Bone marrow transplantation increases sulfatase activity in somatic tissues in a multiple sulfatase deficiency mouse model

Abstract

Multiple Sulfatase Deficiency (MSD) is an ultra-rare autosomal recessive disorder characterized by deficient enzymatic activity of all known sulfatases. MSD patients frequently carry two loss of function mutations in the SUMF1 gene, encoding a formylglycine-generating enzyme (FGE) that activates 17 different sulfatases. MSD patients show common features of other lysosomal diseases like mucopolysaccharidosis and metachromatic leukodystrophy, including neurologic impairments, developmental delay, and visceromegaly. There are currently no approved therapies for MSD patients. Hematopoietic stem cell transplant (HSCT) has been applied with success in the treatment of certain lysosomal diseases. In HSCT, donor-derived myeloid cells are a continuous source of active sulfatase enzymes that can be taken up by sulfatase-deficient host cells. Thus, HSCT could be a potential approach for the treatment of MSD. To test this hypothesis, we used a clinically relevant mouse model for MSD, B6-Sumf1(S153P/S153P) mice, engrafted with bone marrow cells, Sumf1+/+, from B6-PtprcK302E mice (CD45.1 immunoreactive). After 10 months post-transplant, flow cytometric analysis shows an average of 90% of circulating leukocytes of donor origin (Sumf1(+/+)). Enzymatic activity for ARSA, ARSB, and SGSH is significantly increased in spleen of B6-Sumf1(S153P/S153P) recipient mice. In non-lymphoid organs, only liver and heart show a significant correction of sulfatase activity and GAG accumulation. Frequency of inflammatory cells and lysosomal pathology is significantly reduced in liver and heart, while no significant improvement is detected in brain. Our results indicate that HSCT could be a suitable approach to treat MSD-pathology affecting peripheral organs, however that benefit to CNS pathology might be limited. Multiple Sulfatase Deficiency (MSD) is a rare genetic disorder caused by loss-of-function variations in the SUMF1 gene. This deficiency results in the accumulation of toxic compounds, leading to developmental delays and neurological impairments. In a bone marrow transplant (BMT), donor cells are infused into the patient and secrete active proteins that can help remove those toxic compounds. We carried out BMT in a mouse model for MSD and saw beneficial effects on peripheral organs, such as the liver and heart, but less change in neurological symptoms. Our results will be useful for the design of potential cell therapy approaches that could be used clinically to treat MSD. Presa et al. use a mouse model of multiple sulfatase deficiency (MSD) to assess efficacy of bone marrow transplantation to increase sulfatase activity. Sulfatase activity is partially restored in some peripheral tissues such as spleen, liver and heart, but no significant benefit is observed in the brain.