ERT on Morquio A tolerant mice treated for 12 weeks with 250 U/g of E6-GALNS. Light microscopy of liver, heart valve, bone marrow, and cartilage cell layer from (A,C,E,G) untreated and (B,D,F,H) E6 GALNS-treated. The arrows show vacuoles. The (B) liver Kupffer cells and (F) bone marrow had essentially complete clearance of storage by the treatment group. (D) Heart valve showed reduction of vacuoles in a treated mouse and the (H) cartilage cells showed a slight response after 12 weeks of treatment. ERT, enzyme-replacement therapy; GALNS, N-acetylgalactosamine-6-sulfate sulfatase.

ERT on newborn Morquio A tolerant mice (8 weeks with 250 U/g of E6-GALNS). Untreated mice showed numerous vacuoles in (A) liver, (C) heart valves, (E) bone marrow, and (G) chondrocytes in femur growth plates. After 8-weekly intravenous injection of E6-GALNS, reduction of storage materials was observed in (B) liver, (D) heart valves, (F) bone marrow, and (H) cartilage cell layer. ERT, enzyme-replacement therapy; GALNS, N-acetylgalactosamine-6-sulfate sulfatase.

Characterization, pharmacokinetics, and biodistribution of purified GALNSs. (a) SDS-PAGE and silver staining of purified GALNSs. SDS-PAGE; the GALNSs from the gel filtration step were subjected to SDS-PAGE under reducing conditions (0.1 mmol/l DTT), followed by silver staining. Lane 1 is molecular-mass standard. Lane 2 (100 ng) is E6-SUMF1 GALNS. Lane 3 (100 ng) is native SUMF1 GALNS. Both E6-SUMF1 GALNS and native SUMF1 GALNS were purified from CHO secretions. The molecular sizes were indicated with arrows and were calculated by comparison with SDS-PAGE standards (Bio-Rad Laboratories, Hercules, CA). (b) Pharmacokinetics of GALNSs (clearance from the blood circulation). The 250 U/g of native SUMF1 and E6-SUMF1 GALNSs was administered to 3-month-old Morquio A mice (3 mice/group) in the tail vein. The blood sample was taken at 2-, 5-, 15-, 30-, 60-, 120-, 180-, 240-, 1,440, and 2,880-minutes time points. Plasma enzyme activity was assayed. The results graphed are the semilog plots of the average levels of GALNS activity (U/ml) at each time point. (c) Biodistribution of native SUMF1 and E6-SUMF1 GALNSs in femur bone, bone marrow, spine bone, and heart (clearance from the tissues). We infused 250 U/g body weight of the indicated enzymes into three Morquio A mice for each treatment. After 48 hours, the mice treated with 250 U/g were killed, and tissue samples were processed for biochemistry. Levels of enzyme observed in femur bone, bone marrow, spine bone, and heart are shown. (A) Femur bone (adult); (B) spine bone (adult); (C) bone marrow (adult); (D) heart (adult), (E) femur bone (treated from newborn). Open bar: native SUMF1 GALNS, filled bar: E6-SUMF1 GALNS. CHO, Chinese hamster ovary; DTT, dithiothreitol; GALNS, N-acetylgalactosamine-6-sulfate sulfatase; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis; SUMF1, sulfatase modifier factor 1.

ERT on Morquio A tolerant mice treated for 24 weeks with 250 U/g of (a) E6-GALNS or E6-SUMF1 GALNS and (b) native GALNS or native-SUMF1 GALNS. (a) Light microscopy of liver, heart valve, bone marrow, and cartilage cell layer from (A,D,G,J) untreated, (B,E,H,K) E6 GALNS-treated, and (C,F,I,L) E6-SUMF1 GALNS-treated mice for 24 weeks with 250 U/g. The arrows show vacuoles. (A–C) Liver. The (B,C) liver Kupffer cells have essentially complete clearance of storage by both the treatment groups whereas an (A) untreated Morquio A mouse has extensive storage in sinus-lining cells and Kupffer cells. (D–F) Heart valve. The heart valves in an untreated Morquio A mouse have abundant cytoplasmic vacuolization in the valve (arrow). A reduction of storage is seen in the valve in mice treated with (E) E6-GALNS and (F) E6-SUMF1 GALNS. (G–I) Bone marrow. The sinus-lining cells in bone marrow had essentially complete clearance of storage by both (H,I) treatment groups. The sinus-lining cells in (G) bone marrow of untreated mouse (arrow) contain storage material. (J–L) Growth plate. An untreated Morquio A mouse shows marked storage material in (J) chondrocytes. Vacuolated chondrocytes with lysosomal distension are obvious. The cartilage cells have substantial reduction of storage material in both (K,L) treated mice. (b) Light microscopy of liver, heart valve, bone marrow, and cartilage cell layer from (A,C,E,G) native GALNS and (B,D,F,H) native-SUMF1 GALNS-treated mice for 24 weeks with 250 U/g. The arrows show vacuoles. (A,B) Liver. The liver Kupffer cells had essentially complete clearance of storage by both the treatment groups. (C,D) Heart valve. A reduction of storage is seen in the valve in mice treated with (C) native GALNS and (D) native-SUMF1 GALNS. (E,F) Bone marrow. The sinus-lining cells in bone marrow had essentially complete clearance of storage by (E,F) both treatment groups. (G,H) Vacuolated chondrocytes with lysosomal distension remained still obvious. The cartilage cells had substantial storage material in both (G,H) treated mice. ERT, enzyme-replacement therapy; GALNS, N-acetylgalactosamine-6-sulfate sulfatase; SUMF1, sulfatase modifier factor 1.

Level of serum KS in Morquio A mouse. Untreated Morquio A mice (n = 2), E6-GALNS treated (n = 2), and control wild type (n = 2). GALNS, N-acetylgalactosamine-6-sulfate sulfatase; KS, keratan sulfate.