Recombinant hexosaminidases conjugated to magnetite nanoparticles: Alternative therapeutic treatment routes in GM2 fibroblasts

Gangliosidosis GM2 are lysosomal disorders (LD) characterized by a deficiency of the β-hexosaminidases, which are responsible for the degradation of GM2 gangliosides or associated glycolipids. This leads to their intracellular accumulation mainly in central nervous system (CNS) cells. Enzyme replacement therapy (ERT) is one of the most evaluated therapeutic alternatives for LD. Due to its difficulty to cross the blood brain barrier (BBB), ERT has failed to provide a suitable therapeutic route for the treatment of CNS diseases. To address this issue, modern biopharmacology has implemented nanostructured materials as potent delivery vehicles of both small and biological molecules in a controlled and localized manner. Despite the potential benefits, the conjugation of large enzymes on their surface and the subsequent delivery and passing of the BBB remains challenging. Here, we proposed to overcome these limitations by conjugating the therapeutic recombinant hexosaminidases to magnetite nanoparticles. Conjugation proceeded with the aid of a surface spacer and the obtained vehicles were characterized via TGA, FTIR and TEM. The conjugates were subsequently delivered in GM2 patient fibroblasts. The conjugates exhibited superior biocompatibility while promoting disruption of intracellular traffic and degradation of accumulated GM2 gangliosides. These encouraging results strongly suggest that β-hexosaminidase-magnetite nanobioconjugates represent a viable alternative for the administration of ERT-based therapies. Further assays include the evaluation of the ability of the nanobioconjugates to bypass an in vitro model of the BBB.