[Osteoclast differentiation regulated by receptor activator of nuclear factor kappaB probably through a novel signaling pathway].
This study was aimed to investigate the signaling pathways regulating osteoclast (OC) differentiation by receptor activator of nuclear factor kappa (RANK) under physiological condition so as to provide some theoretical basis for clarifying mechanism of bone destruction in multiple myeloma. A mutant TNFR(1)/RANK(2) (named RANK-Mu) chimera consisting of tumor necrosis factor receptor 1 (TNFR(1)) and RANK intramembrane domain was constructed by using deletion mutation for deleting IVVY amino acids in RANK intramembrane domain in accordance with (535-)IVVY(-538) as specific domain regulating OC differentiation by RANK. The RANK-Mu and TNFR(1)/RANK chimera without mutation (RANK-WT) were packaged by using plat E cell line to produce the retrovirus, which were transfected into bone marrow macrophages (BMMs) of TNFR(1)/TNFR(2) double knockout mice. After stimulation of these transfected BMMs with TNF-alpha, the differentiation of BMMs into OCs were observed, meanwhile the phosphorylation of NF-kappab, JNK, p38 and ERK was detected by Western blot after stimulation of these BMMs with TNF-alpha. The results showed that BMMs transfected with RANK-WT could be differentiated into OCs and phosphorylation of NF-kappaB, JNK, P38 and ERK were activated at 5 - 10 minutes after being stimulated by TNFalpha. BMMs transfected with RANK-Mu could not be differentiated into OCs, but phosphorylation of NF-kappaB, JNK, P38 and ERK were activated also. It is concluded that RANK regulates osteoclast differentiation probably not through 4 typical signaling pathways, named as NF-kappaB, JNK, P38 and ERK, in this process other new signaling pathways maybe participate.
Xu
Duo-Rong
DR
Department of Hematology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China. xudr@hotmail.com
Chen
Hui-Zhen
HZ
Wang
He-Hua
HH
Li
Juan
J
Luo
Shao-Kai
SK
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010766:Phosphorylation; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D016328:NF-kappa B; D053246:Receptor Activator of Nuclear Factor-kappa B; D014409:Tumor Necrosis Factor-alpha; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases