Lipoprotein receptor binding, cellular uptake, and lysosomal delivery of fusions between the receptor-associated protein (RAP) and alpha-L-iduronidase or acid alpha-glucosidase.
Enzyme replacement therapy for lysosomal storage disorders depends on efficient uptake of recombinant enzyme into the tissues of patients. This uptake is mediated by oligosaccharide receptors including the cation-independent mannose 6-phosphate receptor and the mannose receptor. We have sought to exploit alternative receptor systems that are independent of glycosylation but allow for efficient delivery to the lysosome. Fusions of the human lysosomal enzymes alpha-l-iduronidase or acid alpha-glucosidase with the receptor-associated protein were efficiently endocytosed by lysosomal storage disorder patient fibroblasts, rat C6 glioma cells, mouse C2C12 myoblasts, and recombinant Chinese hamster ovary cells expressing individual members of the low-density lipoprotein receptor family. Uptake of the fusions exceeded that of phosphorylated enzyme in all cases, often by an order of magnitude or greater. Uptake was specifically mediated by members of the low-density lipoprotein receptor protein family and was followed by delivery of the fusions to the lysosome. The advantages of the lipoprotein receptor system over oligosaccharide receptor systems include more efficient cellular delivery and the potential for transcytosis of ligands across tight endothelia, including the blood-brain barrier.
Prince
William S
WS
BioMarin Pharmaceutical, Inc., Novato, CA 94949, USA.
McCormick
Lynn M
LM
Wendt
Dan J
DJ
Fitzpatrick
Paul A
PA
Schwartz
Keri L
KL
Aguilera
Allora I
AI
Koppaka
Vishwanath
V
Christianson
Terri M
TM
Vellard
Michel C
MC
Pavloff
Nadine
N
Lemontt
Jeff F
JF
Qin
Minmin
M
Starr
Chris M
CM
Bu
Guojun
G
Zankel
Todd C
TC
D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002241:Carbohydrates / Q000737:chemistry; D045744:Cell Line, Tumor; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004586:Electrophoresis; D004705:Endocytosis; D005347:Fibroblasts / Q000378:metabolism; D005910:Glioma / Q000378:metabolism; D006025:Glycosaminoglycans / Q000737:chemistry; D006801:Humans; D007068:Iduronidase / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D008077:Lipoproteins, LDL / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D009844:Oligosaccharides / Q000737:chemistry; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D018110:Receptors, Lipoprotein / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors; D000520:alpha-Glucosidases / Q000378:metabolism*
D002241:Carbohydrates; D006025:Glycosaminoglycans; D008024:Ligands; D008077:Lipoproteins, LDL; D009844:Oligosaccharides; D018110:Receptors, Lipoprotein; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D000520:alpha-Glucosidases; D007068:Iduronidase