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영어

In recent years, liquid biopsy has been noted for its outstanding advantages over tissue biopsy including ease of sampling, effective monitoring, and longitudinal assessment of treatment dynamics. In particular, Cerebrospinal fluid(CSF), a body fluid that directly interacts with the extracellular fluid of the brain and central nervous system, is a representative body fluid used for liquid biopsy and is becoming a potential source for neurological study. Mucopolysaccharidosis is a fatal neurodegenerative lysosomal storage disease caused by lysosomal β-gal deficiency and of galactose-containing substrates accumulate in various tissues such as brain and liver. Therefore, continuous monitoring of changes in the expression of galactose substrates in the brain is important for the diagnosis and treatment of disease. However, the low protein content of the biofluid makes this difficult. Here, we developed a highly sensitive, absolute quantitation platform for N-glycans containing terminal galactose(A2G2/A2G2F) to determine mucopolysaccharidosis using liquid biopsy of mouse CSF within 2hours. N-glycans labeled with InstantPC were quantified using hydrophilic interaction chromatography(HILIC) coupled with multiple response monitoring(MRM)-MS. In particular, A2G2/A2G2F glycans are present in less than 5% even in very small amount of mouse CSF, but it is possible to quantify glycans in 300nL mouse CSF at the femtomole level. Indeed, we were able to achieve high reproducibility within 15% of CV in experimental/instrumental replicates in the concentration range of 0.1 to 500pg/μL with quantitative linearity. Our glycan quantification platform can be potentially applied for diagnosis and monitoring of patients for neurodegenerative diseases at trace amounts of CSF (about 5μL) in a much more convenient and non-invasive manner.