Dataset Information

Protease-resistant modified human ?-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.

ABSTRACT: GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of ?-hexosaminidase A, which comprises an ?? heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring ?-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit ? (HexB), which we have termed mod2B, composed of homodimeric ? subunits that contain amino acid sequences from the ? subunit that confer GM2 ganglioside-degrading activity and protease resistance. We also developed fluorescent probes that allow visualization of endocytosis of mod2B via mannose 6-phosphate receptors and delivery of mod2B to lysosomes in GM2 gangliosidosis models. In addition, we applied imaging mass spectrometry to monitor efficacy of this approach in Sandhoff disease model mice. Following i.c.v. administration, mod2B was widely distributed and reduced accumulation of GM2, asialo-GM2, and bis(monoacylglycero)phosphate in brain regions including the hypothalamus, hippocampus, and cerebellum. Moreover, mod2B administration markedly improved motor dysfunction and a prolonged lifespan in Sandhoff disease mice. Together, the results of our study indicate that mod2B has potential for intracerebrospinal fluid enzyme replacement therapy and should be further explored as a gene therapy for GM2 gangliosidoses.

SUBMITTER: Kitakaze K

PROVIDER: S-EPMC4855921 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Protease-resistant modified human β-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.

Kitakaze Keisuke K Mizutani Yasumichi Y Sugiyama Eiji E Tasaki Chikako C Tsuji Daisuke D Maita Nobuo N Hirokawa Takatsugu T Asanuma Daisuke D Kamiya Mako M Sato Kohei K Setou Mitsutoshi M Urano Yasuteru Y Togawa Tadayasu T Otaka Akira A Sakuraba Hitoshi H Itoh Kohji K

The Journal of clinical investigation 20160328 5

GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of β-hexosaminidase A, which comprises an αβ heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring β-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit β (HexB), which we have termed mod2B, composed of homodimeric β subunits that contain amino acid seque ...[more]

PMID: 27018595

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Project description:Tay-Sachs disease (TSD) is a lethal lysosomal storage disease (LSD) caused by mutations in the HexA gene, which can lead to deficiency of β-hexosaminidase A (HexA) activity and consequent accumulation of its substrate, GM2 ganglioside. Recent reports that progranulin (PGRN) functions as a chaperone of lysosomal enzymes and its deficiency is associated with LSDs, including Gaucher disease and neuronal ceroid lipofuscinosis, prompted us to screen the effects of recombinant PGRN on lysosomal storage in fibroblasts from 11 patients affected by various LSDs, which led to the isolation of TSD in which PGRN demonstrated the best effects in reducing lysosomal storage. Subsequent in vivo studies revealed significant GM2 accumulation and the existence of typical TSD cells containing zebra bodies in both aged and ovalbumin-challenged adult PGRN-deficient mice. In addition, HexA, but not HexB, was aggregated in PGRN-deficient cells. Furthermore, recombinant PGRN significantly reduced GM2 accumulation and lysosomal storage in these animal models. Mechanistic studies indicated that PGRN bound to HexA through granulins G and E domain and increased the enzymatic activity and lysosomal delivery of HexA. More importantly, Pcgin, an engineered PGRN derivative bearing the granulin E domain, also effectively bound to HexA and reduced the GM2 accumulation. Collectively, these studies not only provide new insights into the pathogenesis of TSD but may also have implications for developing PGRN-based therapy for this life-threatening disorder. KEY MESSAGES: GM2 accumulation and the existence of typical TSD cells containing zebra bodies are detected in both aged and ovalbumin-challenged adult PGRN deficient mice. Recombinant PGRN significantly reduces GM2 accumulation and lysosomal storage both in vivo and in vitro, which works through increasing the expression and lysosomal delivery of HexA. Pcgin, an engineered PGRN derivative bearing the granulin E domain, also effectively binds to to HexA and reduces GM2 accumulation.

Dataset Information

Protease-resistant modified human ?-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.

Publications

Protease-resistant modified human β-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.

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