Altered Differentiation Potential of Gaucherâs Disease iPSC Neuronal Progenitors due to Wnt/β-Catenin Downregulation

Summary: Gaucherâs disease (GD) is an autosomal recessive disorder caused by mutations in the GBA1 gene, which encodes acid β-glucocerebrosidase (GCase). Severe GBA1 mutations cause neuropathology that manifests soon after birth, suggesting that GCase deficiency interferes with neuronal development. We found that neuronopathic GD induced pluripotent stem cell (iPSC)-derived neuronal progenitor cells (NPCs) exhibit developmental defects due to downregulation of canonical Wnt/β-catenin signaling and that GD iPSCsâ ability to differentiate to dopaminergic (DA) neurons was strikingly reduced due to early loss of DA progenitors. Incubation of the mutant cells with the Wnt activator CHIR99021 (CHIR) or with recombinant GCase restored Wnt/β-catenin signaling and rescued DA differentiation. We also found that GD NPCs exhibit lysosomal dysfunction, which may be involved in Wnt downregulation by mutant GCase. We conclude that neuronopathic mutations in GCase lead to neurodevelopmental abnormalities due to a critical requirement of this enzyme for canonical Wnt/β-catenin signaling at early stages of neurogenesis. : In this article, Feldman and colleagues describe a new mechanism linking severe GBA1 mutations to neurodevelopmental defects through Wnt/β-catenin downregulation. Using GD iPSCs as a model, the authors show that the ability of neuronopathic GD NPCs to differentiate to DA neurons is strikingly reduced due to early loss of DA progenitors and that lysosomal dysfunction may be directly involved in canonical Wnt downregulation. Keywords: Gaucherâs disease, GBA1, glucocerebrosidase, neuronal progenitors, dopaminergic development, iPSCs, Wnt/β-catenin, lysosomal storage disease, neurodegeneratio