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TRAF-6 dependent signaling pathway is essential for TNF-related apoptosis-inducing ligand (TRAIL) induces osteoclast differentiation.

Yen ML, Hsu PN, Liao HJ, Lee BH, Tsai HF - PLoS ONE (2012)

Bottom Line: In addition to induction of NFATc1, treatment of TRAIL also induced ubiquitination of TRAF6 in osteoclast differentiation.Thus, our data demonstrate that TRAIL induces osteoclastic differentiation via a TRAF-6 dependent signaling pathway.This study suggests TRAF6-dependent signaling may be a central pathway in osteoclast differentiation, and that TNF superfamily molecules other than RANKL may modify RANK signaling by interaction with TRAF6-associated signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of General Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.

ABSTRACT
Human osteoclast formation from mononuclear phagocyte precursors involves interactions between tumor necrosis factor (TNF) ligand superfamily members and their receptors. Recent evidence indicates that in addition to triggering apoptosis, the TNF-related apoptosis-inducing ligand (TRAIL) induces osteoclast differentiation. To understand TRAIL-mediated signal transduction mechanism in osteoclastogenesis, we demonstrated that TRAIL induces osteoclast differentiation via a Tumor necrosis factor receptor-associated factor 6 (TRAF-6)-dependent signaling pathway. TRAIL-induced osteoclast differentiation was significantly inhibited by treatment with TRAF-6 siRNA and TRAF6 decoy peptides in both human monocytes and murine RAW264.7 macrophage cell lines, as evaluated in terms of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and bone resorption activity. Moreover, TRAIL-induced osteoclast differentiation was also abolished in TRAF6 knockout bone marrow macrophages. In addition to induction of NFATc1, treatment of TRAIL also induced ubiquitination of TRAF6 in osteoclast differentiation. Thus, our data demonstrate that TRAIL induces osteoclastic differentiation via a TRAF-6 dependent signaling pathway. This study suggests TRAF6-dependent signaling may be a central pathway in osteoclast differentiation, and that TNF superfamily molecules other than RANKL may modify RANK signaling by interaction with TRAF6-associated signaling.

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Related in: MedlinePlus

TRAIL induces activation of MAP Kinases is dependent on TRAF6.RAW264.7 cells were treated with TRAIL (500 ng/ml), M-CSF (20 ng/ml) and RANKL (50 ng/ml) in the presence or absence of TRAF6 siRNA. After stimulation, cells were solubilized, and cell lysates were subjected to Western blot analysis of TRAF6, p38 MAPK, JNK, and ERK1/2. The trace shown in the top panel for each group indicates the immunoreactivity of the phosphorylated kinase. The same membrane was then stripped and reprobed with the kinase antibody recognizing the total protein level of kinase (bottom panel). The results are representative of five separate experiments.
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pone-0038048-g003: TRAIL induces activation of MAP Kinases is dependent on TRAF6.RAW264.7 cells were treated with TRAIL (500 ng/ml), M-CSF (20 ng/ml) and RANKL (50 ng/ml) in the presence or absence of TRAF6 siRNA. After stimulation, cells were solubilized, and cell lysates were subjected to Western blot analysis of TRAF6, p38 MAPK, JNK, and ERK1/2. The trace shown in the top panel for each group indicates the immunoreactivity of the phosphorylated kinase. The same membrane was then stripped and reprobed with the kinase antibody recognizing the total protein level of kinase (bottom panel). The results are representative of five separate experiments.

Mentions: Three members of MAPKs, ERK, p38 MAPK, and JNK, have been implicated in the mediation of cytokine-regulated osteoclastogenesis [26], [27], [28]. To elucidate the signaling pathways underlying TRAIL's action, we examined the activation of MAPKs in RAW264.7 cells treated with TRAIL, RANKL and M-CSF in the presence or absence of TRAF6 siRNA by immunoblotting. As shown in Figure 3, expression of TRAF6 was upregulated when treated with TRAIL or RANKL plus M-CSF in RAW264.7 macrophages. TRAIL induced the phosphorylation of p38 MAPK, JNK, and ERK in osteoclast precursors, and silencing of TRAF6 by treatment of TRAF6 siRNA inhibited the TRAIL-induced phosphorylation of p38 MAPK, JNK and ERK in RAW264.7 macrophages (Figure 3). These results suggest that TRAF6 is critical in TRAIL-induced activation of MAP kinases in osteoclastogenesis signaling.


TRAF-6 dependent signaling pathway is essential for TNF-related apoptosis-inducing ligand (TRAIL) induces osteoclast differentiation.

Yen ML, Hsu PN, Liao HJ, Lee BH, Tsai HF - PLoS ONE (2012)

TRAIL induces activation of MAP Kinases is dependent on TRAF6.RAW264.7 cells were treated with TRAIL (500 ng/ml), M-CSF (20 ng/ml) and RANKL (50 ng/ml) in the presence or absence of TRAF6 siRNA. After stimulation, cells were solubilized, and cell lysates were subjected to Western blot analysis of TRAF6, p38 MAPK, JNK, and ERK1/2. The trace shown in the top panel for each group indicates the immunoreactivity of the phosphorylated kinase. The same membrane was then stripped and reprobed with the kinase antibody recognizing the total protein level of kinase (bottom panel). The results are representative of five separate experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375273&req=5

pone-0038048-g003: TRAIL induces activation of MAP Kinases is dependent on TRAF6.RAW264.7 cells were treated with TRAIL (500 ng/ml), M-CSF (20 ng/ml) and RANKL (50 ng/ml) in the presence or absence of TRAF6 siRNA. After stimulation, cells were solubilized, and cell lysates were subjected to Western blot analysis of TRAF6, p38 MAPK, JNK, and ERK1/2. The trace shown in the top panel for each group indicates the immunoreactivity of the phosphorylated kinase. The same membrane was then stripped and reprobed with the kinase antibody recognizing the total protein level of kinase (bottom panel). The results are representative of five separate experiments.
Mentions: Three members of MAPKs, ERK, p38 MAPK, and JNK, have been implicated in the mediation of cytokine-regulated osteoclastogenesis [26], [27], [28]. To elucidate the signaling pathways underlying TRAIL's action, we examined the activation of MAPKs in RAW264.7 cells treated with TRAIL, RANKL and M-CSF in the presence or absence of TRAF6 siRNA by immunoblotting. As shown in Figure 3, expression of TRAF6 was upregulated when treated with TRAIL or RANKL plus M-CSF in RAW264.7 macrophages. TRAIL induced the phosphorylation of p38 MAPK, JNK, and ERK in osteoclast precursors, and silencing of TRAF6 by treatment of TRAF6 siRNA inhibited the TRAIL-induced phosphorylation of p38 MAPK, JNK and ERK in RAW264.7 macrophages (Figure 3). These results suggest that TRAF6 is critical in TRAIL-induced activation of MAP kinases in osteoclastogenesis signaling.

Bottom Line: In addition to induction of NFATc1, treatment of TRAIL also induced ubiquitination of TRAF6 in osteoclast differentiation.Thus, our data demonstrate that TRAIL induces osteoclastic differentiation via a TRAF-6 dependent signaling pathway.This study suggests TRAF6-dependent signaling may be a central pathway in osteoclast differentiation, and that TNF superfamily molecules other than RANKL may modify RANK signaling by interaction with TRAF6-associated signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of General Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.

ABSTRACT
Human osteoclast formation from mononuclear phagocyte precursors involves interactions between tumor necrosis factor (TNF) ligand superfamily members and their receptors. Recent evidence indicates that in addition to triggering apoptosis, the TNF-related apoptosis-inducing ligand (TRAIL) induces osteoclast differentiation. To understand TRAIL-mediated signal transduction mechanism in osteoclastogenesis, we demonstrated that TRAIL induces osteoclast differentiation via a Tumor necrosis factor receptor-associated factor 6 (TRAF-6)-dependent signaling pathway. TRAIL-induced osteoclast differentiation was significantly inhibited by treatment with TRAF-6 siRNA and TRAF6 decoy peptides in both human monocytes and murine RAW264.7 macrophage cell lines, as evaluated in terms of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and bone resorption activity. Moreover, TRAIL-induced osteoclast differentiation was also abolished in TRAF6 knockout bone marrow macrophages. In addition to induction of NFATc1, treatment of TRAIL also induced ubiquitination of TRAF6 in osteoclast differentiation. Thus, our data demonstrate that TRAIL induces osteoclastic differentiation via a TRAF-6 dependent signaling pathway. This study suggests TRAF6-dependent signaling may be a central pathway in osteoclast differentiation, and that TNF superfamily molecules other than RANKL may modify RANK signaling by interaction with TRAF6-associated signaling.

Show MeSH
Related in: MedlinePlus