PMID- 16007343
OWN - NLM
STAT- MEDLINE
DCOM- 20051214
LR  - 20131121
IS  - 0884-0431 (Print)
IS  - 0884-0431 (Linking)
VI  - 20
IP  - 8
DP  - 2005 Aug
TI  - Thapsigargin modulates osteoclastogenesis through the regulation of RANKL-induced 
      signaling pathways and reactive oxygen species production.
PG  - 1462-71
AB  - The mechanism by which TG modulates osteoclast formation and apoptosis is not 
      clear. In this study, we showed a biphasic effect of TG on osteoclast formation 
      and apoptosis through the regulation of ROS production, caspase-3 activity, 
      cytosolic Ca2+, and RANKL-induced activation of NF-kappaB and AP-1 activities. 
      INTRODUCTION: Apoptosis and differentiation are among the consequences of changes 
      in intracellular Ca2+ levels. In this study, we investigated the effects of the 
      endoplasmic reticular Ca2+-ATPase inhibitor, thapsigargin (TG), on osteoclast 
      apoptosis and differentiation. MATERIALS AND METHODS: Both RAW264.7 cells and 
      primary spleen cells were used to examine the effect of TG on RANKL-induced 
      osteoclastogenesis. To determine the action of TG on signaling pathways, we used 
      reporter gene assays for NF-kappaB and activator protein-1 (AP-1) activity, 
      Western blotting for phospho-extracellular signal-related kinase (ERK), and 
      fluorescent probes to measure changes in levels of intracellular calcium and 
      reactive oxygen species (ROS). To assess rates of apoptosis, we measured changes 
      in annexin staining, caspase-3 activity, and chromatin and F-actin microfilament 
      structure. RESULTS: At concentrations that caused a rapid rise in intracellular 
      Ca2+, TG increased caspase-3 activity and promoted apoptosis in osteoclast-like 
      cells (OLCs). Low concentrations of TG, which were insufficient to measurably 
      alter intracellular Ca2+, unexpectedly suppressed caspase-3 activity and enhanced 
      RANKL-induced osteoclastogenesis. At these lower concentrations, TG potentiated 
      ROS production and RANKL-induced NF-kappaB activity, but suppressed RANKL-induced 
      AP-1 activity and had little effect on ERK phosphorylation. CONCLUSION: Our novel 
      findings of a biphasic effect of TG are incompletely explained by our current 
      understanding of TG action, but raise the possibility that low intensity or local 
      changes in subcellular Ca2+ levels may regulate intracellular differentiation 
      signaling. The extent of cross-talk between Ca2+ and RANKL-mediated intracellular 
      signaling pathways might be important in determining whether cells undergo 
      apoptosis or differentiate into OLCs.
FAU - Yip, Kirk H M
AU  - Yip KH
AD  - Molecular Orthopaedic Laboratory, School of Surgery and Pathology, and Western 
      Australian Institute for Medical Research, Nedlands, WA 6009, Australia.
FAU - Zheng, Ming H
AU  - Zheng MH
FAU - Steer, James H
AU  - Steer JH
FAU - Giardina, Tindaro M
AU  - Giardina TM
FAU - Han, Renzhi
AU  - Han R
FAU - Lo, Susan Z
AU  - Lo SZ
FAU - Bakker, Anthony J
AU  - Bakker AJ
FAU - Cassady, A Ian
AU  - Cassady AI
FAU - Joyce, David A
AU  - Joyce DA
FAU - Xu, Jiake
AU  - Xu J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20050328
PL  - England
TA  - J Bone Miner Res
JT  - Journal of bone and mineral research : the official journal of the American 
      Society for Bone and Mineral Research
JID - 8610640
RN  - 0 (Carrier Proteins)
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Membrane Glycoproteins)
RN  - 0 (NF-kappa B)
RN  - 0 (RANK Ligand)
RN  - 0 (Reactive Oxygen Species)
RN  - 0 (Receptor Activator of Nuclear Factor-kappa B)
RN  - 0 (Tnfrsf11a protein, mouse)
RN  - 0 (Tnfsf11 protein, mouse)
RN  - 0 (Transcription Factor AP-1)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 3.4.22.- (Casp3 protein, mouse)
RN  - EC 3.4.22.- (Caspase 3)
RN  - EC 3.4.22.- (Caspases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Apoptosis
MH  - Calcium/metabolism
MH  - Calcium Signaling/*drug effects
MH  - Carrier Proteins/*metabolism
MH  - Caspase 3
MH  - Caspases/metabolism
MH  - Cytosol/metabolism
MH  - Enzyme Activation
MH  - Enzyme Inhibitors/*pharmacology
MH  - Membrane Glycoproteins/*metabolism
MH  - Mice
MH  - NF-kappa B/metabolism
MH  - Osteoclasts/*drug effects/metabolism
MH  - Osteogenesis
MH  - RANK Ligand
MH  - Reactive Oxygen Species/*metabolism
MH  - Receptor Activator of Nuclear Factor-kappa B
MH  - Thapsigargin/*pharmacology
MH  - Transcription Factor AP-1/metabolism
EDAT- 2005/07/12 09:00
MHDA- 2005/12/15 09:00
CRDT- 2005/07/12 09:00
PHST- 2004/09/22 00:00 [received]
PHST- 2005/02/14 00:00 [revised]
PHST- 2005/03/28 00:00 [accepted]
PHST- 2005/07/12 09:00 [pubmed]
PHST- 2005/12/15 09:00 [medline]
PHST- 2005/07/12 09:00 [entrez]
AID - 10.1359/JBMR.050324 [doi]
PST - ppublish
SO  - J Bone Miner Res. 2005 Aug;20(8):1462-71. doi: 10.1359/JBMR.050324. Epub 2005 Mar 
      28.