibrosis-associated genes (α-SMA and Col1a2) were also suppressed by the administration of HSA-BMP7. In the carbon tetrachloride-induced liver fibrosis mice, the HSA-BMP7 administration significantly decreased the hepatic fibrosis area and the level of hydroxyproline. Based on these results, it appears that HSA-BMP7 has the potential for serving as a therapeutic agent for the treatment of liver fibrosis.

Albumin-fused long-acting FGF21 analogue for the treatment of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) currently affects about 25% of the world's population, and the numbers continue to rise as the number of obese patients increases. However, there are currently no approved treatments for NAFLD. This study reports on the evaluation of the therapeutic effect of a recombinant human serum albumin-fibroblast growth factor 21 analogue fusion protein (HSA-FGF21) on the pathology of NAFLD that was induced by using two high-fat diets (HFD), HFD-60 and STHD-01. The HFD-60-induced NAFLD model mice with obesity, insulin resistance, dyslipidemia and hepatic lipid accumulation were treated with HSA-FGF21 three times per week for 4 weeks starting at 12 weeks after the HFD-60 feeding. The administration of HSA-FGF21 suppressed the increased body weight, improved hyperglycemia, hyperinsulinemia, and showed a decreased accumulation of plasma lipid and hepatic lipid levels. The elevation of C16:0, C18:0 and C18:1 fatty acids in the liver that were observed in the HFD-60 group was recovered by the HSA-FGF21 administration. The increased expression levels of the hepatic fatty acid uptake receptor (CD36) and fatty acid synthase (SREBP-1c, FAS, SCD-1, Elovl6) were also suppressed. In adipose tissue, HSA-FGF21 caused an improved adipocyte hypertrophy, a decrease in the levels of inflammatory cytokines and induced the expression of adiponectin and thermogenic factors. The administration of HSA-FGF21 to the STHD-01-induced NAFLD model mice resulted in suppressed plasma ALT and AST levels, oxidative stress, inflammatory cell infiltration and fibrosis. Together, HSA-FGF21 has some potential for use as a therapeutic agent for the treatment of NAFLD.

Engineering of a Long-Acting Bone Morphogenetic Protein-7 by Fusion with Albumin for the Treatment of Renal Injury.

The bone morphogenetic protein-7 (BMP7) is capable of inhibiting TGF-ß/Smad3 signaling, which subsequently results in protecting the kidney from renal fibrosis, but its lower blood retention and osteogenic activity are bottlenecks for its clinical application. We report herein on the fusion of carbohydrate-deficient human BMP7 and human serum albumin (HSA-BMP7) using albumin fusion technology and site-directed mutagenesis. When using mouse myoblast cells, no osteogenesis was observed in the glycosylated BMP7 derived from Chinese hamster ovary cells in the case of unglycosylated BMP7 derived from Escherichia coli and HSA-BMP7. On the contrary, the specific activity for the Smad1/5/8 phosphorylation of HSA-BMP7 was about 25~50-times lower than that for the glycosylated BMP7, but the phosphorylation activity of the HSA-BMP7 was retained. A pharmacokinetic profile showed that the plasma half-life of HSA-BMP7 was similar to that for HSA and was nearly 10 times longer than that of BMP7. In unilateral ureteral obstruction mice, weekly dosing of HSA-BMP7 significantly attenuated renal fibrosis, but the individual components, i.e., HSA or BMP7, did not. HSA-BMP7 also attenuated a cisplatin-induced acute kidney dysfunction model. The findings reported herein indicate that HSA-BMP7 has the potential for use in clinical applications for the treatment of renal injuries.

Development of a long acting FGF21 analogue-albumin fusion protein and its anti-diabetic effects.

Fibroblast growth factor 21 (FGF21) is a hormone-like protein that improves blood glucose and lipid metabolism. However, its short half-life and instability are bottlenecks to its clinical applications. In this study, to extend its pharmacological action, we created a stabilized mutant FGF21 (mFGF21:ΔHPIP, P171G, A180E, L118C-A134C, S167A) and then genetically fused it with human albumin (HSA-mFGF21) via a polypeptide linker. Physicochemical analyses suggested that HSA-mFGF21 was formed from both intact HSA and mFGF21. Pharmacokinetic findings indicated the half-life of HSA-mFGF21 was 20 times longer than that of FGF21. In addition, HSA-mFGF21 was persistently distributed in adipose tissue as a target tissue. The in vivo hypoglycemic activity of HSA-mFGF21 using streptozotocin (STZ)-induced type I diabetes model mice, in which insulin secretion was suppressed, showed that a single intravenous administration of HSA-mFGF21 rapidly alleviated hyperglycemia. At that time, HSA-mFGF21 increased GLUT1 mRNA expression in adipose tissue without having any effect on insulin secretion. A twice weekly administration of HSA-mFGF21 continuously suppressed blood glucose levels and ameliorated the abnormalities of adipose tissue induced by STZ treatment. Interestingly, HSA-mFGF21 showed no hypoglycemic effects in healthy mice. Together, HSA-mFGF21 could be a novel biotherapeutic for the treatment of metabolic disorders including diabetes mellitus.