scholarly journals Estrogen Decreases Cytoskeletal Organization by Forming an ERα/SHP2/c-Src Complex in Osteoclasts to Protect against Ovariectomy-Induced Bone Loss in Mice

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 619
Author(s):  
Hyun-Jung Park ◽  
Malihatosadat Gholam-Zadeh ◽  
Sun-Young Yoon ◽  
Jae-Hee Suh ◽  
Hye-Seon Choi
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Ring Formation ◽  
Tartrate Resistant Acid Phosphatase ◽  
Actin Ring ◽  
Collagen Crosslinks ◽  
Trap Staining ◽  
Src Activation

Loss of ovarian function is closely related to estrogen (E2) deficiency, which is responsible for increased osteoclast (OC) differentiation and activity. We aimed to investigate the action mechanism of E2 to decrease bone resorption in OCs to protect from ovariectomy (OVX)-induced bone loss in mice. In vivo, tartrate-resistant acid phosphatase (TRAP) staining in femur and serum carboxy-terminal collagen crosslinks-1 (CTX-1) were analyzed upon E2 injection after OVX in mice. In vitro, OCs were analyzed by TRAP staining, actin ring formation, carboxymethylation, determination of reactive oxygen species (ROS) level, and immunoprecipitation coupled with Western blot. In vivo and in vitro, E2 decreased OC size more dramatically than OC number and Methyl-piperidino-pyrazole hydrate dihydrochloride (MPPD), an estrogen receptor alpha (ERα) antagonist, augmented the OC size. ERα was found in plasma membranes and E2/ERα signaling affected receptor activator of nuclear factor κB ligand (RANKL)-induced actin ring formation by rapidly decreasing a proto-oncogene tyrosine-protein kinase, cellular sarcoma (c-Src) (Y416) phosphorylation in OCs. E2 exposure decreased physical interactions between NADPH oxidase 1 (NOX1) and the oxidized form of c-Src homology 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2), leading to higher levels of reduced SHP2. ERα formed a complex with the reduced form of SHP2 and c-Src to decrease c-Src activation upon E2 exposure, which blocked a signal for actin ring formation by decreased Vav guanine nucleotide exchange factor 3 (Vav3) (p–Y) and Ras-related C3 botulinum toxin substrate 1 (Rac1) (GTP) activation in OCs. E2/ERα signals consistently inhibited bone resorption in vitro. In conclusion, our study suggests that E2-binding to ERα forms a complex with SHP2/c-Src to attenuate c-Src activation that was induced upon RANKL stimulation in a non-genomic manner, resulting in an impaired actin ring formation and reducing bone resorption.

Elevation of fibrinogen due to loss of ovarian function enhances actin ring formation and leads to increased bone resorption

2012 ◽  
Vol 303 (11) ◽  
pp. E1296-E1303 ◽  
Author(s):  
Ke Ke ◽  
Woon-Ki Kim ◽  
Ok-Joo Sul ◽  
Van Tien Phan ◽  
Mi-Hyun Lee ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Ovarian Function ◽  
Annexin V ◽  
Ring Formation ◽  
Tartrate Resistant Acid Phosphatase ◽  
Actin Ring ◽  
Macrophage Colony ◽  
And Function

The aim of the present study was to evaluate the effect of fibrinogen on number and function of osteoclasts (OC) consequently resulting in bone loss. It was hypothesized that the enhanced level of released fibrinogen due to loss of ovarian function caused bone loss by acting on OCs. Bone loss was induced by ovariectomy (OVX) in mice and analyzed by micro-CT. The effect of fibrinogen on OCs was evaluated by tartrate-resistant acid phosphatase, annexin V, actin staining, pit formation observed on dentine slices, and Western blotting. Exogenous fibrinogen increased OC survival, actin ring formation, and bone resorption in vitro. The effect of fibrinogen was dependent on β3-integrin, which is a marker for mature OCs. Fibrinogen induced the activation of transforming oncogene from Ak strain (Akt), Ras-related C3 botulinum toxin substrate 1 (Rac1), and Rho family of GTPase (Rho) and the degradation of the Bcl-2 interacting mediator of cell death (Bim) in a manner similar to macrophage colony-stimulating factor (M-CSF). OVX increased plasma fibrinogen and serum M-CSF together with elevated actin ring formation and bone loss. The increased fibrinogen level due to loss of ovarian function may contribute, at least partly, to bone loss through the enhanced number and activity of OCs.

scholarly journals Dauricine Protects from LPS-Induced Bone Loss via the ROS/PP2A/NF-κB Axis in Osteoclasts

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 588 ◽  
Author(s):  
Hyun-Jung Park ◽  
Malihatosadat Gholam Zadeh ◽  
Jae-Hee Suh ◽  
Hye-Seon Choi
Keyword(s):  
Reactive Oxygen Species ◽  
Bone Loss ◽  
Nuclear Localization ◽  
Therapeutic Potential ◽  
Isoquinoline Alkaloid ◽  
Tartrate Resistant Acid Phosphatase ◽  
Oxygen Species ◽  
Trap Staining

Dauricine (DAC), an isoquinoline alkaloid, exhibits anti-inflammatory activity. We hypothesized that DAC may prevent the inflammatory bone loss induced by lipopolysaccharide (LPS). LPS-induced bone loss was decreased by DAC in female C57BL/6J mice as evaluated by micro-computerized tomography (μCT) analysis. In vivo tartrate-resistant acid phosphatase (TRAP) staining showed that the increased number of osteoclasts (OCs) in LPS-treated mice was attenuated by DAC, indicating that DAC exhibited bone sparing effects through acting on OCs. DAC also decreased the differentiation and activity of OCs after LPS stimulation in vitro. LPS-induced cytosolic reactive oxygen species (cROS) oxidized PP2A, a serine/threonine phosphatase, leading to the activation of IKKα/β, followed by the nuclear localization of p65. DAC decreased LPS-induced ROS, resulting in the recovery of the activity of PP2A by reducing its oxidized form. Consequently, DAC reduced the phosphorylation of IKKα/β to block the nuclear localization of p65, which decreased NF-κB activation. Taken together, DAC reduced the differentiation and activity of OCs by decreasing ROS via the ROS/PP2A/NF-κB axis, resulting in protection from LPS-induced bone loss. We have demonstrated that LPS-induced bone loss was inhibited by DAC via its action on OCs, implying the therapeutic potential of DAC against inflammatory bone loss.

scholarly journals A novel BRD4 inhibitor suppresses osteoclastogenesis and ovariectomized osteoporosis by blocking RANKL-mediated MAPK and NF-κB pathways

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ying Liu ◽  
Wenjie Liu ◽  
Ziqiang Yu ◽  
Yan Zhang ◽  
Yinghua Li ◽  
...  
Keyword(s):  
Bone Loss ◽  
Osteoporosis Treatment ◽  
Inhibitory Effect ◽  
Specific Gene ◽  
Actin Ring ◽  
Treatment Target ◽  
Significant Inhibitory Effect ◽  
Promising Treatment

AbstractBromodomain-containing protein 4 (BRD4) has emerged as a promising treatment target for bone-related disorders. (+)-JQ1, a thienotriazolodiazepine compound, has been shown to inhibit pro-osteoclastic activity in a BRD4-dependent approach and impede bone loss caused by ovariectomy (OVX) in vivo. However, clinical trials of (+)-JQ1 are limited because of its poor druggability. In this study, we synthesized a new (+)-JQ1 derivative differing in structure and chirality. One such derivative, (+)-ND, exhibited higher solubility and excellent inhibitory activity against BRD4 compared with its analogue (+)-JQ1. Interestingly, (-)-JQ1 and (-)-ND exhibited low anti-proliferative activity and had no significant inhibitory effect on RANKL-induced osteoclastogenesis as compared with (+)-JQ1 and (+)-ND, suggesting the importance of chirality in the biological activity of compounds. Among these compounds, (+)-ND displayed the most prominent inhibitory effect on RANKL-induced osteoclastogenesis. Moreover, (+)-ND could inhibit osteoclast-specific gene expression, F‐actin ring generation, and bone resorption in vitro and prevent bone loss in OVX mice. Collectively, these findings indicated that (+)-ND represses RANKL‐stimulated osteoclastogenesis and averts OVX-triggered osteoporosis by suppressing MAPK and NF-κB signalling cascades, suggesting that it may be a prospective candidate for osteoporosis treatment.

Artesunate inhibits RANKL-induced osteoclastogenesis and bone resorption in vitro and prevents LPS-induced bone loss in vivo

2017 ◽  
Vol 233 (1) ◽  
pp. 476-485 ◽  
Author(s):  
Cheng-Ming Wei ◽  
Qian Liu ◽  
Fang-Ming Song ◽  
Xi-Xi Lin ◽  
Yi-Ji Su ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss

scholarly journals 1,25-Dihydroxy-19-nor-vitamin D2, a Vitamin D Analog with Reduced Bone Resorbing Activity In Vitro

2000 ◽  
Vol 11 (10) ◽  
pp. 1857-1864
Author(s):  
L. SHANNON HOLLIDAY ◽  
STEPHEN L. GLUCK ◽  
EDUARDO SLATOPOLSKY ◽  
ALEX J. BROWN
Keyword(s):  
Vitamin D ◽  
Acid Phosphatase ◽  
Bone Resorption ◽  
Vitamin D Receptor ◽  
Intrinsic Activity ◽  
Tartrate Resistant Acid Phosphatase ◽  
Mouse Bone Marrow ◽  
Bone Resorbing Activity

Abstract. 1,25-Dihydroxy-19-nor-vitamin D2 (19-norD2), a new analog of 1,25(OH)2D3, suppresses parathyroid hormone in renal failure patients and in uremic rats but has less calcemic activity than 1,25(OH)2D3. Although 19-norD2 has high affinity for the vitamin D receptor and similar pharmacokinetics to those of 1,25(OH)2D3, it has much less bone resorbing activity in vivo. The intrinsic activity of 19-norD2 on osteoclastogenesis and activation of bone resorption in mouse bone marrow cultures was examined to determine the mechanism involved. 19-norD2 and 1,25(OH)2D3 (10 nM) were equivalent in stimulating the formation and maintenance of large multinucleated, tartrate-resistant acid phosphatase-positive cells. However, the amount of bone resorbed by osteoclasts stimulated by 10 nM 19-norD2, as measured by pit-forming assays, was reduced 62% compared with 10 nM 1,25(OH)2D3-stimulated osteoclasts (P < 0.05). This difference could not be attributed to enhanced catabolism or to downregulated vitamin D receptor. The rate of degradation of 19-norD2 in cultures was approximately 20% greater than 1,25(OH)2D3, not enough to account for the different effects on bone resorption. The VDR levels were identical in cultures that were treated with 19-norD2 and 1,25(OH)2D3. In summary, 19-norD2 is less effective than 1,25(OH)2D3 in stimulating mouse marrow osteoclasts to resorb bone. The reason for this difference is not clear but seems to involve the late maturation and/or activation of osteoclasts as the number of pits produced by each tartrate-resistant acid phosphatase-positive cell is reduced under stimulation by 19-norD2 compared with 1,25(OH)2D3.

scholarly journals TNFα Potently Activates Osteoclasts, through a Direct Action Independent of and Strongly Synergistic with RANKL

Endocrinology ◽  
2002 ◽  
Vol 143 (3) ◽  
pp. 1108-1118 ◽  
Author(s):  
Karen Fuller ◽  
Chiho Murphy ◽  
Barrie Kirstein ◽  
Simon W. Fox ◽  
Timothy J. Chambers
Keyword(s):  
Direct Action ◽  
Ring Formation ◽  
Actin Ring ◽  
Independent Manner ◽  
Low Concentrations ◽  
Order Of Magnitude ◽  
Extreme Sensitivity ◽  
Osteoclastic Differentiation

Abstract TNFα is pivotal to the pathogenesis of inflammatory and possibly postmenopausal osteolysis. Much recent work has clarified mechanisms by which TNFα promotes osteoclastogenesis, but the means by which it activates osteoclasts to resorb bone remain uncertain. We found that very low concentrations of TNFα promoted actin ring formation, which correlates with functional activation in osteoclasts, both in osteoclasts formed in vitro and extracted from newborn rats. TNFα was equipotent with RANKL for this action. Activation by TNFα was unaffected by blockade of RANKL by OPG, its soluble decoy receptor, suggesting that this was due to a direct action on osteoclasts. Bone resorption was similarly directly and potently stimulated, in a RANKL-independent manner in osteoclasts, whether these were formed in vitro or in vivo. Interestingly, TNFα promoted actin ring formation at concentrations an order of magnitude below those required for osteoclastic differentiation. Moreover, TNFα strongly synergized with RANKL, such that miniscule concentrations of TNFα were sufficient to substantially augment osteoclast activation. The extreme sensitivity of osteoclasts to activation by TNFα suggests that the most sensitive osteolytic response of bone to TNFα is through activation of existing osteoclasts; and the strong synergy with RANKL provides a mechanism whereby increased osteolysis can be achieved without disturbance to the underlying pattern of osteoclastic localization.

scholarly journals Pristimerin Inhibits Osteoclast Differentiation and Bone Resorption in vitro and Prevents Ovariectomy-Induced Bone Loss in vivo

2020 ◽  
Vol Volume 14 ◽  
pp. 4189-4203
Author(s):  
Peng Sun ◽  
Qichang Yang ◽  
Yanben Wang ◽  
Jiaxuan Peng ◽  
Kangxian Zhao ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Osteoclast Differentiation

scholarly journals The Role of IL-1βin the Bone Loss during Rheumatic Diseases

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Piero Ruscitti ◽  
Paola Cipriani ◽  
Francesco Carubbi ◽  
Vasiliki Liakouli ◽  
Francesca Zazzeroni ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Rheumatic Diseases ◽  
Nuclear Factor Kappa B ◽  
Inflammatory Diseases ◽  
Receptor Activator ◽  
Main Factor

Several inflammatory diseases have been associated with increased bone resorption and fracture rates and different studies supported the relation between inflammatory cytokines and osteoclast activity. The main factor required for osteoclast activation is the stimulation by receptor activator of nuclear factor kappa-B ligand (RANKL) expressed on osteoblasts. In this context, interleukin- (IL-) 1β, one of the most powerful proinflammatory cytokines, is a strong stimulator of in vitro and in vivo bone resorption via upregulation of RANKL that stimulates the osteoclastogenesis. The resulting effects lead to an imbalance in bone metabolism favouring bone resorption and osteoporosis. In this paper, we review the available literature on the role of IL-1βin the pathogenesis of bone loss. Furthermore, we analysed the role of IL-1βin bone resorption during rheumatic diseases and, when available, we reported the efficacy of anti-IL-1βtherapy in this field.

scholarly journals Inhibition of bone resorption in vitro and prevention of ovariectomy-induced bone loss in vivo by flurbiprofen nitroxybutylester (HCT1026)

2001 ◽  
Vol 44 (9) ◽  
pp. 2185-2192 ◽  
Author(s):  
Kenneth J. Armour ◽  
Robert J. Van 't Hof ◽  
Katharine E. Armour ◽  
Anne C. Torbergsen ◽  
Piero Del Soldato ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss

scholarly journals The Ligand for Osteoprotegerin (OPGL) Directly Activates Mature Osteoclasts

1999 ◽  
Vol 145 (3) ◽  
pp. 527-538 ◽  
Author(s):  
Teresa L. Burgess ◽  
Yi-xin Qian ◽  
Stephen Kaufman ◽  
Brian D. Ring ◽  
Gwyneth Van ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Primary Cultures ◽  
Osteoclast Differentiation ◽  
Ring Formation ◽  
Surface Erosion ◽  
Direct Effects ◽  
Bone Surface ◽  
Actin Ring ◽  
Scanning Electron

Osteoprotegerin (OPG) and OPG-ligand (OPGL) potently inhibit and stimulate, respectively, osteoclast differentiation (Simonet, W.S., D.L. Lacey, C.R. Dunstan, M. Kelley, M.-S. Chang, R. Luethy, H.Q. Nguyen, S. Wooden, L. Bennett, T. Boone, et al. 1997. Cell. 89:309–319; Lacey, D.L., E. Timms, H.-L. Tan, M.J. Kelley, C.R. Dunstan, T. Burgess, R. Elliott, A. Colombero, G. Elliott, S. Scully, et al. 1998. Cell. 93: 165–176), but their effects on mature osteoclasts are not well understood. Using primary cultures of rat osteoclasts on bone slices, we find that OPGL causes approximately sevenfold increase in total bone surface erosion. By scanning electron microscopy, OPGL-treated osteoclasts generate more clusters of lacunae on bone suggesting that multiple, spatially associated cycles of resorption have occurred. However, the size of individual resorption events are unchanged by OPGL treatment. Mechanistically, OPGL binds specifically to mature OCs and rapidly (within 30 min) induces actin ring formation; a marked cytoskeletal rearrangement that necessarily precedes bone resorption. Furthermore, we show that antibodies raised against the OPGL receptor, RANK, also induce actin ring formation. OPGL-treated mice exhibit increases in blood ionized Ca++ within 1 h after injections, consistent with immediate OC activation in vivo. Finally, we find that OPG blocks OPGL's effects on both actin ring formation and bone resorption. Together, these findings indicate that, in addition to their effects on OC precursors, OPGL and OPG have profound and direct effects on mature OCs and indicate that the OC receptor, RANK, mediates OPGL's effects.

Sign in / Sign up

Export Citation Format

Share Document