A novel mucopolysaccharidosis type II mouse model with an iduronate-2-sulfatase-P88L mutation.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder characterized by an accumulation of glycosaminoglycans (GAGs), including heparan sulfate, in the body. Major manifestations involve the central nerve system (CNS), skeletal deformation, and visceral manifestations. About 30% of MPS II is linked with an attenuated type of disease subtype with visceral involvement.

LC-MS/MS-based enzyme assay for lysosomal acid lipase using dried blood spots.

Lysosomal acid lipase deficiency (LAL-D) (OMIM: 278000) is a lysosomal storage disorder with two distinct disease phenotypes such as Wolman disease and cholesteryl ester storage disorder (CESD), characterized by an accumulation of endocytosed cholesterol in the body. Due to the presence of multiple lipases in DBS, previous studies measured LAL enzyme activity in the presence of Lalistat-2, an established LAL-specific inhibitor (Hamilton J Chim Clin Acta (2012) 413:1207-1210). Alternatively, a novel substrate specific for LAL has been reported very recently (Masi S.

Physiology and Pathophysiology of Heparan Sulfate in Animal Models: Its Biosynthesis and Degradation.

Heparan sulfate (HS) is a type of glycosaminoglycan that plays a key role in a variety of biological functions in neurology, skeletal development, immunology, and tumor metastasis. Biosynthesis of HS is initiated by a link of xylose to Ser residue of HS proteoglycans, followed by the formation of a linker tetrasaccharide. Then, an extension reaction of HS disaccharide occurs through polymerization of many repetitive units consisting of iduronic acid and -acetylglucosamine.

Production of therapeutic iduronate-2-sulfatase enzyme with a novel single-stranded RNA virus vector.

The Sendai virus vector has received a lot of attention due to its broad tropism for mammalian cells. As a result of efforts for genetic studies based on a mutant virus, we can now express more than 10 genes of up to 13.5 kilo nucleotides in a single vector with high protein expression efficiency.

Biomarkers for Lysosomal Storage Disorders with an Emphasis on Mass Spectrometry.

Lysosomal storage disorders (LSDs) are characterized by an accumulation of various substances, such as sphingolipids, mucopolysaccharides, and oligosaccharides. The LSD enzymes responsible for the catabolism are active at acidic pH in the lysosomal compartment. In addition to the classically established lysosomal degradation biochemistry, recent data have suggested that lysosome plays a key role in the autophagy where the fusion of autophagosome and lysosome facilitates the degradation of amino acids.

Biosynthesis of long chain base in sphingolipids in animals, plants and fungi.

Long chain base (LCB) is a unique building block found in sphingolipids. The initial step of LCB biosynthesis stems from serine:palmitoyl-CoA transferase enzyme, producing 3-ketodihydrosphingosine with multiple regulatory proteins including small subunit SPT a/b and orosomucoid-like protein1-3. 3-Ketodihydrosphingosine reductase and sphingolipid Δ4-desaturase, both of them poorly characterized mammalian enzymes, play key roles for neurological homeostasis based on their pathogenic mutation in humans.

Quantification of 11 enzyme activities of lysosomal storage disorders using liquid chromatography-tandem mass spectrometry.

Lysosomal storage disorders (LSDs) are characterized by the accumulation of lipids, glycolipids, oligosaccharides, mucopolysaccharides, and other biological substances because of the pathogenic deficiency of lysosomal enzymes. Such diseases are rare; thus, a multiplex assay for these disorders is effective for the identification of affected individuals during the presymptomatic period. Previous studies have demonstrated that such assays can be performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM) detection.

Quantification of the enzyme activities of iduronate-2-sulfatase, -acetylgalactosamine-6-sulfatase and -acetylgalactosamine-4-sulfatase using liquid chromatography-tandem mass spectrometry.

Mucopolysaccharidosis (MPS) is a genetic disorder characterized by the accumulation of glycosaminoglycans in the body. Of the multiple MPS disease subtypes, several are caused by defects in sulfatases. Specifically, a defect in iduronate-2-sulfatase (ID2S) leads to MPS II, whereas -acetylgalactosamine-6-sulfatase (GALN) and -acetylgalactosamine-4-sulfatase (ARSB) defects relate to MPS IVA and MPS VI, respectively.