scholarly journals ATP downregulates P2X7 and inhibits osteoclast formation in RAW cells

2004 ◽  
Vol 287 (2) ◽  
pp. C403-C412 ◽  
Author(s):  
Jeffrey F. Hiken ◽  
Thomas H. Steinberg
Keyword(s):  
Prolonged Exposure ◽  
Nuclear Factor Κb ◽  
Giant Cells ◽  
Osteoclast Formation ◽  
Marker Genes ◽  
Tartrate Resistant Acid Phosphatase ◽  
Marker Enzyme ◽  
Multinucleated Giant Cells ◽  
Membrane Pores ◽  
Receptor Activator

Multinucleated giant cells derive from fusion of precursor cells of the macrophage lineage. It has been proposed that the purinoreceptor P2X7 is involved in this fusion process. Prolonged exposure of macrophages to ATP, the ligand for P2X7, induces the formation of plasma membrane pores and eventual cell death. We took advantage of this cytolytic property to select RAW 264.7 (RAW) cells that lacked P2X7 function by maintaining them in ATP (RAW ATP-R cells). RAW ATP-R cells failed to fuse to form multinucleated osteoclasts in response to receptor activator nuclear factor-κB ligand, although they did become positive for the osteoclast marker enzyme tartrate-resistant acid phosphatase, and upregulated expression of other osteoclast marker genes. RAW ATP-R cells and wild-type RAW cells expressed similar amounts of P2X7 protein, but little P2X7 was present on the surface of RAW ATP-R cells. After ATP was removed from the medium of RAW ATP-R cells, the cells reexpressed P2X7 on the cell surface, regained sensitivity to ATP, and formed multinucleated osteoclasts. These results suggest that P2X7 or another protein that is downregulated in concert with P2X7 is involved either in the mechanics of cell fusion to form osteoclasts or in a signaling pathway proximal to this event. These results also suggest that P2X7 may be regulated by ligand-mediated internalization and that extracellular ATP may regulate the formation of osteoclasts and other multinucleated giant cells.

scholarly journals RANKL-induced DC-STAMP Is Essential for Osteoclastogenesis

2004 ◽  
Vol 200 (7) ◽  
pp. 941-946 ◽  
Author(s):  
Toshio Kukita ◽  
Naohisa Wada ◽  
Akiko Kukita ◽  
Takashi Kakimoto ◽  
Ferry Sandra ◽  
...  
Keyword(s):  
Transmembrane Protein ◽  
Nuclear Factor Κb ◽  
Giant Cells ◽  
Precursor Cells ◽  
Tartrate Resistant Acid Phosphatase ◽  
Small Interfering Rnas ◽  
Surface Molecules ◽  
Receptor Activator ◽  
Targeted Inhibition ◽  
First Time

Osteoclasts are bone-resorbing, multinucleated giant cells that are essential for bone remodeling and are formed through cell fusion of mononuclear precursor cells. Although receptor activator of nuclear factor–κB ligand (RANKL) has been demonstrated to be an important osteoclastogenic cytokine, the cell surface molecules involved in osteoclastogenesis are mostly unknown. Here, we report that the seven-transmembrane receptor-like molecule, dendritic cell–specific transmembrane protein (DC-STAMP) is involved in osteoclastogenesis. Expression of DC-STAMP is rapidly induced in osteoclast precursor cells by RANKL and other osteoclastogenic stimulations. Targeted inhibition of DC-STAMP by small interfering RNAs and specific antibody markedly suppressed the formation of multinucleated osteoclast-like cells. Overexpression of DC-STAMP enhanced osteoclastogenesis in the presence of RANKL. Furthermore, DC-STAMP directly induced the expression of the osteoclast marker tartrate-resistant acid phosphatase. These data demonstrate for the first time that DC-STAMP has an essential role in osteoclastogenesis.

scholarly journals Isofraxidin Inhibits Receptor Activator of Nuclear Factor-κB Ligand–Induced Osteoclastogenesis in Bone Marrow–Derived Macrophages Isolated from Sprague–Dawley Rats by Regulating NF-κB/NFATc1 and Akt/NFATc1 Signaling Pathways

2021 ◽  
Vol 30 ◽  
pp. 096368972199032
Author(s):  
Wei Wang ◽  
Bo Wang
Keyword(s):  
Bone Marrow ◽  
Signaling Pathways ◽  
Cathepsin K ◽  
Nuclear Factor Κb ◽  
Osteoclast Formation ◽  
Luciferase Reporter ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Receptor Activator

Osteoporosis is a common bone disease that is characterized by decreased bone mass and fragility fractures. Isofraxidin is a hydroxy coumarin with several biological and pharmacological activities including an anti-osteoarthritis effect. However, the role of isofraxidin in osteoporosis has not yet been investigated. In the present study, we used receptor activator of nuclear factor-κB ligand (RANKL) to induce osteoclast formation in primary bone marrow macrophages (BMMs). Our results showed that RANKL treatment significantly increased tartrate-resistant acid phosphatase (TRAP) activity, as well as the expression of osteoclastogenesis-related markers including MMP-9, c-Src, and cathepsin K at both mRNA and protein levels; however, these effects were inhibited by isofraxidin in BMMs. In addition, luciferase reporter assay demonstrated that isofraxidin treatment suppressed the RANKL-induced an increase in nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) transcriptional activity. Besides, the decreased expression level of IκBα and increased levels of p-p65, p-IκBα, and p-Akt in RANKL-induced BMMs were attenuated by isofraxidin. Moreover, NFATc1 overexpression rescued the anti-osteoclastogenic effect of isofraxidin with increased expression levels of MMP-9, c-Src, and cathepsin K. Taken together, these findings indicated that isofraxidin inhibited RANKL-induced osteoclast formation in BMMs via inhibiting the activation of NF-κB/NFATc1 and Akt/NFATc1 signaling pathways. Thus, isofraxidin might be a therapeutic agent for the treatment of osteoporosis.

scholarly journals The Role of miR-21 in Osteoblasts–Osteoclasts Coupling In Vitro

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 479 ◽  
Author(s):  
Agnieszka Smieszek ◽  
Klaudia Marcinkowska ◽  
Ariadna Pielok ◽  
Mateusz Sikora ◽  
Lukas Valihrach ◽  
...  
Keyword(s):  
Cathepsin K ◽  
Nuclear Factor Κb ◽  
Tartrate Resistant Acid Phosphatase ◽  
Type I ◽  
Nuclear Factor ◽  
Paracrine Signaling ◽  
Receptor Activator ◽  
The Impact

MiR-21 is being gradually more and more recognized as a molecule regulating bone tissue homeostasis. However, its function is not fully understood due to the dual role of miR-21 on bone-forming and bone-resorbing cells. In this study, we investigated the impact of miR-21 inhibition on pre-osteoblastic cells differentiation and paracrine signaling towards pre-osteoclasts using indirect co-culture model of mouse pre-osteoblast (MC3T3) and pre-osteoclast (4B12) cell lines. The inhibition of miR-21 in MC3T3 cells (MC3T3inh21) modulated expression of genes encoding osteogenic markers including collagen type I (Coll-1), osteocalcin (Ocl), osteopontin (Opn), and runt-related transcription factor 2 (Runx-2). Inhibition of miR-21 in osteogenic cultures of MC3T3 also inflected the synthesis of OPN protein which is essential for proper mineralization of extracellular matrix (ECM) and anchoring osteoclasts to the bones. Furthermore, it was shown that in osteoblasts miR-21 regulates expression of factors that are vital for survival of pre-osteoclast, such as receptor activator of nuclear factor κB ligand (RANKL). The pre-osteoclast cultured with MC3T3inh21 cells was characterized by lowered expression of several markers associated with osteoclasts’ differentiation, foremost tartrate-resistant acid phosphatase (Trap) but also receptor activator of nuclear factor-κB ligand (Rank), cathepsin K (Ctsk), carbonic anhydrase II (CaII), and matrix metalloproteinase (Mmp-9). Collectively, our data indicate that the inhibition of miR-21 in MC3T3 cells impairs the differentiation and ECM mineralization as well as influences paracrine signaling leading to decreased viability of pre-osteoclasts.

Spatholobus suberectus Inhibits Osteoclastogenesis and Stimulates Chondrogenesis

2014 ◽  
Vol 42 (05) ◽  
pp. 1123-1138 ◽  
Author(s):  
Nam-Kyung Im ◽  
Sung-Gyu Lee ◽  
Dong-Sung Lee ◽  
Pil-Hoon Park ◽  
In-Seon Lee ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Tartrate Resistant Acid Phosphatase ◽  
Chondral Defect ◽  
Active Components ◽  
Tnf Α ◽  
Receptor Activator ◽  
The Matrix ◽  
Spatholobus Suberectus

This study was carried out to investigate the effect of Spatholobus suberectus Dunn (SS) on the protection of chondral defect and inhibition of osteoclastogenesis. To examine these effects, we measured the matrix metalloproteinase (MMP) levels in SW1353 chondrosarcoma cells and performed tartrate-resistant acid phosphatase (TRAP) staining in bone marrow macrophage (BMM)-derived osteoclasts. To investigate the anti-osteoarthritis (OA) effects, we assessed TNF-α-induced MMP-1, -3, -9 and tissue inhibitors of matrix metalloproteinase (TIMP) expression levels in SW1353 cells. We observed that SS extract significantly inhibited MMP and TIMP expression in SW1353 cells. Also, SS extract inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. These results suggest that SS extract may have a potential in the treatment of bone loss and chondral defect by suppressing osteoclast differentiation and decreasing the expression of OA factors. Therefore, clarification of the mechanism of the action of SS extract and its active components is needed.

scholarly journals Osteoclasts are important for bone angiogenesis

Blood ◽  
2010 ◽  
Vol 115 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Frank C. Cackowski ◽  
Judith L. Anderson ◽  
Kenneth D. Patrene ◽  
Rushir J. Choksi ◽  
Steven D. Shapiro ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Osteoclast Formation ◽  
Angiogenic Factor ◽  
Adult Mice ◽  
Parathyroid Hormone Related Protein ◽  
Receptor Activator ◽  
Metalloproteinase 9

Abstract Increased osteoclastogenesis and angiogenesis occur in physiologic and pathologic conditions. However, it is unclear if or how these processes are linked. To test the hypothesis that osteoclasts stimulate angiogenesis, we modulated osteoclast formation in fetal mouse metatarsal explants or in adult mice and determined the effect on angiogenesis. Suppression of osteoclast formation with osteoprotegerin dose-dependently inhibited angiogenesis and osteoclastogenesis in metatarsal explants. Conversely, treatment with parathyroid hormone related protein (PTHrP) increased explant angiogenesis, which was completely blocked by osteoprotegerin. Further, treatment of mice with receptor activator of nuclear factor-κB ligand (RANKL) or PTHrP in vivo increased calvarial vessel density and osteoclast number. We next determined whether matrix metalloproteinase-9 (MMP-9), an angiogenic factor predominantly produced by osteoclasts in bone, was important for osteoclast-stimulated angiogenesis. The pro-angiogenic effects of PTHrP or RANKL were absent in metatarsal explants or calvaria in vivo, respectively, from Mmp9−/− mice, demonstrating the importance of MMP-9 for osteoclast-stimulated angiogenesis. Lack of MMP-9 decreased osteoclast numbers and abrogated angiogenesis in response to PTHrP or RANKL in explants and in vivo but did not decrease osteoclast differentiation in vitro. Thus, MMP-9 modulates osteoclast-stimulated angiogenesis primarily by affecting osteoclasts, most probably by previously reported migratory effects on osteoclasts. These results clearly demonstrate that osteoclasts stimulate angiogenesis in vivo through MMP-9.

scholarly journals Anti-Müllerian Hormone Negatively Regulates Osteoclast Differentiation by Suppressing the Receptor Activator of Nuclear Factor-κB Ligand Pathway

2021 ◽  
Vol 28 (3) ◽  
pp. 223-230
Author(s):  
Jung Ha Kim ◽  
Yong Ryoul Yang ◽  
Ki-Sun Kwon ◽  
Nacksung Kim
Keyword(s):  
Osteoblast Differentiation ◽  
Bone Cells ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Bone Morphogenetic Protein 2 ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Bone Homeostasis ◽  
Alizarin Red ◽  
Receptor Activator

Background: Multiple members of the transforming growth factor-β (TGF-β) superfamily have well-established roles in bone homeostasis. Anti-Müllerian hormone (AMH) is a member of TGF-β superfamily of glycoproteins that is responsible for the regression of fetal Müllerian ducts and the transcription inhibition of gonadal steroidogenic enzymes. However, the involvement of AMH in bone remodeling is unknown. Therefore, we investigated whether AMH has an effect on bone cells as other TGF-β superfamily members do.Methods: To identify the roles of AMH in bone cells, we administered AMH during osteoblast and osteoclast differentiation, cultured the cells, and then stained the cultured cells with Alizarin red and tartrate-resistant acid phosphatase, respectively. We analyzed the expression of osteoblast- or osteoclast-related genes using real-time polymerase chain reaction and western blot.Results: AMH does not affect bone morphogenetic protein 2-mediated osteoblast differentiation but inhibits receptor activator of nuclear factor-κB (NF-κB) ligand-induced osteoclast differentiation. The inhibitory effect of AMH on osteoclast differentiation is mediated by IκB-NF-κB signaling.Conclusions: AMH negatively regulates osteoclast differentiation without affecting osteoblast differentiation.

CGRP inhibits osteoprotegerin production in human osteoblast-like cells via cAMP/PKA-dependent pathway

2006 ◽  
Vol 291 (3) ◽  
pp. C529-C537 ◽  
Author(s):  
I. Villa ◽  
E. Mrak ◽  
A. Rubinacci ◽  
F. Ravasi ◽  
F. Guidobono
Keyword(s):  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Primary Cultures ◽  
Nuclear Factor Κb ◽  
Conditioned Media ◽  
Fine Tuning ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Human Osteoblast ◽  
Receptor Activator

The osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/receptor activator of nuclear factor-κB (RANK) system was evaluated as a potential target of CGRP anabolic activity on bone. Primary cultures of human osteoblast-like cells (hOB) express calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1, and, because CGRP stimulates cAMP (one of the modulators of OPG production in osteoblasts), it was investigated whether it affects OPG secretion and expression in hOB. CGRP treatment of hOB (10−11 M–10−7 M) dose-dependently inhibited OPG secretion with an EC50 of 1.08 × 10−10 M, and also decreased its expression. This action was blocked by the antagonist CGRP8–37. Forskolin, a stimulator of cAMP production, and dibutyryl cAMP also reduced the production of OPG. CGRP (10−8 M) enhanced protein kinase A (PKA) activity in hOB, and hOB exposure to the PKA inhibitor, H89 (2 × 10−6 M), abolished the inhibitory effect of CGRP on OPG secretion. Conditioned media from CGRP-treated hOB increased the number of multinucleated tartrate-resistant acid phosphatase-positive cells and the secretion of cathepsin K in human peripheral blood mononuclear cells compared with the conditioned media of untreated hOB. These results show that the cAMP/PKA pathway is involved in the CGRP inhibition of OPG mRNA and protein secretion in hOB and that this effect favors osteoclastogenesis. CGRP could thus modulate the balance between osteoblast and osteoclast activity, participating in the fine tuning of all of the bone remodeling phases necessary for the subsequent anabolic effect.

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