RANK ligand-induced elevation of cytosolic Ca2+ accelerates nuclear translocation of nuclear factor κB in osteoclasts
RANK ligand-induced elevation of cytosolic Ca2+ accelerates nuclear translocation of nuclear factor κB in osteoclasts
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DOI：
10.1074/jbc.m206421200
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发表时间：
2003-03-07
影响因子：
4.8
通讯作者：
Sims, SM
中科院分区：
文献类型：
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作者：
Komarova, SV;Pilkington, MF;Sims, SM
PLANK配体（RANKL）诱导NF κ B活化，增强破骨细胞的形成、再吸收活性和存活。Ca2+转导许多信号传导事件，然而，RANKL的作用是否涉及Ca2+信号传导尚不清楚。我们研究了RANKL对大鼠破骨细胞的影响，采用显微荧光光谱法和膜片钳。RANKL诱导胞浆游离Ca2+浓度（[Ca2 +]（i））瞬时升高至高于基线220 nm处的最大值，导致Ca2+依赖性K+电流激活。PANEL在含Ca2+和不含Ca2+的培养基中升高[Ca2 +]（i），并通过磷脂酶C抑制剂U73122阻止反应。使用细胞内Ca2+螯合剂1，2-双（O-氨基苯氧基）乙烷-N，N，N'，N'-四乙酸（BAPTA）抑制[Ca2 +]（i）升高可消除RANKL增强破骨细胞存活的能力。使用免疫荧光，NF κ B主要存在于未处理的破骨细胞的胞质溶胶中。RANKL诱导NF κ B瞬时易位至细胞核，在15 min时达到最大值。U73122或BAPTA延迟NF κ B的核易位。在抑制钙调磷酸酶或蛋白激酶C时也观察到延迟。我们得出结论，RANKL通过磷脂酶C从细胞内储存中释放Ca2+，加速NF κ B的核转位并促进破骨细胞存活。NF κ B和Ca2+信号之间的这种相互作用为破骨细胞和其他细胞类型中基因表达的时间调节提供了一种新的机制。
PLANK ligand (RANKL) induces activation of NFkappaB, enhancing the formation, resorptive activity, and survival of osteoclasts. Ca2+ transduces many signaling events, however, it is not known whether the actions of RANKL involve Ca2+ signaling. We investigated the effects of RANKL on rat osteoclasts using microspectrofluorimetry and patch clamp. RANKL induced transient elevation of cytosolic free Ca2+ concentration ([Ca2+](i)) to maxima 220 nm above basal, resulting in activation of Ca2+-dependent K+ current. PANEL elevated [Ca2+](i) in Ca2+-containing and Ca2+-free media, and responses were prevented by the phospholipase C inhibitor U73122. Suppression of [Ca2+](i) elevation using the intracellular Ca2+ chelator 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) abolished the ability of RANKL to enhance osteoclast survival. Using immunofluorescence, NFkappaB was found predominantly in the cytosol of untreated osteoclasts. RANKL induced transient translocation of NFkappaB to the nuclei, which was maximal at 15 min. U73122 or BAPTA delayed nuclear translocation of NFkappaB. Delays were also observed upon inhibition of calcineurin or protein kinase C. We conclude that RANKL acts through phospholipase C to release Ca2+ from intracellular stores, accelerating nuclear translocation of NFkappaB and promoting osteoclast survival. Such cross-talk between NFkappaB and Ca2+ signaling provides a novel mechanism for the temporal regulation of gene expression in osteoclasts and other cell types.