Exploring hurler syndrome through the study of disease-specific multipotent and pluripotent stem cells

Mucopolysaccharidosis type I (or Hurler syndrome) is a rare genetic disorder, caused by mutations in the idua gene, resulting in the deficiency of α-L-iduronidase enzyme activity and intra-cellular accumulation of glycosaminoglycans. The aim of the present project was focused on the isolation and characterization of two different stem cell populations, multipotent and pluripotent, derived from patients affected by Hurler syndrome. We aim to use Mesenchymal Stem Cells (MSCs) and induced Pluripotent Stem Cells (iPSCs) as a tool to explore still unknown disease mechanisms involved in the genetic metabolic disorder of our interest. Our recently published study focused on the characterization of MSCs isolated from bone marrow of Hurler patients. The MSCs were characterized for their expansion rate, phenotype, telomerase activity, IDUA activity and differentiation capacity towards adipocytes, osteoblasts, chondrocytes and smooth muscle cells in vitro. Interestingly, affected MSCs displayed increased capacity to support osteoclastogenesis according to the upregulation of the RANKL/RANK/OPG molecular pathway in Hurler MSCs. The second study describes the isolation of iPSCs from fibroblasts of Hurler patients. The generated cell lines were fully characterized for their pluripotency markers, gene expression profile, viral copy number integration and differentiation potential both in vitro and in vivo. As a proof of principle, we are attempting to gene correct patient-derived iPSCs with an alternative and safer method than viral vectors, using a Zinc Finger Nucleases-mediated approach for gene targeting of pluripotent cells.