title: Guanidinylated neomycin mediates heparan sulfate-dependent transport of active enzymes to lysosomes.
abstract: Guanidinylated neomycin (GNeo) can transport bioactive, high molecular weight cargo into the interior of cells in a process that depends on cell surface heparan sulfate proteoglycans. In this report, we show that GNeo-modified quantum dots bind to cell surface heparan sulfate, undergo endocytosis and eventually reach the lysosomal compartment. An N-hydroxysuccinimide activated ester of GNeo (GNeo-NHS) was prepared and conjugated to two lysosomal enzymes, beta-D-glucuronidase (GUS) and alpha-L-iduronidase. Conjugation did not interfere with enzyme activity and enabled binding of the enzymes to heparin-Sepharose and heparan sulfate on primary human fibroblasts. Cells lacking the corresponding lysosomal enzyme took up sufficient amounts of the conjugated enzymes to restore normal turnover of glycosaminoglycans. The high capacity of proteoglycan-mediated uptake suggests that this method of delivery might be used for enzyme replacement or introduction of foreign enzymes into cells.
authors.affiliation: Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California-San Diego, La Jolla, California 92093-0687, USA.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Sarrazin
authors.forename: Beth
authors.initials: B
authors.lastname: Wilson
authors.forename: William S
authors.initials: WS
authors.lastname: Sly
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Tor
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Esko
mesh_terms: D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis / Q000502:physiology; D005966:Glucuronidase / Q000737:chemistry / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007068:Iduronidase / Q000737:chemistry / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D015394:Molecular Structure; D009355:Neomycin / Q000737:chemistry / Q000378:metabolism*; D045663:Quantum Dots
chemical_list: D005966:Glucuronidase; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D007068:Iduronidase; D009355:Neomycin