Wortmannin, a specific inhibitor of phosphatidylinositol‐3 kinase, blocks osteoclastic bone resorption

Nakamura, Ichiro; Takahashi, Naoyuki; Sasaki, Takahísa; Tanaka, Sakae; Udagawa, Nobuyuki; Murakami, Hiroshi; Kimura, Koutaro; Kabuyama, Yukihito; Kurokawa, Takahide; Suda, Toshio; Fukui, Yoshihiro

doi:10.1016/0014-5793(95)00153-z

Cited by 142 publications

(84 citation statements)

References 27 publications

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“…The sealing zones serve to attach osteoclasts to the bone surface and isolate the resorption areas from the surrounding areas (Chambers and Magnus 1982;Väänänen et al 2000). It has been reported that disruption of the sealing zones suppresses the boneresorbing activities of osteoclasts (Lakkakorpi and Väänänen 2004;Nakamura et al 1991;Suzuki et al 1996). In the present study, we have demonstrated that luteolin inhibits osteoclastic bone resorption.…”

Section: Discussionsupporting

confidence: 70%

Inhibitory effect of luteolin on osteoclast differentiation and function

et al. 2009

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Osteoclasts are multinucleated cells that play a crucial role in bone resorption, and are formed by the fusion of mononuclear osteoclasts derived from osteoclast precursors of the macrophage lineage. Compounds that specifically target functional osteoclasts would be ideal candidates for anti-resorptive agents for clinical applications. In the present study, we investigated the effects of luteolin, a flavonoid, on the regulation of receptor activator of nuclear factorjB ligand (RANKL)-induced osteoclastogenesis, functions and signaling pathway. Addition of luteolin to a coculture system of mouse bone marrow cells and ST2 cells in the presence of 10 -8 M 1a,25(OH) 2 D 3 caused significant inhibition of osteoclastogenesis. Luteolin had no effects on the 1a,25(OH) 2 D 3 -induced expressions of RANKL, osteoprotegerin and macrophage colony-stimulating factor mRNAs. Next, we examined the direct effects of luteolin on osteoclast precursors using bone marrow macrophages and RAW264.7 cells. Luteolin completely inhibited RANKL-induced osteoclast formation. Moreover, luteolin inhibited the bone resorption by mature osteoclasts accompanied by the disruption of their actin rings, and these effects were reversely induced by the disruption of the actin rings in mature osteoclasts. Finally, we found that luteolin inhibited RANKLinduced osteoclastogenesis through the suppression of ATF2, downstream of p38 MAPK and nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) expression, respectively. Taken together, the present results indicate that naturally occurring luteolin has inhibitory activities toward both osteoclast differentiation and functions through inhibition of RANKL-induced signaling pathway as well as actin ring disruption, respectively.

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Section: Discussionsupporting

confidence: 70%

Inhibitory effect of luteolin on osteoclast differentiation and function

et al. 2009

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“…(21)(22)(23) However, the in vivo data indicated a normal number of osteoclasts in Pik3r1 DOc/À Pik3r2 À/À mice, and the formation of TRAP-positive osteoclasts from Pik3r1 DOc/À Pik3r2 À/À cells was comparable to control cells in vitro. Our results suggest that class IA PI3K is dispensable for the differentiation and survival of osteoclasts, and indicate that other PI3Ks sensitive to the PI3K inhibitors evidently play a redundant role.…”

Section: Discussionmentioning

confidence: 84%

“…(14,15) PI3K is known to be stimulated by M-CSF and integrin a v b 3 , both of which are crucial for osteoclast function. (8,9) In vitro inhibitor experiments suggest that PI3K is involved in the differentiation (21) and the bone-resorbing activity (22,23) of osteoclasts, but the level of PI-3,4,5-P 3 has not been quantitated in osteoclasts, and the in vivo function of PI3K in osteoclasts has also not been elucidated. In addition, because the PI3K inhibitors such as wortmannin and LY294002 suppress the catalytic activity of all classes of the PI3Ks, (16,24) the role of each PI3K class needs to be clarified.…”

Section: Introductionmentioning

confidence: 99%

Class IA phosphatidylinositol 3-kinase regulates osteoclastic bone resorption through protein kinase B–mediated vesicle transport

Shirakawa

Nakamura

Masuda

et al. 2012

Journal of Bone and Mineral Research

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Class IA phosphatidylinositol 3-kinases (PI3Ks) are activated by growth factor receptors and regulate a wide range of cellular processes. In osteoclasts, they are activated downstream of a v b 3 integrin and colony-stimulating factor-1 receptor (c-Fms), which are involved in the regulation of bone-resorbing activity. The physiological relevance of the in vitro studies using PI3K inhibitors has been of limited value, because they inhibit all classes of PI3K. Here, we show that the osteoclast-specific deletion of the p85 genes encoding the regulatory subunit of the class IA PI3K results in an osteopetrotic phenotype caused by a defect in the bone-resorbing activity of osteoclasts. Class IA PI3K is required for the ruffled border formation and vesicular transport, but not for the formation of the sealing zone. p85a/b doubly deficient osteoclasts had a defect in macrophage colony-stimulating factor (M-CSF)-induced protein kinase B (Akt) activation and the introduction of constitutively active Akt recovered the bone-resorbing activity. Thus, the class IA PI3K-Akt pathway regulates the cellular machinery crucial for osteoclastic bone resorption, and may provide a molecular basis for therapeutic strategies against bone diseases. ß

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“…Osteoclastic cells were prepared as described previously (Nakamura et al, 1995). Briefly, osteoblastic cells were isolated from the calvariae of 2-day-old newborn ddYstrain mice and cultured on type I collagen gel.…”

Section: Materials and Methods Cell Culture Systemmentioning

confidence: 99%

Specific biological functions of vacuolar‐type H⁺‐ATPase and lysosomal cysteine proteinase, cathepsin K, in osteoclasts

et al. 2003

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We report the effects of specific and potent inhibitors of vacular-type H ϩ -ATPase and lysosomal cysteine proteinases, cathepsins, on the ultrastructure, expression of these enzymes, and resorptive functions of cultured osteoclasts. Osteoclasts were formed by co-culture of marrow cells and calvarial primary osteoblasts of ddY mice. Formed osteoclasts were cultured on dentine slices for 6 -48 hr with either an H ϩ -ATPase inhibitor, bafilomycin A1, or a cysteine proteinase inhibitor, E-64. In control cultures with no additive, osteoclasts were structurally characterized by the development of ruffled borders and clear zones, and formed many resorption lacunae on dentine slices. Both H ϩ -ATPase and cathepsin K were strongly expressed in the ruffled borders of these osteoclasts. In bafilomycin A1-treated cultures, osteoclasts lacked ruffled borders, and resorption lacuna formation was markedly diminished. This effect of bafilomycin A1 on osteoclast structure was reversible by removal of the compound. Bafilomycin A1 treatment altered the subcellular localization and decreased the expression of H ϩ -ATPase molecules. H ϩ -ATPase expression was observed throughout the cytoplasm, but not along the plasma membranes facing dentine slices. On the other hand, E-64 treatment did not affect the ultrastructure of osteoclasts and the expression of enzyme molecules. Although E-64 showed no effect on demineralization of dentine slices, it dose-dependently reduced resorption lacuna formation. Our results suggest that 1) bafilomycin A1 dose-dependently inhibits resorption lacuna formation via inhibition of ruffled border formation, 2) H ϩ -ATPase expression is closely associated with the cytoskeleton of osteoclasts, and 3) E-64 treatment decreases the depth of resorption lacunae, by inhibition of secreted cathepsin K activity, but does not impair ruffled border formation and the associated expression of H ϩ -ATPase and cathepsin K in osteoclasts. Anat Rec Part A 270A: 152-161, 2003.

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Wortmannin, a specific inhibitor of phosphatidylinositol‐3 kinase, blocks osteoclastic bone resorption

Cited by 142 publications

References 27 publications

Inhibitory effect of luteolin on osteoclast differentiation and function

Inhibitory effect of luteolin on osteoclast differentiation and function

Class IA phosphatidylinositol 3-kinase regulates osteoclastic bone resorption through protein kinase B–mediated vesicle transport

Specific biological functions of vacuolar‐type H⁺‐ATPase and lysosomal cysteine proteinase, cathepsin K, in osteoclasts

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Wortmannin, a specific inhibitor of phosphatidylinositol‐3 kinase, blocks osteoclastic bone resorption

Cited by 142 publications

References 27 publications

Inhibitory effect of luteolin on osteoclast differentiation and function

Inhibitory effect of luteolin on osteoclast differentiation and function

Class IA phosphatidylinositol 3-kinase regulates osteoclastic bone resorption through protein kinase B–mediated vesicle transport

Specific biological functions of vacuolar‐type H+‐ATPase and lysosomal cysteine proteinase, cathepsin K, in osteoclasts

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Specific biological functions of vacuolar‐type H⁺‐ATPase and lysosomal cysteine proteinase, cathepsin K, in osteoclasts