scholarly journals β2-Adrenergic Receptor Signaling in Osteoblasts Contributes to the Catabolic Effect of Glucocorticoids on Bone

Endocrinology ◽  
2011 ◽  
Vol 152 (4) ◽  
pp. 1412-1422 ◽  
Author(s):  
Yun Ma ◽  
Jeffry S. Nyman ◽  
Huan Tao ◽  
Heather H. Moss ◽  
Xiangli Yang ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Cells ◽  
Sympathetic Nerves ◽  
Bone Diseases ◽  
Autonomic Nerves ◽  
High Dose ◽  
Bone Homeostasis ◽  
Adrenergic Stimulation

Abstract The sympathetic nervous system is a physiological regulator of bone homeostasis. Autonomic nerves are indeed present in bone, bone cells express the β2-adrenergic receptors (β2AR), and pharmacological or genetic disruption of sympathetic outflow to bone induces bone gain in rodents. These recent findings implied that conditions that affect β2AR signaling in osteoblasts and/or sympathetic drive to bone may contribute to bone diseases. In this study, we show that dexamethasone stimulates the expression of the β2AR in differentiated primary calvarial osteoblasts, as measured by an increase in Adrβ2 mRNA and β2AR protein level after short-term dexamethasone treatment. Isoproterenol-induced cAMP accumulation and the expression of the β2AR target gene Rankl were also significantly increased after dexamethasone pretreatment, indicating that dexamethasone promotes the responsiveness of differentiated osteoblasts to adrenergic stimulation. These in vitro results led to the hypothesis that glucocorticoid-induced bone loss, provoked by increased endogenous or high-dose exogenous glucocorticoids given for the treatment of inflammatory diseases, might, at least in part, be mediated by increased sensitivity of bone-forming cells to the tonic inhibitory effect of sympathetic nerves on bone formation or their stimulatory effect on bone resorption. Supporting this hypothesis, both pharmacological and genetic β2AR blockade in mice significantly reduced the bone catabolic effect of high-dose prednisolone in vivo. This study emphasizes the importance of sympathetic nerves in the regulation of bone homeostasis and indicates that this neuroskeletal signaling axis can be modulated by hormones or drugs and contribute to enhance pathological bone loss.

scholarly journals Transcriptional Modulator Ifrd1 Regulates Osteoclast Differentiation through Enhancing the NF-κB/NFATc1 Pathway

2016 ◽  
Vol 36 (19) ◽  
pp. 2451-2463 ◽  
Author(s):  
Takashi Iezaki ◽  
Kazuya Fukasawa ◽  
Gyujin Park ◽  
Tetsuhiro Horie ◽  
Takashi Kanayama ◽  
...  
Keyword(s):  
Bone Loss ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Bone Diseases ◽  
Nuclear Factor ◽  
Activator Protein 1 ◽  
Bone Homeostasis ◽  
Activated T Cells

Bone homeostasis is maintained by the synergistic actions of bone-resorbing osteoclasts and bone-forming osteoblasts. Here, we show that the transcriptional coactivator/repressor interferon-related developmental regulator 1 (Ifrd1) is expressed in osteoclast lineages and represents a component of the machinery that regulates bone homeostasis. Ifrd1 expression was transcriptionally regulated in preosteoclasts by receptor activator of nuclear factor κB (NF-κB) ligand (RANKL) through activator protein 1. Global deletion of murineIfrd1increased bone formation and decreased bone resorption, leading to a higher bone mass. Deletion ofIfrd1in osteoclast precursors prevented RANKL-induced bone loss, although no bone loss was observed under normal physiological conditions. RANKL-dependent osteoclastogenesis was impairedin vitroinIfrd1-deleted bone marrow macrophages (BMMs).Ifrd1deficiency increased the acetylation of p65 at residues K122 and K123 via the inhibition of histone deacetylase-dependent deacetylation in BMMs. This repressed the NF-κB-dependent transcription of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), an essential regulator of osteoclastogenesis. These findings suggest that an Ifrd1/NF-κB/NFATc1 axis plays a pivotal role in bone remodelingin vivoand represents a therapeutic target for bone diseases.

Lactoferrin in Bone Tissue Regeneration

2020 ◽  
Vol 27 (6) ◽  
pp. 838-853 ◽  
Author(s):  
Madalina Icriverzi ◽  
Valentina Dinca ◽  
Magdalena Moisei ◽  
Robert W. Evans ◽  
Mihaela Trif ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Tissue Regeneration ◽  
Bone Cells ◽  
Bone Diseases ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Bone Tissue Regeneration ◽  
Bone Homeostasis ◽  
Active Compounds

: Among the multiple properties exhibited by lactoferrin (Lf), its involvement in bone regeneration processes is of great interest at the present time. A series of in vitro and in vivo studies have revealed the ability of Lf to promote survival, proliferation and differentiation of osteoblast cells and to inhibit bone resorption mediated by osteoclasts. Although the mechanism underlying the action of Lf in bone cells is still not fully elucidated, it has been shown that its mode of action leading to the survival of osteoblasts is complemented by its mitogenic effect. Activation of several signalling pathways and gene expression, in an LRPdependent or independent manner, has been identified. Unlike the effects on osteoblasts, the action on osteoclasts is different, with Lf leading to a total arrest of osteoclastogenesis. : Due to the positive effect of Lf on osteoblasts, the potential use of Lf alone or in combination with different biologically active compounds in bone tissue regeneration and the treatment of bone diseases is of great interest. Since the bioavailability of Lf in vivo is poor, a nanotechnology- based strategy to improve the biological properties of Lf was developed. The investigated formulations include incorporation of Lf into collagen membranes, gelatin hydrogel, liposomes, loading onto nanofibers, porous microspheres, or coating onto silica/titan based implants. Lf has also been coupled with other biologically active compounds such as biomimetic hydroxyapatite, in order to improve the efficacy of biomaterials used in the regulation of bone homeostasis. : This review aims to provide an up-to-date review of research on the involvement of Lf in bone growth and healing and on its use as a potential therapeutic factor in bone tissue regeneration.

β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

2014 ◽  
Vol 112 (11) ◽  
pp. 951-959 ◽  
Author(s):  
Morten Eriksen ◽  
Arnfinn Ilebekk ◽  
Alessandro Cataliotti ◽  
Cathrine Rein Carlson ◽  
Torstein Lyberg ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Sympathetic Nerves ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Β2 Adrenergic Receptor ◽  
Β Blocker

SummaryBradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and nonstimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

scholarly journals Protocol of Co-Culture of Human Osteoblasts and Osteoclasts to Test Biomaterials for Bone Tissue Engineering

2022 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Giorgia Borciani ◽  
Giorgia Montalbano ◽  
Nicola Baldini ◽  
Chiara Vitale-Brovarone ◽  
Gabriela Ciapetti
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Bone Cells ◽  
Bone Cell ◽  
Seeding Density ◽  
Bone Homeostasis ◽  
Bone Microenvironment

New biomaterials and scaffolds for bone tissue engineering (BTE) applications require to be tested in a bone microenvironment reliable model. On this assumption, the in vitro laboratory protocols with bone cells represent worthy experimental systems improving our knowledge about bone homeostasis, reducing the costs of experimentation. To this day, several models of the bone microenvironment are reported in the literature, but few delineate a protocol for testing new biomaterials using bone cells. Herein we propose a clear protocol to set up an indirect co-culture system of human-derived osteoblasts and osteoclast precursors, providing well-defined criteria such as the cell seeding density, cell:cell ratio, the culture medium, and the proofs of differentiation. The material to be tested may be easily introduced in the system and the cell response analyzed. The physical separation of osteoblasts and osteoclasts allows distinguishing the effects of the material onto the two cell types and to evaluate the correlation between material and cell behavior, cell morphology, and adhesion. The whole protocol requires about 4 to 6 weeks with an intermediate level of expertise. The system is an in vitro model of the bone remodeling system useful in testing innovative materials for bone regeneration, and potentially exploitable in different application fields. The use of human primary cells represents a close replica of the bone cell cooperation in vivo and may be employed as a feasible system to test materials and scaffolds for bone substitution and regeneration.

scholarly journals Fucoidan Prevents RANKL-Stimulated Osteoclastogenesis and LPS-Induced Inflammatory Bone Loss via Regulation of Akt/GSK3β/PTEN/NFATc1 Signaling Pathway and Calcineurin Activity

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 345 ◽  
Author(s):  
Sheng-Hua Lu ◽  
Yi-Jan Hsia ◽  
Kuang-Chung Shih ◽  
Tz-Chong Chou
Keyword(s):  
Bone Loss ◽  
Molecular Mechanisms ◽  
Bone Erosion ◽  
Osteoclast Differentiation ◽  
Bone Diseases ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Calcineurin Activity

Excessive osteoclast differentiation and/or function plays a pivotal role in the pathogenesis of bone diseases such as osteoporosis and rheumatoid arthritis. Here, we examined whether fucoidan, a sulfated polysaccharide present in brown algae, attenuates receptor activator of nuclear factor-κB ligand (RANKL)-stimulated osteoclastogenesis in vitro and lipopolysaccharide (LPS)-induced bone resorption in vivo, and investigated the molecular mechanisms involved. Our results indicated that fucoidan significantly inhibited osteoclast differentiation in RANKL-stimulated macrophages and the bone resorbing activity of osteoclasts. The effects of fucoidan may be mediated by regulation of Akt/GSK3β/PTEN signaling and suppression of the increase in intracellular Ca2+ level and calcineurin activity, thereby inhibiting the translocation of nuclear factor-activated T cells c1 (NFATc1) into the nucleus. However, fucoidan-mediated NFATc1 inactivation was greatly reversed by kenpaullone, a GSK3β inhibitor. In addition, using microcomputer tomography (micro-CT) scanning and bone histomorphometry, we found that fucoidan treatment markedly prevented LPS-induced bone erosion in mice. Collectively, we demonstrated that fucoidan was capable of inhibiting osteoclast differentiation and inflammatory bone loss, which may be modulated by regulation of Akt/GSK3β/PTEN/NFATc1 and Ca2+/calcineurin signaling cascades. These findings suggest that fucoidan may be a potential agent for the treatment of osteoclast-related bone diseases.

scholarly journals Anti-Osteoporosis Effects of the Eleutherococcus senticosus, Achyranthes japonica, and Atractylodes japonica Mixed Extract Fermented with Nuruk

Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 3904
Author(s):  
So Young Eun ◽  
Yoon-Hee Cheon ◽  
Gyeong Do Park ◽  
Chong Hyuk Chung ◽  
Chang Hoon Lee ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Diseases ◽  
Marker Genes ◽  
Tartrate Resistant Acid Phosphatase ◽  
Specific Marker ◽  
Eleutherococcus Senticosus ◽  
Achyranthes Japonica ◽  
Atractylodes Japonica

Vigeo is a mixture of fermented extracts of Eleutherococcus senticosus Maxim (ESM), Achyranthes japonica (Miq.) Nakai (AJN), and Atractylodes japonica Koidzumi (AJK) manufactured using the traditional Korean nuruk fermentation method. Although the bioactive effects of ESM, AJN, and AJK have already been reported, the pharmacological effects of Vigeo have not been proven. Therefore, in this study, we investigated whether Vigeo had inhivitory effects on lipopolysaccharide (LPS)-induced inflammatory bone loss in vivo and receptor activator of nuclear factor-B ligand (RANKL)-induced osteoclastogenesis and the related mechanism in vitro. Vigeo administration conferred effective protection against bone loss induced by excessive inflammatory response and activity of osteoclasts in LPS-induced inflammatory osteoporosis mouse model. In addition, Vigeo significantly suppressed the formation of tartrate-resistant acid phosphatase-positive osteoclasts induced by RANKL and inhibited F-actin formation and bone resorbing activity without any cytotoxicity. Moreover, Vigeo significantly inhibited RANKL-induced phosphorylation of p38, ERK, JNK, IκB, and AKT and degradation of IkB. Additionally, Vigeo strongly inhibited the mRNA and protein expression of c-FOS and NFATc1 and subsequently attenuated the expression of osteoclast specific marker genes induced by RANKL. We demonstrated for the first time the anti-osteoporosis effect of Vigeo, suggesting that it could be a potential therapeutic candidate for the treatment of osteoclast-mediated inflammatory bone diseases.

scholarly journals The Influence of Radiation on Bone and Bone Cells—Differential Effects on Osteoclasts and Osteoblasts

2020 ◽  
Vol 21 (17) ◽  
pp. 6377
Author(s):  
Anna-Jasmina Donaubauer ◽  
Lisa Deloch ◽  
Ina Becker ◽  
Rainer Fietkau ◽  
Benjamin Frey ◽  
...  
Keyword(s):  
Bone Remodeling ◽  
Bone Cells ◽  
Positive Impact ◽  
Inflammatory Diseases ◽  
Future Research ◽  
Special Focus ◽  
Bone Homeostasis ◽  
Bone Microenvironment

The bone is a complex organ that is dependent on a tight regulation between bone formation by osteoblasts (OBs) and bone resorption by osteoclasts (OCs). These processes can be influenced by environmental factors such as ionizing radiation (IR). In cancer therapy, IR is applied in high doses, leading to detrimental effects on bone, whereas radiation therapy with low doses of IR is applied for chronic degenerative and inflammatory diseases, with a positive impact especially on bone homeostasis. Moreover, the effects of IR are of particular interest in space travel, as astronauts suffer from bone loss due to space radiation and microgravity. This review summarizes the current state of knowledge on the effects of IR on bone with a special focus on the influence on OCs and OBs, as these cells are essential in bone remodeling. In addition, the influence of IR on the bone microenvironment is discussed. In summary, the effects of IR on bone and bone remodeling cells strongly depend on the applied radiation dose, as differential results are provided from in vivo as well as in vitro studies with varying doses of IR. Furthermore, the isolated effects of IR on a single cell type are difficult to determine, as the bone cells and bone microenvironment are building a tightly regulated network, influencing on one another. Therefore, future research is necessary in order to elucidate the influence of different bone cells on the overall radiation-induced effects on bone.

scholarly journals ELMO1 Regulates RANKL-Stimulated Differentiation and Bone Resorption of Osteoclasts

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinyue Liang ◽  
Yafei Hou ◽  
Lijuan Han ◽  
Shuxiang Yu ◽  
Yunyun Zhang ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Bone Resorption ◽  
Bone Erosion ◽  
Osteoclast Differentiation ◽  
Small Gtpases ◽  
Bone Diseases ◽  
Bone Homeostasis ◽  
Nucleotide Exchange

Bone homeostasis is a metabolic balance between the new bone formation by osteoblasts and old bone resorption by osteoclasts. Excessive osteoclastic bone resorption results in low bone mass, which is the major cause of bone diseases such as rheumatoid arthritis. Small GTPases Rac1 is a key regulator of osteoclast differentiation, but its exact mechanism is not fully understood. ELMO and DOCK proteins form complexes that function as guanine nucleotide exchange factors for Rac activation. Here, we report that ELMO1 plays an important role in differentiation and bone resorption of osteoclasts. Osteoclast precursors derived from bone marrow monocytes (BMMs) of Elmo1–/– mice display defective adhesion and migration during differentiation. The cells also have a reduced activation of Rac1, p38, JNK, and AKT in response to RANKL stimulation. Importantly, we show that bone erosion is alleviated in Elmo1–/– mice in a rheumatoid arthritis mouse model. Taken together, our results suggest that ELMO1, as a regulator of Rac1, regulates osteoclast differentiation and bone resorption both in vitro and in vivo.

scholarly journals Shikimic Acid Inhibits Osteoclastogenesis in Vivo and in Vitro by Blocking RANK/TRAF6 Association and Suppressing NF-κB and MAPK Signaling Pathways

2018 ◽  
Vol 51 (6) ◽  
pp. 2858-2871 ◽  
Author(s):  
Xiao Chen ◽  
Xiaoqun Li ◽  
Xiao Zhai ◽  
Xin Zhi ◽  
Liehu Cao ◽  
...  
Keyword(s):  
Bone Loss ◽  
Signaling Pathways ◽  
Shikimic Acid ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Bone Homeostasis ◽  
Actin Ring ◽  
Ovariectomized Mice

Background/Aims: Bone homeostasis is associated with the balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Unbalanced bone homeostasis as a result of reduced osteogenesis or excessive osteoclastogenesis can lead to disorders such as osteoporosis, Paget’s disease, and rheumatoid arthritis. Shikimic acid is a cyclohexanecarboxylic acid, reported to exhibit pharmacological properties including anti-inflammatory and antioxidant activities. However, its effects on bone homeostasis remain unknown. Methods: First, the in vitro MTT cell viability assay was performed. Tartrate-resistant acid phosphatase (TRAP) and actin ring formation assays, as well as immunofluorescence staining were then performed to evaluate osteoclastogenesis. Potential signaling pathways were characterized by western blotting and verified in overexpression experiments. Related factors were examined by western blotting, reverse transcription polymerase chain reaction, electrophoretic mobility shift assay, and co-immunoprecipitation. Ovariectomized mice were used for the in vivo study. Results: TRAP staining showed that shikimic acid significantly inhibited osteoclastogenesis and pit resorption in bone marrow monocytes and RAW264.7 cells, and actin ring formation assays showed that shikimic acid suppressed the bone resorption function of osteoclasts. Furthermore, shikimic acid inhibited the receptor activator of nuclear factor-κB RANK/tumor necrosis factor receptor-associated factor 6 (TRAF6) association, suppressed nuclear factor-κB and mitogen-activated protein kinase signaling pathways, and downregulated nuclear factor of activated T-cell cytoplasmic 1. The expression of osteoclastogenesis biomarkers, including TRAF6, calcitonin receptor, TRAP, cathepsin K, and matrix metalloproteinase-9, was inhibited. In vivo, shikimic acid also significantly ameliorated bone loss and prevented osteoclastogenesis in ovariectomized mice. Conclusion: Shikimic acid inhibited osteoclastogenesis and osteoclast function by blocking RANK ligand-induced recruitment of TRAF6, as well as downstream signaling pathways in vitro. Shikimic acid also reduced ovariectomy-induced osteoclastogenesis and bone loss in vivo.

Berberine Suppresses RANKL-Induced Osteoclast Differentiation by Inhibiting c-Fos and NFATc1 Expression

2019 ◽  
Vol 47 (02) ◽  
pp. 439-455 ◽  
Author(s):  
Sang-Yong Han ◽  
Yun-Kyung Kim
Keyword(s):  
Bone Loss ◽  
Osteoclast Differentiation ◽  
Osteoclast Formation ◽  
Bone Diseases ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Murine Bone Marrow

Osteoporosis is a common disorder of bone remodeling, marked by excessive osteoclast formation. Recent studies indicated that berberine (BBR) is a potential natural drug for the treatment of various bone diseases. However, it still needs to be further studied for the treatment of osteoporosis. The current study investigated the inhibitory effects of BBR on receptor activator of nuclear factor-[Formula: see text]B ligand (RANKL)-induced osteoclast differentiation in vitro and in vivo. Cell-based assays were performed using osteoclasts generated in cultures of murine bone marrow-derived macrophages (BMMs) treated with RANKL and M-CSF. The effects of BBR on in vivo lipopolysaccharide (LPS)-mediated bone loss were evaluated using ICR mice. BBR significantly inhibited TRAP-positive osteoclast formation induced by RANKL. BBR also inhibited RANKL-induced Akt, p38 and ERK phosphorylation and I[Formula: see text]B degradation, and suppressed RANKL-induced expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1), which is a key transcription factors for osteoclast formation. BBR reduced the mRNA levels of osteoclast markers, including TRAP, osteoclast-associated receptor (OSCAR), cathepsin K, and ATPase H[Formula: see text] transporting V0 subunit d2 (ATP6v0d2). Moreover, BBR prevented LPS-mediated bone loss in vivo. We suggest BBR as a natural compound that can be a potential therapeutic agent for osteoclast-related bone diseases.

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