Developing a Gaucher Disease Pharmacological Model of the Blood-Brain Barrier

Abstract

Gaucher disease is a genetic disorder that leads to the lysosomal enzyme glucocerebrosidase (GCase) being unable to function correctly. The enzyme breaks down glucocerebroside (GluCer) and in the case of Gaucher disease, a buildup of GluCer leads to various conditions which can often be neuropathic. A common treatment for Gaucher disease and other lysosomal storage diseases is enzyme replacement therapy, which consists of intravenously delivered recombinant enzymes. However, this treatment has an inability to treat the central nervous system (CNS) because of its inability to cross the blood-brain barrier (BBB). In vitro studies with Gaucher afflicted BBB cellular systems are needed to test the delivery of novel recombinant enzymes across the BBB. These experiments however are severely limited by the scarcity and expense of Gaucher endothelial cells, astrocytes, and neurons, which compose the BBB. This project's goal was to develop a pharmacological model of Gaucher disease using cellular systems involving treating healthy endothelial cells, astrocytes, to exhibit the Gaucher phenotype, and iPS service Gaucher neurons. First, cellular systems were treated with conduritol beta-epoxide (CBE), an inhibitor of GCase. Treatment with CBE lowered GCase activity and increased GluCer accumulation in both cell types, and to a similar extent as a genetic model- Gaucher skin fibroblasts. An in vitro model of the Gaucher BBB was created using a transwell system with CBE treated endothelial cells on the apical side, astrocytes on the basal side of the filter and iPS service Gaucher neurons in the basal well. Transport of GCase, modified to transcytose more efficiently was tested on the Gaucher BBB model, where more efficient transcytosis, lysosomal colocalization, and effects were observed when compared to control GCase. This model presents a promising step towards testing potential therapeutics for Gaucher disease.