Reversal of neuroinflammation in novel GS model mice by single i.c.v. administration of CHO-derived rhCTSA precursor protein

Yuto Horii; Toshiki Iniwa; Masayoshi Onitsuka; Jun Tsukimoto; Yuki Tanaka; Hironobu Ike; Yuri Fukushi; Haruna Ando; Yoshie Takeuchi; So-Ichiro Nishioka; Daisuke Tsuji; Mariko Ikuo; Naoshi Yamazaki; Yoshiharu Takiguchi; Naozumi Ishimaru; Kohji Itoh

doi:10.1016/j.omtm.2022.04.001

Reversal of neuroinflammation in novel GS model mice by single i.c.v. administration of CHO-derived rhCTSA precursor protein

Mol Ther Methods Clin Dev. 2022 Apr 15:25:297-310. doi: 10.1016/j.omtm.2022.04.001. eCollection 2022 Jun 9.

Authors

Yuto Horii¹, Toshiki Iniwa¹, Masayoshi Onitsuka², Jun Tsukimoto¹, Yuki Tanaka³, Hironobu Ike¹, Yuri Fukushi¹, Haruna Ando¹, Yoshie Takeuchi³, So-Ichiro Nishioka¹, Daisuke Tsuji¹, Mariko Ikuo¹, Naoshi Yamazaki⁴, Yoshiharu Takiguchi⁴, Naozumi Ishimaru⁵, Kohji Itoh^{1

3}

Affiliations

¹ Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan.
² Division of Bioscience and Biotechnology, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan.
³ Department of Medicinal Biotechnology, Faculty of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan.
⁴ Department of Clinical Pharmacology, Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan.
⁵ Department of Oral Molecular Pathology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan.

Abstract

Galactosialidosis (GS) is a lysosomal cathepsin A (CTSA) deficiency. It associates with a simultaneous decrease of neuraminidase 1 (NEU1) activity and sialylglycan storage. Central nervous system (CNS) symptoms reduce the quality of life of juvenile/adult-type GS patients, but there is no effective therapy. Here, we established a novel GS model mouse carrying homozygotic Ctsa IVS6+1g→a mutation causing partial exon 6 skipping with concomitant deficiency of Ctsa/Neu1. The GS mice developed juvenile/adult GS-like symptoms, such as gargoyle-like face, edema, proctoprosia due to sialylglycan accumulation, and neurovisceral inflammation, including activated microglia/macrophage appearance and increase of inflammatory chemokines. We produced human CTSA precursor proteins (proCTSA), a homodimer carrying terminal mannose 6-phosphate (M6P)-type N-glycans. The CHO-derived proCTSA was taken up by GS patient-derived fibroblasts via M6P receptors and delivered to lysosomes. Catalytically active mature CTSA showed a shorter half-life due to intralysosomal proteolytic degradation. Following single i.c.v. administration, proCTSA was widely distributed, restored the Neu1 activity, and reduced the sialylglycans accumulated in brain regions. Moreover, proCTSA suppressed neuroinflammation associated with reduction of activated microglia/macrophage and up-regulated Mip1α. The results show therapeutic effects of intracerebrospinal enzyme replacement utilizing CHO-derived proCTSA and suggest suppression of CNS symptoms.

Keywords: disease model mouse; galactosialidosis; intracerebroventricular enzyme replacement therapy; lysosomal storage disease; protective protein/cathepsin A.