Cathepsin K antisense oligodeoxynucleotide inhibits osteoclastic bone resorption.
Cathepsin K is a recently identified cysteine protease which is abundantly and selectively expressed in osteoclasts. To evaluate the contribution of cathepsin K to bone resorption processes, we investigated the effect of cathepsin K antisense phosphothiorate oligodeoxynucleotide (S-ODN) on the bone-resorbing activity of osteoclasts. Rabbit osteoclasts were cultured on dentine slices for 24 h in the presence or absence of antisense S-ODN in a medium containing 100 nM TfxTM-50, polycationic liposome, as a carrier of the S-ODN. Uptake of the S-ODN by osteoclasts was confirmed microscopically using fluorescein-labeled S-ODN. The treatment with antisense significantly decreased the amount of cathepsin K protein in osteoclasts. The antisense inhibited the osteoclastic pit formation in a concentration-dependent fashion. At 10 microM the antisense reduced the total pit number and area and average pit depth by 46, 52, and 30%, respectively. The sense and mismatch S-ODNs, which were used as negative controls, had no effect on either the cathepsin K protein level or the pit formation. A nonspecific cysteine protease inhibitor, E-64, also reduced pit formation in a concentration-dependent manner with maximum reductions at 1 microM of 46, 48, and 35% in the above pit parameters. The inhibitory effect of the antisense almost equal to that of E-64 demonstrates that cathepsin K is a cysteine protease playing a crucial role in osteoclastic bone resorption.
Inui
T
T
International Research Laboratories, Ciba-Geigy Japan Ltd., 10-66 Miyuki-cho, Takarazuka 665, Japan.
Ishibashi
O
O
Inaoka
T
T
Origane
Y
Y
Kumegawa
M
M
Kokubo
T
T
Yamamura
T
T
D000818:Animals; D015153:Blotting, Western; D001862:Bone Resorption / Q000201:enzymology* / Q000235:genetics; D056657:Cathepsin K; D002403:Cathepsins / Q000235:genetics* / Q000502:physiology; D003034:Coated Pits, Cell-Membrane / Q000187:drug effects; D004337:Drug Carriers; D008081:Liposomes; D008856:Microscopy, Fluorescence; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits; D013873:Thionucleotides / Q000008:administration & dosage / Q000494:pharmacology*
D004337:Drug Carriers; D008081:Liposomes; D016376:Oligonucleotides, Antisense; D013873:Thionucleotides; D002403:Cathepsins; D056657:Cathepsin K