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Expression of Either NF‐κB p50 or p52 in Osteoclast Precursors Is Required for IL‐1‐Induced Bone Resorption
Author(s) -
Xing Lianping,
Carlson Louise,
Story Beryl,
Tai Zhenxing,
Keng Peter,
Siebenlist Ulrich,
Boyce Brendan F
Publication year - 2003
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.2003.18.2.260
Subject(s) - osteoclast , bone resorption , p50 , resorption , nf κb , microbiology and biotechnology , chemistry , cancer research , medicine , biology , signal transduction , biochemistry , gene , transcription factor , receptor
Interleukin (IL)‐1 is implicated in postmenopausal‐ and inflammation‐mediated bone loss. Its expression is regulated by NF‐κB and vice versa. To examine the role of NF‐κB p50 and p52 (they are required for osteoclast formation during embryonic development) in IL‐1‐induced resorption, we used various NF‐κB knockout (KO) mice, including p50 −/− and p52 −/− single KO, p50 −/− and p52 +/− (3/4KO), and p50 −/− and p52 −/− double KO (dKO) mice. IL‐1 increased blood calcium and bone resorption in wild‐type (wt), p50, and p52 single KO mice, but not in 3/4KO or dKO mice. Osteoclast formation was impaired in bone marrow cultures from 3/4KO compared with single KO and wt mice treated with IL‐1. IL‐1 receptor expression was similar in colony forming unit‐granulocyte macrophage (CFU‐GM) colony cells from wt and dKO mice. However, IL‐1 promoted CFU‐GM colony formation and survival as well as the formation, activity, and survival of osteoclasts generated from these colonies from wt mouse splenocytes, but not from dKO splenocytes. No difference in expression of the osteoclast regulatory cytokines, RANKL, and OPG, was observed in osteoblasts from wt and dKO mice. Thus, expression of either NF‐κB p50 or p52 is required in osteoclasts and their precursors, rather than osteoblasts, for IL‐1‐mediated bone resorption.