Figure 3.

Correction of metabolic disease in organs of NOD/SCID MPS I mice 18 weeks following injection of 25 µg DNA. Female and male mice were treated with 25 µg of transposon plasmid +SB (respectively, F+ and M+) or −SB (respectively, F− and M−). Clarified homogenates of the indicated organs were assayed for IDUA and GUSB enzyme activity and soluble GAG levels. (a) Organs apparently cleared of GAG storage: liver, spleen, lung, ovary, and gonads showed complete GAG correction in all treatment groups. (b) Organs incompletely cleared of GAG storage: kidney, heart, and aorta had complete correction in males and females receiving the full SB system (SB transposon + SB transposase), but incomplete GAG correction in −SB females. (c) Effects of treatment on the brain. Values are compared to the respective values in untreated NOD/SCID MPS I mice (black asterisks) and to WT values (gray asterisks). *P < 0.05; **P < 0.01; ***P < 0.001. IDUA activity was assayed with 4-methylumbelliferyl-α-L-iduronide and expressed as nmol 4 MU/mg protein/hour; GUSB activity (nmol 4 MU/mg protein/hour); GAG levels (µg GAG/mg protein). Individual values for each mouse are shown. Black horizontal dash indicates the mean level in each group. Filled dark circles, F+; open circles, F−; filled dark squares, M+ and open squares, M−. Diamonds: mixed group (males + females); gray, untreated WT NOD/SCID; black, untreated MPS I NOD/SCID mice. GAG, glycosaminoglycan; GUSB, β-glucuronidase; IDUA, α-L-iduronidase; MPS I, mucopolysaccharidosis type I; NOD/SCID, nonobese diabetic/severe combined immunodeficiency; SB, Sleeping Beauty; WT, wild type.