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.

scholarly journals Letrozole Suppresses the Fusion of Osteoclast Precursors through Inhibition of p38-Mediated DC-STAMP Pathway

2020 ◽  
Vol 21 (21) ◽  
pp. 8396
Author(s):  
Hyung Joon Kim ◽  
Hwa-Sik Seong ◽  
YunJeong Choi ◽  
Soon Chul Heo ◽  
Yong-Deok Kim
Keyword(s):  
Bone Cells ◽  
Transmembrane Protein ◽  
Postmenopausal Breast Cancer ◽  
Cathepsin K ◽  
Nuclear Factor Κb ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Breast Cancer Patients ◽  
Estrogen Depletion

Letrozole is a reversible nonsteroidal aromatase inhibitor that is widely used in postmenopausal breast cancer patients. It is well established that letrozole decreases bone density owing to estrogen depletion; however, few studies have reported its direct effect on bone cells in vitro. Therefore, we investigated the effect of letrozole on bone metabolism, focusing on osteoclastogenesis. Letrozole did not affect the viability, proliferation, or migration of bone marrow-derived macrophages (BMMs); however, it reduced the multinucleation of immature osteoclasts and subsequent bone resorption in vitro. Overall, letrozole inhibited the expression of dendritic cell-specific transmembrane protein (DC-STAMP), tartrate-resistant acid phosphatase, calcitonin receptor, and cathepsin K. Among them, the reduced expression of DC-STAMP was the most prominent. However, this downregulation of DC-STAMP expression following letrozole treatment was not related to the inhibition of major osteoclastogenesis pathways, such as the nuclear factor-κB (NF-κB), c-Fos, and nuclear factor of activated T cell c1 (NFATc1) pathways, but was attributed to the inhibition of p38, which is known to reside upstream of DC-STAMP expression. Notably, the anti-osteoclastogenic effect of letrozole was abolished following treatment with the p38 activator anisomycin. Contrary to our expectations, these results strongly suggest a previously unknown anti-osteoclastogenic activity of letrozole, mediated by the downregulation of the p38/DC-STAMP pathway.

scholarly journals Osteoprotegerin Expressed by Osteoclasts

2014 ◽  
Vol 93 (11) ◽  
pp. 1116-1123 ◽  
Author(s):  
J.H. Kang ◽  
H.M. Ko ◽  
J.S. Moon ◽  
H.I. Yoo ◽  
J.Y. Jung ◽  
...  
Keyword(s):  
Late Phase ◽  
Nuclear Factor Κb ◽  
Tunel Staining ◽  
Tartrate Resistant Acid Phosphatase ◽  
Mouse Bone Marrow ◽  
Nuclear Factor ◽  
Chromosomal Dna ◽  
Receptor Activator ◽  
Bone Resorbing Activity

Osteoprotegerin (OPG) is secreted by stromal and osteoblastic lineage cells and inhibits osteoclastogenesis by preventing the interaction of receptor activator of nuclear factor-κB ligand (RANKL) with receptor activator of nuclear factor-κB (RANK). In this study, the expression of OPG in osteoclasts themselves and its biological functions during osteoclastogenesis were investigated for the first time. OPG expression in vivo in the developing rat maxilla was examined by immunofluorescence analysis. OPG expression in osteoclasts during in vitro osteoclastogenesis was determined by reverse-transcription polymerase chain-reaction (RT-PCR), Western blot, and immunofluorescence staining. We determined the function of OPG produced by osteoclasts during osteoclastogenesis by silencing the OPG gene. The effects of OPG on bone-resorbing activity and apoptosis of mature osteoclasts were examined by the assay of resorptive pit formation on calcium-phosphate-coated plate and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, respectively. In the immunofluorescence findings, strong immunoreactivities were unexpectedly seen in multinucleated tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts around the growing and erupting tooth germs in the rat alveolar bone. In vitro, OPG expression was significantly increased during the differentiation of osteoclasts from mouse bone-marrow-derived cells treated with a combination of macrophage colony-stimulating factor (M-CSF) and RANKL. Interestingly, it was found that OPG small interfering (si)RNA treatment during osteoclastogenesis enhanced the sizes of osteoclasts, but attenuated their bone-resorbing activity. Also, the increased chromosomal DNA fragmentation and caspase-3 activity in the late phase of osteoclastogenesis were found to be decreased by treatment with OPG siRNA. Furthermore, effects of OPG siRNA treatment on osteoclastogenesis and bone-resorbing activity were recovered by the treatment of exogenous OPG. These results suggest that OPG, expressed by the osteoclasts themselves, may play an auto-regulatory role in the late phase of osteoclastogenesis through the induction of apoptosis.

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.

Cells in regenerating deer antler cartilage provide a microenvironment that supports osteoclast differentiation

2001 ◽  
Vol 204 (3) ◽  
pp. 443-455
Author(s):  
C. Faucheux ◽  
S. Nesbitt ◽  
M. Horton ◽  
J. Price
Keyword(s):  
Type I Collagen ◽  
Mononuclear Cells ◽  
Osteoclast Differentiation ◽  
Cathepsin K ◽  
Collagen Matrix ◽  
Tartrate Resistant Acid Phosphatase ◽  
Type I ◽  
Deer Antler

Deer antlers are a rare example of mammalian epimorphic regeneration. Each year, the antlers re-grow by a modified endochondral ossification process that involves extensive remodelling of cartilage by osteoclasts. This study identified regenerating antler cartilage as a site of osteoclastogenesis in vivo. An in vitro model was then developed to study antler osteoclast differentiation. Cultured as a high-density micromass, cells from non-mineralised cartilage supported the differentiation of large numbers of osteoclast-like multinucleated cells (MNCs) in the absence of factors normally required for osteoclastogenesis. After 48 h of culture, tartrate-resistant acid phosphatase (TRAP)-positive mononuclear cells (osteoclast precursors) were visible, and by day 14 a large number of TRAP-positive MNCs had formed (783+/−200 per well, mean +/− s.e.m., N=4). Reverse transcriptase/polymerase chain reaction (RT-PCR) showed that receptor activator of NF κ B ligand (RANKL) and macrophage colony stimulating factor (M-CSF) mRNAs were expressed in micromass cultures. Antler MNCs have the phenotype of osteoclasts from mammalian bone; they expressed TRAP, vitronectin and calcitonin receptors and, when cultured on dentine, formed F-actin rings and large resorption pits. When cultured on glass, antler MNCs appeared to digest the matrix of the micromass and endocytose type I collagen. Matrix metalloproteinase-9 (MMP-9) may play a role in the resorption of this non-mineralised matrix since it is highly expressed in 100 % of MNCs. In contrast, cathepsin K, another enzyme expressed in osteoclasts from bone, is only highly expressed in resorbing MNCs cultured on dentine. This study identifies the deer antler as a valuable model that can be used to study the differentiation and function of osteoclasts in adult regenerating mineralised tissues.

An adherent condition is required for formation of multinuclear osteoclasts in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor κB ligand

Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4335-4343 ◽  
Author(s):  
Takeshi Miyamoto ◽  
Fumio Arai ◽  
Osamu Ohneda ◽  
Katsumasa Takagi ◽  
Dirk M. Anderson ◽  
...  
Keyword(s):  
Culture Medium ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Precursor Cells ◽  
Osteoclast Precursor ◽  
Nuclear Factor ◽  
Receptor Activator ◽  
Multinuclear Cells ◽  
Differentiation And Proliferation

Abstract Identification of receptor activator of nuclear factor-κB (RANK) and RANK-ligand (RANKL) has provided new insights into the osteoclast differentiation pathway. Osteoclast precursor cells were isolated using monoclonal antibodies against c-Fms and RANK, and the effect of adherence on the in vitro differentiation and proliferation of these cells was examined in 2 different types of stromal-cell–free culture systems: a semisolid culture medium (a nonadherent system) and a liquid culture medium (an adherent system). Osteoclast precursor cells were not able to differentiate into mature osteoclasts efficiently in the semisolid culture system. Trimerized RANKL enhanced osteoclast differentiation in semisolid cultures, but not to the extent seen when cells were allowed to adhere to plastic. Initial precursor cells were capable of differentiating into macrophages or osteoclasts. Once these cells were transferred to adherent conditions, striking differentiation was induced. Multinuclear cells were observed even after they had displayed phagocytic activity, which suggests that cell adhesion plays an important role in the differentiation of osteoclast precursor cells. Integrins, especially the arginine-glycine-aspartic acid (RGD)–recognizing integrins αv and β3, were needed for osteoclast-committed precursor cells to proliferate in order to form multinuclear osteoclasts, and the increase in cell density affected the formation of multinuclear cells. A model of osteoclast differentiation with 2 stages of precursor development is proposed: (1) a first stage, in which precursor cells are bipotential and capable of anchorage-independent growth, and (2) a second stage, in which the further proliferation and differentiation of osteoclast-committed precursor cells is anchorage-dependent.

scholarly journals Increased Osteoclast Activity in the Presence of Increased Homocysteine Concentrations

2005 ◽  
Vol 51 (12) ◽  
pp. 2348-2353 ◽  
Author(s):  
Markus Herrmann ◽  
Thomas Widmann ◽  
Graziana Colaianni ◽  
Silvia Colucci ◽  
Alberta Zallone ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Osteoporotic Fractures ◽  
Nuclear Factor Κb ◽  
Tartrate Resistant Acid Phosphatase ◽  
Peripheral Blood Mononuclear ◽  
Therapeutic Implications ◽  
Trap Activity ◽  
K Activity

Abstract Background: Increased plasma homocysteine (HCY) may be an independent risk factor for osteoporotic fractures and therefore may also adversely affect bone metabolism. We analyzed the effect of HCY on human osteoclast (OC) activity. Methods: We cultured peripheral blood mononuclear cells from 17 healthy male donors [median (SD) age, 30 (5) years] for 20 days with 25 μg/L macrophage-colony-stimulating factor (days 0–11), 20 μg/L receptor-activator of nuclear factor-κB ligand (days 6–20), and 4 different concentrations of HCY (0, 10, 50, and 100 μmol/L; days 0–20). For control purposes, cysteine and glutathione were tested in equimolar concentrations. OCs were identified as large, multinucleated cells with tartrate-resistant acid phosphatase (TRAP) activity and surface vitronectin receptors. We quantified OC activity by measuring TRAP activity. We analyzed cathepsin K (CP-K) activity in 9 donor samples and estimated the dentine-resorbing activity on standard dentine slices in 3 samples. Results: After 20 days of culture, most cells were fully differentiated OCs. TRAP activity increased with increasing HCY concentrations (P <0.001). HCY concentrations of 10, 50, and 100 μmol/L stimulated TRAP activity by 20%, 15%, and 42%. Additionally, HCY stimulated CP-K activity (P = 0.005): in the presence of 100 μmol/L HCY, CP-K activity was ∼38% higher than in controls (P = 0.002). Bone-resorbing activity was significantly increased in cultures with 50 and 100 μmol/L HCY. Cysteine and glutathione significantly decreased TRAP and CP-K activity. Conclusions: Increased HCY concentrations specifically stimulate OC activity in vitro, suggesting a mechanistic role of HCY for bone resorption. Future studies clarifying the mechanistic role of increased HCY concentrations in osteoporosis could have interesting therapeutic implications.

scholarly journals Interleukin-6 Inhibits Receptor Activator of Nuclear Factor κB Ligand-Induced Osteoclastogenesis by Diverting Cells into the Macrophage Lineage: Key Role of Serine727 Phosphorylation of Signal Transducer and Activator of Transcription 3

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3688-3697 ◽  
Author(s):  
Laurence Duplomb ◽  
Marc Baud’huin ◽  
Céline Charrier ◽  
Martine Berreur ◽  
Valérie Trichet ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Mouse Bone Marrow ◽  
Nuclear Factor ◽  
Signal Transducer ◽  
Blood Monocytes ◽  
Receptor Activator ◽  
Few Data ◽  
Macrophage Lineage

Osteoclasts are bone-resorptive cells that differentiate from hematopoietic precursors upon receptor activator of nuclear factor κB ligand (RANKL) activation. Previous studies demonstrated that IL-6 indirectly stimulates osteoclastogenesis through the production of RANKL by osteoblasts. However, few data described the direct effect of IL-6 on osteoclasts. To investigate this effect, we used several models: murine RAW264.7 cells, mouse bone marrow, and human blood monocytes. In the three models used, the addition of IL-6 inhibited RANKL-induced osteoclastogenesis. Furthermore, IL-6 decreased the expression of osteoclast markers and up-modulated macrophage markers. To elucidate this inhibition, signal transducer and activator of transcription (STAT) 3, the main signaling molecule activated by IL-6, was analyzed. Addition of two STAT3 inhibitors completely abolished RANKL-induced osteoclastogenesis, revealing a key role of STAT3. We demonstrated that a basal level of phosphorylated-STAT3 on Serine727 associated with an absence of phosphorylation on Tyrosine705 is essential for osteoclastogenesis. Furthermore, a decrease of Serine727 phosphorylation led to an inhibition of osteoclast differentiation, whereas an increase of Tyrosine705 phosphorylation upon IL-6 stimulation led to the formation of macrophages instead of osteoclasts. In conclusion, we showed for the first time that IL-6 inhibits RANKL-induced osteoclastogenesis by diverting cells into the macrophage lineage, and demonstrated the functional role of activated-STAT3 and its form of phosphorylation in the control of osteoclastogenesis.

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