Inhibition of cysteine protease cathepsin L increases the level and activity of lysosomal glucocerebrosidase

Developing nanobodies as allosteric molecular chaperones of glucocerebrosidase function

The enzyme glucocerebrosidase (GCase) catalyses the hydrolysis of glucosylceramide to glucose and ceramide within lysosomes. Homozygous or compound heterozygous mutations in the GCase-encoding GBA1 gene cause the lysosomal storage disorder Gaucher disease, while heterozygous and homozygous mutations are the most frequent genetic risk factor for Parkinson's disease. These mutations commonly affect GCase stability, trafficking or activity. Here, we report the development and characterization of nanobodies (Nbs) targeting and acting as molecular chaperones for GCase. We identify several Nb families that bind with nanomolar affinity to GCase. Based on biochemical characterization, we group the Nbs in two classes: Nbs that improve the activity of the enzyme and Nbs that increase GCase stability in vitro. A selection of the most promising Nbs is shown to improve GCase function in cell models and positively impact the activity of the N370S mutant GCase. These results lay the foundation for the development of new therapeutic routes.

Clinical, mechanistic, biomarker, and therapeutic advances in GBA1-associated Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease. The development of PD is closely linked to genetic and environmental factors, with GBA1 variants being the most common genetic risk. Mutations in the GBA1 gene lead to reduced activity of the coded enzyme, glucocerebrosidase, which mediates the development of PD by affecting lipid metabolism (especially sphingolipids), lysosomal autophagy, endoplasmic reticulum, as well as mitochondrial and other cellular functions. Clinically, PD with GBA1 mutations (GBA1-PD) is characterized by particular features regarding the progression of symptom severity. On the therapeutic side, the discovery of the relationship between GBA1 variants and PD offers an opportunity for targeted therapeutic interventions. In this review, we explore the genotypic and phenotypic correlations, etiologic mechanisms, biomarkers, and therapeutic approaches of GBA1-PD and summarize the current state of research and its challenges.