Development and characterization of a model of mucopolysaccharidosis type IVA for evaluating therapies targeting bone disease

Mucopolysaccharidosis type IVA (MPSIVA) is a lysosomal storage disease (LSD) caused by deficiency of N-acetylgalactosamine-6 sulfate sulfatase (GALNS), which causes the accumulation of keratan sulphate (KS) and chondroitin sulphate (CS). Patients with MPSIVA typically present with severe skeletal and joint disorders, which are not addressed by conventional therapies. Currently, no animal model accurately replicates the human disease, hindering the development of novel therapeutic interventions. To overcome this limitation, we established, by CRISPR-Cas9 technology, a Galns−/− mouse model that expresses a non-functional enzyme and accumulates CS and KS in the urine, plasma and distinct tissues, and glycosaminoglycans in the spleen. The mice exhibit shortened long bones, trabecular bone alterations and skeletal abnormalities in the growth plate. Additionally, we observed increased levels of inflammatory and oxidative markers in visceral organs and plasma. Our newly developed model of MPSIVA demonstrates clearand quantifiable signs of skeletal alterations, providing novel means of assessment of the safetyandefficacyof innovative therapies, including hematopoietic stem and progenitor cell gene therapy, which has recently been shown to provide a beneficial effect on skeletal alterations in Hurler syndrome.