title: Therapeutic potential of intracerebroventricular replacement of modified human β-hexosaminidase B for GM2 gangliosidosis.
abstract: To develop a novel enzyme replacement therapy for neurodegenerative Tay-Sachs disease (TSD) and Sandhoff disease (SD), which are caused by deficiency of β-hexosaminidase (Hex) A, we designed a genetically engineered HEXB encoding the chimeric human β-subunit containing partial amino acid sequence of the α-subunit by structure-based homology modeling. We succeeded in producing the modified HexB by a Chinese hamster ovary (CHO) cell line stably expressing the chimeric HEXB, which can degrade artificial anionic substrates and GM2 ganglioside in vitro, and also retain the wild-type (WT) HexB-like thermostability in the presence of plasma. The modified HexB was efficiently incorporated via cation-independent mannose 6-phosphate receptor into fibroblasts derived from Tay-Sachs patients, and reduced the GM2 ganglioside accumulated in the cultured cells. Furthermore, intracerebroventricular administration of the modified HexB to Sandhoff mode mice restored the Hex activity in the brains, and reduced the GM2 ganglioside storage in the parenchyma. These results suggest that the intracerebroventricular enzyme replacement therapy involving the modified HexB should be more effective for Tay-Sachs and Sandhoff than that utilizing the HexA, especially as a low-antigenic enzyme replacement therapy for Tay-Sachs patients who have endogenous WT HexB.
authors.affiliation: Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Tomomi
authors.initials: T
authors.lastname: Tamura
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsuji
authors.forename: Yukie
authors.initials: Y
authors.lastname: Dohzono
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kitakaze
authors.forename: Kazuki
authors.initials: K
authors.lastname: Ohno
authors.forename: Seiji
authors.initials: S
authors.lastname: Saito
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakuraba
authors.forename: Kohji
authors.initials: K
authors.lastname: Itoh
mesh_terms: D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D005678:G(M2) Ganglioside / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D012497:Sandhoff Disease / Q000188:drug therapy; D013661:Tay-Sachs Disease / Q000188:drug therapy; D054821:beta-Hexosaminidase beta Chain / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000627:therapeutic use
chemical_list: D005678:G(M2) Ganglioside; D054821:beta-Hexosaminidase beta Chain