BACKGROUND/AIMS: Drug targeting to hepatic stellate cells (HSC) may improve the pharmacological effects of antifibrotic drugs. Recently, albumin substituted with 28 mannose 6-phosphate moieties (M6P(28)-HSA) was found to distribute selectively to HSC in fibrotic rat livers. To assess whether this albumin can be used as a carrier for intracellular drug delivery, we explored the cellular handling of M6P(28)-HSA in HSC. METHODS/ RESULTS: Application of competitive substrates for the M6P/IGFII receptor or other receptors showed that the binding of M6P-HSA to the M6P/IGFII receptor is specific. Binding was strong to activated HSC, but not to quiescent HSC. Furthermore, M6P(28)-HSA was extensively internalized by these cells. Using monensin, a specific inhibitor of the lysosomal pathway, proof was obtained that M6P-HSA is endocytosed via this route. The experiments performed with tissue slices, prepared from rat and human livers, revealed a specific binding and uptake of M6P(28)-HSA in both normal and cirrhotic livers. In livers from cirrhotic patients, HSC contributed predominantly to the uptake of this neoglycoprotein. CONCLUSIONS: Based on our in vivo data demonstrating the HSC-selectivity and on our in vitro data demonstrating binding and rapid internalization in activated HSC, we conclude that M6P(28)-HSA is applicable as a stellate cell-selective carrier for antifibrotic drugs that act intracellularly. This may have implications for the design of new strategies for the treatment of liver fibrosis.
BACKGROUND/AIMS: Drug targeting to hepatic stellate cells (HSC) may improve the pharmacological effects of antifibrotic drugs. Recently, albumin substituted with 28 mannose 6-phosphate moieties (M6P(28)-HSA) was found to distribute selectively to HSC in fibrotic rat livers. To assess whether this albumin can be used as a carrier for intracellular drug delivery, we explored the cellular handling of M6P(28)-HSA in HSC. METHODS/ RESULTS: Application of competitive substrates for the M6P/IGFII receptor or other receptors showed that the binding of M6P-HSA to the M6P/IGFII receptor is specific. Binding was strong to activated HSC, but not to quiescent HSC. Furthermore, M6P(28)-HSA was extensively internalized by these cells. Using monensin, a specific inhibitor of the lysosomal pathway, proof was obtained that M6P-HSA is endocytosed via this route. The experiments performed with tissue slices, prepared from rat and human livers, revealed a specific binding and uptake of M6P(28)-HSA in both normal and cirrhotic livers. In livers from cirrhotic patients, HSC contributed predominantly to the uptake of this neoglycoprotein. CONCLUSIONS: Based on our in vivo data demonstrating the HSC-selectivity and on our in vitro data demonstrating binding and rapid internalization in activated HSC, we conclude that M6P(28)-HSA is applicable as a stellate cell-selective carrier for antifibrotic drugs that act intracellularly. This may have implications for the design of new strategies for the treatment of liver fibrosis.
Authors: Inge A M de Graaf; Peter Olinga; Marina H de Jager; Marjolijn T Merema; Ruben de Kanter; Esther G van de Kerkhof; Geny M M Groothuis Journal: Nat Protoc Date: 2010-08-19 Impact factor: 13.491
Authors: Marike Marjolijn van Beuge; Jai Prakash; Marie Lacombe; Eduard Post; Catharina Reker-Smit; Leonie Beljaars; Klaas Poelstra Journal: Pharm Res Date: 2011-03-26 Impact factor: 4.200
Authors: Werner I Hagens; Adriana Mattos; Rick Greupink; Alie de Jager-Krikken; Catharina Reker-Smit; Annemiek van Loenen-Weemaes; I Annette S H Gouw; Klaas Poelstra; Leonie Beljaars Journal: Pharm Res Date: 2007-03 Impact factor: 4.200
Authors: Marike Marjolijn van Beuge; Jai Prakash; Marie Lacombe; Eduard Post; Catharina Reker-Smit; Leonie Beljaars; Klaas Poelstra Journal: PLoS One Date: 2013-02-18 Impact factor: 3.752