Screening for Krabbe disease: The first 2 years' experience

Nanomedicines to treat rare neurological disorders: The case of Krabbe disease

The brain remains one of the most challenging therapeutic targets due to the low and selective permeability of the blood-brain barrier and complex architecture of the brain tissue. Nanomedicines, despite their relatively large size compared to small molecules and nucleic acids, are being heavily investigated as vehicles to delivery therapeutics into the brain. Here we elaborate on how nanomedicines may be used to treat rare neurodevelopmental disorders, using Krabbe disease (globoid cell leukodystrophy) to frame the discussion. As a monogenetic disorder and lysosomal storage disease affecting the nervous system, the lessons learned from examining nanoparticle delivery to the brain in the context of Krabbe disease can have a broader impact on the treatment of various other neurodevelopmental and neurodegenerative disorders. In this review, we introduce the epidemiology and genetic basis of Krabbe disease, discuss current in vitro and in vivo models of the disease, as well as current therapeutic approaches either approved or at different stage of clinical developments. We then elaborate on challenges in particle delivery to the brain, with a specific emphasis on methods to transport nanomedicines across the blood-brain barrier. We highlight nanoparticles for delivering therapeutics for the treatment of lysosomal storage diseases, classified by the therapeutic payload, including gene therapy, enzyme replacement therapy, and small molecule delivery. Finally, we provide some useful hints on the design of nanomedicines for the treatment of rare neurological disorders.

Identifying altered developmental pathways in human globoid cell leukodystrophy iPSCs-derived NSCs using transcriptome profiling

BACKGROUND

Globoid cell leukodystrophy (GLD) is a devastating neurodegenerative disease characterized by widespread demyelination caused by galactocerebrosidase defects. Changes in GLD pathogenesis occurring at the molecular level have been poorly studied in human-derived neural cells. Patient-derived induced pluripotent stem cells (iPSCs) are a novel disease model for studying disease mechanisms and allow the generation of patient-derived neuronal cells in a dish.

RESULTS

In this study, we identified gene-expression changes in iPSCs and iPSC-derived neural stem cells (NSCs) from a patient with GLD (K-iPSCs/NSCs) and normal control (AF-iPSCs/NSCs), in order to investigate the potential mechanism underlying GLD pathogenesis. We identified 194 (K-iPSCs vs. AF-iPSCs) and 702 (K-NSCs vs. AF-NSCs) significantly dysregulated mRNAs when comparing the indicated groups. We also identified dozens of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway terms that were enriched for the differentially expressed genes. Among them, 25 differentially expressed genes identified by RNA-sequencing analysis were validated using real-time quantitative polymerase chain reaction analysis. Dozens of pathways involved in neuroactive ligand-receptor interactions, synaptic vesicle cycle signaling, serotonergic synapse signaling, phosphatidylinositol-protein kinase B signaling, and cyclic AMP signaling were identified as potential contributors to GLD pathogenesis.

CONCLUSIONS

Our results correspond to the fact that mutations in the galactosylceramidase gene may disrupt the identified signaling pathways during neural development, suggesting that alterations in signaling pathways contribute to GLD pathogenesis. At the same time, our results demonstrates that the model based on K-iPSCs is a novel tool that can be used to study the underlying molecular basis of GLD.