title: Production of human beta-hexosaminidase A with highly phosphorylated N-glycans by the overexpression of the Ogataea minuta MNN4 gene.
abstract: Effective enzyme replacement therapy for lysosomal storage diseases requires a recombinant enzyme with highly phosphorylated N-glycans. Recombinant human beta-hexosaminidase A is a potentially therapeutic enzyme for GM2-gangliosidosis. Recombinant HexA has been produced by using the methylotrophic yeast Ogataea minuta as a host, and the purified enzyme was tested for its replacement effect on cultured fibroblasts derived from GM2-gangliosidosis patients. Although the therapeutic effect was observed, in order to obtain the higher therapeutic effect with a little dose as possible, increased phosphorylation of recombinant beta-hexosaminidase A N-glycans is suggested to be prerequisite. In the budding yeast Saccharomyces cerevisiae, the overexpression of MNN4, which encodes a positive regulator of mannosylphosphate transferase, led to increased mannosylphosphate contents. In the present study, we cloned OmMNN4, a homologous gene to ScMNN4, based on the genomic sequence of O. minuta. We overexpressed the cloned gene under the control of the alcohol oxidase promoter in a beta-hexosaminidase A-producing yeast strain. Structural analysis of pyridylamine-labeled N-glycans by high-performance liquid chromatography revealed that the overexpression of MNN4 caused a 3-fold increase in phosphorylated N-glycans of recombinant beta-hexosaminidase A. The recombinant enzyme prepared from strains overexpressing OmMNN4 was more effectively incorporated into cultured fibroblasts and neural cells, and it more rapidly degraded the accumulated GM2-ganglioside as compared to the control enzyme. These results suggest that beta-hexosaminidase A produced in a strain that overexpresses OmMNN4 will act as an effective enzyme for use in replacement therapy of GM2-gangliosidosis.
authors.affiliation: Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Akeboshi
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kasahara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsuji
authors.forename: Kohji
authors.initials: K
authors.lastname: Itoh
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakuraba
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Chiba
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Jigami
mesh_terms: D000595:Amino Acid Sequence; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011134:Polysaccharides / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D001619:beta-N-Acetylhexosaminidases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D011134:Polysaccharides; D001619:beta-N-Acetylhexosaminidases