The heat shock protein amplifier arimoclomol improves refolding, maturation and lysosomal activity of glucocerebrosidase.

BACKGROUND: Gaucher Disease is caused by mutations of the GBA gene which encodes the lysosomal enzyme acid beta-glucosidase (GCase). GBA mutations commonly affect GCase function by perturbing its protein homeostasis rather than its catalytic activity. Heat shock proteins are well known cytoprotective molecules with functions in protein homeostasis and lysosomal function and their manipulation has been suggested as a potential therapeutic strategy for GD. The investigational drug arimoclomol, which is in phase II/III clinical trials, is a well-characterized HSP amplifier and has been extensively clinically tested. Importantly, arimoclomol efficiently crosses the blood-brain-barrier presenting an opportunity to target the neurological manifestations of GD, which remains without a disease-modifying therapy. METHODS: We used a range of biological and biochemical in vitro assays to assess the effect of arimoclomol on GCase activity in ex vivo systems of primary fibroblasts and neuronal-like cells from GD patients. FINDINGS: We found that arimoclomol induced relevant HSPs such as ER-resident HSP70 (BiP) and enhanced the folding, maturation, activity, and correct cellular localization of mutated GCase across several genotypes including the common L444P and N370S mutations in primary cells from GD patients. These effects where recapitulated in a human neuronal model of GD obtained by differentiation of multipotent adult stem cells. INTERPRETATION: These data demonstrate the potential of HSP-targeting therapies in GCase-deficiencies and strongly support the clinical development of arimoclomol as a potential therapeutic option for the neuronopathic forms of GD. FUNDING: The research was funded by Orphazyme A/S, Copenhagen, Denmark.

Heat shock protein-based therapy as a potential candidate for treating the sphingolipidoses.

Lysosomal storage diseases (LSDs) often manifest with severe systemic and central nervous system (CNS) symptoms. The existing treatment options are limited and have no or only modest efficacy against neurological manifestations of disease. We demonstrate that recombinant human heat shock protein 70 (HSP70) improves the binding of several sphingolipid-degrading enzymes to their essential cofactor bis(monoacyl)glycerophosphate in vitro. HSP70 treatment reversed lysosomal pathology in primary fibroblasts from 14 patients with eight different LSDs. HSP70 penetrated effectively into murine tissues including the CNS and inhibited glycosphingolipid accumulation in murine models of Fabry disease (Gla(-/-)), Sandhoff disease (Hexb(-/-)), and Niemann-Pick disease type C (Npc1(-/-)) and attenuated a wide spectrum of disease-associated neurological symptoms in Hexb(-/-) and Npc1(-/-) mice. Oral administration of arimoclomol, a small-molecule coinducer of HSPs that is currently in clinical trials for Niemann-Pick disease type C (NPC), recapitulated the effects of recombinant human HSP70, suggesting that heat shock protein-based therapies merit clinical evaluation for treating LSDs.

Development of a transgenic mouse model immune tolerant for human interferon Beta.

PURPOSE: Therapeutic proteins may induce antibodies that inhibit their efficacy or have other serious biological effects. There is a great need for strategies to predict whether a certain formulation will induce an immune response. In principle, conventional animals develop an immune response against all human proteins no matter how they are formulated, which restricts their use. The aim of this study was to develop a mouse model immune tolerant for human interferon beta (hIFNbeta). METHODS: A transgenic mouse model immune tolerant for hIFNbeta was developed by making C57Bl/6 mice transgenic for the hIFNbeta gene. To evaluate the model, both wild-type and transgenic mice were immunized with recombinant human interferon beta 1a (rhIFNbeta-1a) and recombinant human interferon beta 1b (rhIFNbeta-1b). Serum antibodies against rhIFNbeta were detected by ELISA. RESULTS: The genetically modified mice were shown to be immune tolerant for mammalian cell-derived rhIFNbeta-1a, which has a relative low immunogenicity in patients. However, Escherichia coli-derived rhIFNbeta-1b, known to have a relatively high immunogenicity in patients, was shown not only to be immunogenic in the wild-type mice but could also break the immune tolerance of the genetically modified mice. CONCLUSIONS: This animal model offers the possibility to study the many factors influencing the immunogenicity of hIFNbeta and test new formulations before going into clinical trials. The model also provides the first evidence that the rhIFNbetas differ in the immunological mechanisms responsible for the development of antibodies.