Figure 2.

Single Concentration Substrate Clearance Time Course in MPS IIIB Human Patient Fibroblasts

(Top) HS levels were measured in cultures of MPS patient dermal fibroblast that were either untreated (untx) or treated with 6.25 nM of either NAGLU-IGF2 (blue bars) or unmodified NAGLU (gray bars) for increasing amounts of time from 30 min up to 10 days, continuously (30 min; 2, 4, 8, 16, 24, and 48 h; and 4 and 10 days). (Bottom) In order to allow cells to accumulate lysosomal HS, fibroblasts were seeded at 15,000 cells/well and cultured for 10 days before the time course was initiated. Treatments were done in triplicate with the results (the mean ± SD) shown as picomoles total HS/microgram protein. For the untreated controls, we analyzed HS levels at both 10 days just before the start of treatment (white bar) and at the end of the treatment period (black bar), in order to detect significant increases in HS levels that might skew the treatment results. No significant increases were observed.