Tags

Type your tag names separated by a space and hit enter

Impaired bone resorption in cathepsin K-deficient mice is partially compensated for by enhanced osteoclastogenesis and increased expression of other proteases via an increased RANKL/OPG ratio.
Bone. 2005 Jan; 36(1):159-72.BONE

Abstract

Previous reports indicate that mice deficient for cathepsin K (Ctsk), a key protease in osteoclastic bone resorption, develop osteopetrosis due to their inability to properly degrade organic bone matrix. Some features of the phenotype of Ctsk knockout mice, however, suggest the presence of mechanisms by which Ctsk-deficient mice compensate for the lack of cathepsin K. To study these mechanisms in detail, we generated Ctsk-deficient (Ctsk-/-) mice and analyzed them at the age of 2, 7, and 12 months using peripheral quantitative computed tomography, histomorphometry, resorption marker measurements, osteoclast and osteoblast differentiation cultures, and gene expression analyses. The present study verified the previously published osteopetrotic features of Ctsk-deficient mice. However, these changes did not exacerbate during aging indicating the absence of Ctsk to have its most severe effects during the rapid growth period. Resorption markers ICTP and CTX were decreased in the media of Ctsk-/- osteoclasts cultured on bone slices indicating impaired bone resorption. Ctsk-/- mice exhibited several mechanisms attempting to compensate for Ctsk deficiency. The number of osteoclasts in trabecular bone was significantly increased in Ctsk-/- mice compared to controls, as was the number of osteoclast precursors in bone marrow. The mRNA levels for receptor activator of nuclear factor (kappa)B ligand (RANKL) in Ctsk-/- bones were increased resulting in increased RANKL/OPG ratio favoring osteoclastogenesis. In addition, expression of mRNAs of osteoclastic enzymes (MMP-9, TRACP) and for osteoblastic proteases (MMP-13, MMP-14) were increased in Ctsk-/- mice compared to controls. Impaired osteoclastic bone resorption in Ctsk-/- mice results in activation of osteoblastic cells to produce increased amounts of other proteolytic enzymes and RANKL in vivo. We suggest that increased RANKL expression mediates enhanced osteoclastogenesis and increased protease expression by osteoclasts. These observations underline the important role of osteoblastic cells in regulation of osteoclast activity and bone turnover.

Authors+Show Affiliations

Department of Medical Biochemistry and Molecular Biology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15664014

Citation

Kiviranta, Riku, et al. "Impaired Bone Resorption in Cathepsin K-deficient Mice Is Partially Compensated for By Enhanced Osteoclastogenesis and Increased Expression of Other Proteases Via an Increased RANKL/OPG Ratio." Bone, vol. 36, no. 1, 2005, pp. 159-72.
Kiviranta R, Morko J, Alatalo SL, et al. Impaired bone resorption in cathepsin K-deficient mice is partially compensated for by enhanced osteoclastogenesis and increased expression of other proteases via an increased RANKL/OPG ratio. Bone. 2005;36(1):159-72.
Kiviranta, R., Morko, J., Alatalo, S. L., NicAmhlaoibh, R., Risteli, J., Laitala-Leinonen, T., & Vuorio, E. (2005). Impaired bone resorption in cathepsin K-deficient mice is partially compensated for by enhanced osteoclastogenesis and increased expression of other proteases via an increased RANKL/OPG ratio. Bone, 36(1), 159-72.
Kiviranta R, et al. Impaired Bone Resorption in Cathepsin K-deficient Mice Is Partially Compensated for By Enhanced Osteoclastogenesis and Increased Expression of Other Proteases Via an Increased RANKL/OPG Ratio. Bone. 2005;36(1):159-72. PubMed PMID: 15664014.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Impaired bone resorption in cathepsin K-deficient mice is partially compensated for by enhanced osteoclastogenesis and increased expression of other proteases via an increased RANKL/OPG ratio. AU - Kiviranta,Riku, AU - Morko,Jukka, AU - Alatalo,Sari L, AU - NicAmhlaoibh,Roisin, AU - Risteli,Juha, AU - Laitala-Leinonen,Tiina, AU - Vuorio,Eero, Y1 - 2004/11/24/ PY - 2004/06/08/received PY - 2004/09/15/revised PY - 2004/09/27/accepted PY - 2005/1/25/pubmed PY - 2005/7/6/medline PY - 2005/1/25/entrez SP - 159 EP - 72 JF - Bone JO - Bone VL - 36 IS - 1 N2 - Previous reports indicate that mice deficient for cathepsin K (Ctsk), a key protease in osteoclastic bone resorption, develop osteopetrosis due to their inability to properly degrade organic bone matrix. Some features of the phenotype of Ctsk knockout mice, however, suggest the presence of mechanisms by which Ctsk-deficient mice compensate for the lack of cathepsin K. To study these mechanisms in detail, we generated Ctsk-deficient (Ctsk-/-) mice and analyzed them at the age of 2, 7, and 12 months using peripheral quantitative computed tomography, histomorphometry, resorption marker measurements, osteoclast and osteoblast differentiation cultures, and gene expression analyses. The present study verified the previously published osteopetrotic features of Ctsk-deficient mice. However, these changes did not exacerbate during aging indicating the absence of Ctsk to have its most severe effects during the rapid growth period. Resorption markers ICTP and CTX were decreased in the media of Ctsk-/- osteoclasts cultured on bone slices indicating impaired bone resorption. Ctsk-/- mice exhibited several mechanisms attempting to compensate for Ctsk deficiency. The number of osteoclasts in trabecular bone was significantly increased in Ctsk-/- mice compared to controls, as was the number of osteoclast precursors in bone marrow. The mRNA levels for receptor activator of nuclear factor (kappa)B ligand (RANKL) in Ctsk-/- bones were increased resulting in increased RANKL/OPG ratio favoring osteoclastogenesis. In addition, expression of mRNAs of osteoclastic enzymes (MMP-9, TRACP) and for osteoblastic proteases (MMP-13, MMP-14) were increased in Ctsk-/- mice compared to controls. Impaired osteoclastic bone resorption in Ctsk-/- mice results in activation of osteoblastic cells to produce increased amounts of other proteolytic enzymes and RANKL in vivo. We suggest that increased RANKL expression mediates enhanced osteoclastogenesis and increased protease expression by osteoclasts. These observations underline the important role of osteoblastic cells in regulation of osteoclast activity and bone turnover. SN - 8756-3282 UR - https://www.unboundmedicine.com/medline/citation/15664014/Impaired_bone_resorption_in_cathepsin_K_deficient_mice_is_partially_compensated_for_by_enhanced_osteoclastogenesis_and_increased_expression_of_other_proteases_via_an_increased_RANKL/OPG_ratio_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S8756-3282(04)00381-3 DB - PRIME DP - Unbound Medicine ER -