Decitabine Inhibits Bone Resorption in Periodontitis by Upregulating Anti-Inflammatory Cytokines and Suppressing Osteoclastogenesis

DNA methylation controls several inflammatory genes affecting bone homeostasis. Hitherto, inhibition of DNA methylation in vivo in the context of periodontitis and osteoclastogenesis has not been attempted. Ligature-induced periodontitis in C57BL/6J mice was induced by placing ligature for five days with Decitabine (5-aza-2′-deoxycytidine) (1 mg/kg/day) or vehicle treatment. We evaluated bone resorption, osteoclast differentiation by tartrate-resistant acid phosphatase (TRAP) and mRNA expression of anti-inflammatory molecules using cluster differentiation 14 positive (CD14+) monocytes from human peripheral blood. Our data showed that decitabine inhibited bone loss and osteoclast differentiation experimental periodontitis, and suppressed osteoclast CD14+ human monocytes; and conversely, that it increased bone mineralization in osteoblastic cell line MC3T3-E1 in a concentration-dependent manner. In addition to increasing IL10 (interleukin-10), TGFB (transforming growth factor beta-1) in CD14+ monocytes, decitabine upregulated KLF2 (Krüppel-like factor-2) expression. Overexpression of KLF2 protein enhanced the transcription of IL10 and TGFB. On the contrary, site-directed mutagenesis of KLF2 binding site in IL10 and TFGB abrogated luciferase activity in HEK293T cells. Decitabine reduces bone loss in a mouse model of periodontitis by inhibiting osteoclastogenesis through the upregulation of anti-inflammatory cytokines via KLF2 dependent mechanisms. DNA methyltransferase inhibitors merit further investigation as a possible novel therapy for periodontitis.

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N-[2-(4-Acetyl-1-Piperazinyl)Phenyl]-2-(3-Methylphenoxy)Acetamide (NAPMA) Inhibits Osteoclast Differentiation and Protects against Ovariectomy-Induced Osteoporosis

Molecules ◽

10.3390/molecules25204855 ◽

2020 ◽

Vol 25 (20) ◽

pp. 4855

Author(s):

Jinkyung Lee ◽

Sun-Hee Ahn ◽

Zhihao Chen ◽

Sohi Kang ◽

Dong Kyu Choi ◽

...

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Osteoclast Differentiation ◽

Cathepsin K ◽

Bone Diseases ◽

Drug Candidate ◽

Tartrate Resistant Acid Phosphatase ◽

Dependent Manner ◽

Osteoclast Activity ◽

Protein Levels

Osteoclasts are large, multinucleated cells responsible for bone resorption and are induced in response to the regulatory activity of receptor activator of nuclear factor-kappa B ligand (RANKL). Excessive osteoclast activity causes pathological bone loss and destruction. Many studies have investigated molecules that specifically inhibit osteoclast activity by blocking RANKL signaling or bone resorption. In recent years, we screened compounds from commercial libraries to identify molecules capable of inhibiting RANKL-induced osteoclast differentiation. Consequently, we reported some compounds that are effective at attenuating osteoclast activity. In this study, we found that N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(3-methylphenoxy)acetamide (NAPMA) significantly inhibited the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells from bone marrow-derived macrophages in a dose-dependent manner, without cytotoxic effects. NAPMA downregulated the expression of osteoclast-specific markers, such as c-Fos, NFATc1, DC-STAMP, cathepsin K, and MMP-9, at the transcript and protein levels. Accordingly, bone resorption and actin ring formation were decreased in response to NAPMA treatment. Furthermore, we demonstrated the protective effect of NAPMA against ovariectomy-induced bone loss using micro-CT and histological analysis. Collectively, the results showed that NAPMA inhibited osteoclast differentiation and attenuated bone resorption. It is thus a potential drug candidate for the treatment of osteoporosis and other bone diseases associated with excessive bone resorption.

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Orostachys japonicus Suppresses Osteoclast Differentiation by Inhibiting NFATc1 Expression

The American Journal of Chinese Medicine ◽

10.1142/s0192415x15500585 ◽

2015 ◽

Vol 43 (05) ◽

pp. 1013-1030 ◽

Cited By ~ 2

Author(s):

Ki-Shuk Shim ◽

Hyunil Ha ◽

Taesoo Kim ◽

Chung-Jo Lee ◽

Jin Yeul Ma

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Therapeutic Potential ◽

Osteoclast Differentiation ◽

Water Extract ◽

Bone Diseases ◽

Tartrate Resistant Acid Phosphatase ◽

Dependent Manner ◽

Nuclear Factor ◽

Activated T Cells

The herb Orostachys japonicus has been traditionally used to treat chronic diseases, such as hepatitis, hemorrhoids, and cancer, in Asia. In this study, we investigated the effect of Orostachys japonicus water extract (OJWE) on the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and bone loss. We found that OJWE inhibited RANKL-induced osteoclast differentiation in a dose-dependent manner without affecting bone resorption in bone marrow-derived macrophage cells. Interestingly, OJWE significantly reduced serum levels of C-terminal telopeptide of type 1 collagen and tartrate-resistant acid phosphatase (TRAP) 5b, markers of bone resorption and osteoclast number, respectively, in an animal model of bone loss. Furthermore, OJWE suppressed the RANKL-induced up-regulation of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) expression, and activation of the p38 signaling pathway, but prevented the RANKL-mediated down-regulation of interferon regulatory factor-8 (IRF-8), which is known to be an anti-osteoclastogenic factor that represses NFATc1 expression. We also identified gallic acid and quercetin-3-O-β-D-glucoside as the OJWE components that inhibit RANKL-induced osteoclast differentiation. These results suggest that OJWE inhibits osteoclast differentiation by inhibiting RANKL-induced NFATc1 expression, which prevents osteoclast differentiation and bone loss. The present study elucidated a mechanism of action underlying the inhibitory effect of OJWE on osteoclast differentiation. Our findings suggest that O. japonicus has therapeutic potential for use in the treatment of bone diseases.

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Constitutive Activation of β-Catenin in Differentiated Osteoclasts Induces Bone Loss in Mice

Cellular Physiology and Biochemistry ◽

10.1159/000492549 ◽

2018 ◽

Vol 48 (5) ◽

pp. 2091-2102 ◽

Cited By ~ 3

Author(s):

Xin Sui ◽

Shijian Deng ◽

Mengmeng Liu ◽

Linlin Fan ◽

Yunfei Wang ◽

...

Keyword(s):

Bone Loss ◽

Bone Mass ◽

Bone Growth ◽

Osteoclast Differentiation ◽

Marker Genes ◽

Tartrate Resistant Acid Phosphatase ◽

Bone Homeostasis ◽

Micro Computed Tomography ◽

Constitutive Activation

Background/Aims: Activation of the Wnt/β-catenin signalling pathway has been widely investigated in bone biology and shown to promote bone formation. However, its specific effects on osteoclast differentiation have not been fully elucidated. Our study aimed to identify the role of β-catenin in osteoclastogenesis and bone homeostasis. Methods: In the present study, exon 3 in the β-catenin gene (Ctnnb1) allele encoding phosphorylation target serine/threonine residues was flanked by floxP sequences. We generated mice exhibiting conditional β-catenin activation (Ctsk-Cre;Ctnnb1flox(exon3)/+, designated CA-β-catenin) by crossing Ctnnb1flox(exon3)/flox(exon3) mice with osteoclast-specific Ctsk-Cre mice. Bone growth and bone mass were analysed by micro-computed tomography (micro-CT) and histomorphometry. To further examine osteoclast activity, osteoclasts were induced from bone marrow monocytes (BMMs) isolated from CA-β-catenin and Control mice in vitro. Osteoclast differentiation was detected by tartrate-resistant acid phosphatase (TRAP) staining, immunofluorescence staining and reverse transcription-quantitative PCR (RT–qPCR) analysis. Results: Growth retardation and low bone mass were observed in CA-β-catenin mice. Compared to controls, CA-β-catenin mice had significantly reduced trabecular bone numbers under growth plates as well as thinner cortical bones. Moreover, increased TRAP-positive osteoclasts were observed on the surfaces of trabecular bones and cortical bones in the CA-β-catenin mice; consistent results were observed in vitro. In the CA-β-catenin group, excessive numbers of osteoclasts were induced from BMMs, accompanied by the increased expression of osteoclast-associated marker genes. Conclusion: These results indicated that the constitutive activation of β-catenin in osteoclasts promotes osteoclast formation, resulting in bone loss.

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The emerging role of IMD 0354 on bone homeostasis by suppressing osteoclastogenesis and bone resorption, but without affecting bone formation

Cell Death and Disease ◽

10.1038/s41419-019-1914-5 ◽

2019 ◽

Vol 10 (9) ◽

Cited By ~ 2

Author(s):

Wenxiang Chen ◽

Ziang Xie ◽

Pan Tang ◽

Yongli Wang ◽

Zhiwei Jie ◽

...

Keyword(s):

Bone Resorption ◽

Bone Formation ◽

Osteoclast Differentiation ◽

Nuclear Factor Κb ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Therapeutic Drug ◽

Tartrate Resistant Acid Phosphatase ◽

Nuclear Factor ◽

Bone Homeostasis

Abstract Osteoporosis is caused by an imbalance between bone formation and bone resorption. Receptor activator of nuclear factor-κB ligand (RANKL) promotes the activity and differentiation of osteoclasts via activating the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. IMD 0354 is a selective molecular inhibitor of inhibitor of NF-κB kinase subunit beta (IKKβ) and effective for treatment of acute and subacute inflammatory diseases through the suppression of NF-κB activation. However, the effect of IMD 0354 on bone homeostasis is unknown. In this study, we demonstrated that IMD 0354 significantly attenuated ovariectomy-induced bone loss and inhibited osteoclastogenesis in mice, whereas bone formation was not affected. Additionally, IMD 0354 dramatically inhibited osteoclast differentiation and function induced by RANKL and macrophage colony-stimulating factor in bone marrow monocytes as verified by tartrate-resistant acid phosphatase (TRAP) staining as well as bone resorption assay in vitro. Subsequently, we found that activation of NF-κB signaling and the ERK/c-Fos axis were blunted during osteoclast formation induced by RANKL. Transcription factors nuclear factor of activated T cells c1 (NFATc1) and c-Fos were suppressed with the decreased expression of osteoclast-related genes by IMD 0354. Our findings suggest that IMD 0354 could be a potential preventive and therapeutic drug for osteoporosis.

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Inhibitory Effects of 2N1HIA (2-(3-(2-Fluoro-4-Methoxyphenyl)-6-Oxo-1(6H)-Pyridazinyl)-N-1H-Indol-5-Ylacetamide) on Osteoclast Differentiation via Suppressing Cathepsin K Expression

Molecules ◽

10.3390/molecules23123139 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3139 ◽

Cited By ~ 6

Author(s):

Sun-Hee Ahn ◽

Zhihao Chen ◽

Jinkyung Lee ◽

Seok-Woo Lee ◽

Sang Min ◽

...

Keyword(s):

Bone Resorption ◽

Osteoclast Differentiation ◽

Cell Formation ◽

Cathepsin K ◽

Bone Diseases ◽

Specific Gene ◽

Tartrate Resistant Acid Phosphatase ◽

Potential Candidate ◽

Dependent Manner ◽

Gene Markers

Osteoclasts are large multinucleated cells which are induced by the regulation of the receptor activator of nuclear factor kappa-Β ligand (RANKL), which is important in bone resorption. Excessive osteoclast differentiation can cause pathologic bone loss and destruction. Numerous studies have targeted molecules inhibiting RANKL signaling or bone resorption activity. In this study, 11 compounds from commercial libraries were examined for their effect on RANKL-induced osteoclast differentiation. Of these compounds, only 2-(3-(2-fluoro-4-methoxyphenyl)-6-oxo-1(6H)-pyridazinyl)-N-1H-indol-5-ylacetamide (2N1HIA) caused a significant decrease in multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cell formation in a dose-dependent manner, without inducing cytotoxicity. The 2N1HIA compound neither affected the expression of osteoclast-specific gene markers such as TRAF6, NFATc1, RANK, OC-STAMP, and DC-STAMP, nor the RANKL signaling pathways, including p38, ERK, JNK, and NF-κB. However, 2N1HIA exhibited a significant impact on the expression levels of CD47 and cathepsin K, the early fusion marker and critical protease for bone resorption, respectively. The activity of matrix metalloprotease-9 (MMP-9) decreased due to 2N1HIA treatment. Accordingly, bone resorption activity and actin ring formation decreased in the presence of 2N1HIA. Taken together, 2N1HIA acts as an inhibitor of osteoclast differentiation by attenuating bone resorption activity and may serve as a potential candidate in preventing and/or treating osteoporosis, or other bone diseases associated with excessive bone resorption.

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Magnolol Ameliorates Ligature-Induced Periodontitis in Rats and Osteoclastogenesis:In VivoandIn VitroStudy

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/634095 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 12

Author(s):

Sheng-Hua Lu ◽

Ren-Yeong Huang ◽

Tz-Chong Chou

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Periodontal Disease ◽

Alveolar Bone ◽

Morphological Changes ◽

Osteoclast Differentiation ◽

Alveolar Bone Loss ◽

Tartrate Resistant Acid Phosphatase ◽

Nuclear Factor ◽

Raw264.7 Macrophages

Periodontal disease characterized by alveolar bone resorption and bacterial pathogen-evoked inflammatory response has been believed to have an important impact on human oral health. The aim of this study was to evaluate whether magnolol, a main constituent ofMagnolia officinalis, could inhibit the pathological features in ligature-induced periodontitis in rats and osteoclastogenesis. The sterile, 3–0 (diameter; 0.2 mm) black braided silk thread, was placed around the cervix of the upper second molars bilaterally and knotted medially to induce periodontitis. The morphological changes around the ligated molars and alveolar bone were examined by micro-CT. The distances between the amelocemental junction and the alveolar crest of the upper second molars bilaterally were measured to evaluate the alveolar bone loss. Administration of magnolol (100 mg/kg, p.o.) significantly inhibited alveolar bone resorption, the number of osteoclasts on bony surface, and protein expression of receptor activator of nuclear factor-κB ligand (RANKL), a key mediator promoting osteoclast differentiation, in ligated rats. Moreover, the ligature-induced neutrophil infiltration, expression of inducible nitric oxide synthase, cyclooxygenase-2, matrix metalloproteinase (MMP)-1 and MMP-9, superoxide formation, and nuclear factor-κB activation in inflamed gingival tissues were all attenuated by magnolol. In thein vitrostudy, magnolol also inhibited the growth ofPorphyromonas gingivalis and Aggregatibacter actinomycetemcomitansthat are key pathogens initiating periodontal disease. Furthermore, magnolol dose dependently reduced RANKL-induced osteoclast differentiation from RAW264.7 macrophages, tartrate-resistant acid phosphatase (TRAP) activity of differentiated cells accompanied by a significant attenuation of resorption pit area caused by osteoclasts. Collectively, we demonstrated for the first time that magnolol significantly ameliorates the alveolar bone loss in ligature-induced experimental periodontitis by suppressing periodontopathic microorganism accumulation, NF-κB-mediated inflammatory mediator synthesis, RANKL formation, and osteoclastogenesis. These activities support that magnolol is a potential agent to treat periodontal disease.

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Alpinetin Inhibits RANKL-Induced Osteoclastogenesis and Ovariectomy-Induced Bone Loss by Modulating NFATc1 Transcription and Lysosomal Function

10.21203/rs.3.rs-132706/v1 ◽

2020 ◽

Author(s):

Rongxin He ◽

Jinwei Lu ◽

Yazhou Chen ◽

Yong Li ◽

Chenyi Ye ◽

...

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Bone Matrix ◽

Osteoclast Differentiation ◽

Estrogen Deficiency ◽

Bone Diseases ◽

Dependent Manner ◽

Metabolic Bone Diseases ◽

Lysosomal Function ◽

Metabolic Bone

Abstract BackgroundPostmenopausal osteoporosis is a chronic metabolic bone disease caused by excessive osteoclast activation, and osteoclasts are considered to be the sole participants in the degeneration and resorption of bone matrix for controlling bone integrity and continuity. The biological functions of osteoclasts depend critically on the number and activity of fused polykaryon. Hence, targeting osteoclast differentiation and activity can modulate bone resorption and alleviate osteoporosis. Alpinetin is widely used for excellent anti-inflammatory activities and little side-effect, but its role in osteoporosis remains unknown.ResultsIn this study, we investigated for the first time the ability of alpinetin to inhibit estrogen deficiency-induced bone loss. Alpinetin significantly reduced the expression levels of NFATc1 and its downstream genes, thereby inhibiting osteoclast differentiation in a concentration- and time-dependent manner. Additionally, alpinetin inhibited F-actin ring formation and bone resorption, as well as reduced the activation levels of NF-κB, ERK, and AKT signaling cascades. In mature osteoclasts, alpinetin remarkably inhibited integrin-mediated migration and lysosomal biogenesis and trafficking by modulating the PKCβ/TFEB and ATG5/LC3 axes. Importantly, alpinetin treatment in mice alleviated ovariectomy-induced bone volume loss. ConclusionOur findings strongly suggest that alpinetin plays a significant role in the regulation of NFATc1 production for the differentiation of osteoclasts and inhibits integrin-mediated cell migration and lysosomal function in mature osteoclasts, thus weaken the increased osteolytic ability due to estrogen deficiency. Alpinetin may represent a promising agent for the treatment of osteoporosis and other metabolic bone diseases.

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Lenalidomide and Bortezomib Inhibit Osteoclast Differentiation and Activation in Multiple Myeloma: Clinical Implications.

Blood ◽

10.1182/blood.v108.11.3485.3485 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3485-3485 ◽

Cited By ~ 1

Author(s):

Iris Breitkreutz ◽

Sonia Vallet ◽

Marc S. Raab ◽

Yu-Tzu Tai ◽

Noopur Raje ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Resorption ◽

Mononuclear Cells ◽

Osteoclast Differentiation ◽

Flow Cytometric Analysis ◽

Tartrate Resistant Acid Phosphatase ◽

Normal Donor ◽

Dependent Manner ◽

Osteolytic Bone Disease ◽

Dose Dependent

Abstract Osteolytic bone disease in Multiple Myeloma (MM) is caused by enhanced osteoclast (OCL) activation and inhibition of osteoblast function. The proteasome inhibitor bortezomib (PS341, Velcade) has potent anti-myeloma activity with impressive clinical responses. A recent study indicated that bortezomib has inhibitory effects on OCL (ASH 2005, Abstract #2488). Lenalidomide (CC-5013, Revlimid) is an immunomodulatory derivative of thalidomide that has shown promising anti-MM effects in patients with relapsed or refractory MM (Richardson et. al, Blood Jul 06). Significantly, a phase I clinical trial showed that lenalidomide and bortezomib could achieve responses in the majority of patients with MM, refractory to either agent alone (ASH 2005, Abstract #365). However, the effect of lenalidomide on human OCL lineage is unknown. Here we investigated the effect of lenalidomide and bortezomib on human OCL. Peripheral blood mononuclear cells (PBMC) from MM patients (n=11) and healthy donors (n=5) were stimulated with receptor activator of NFk-B ligand (RANKL) (50ng/ml) and M-CSF (25ng/ml) for two weeks to induce OCL formation, in the presence or absence of lenalidomide or bortezomib. OCL were identified by flow cytometric analysis using anti-aVb3 integrin. Lenalidomide and bortezomib inhibited OCL differentiation in a dose-dependent manner (n=13, median control: 70.9% at 0 μM; 63% at lenalidomide 2μM and 45% at 10μM; 35% at bortezomib 2nM and 11% at 5nM). TRAP staining (tartrate-resistant acid phosphatase) was performed to identify OCL and confirm OCL activity. Lenalidomide, as well as bortezomib inhibited OCL in a dose-dependent manner, as evidenced by a marked decrease in TRAP+ cells. To assess bone resorption activity, OCL were cultured with dentine discs, in the presence or absence of lenalidomide and bortezomib, followed by light microscopic analysis and additional measurement of soluble collagen I fragments from the supernatant. Both lenalidomide and bortezomib inhibited bone resorption in a dose-dependent manner. We next asked whether mature OCL were affected. OCL were induced by cytokine stimulation for 3 weeks and treated for 72h, followed by flow cytometry. Neither lenalidomide nor bortezomib altered total number of aVb3 integrin-expressing mature OCL (n=6). In addition, OCL culture supernatants were collected, and two major MM growth and survival factors produced by OCL, B-cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL), were measured by specific ELISA. Both lenalidomide and bortezomib strongly inhibited secretion of BAFF and APRIL. Finally, we determined whether lenalidomide and bortezomib inhibited expression of transcriptional factors important for OCL differentiation and survival. Cell lysates of CD14-expressing monocytic cells from normal donor PBMCs were subject to immunoblotting. Importantly, lenalidomide inhibited OCL differentiation by downregulation of PU.1 expression. These results therefore indicate, that lenalidomide and bortezomib inhibit OCL differentiation, thereby directly preventing the development of new osteolytic lesions. Moreover, BAFF and APRIL secretion by OCL is downregulated, thereby inhibiting MM cell survival in the bone marrow microenvironment.

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Inhibitory Effects of N-[2-(4-acetyl-1-piperazinyl) phenyl]-2-(2-chlorophenoxy) acetamide on Osteoclast Differentiation In Vitro via the Downregulation of TRAF6

International Journal of Molecular Sciences ◽

10.3390/ijms20205196 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5196 ◽

Cited By ~ 5

Author(s):

Zhihao Chen ◽

Eunjin Cho ◽

Jinkyung Lee ◽

Sunwoo Lee ◽

Tae-Hoon Lee

Keyword(s):

Bone Resorption ◽

Mononuclear Cells ◽

Osteoclast Differentiation ◽

Bone Diseases ◽

Marker Genes ◽

Tartrate Resistant Acid Phosphatase ◽

Specific Marker ◽

Potential Candidate ◽

Dependent Manner

Osteoclasts are poly-nuclear cells that resorb mineral components from old or damaged bone tissue. Primary mononuclear cells are activated by receptor activator of nuclear factor kappa-Β ligand (RANKL) and differentiate into large multinucleated cells. Dysregulation of osteoclast differentiation can lead to pathological bone loss and destruction. Many studies have focused on the development of new molecules to regulate RANKL-mediated signaling. In this study, N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(2-chlorophenoxy) acetamide (PPOA-N-Ac-2-Cl) led to a significant decrease in the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells in a dose-dependent manner, without inducing significant cytotoxicity. PPOA-N-Ac-2-Cl affected the expression of osteoclast-specific marker genes, such as TRAF6, c-fos, DC-STAMP, NFATc1, MMP9, CtsK, and TRAP (Acp5), during RANKL-mediated osteoclastogenesis. Moreover, PPOA-N-Ac-2-Cl significantly attenuated the protein levels of CtsK, a critical protease involved in bone resorption. Accordingly, bone resorption activity and F-actin ring formation decreased in the presence of PPOA-N-Ac-2-Cl. In conclusion, this study shows that PPOA-N-Ac-2-Cl acts as an inhibitor of osteoclast differentiation and may serve as a potential candidate agent for the treatment of osteoclast-related bone diseases by virtue of attenuating bone resorption.

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Advanced glycation end products biphasically modulate bone resorption in osteoclast-like cells

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00309.2015 ◽

2016 ◽

Vol 310 (5) ◽

pp. E355-E366 ◽

Cited By ~ 22

Author(s):

Ziqing Li ◽

Chaohong Li ◽

Yuhuan Zhou ◽

Weishen Chen ◽

Guotian Luo ◽

...

Keyword(s):

Bone Resorption ◽

Cell Fusion ◽

Advanced Glycation End Products ◽

Osteoclast Differentiation ◽

Mature Stage ◽

Tartrate Resistant Acid Phosphatase ◽

Dependent Manner ◽

Advanced Glycation ◽

Glycation End Products ◽

End Products

Advanced glycation end products (AGEs) disturb bone remodeling during aging, and this process is accelerated in diabetes. However, their role in modulation of osteoclast-induced bone resorption is controversial, with some studies indicating that AGEs enhance bone resorption and others showing the opposite effect. We determined whether AGEs present at different stages of osteoclast differentiation affect bone resorption differently. Based on increased levels of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), we identified day 4 of induction as the dividing time of cell fusion stage and mature stage in RAW264.7 cell-derived osteoclast-like cells (OCLs). AGE-modified BSA (50–400 μg/ml) or control BSA (100 μg/ml) was then added at the beginning of each stage. Results showed that the presence of AGEs at the cell fusion stage reduced pit numbers, resorption area, and CTSK expression. Moreover, expression of receptor activator of nuclear factor-κB (RANK) as well as the number of TRAP-positive cells, nuclei per OCL, actin rings, and podosomes also decreased. However, the presence of AGEs at the mature stage enlarged the resorption area markedly and increased pit numbers slightly. Intriguingly, only the number of nuclei per OCL and podosomes increased. These data indicate that AGEs biphasically modulate bone resorption activity of OCLs in a differentiation stage-dependent manner. AGEs at the cell fusion stage reduce bone resorption dramatically, mainly via suppression of RANK expression in osteoclast precursors, whereas AGEs at the mature stage enhance bone resorption slightly, most likely by increasing the number of podosomes in mature OCLs.

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