Differentiation Of Bone Marrow-derived Macrophages Research Articles

Anti-osteoclastogenic diacetylenic components of Dendropanax morbifera.

Methanol (MeOH) extract of the aerial parts of Dendropanax morbifera (Araliaceae) has demonstrated a significant dose-dependent inhibitory effect on the RANKL-induced differentiation of bone marrow-derived macrophages to osteoclasts. Bioassay-guided fractionation of the extract resulted in the isolation of a novel diacetylene carboxylic acid (1), together with a known diacetylenic compounds (2) as phytochemicals to strongly inhibit the osteoclast differentiation. The chemical structure of 1 was determined by spectroscopic analyses as (9Z,16S)-16-O-acetyl-9,17-octadecadiene-12,14-diynoic acid, that is acetyl derivative of 2. Two diacetylenic components of D. morbifera, 1 and 2 exhibited a dose-dependent inhibitory effect on the RANKL-induced formation of tartrate-resistant acid phosphatase-positive multinucleated cells with IC50 values of 2.4 and 3.1 μM, respectively. Seven other known components (3-9) were also isolated from the extract: dendropanoxide (3), friedelin (4), epifriedelanol (5), α-amyrin (6), β-amyrin (7), β-sitosterol (8), and stigmasterol (9). The significant anti-osteoclastogenic activities of 3, 4, 5, and 7 were first reported in this study.

Endothelial Progenitor Cells Enhance the Migration and Osteoclastic Differentiation of Bone Marrow-Derived Macrophages in vitro and in a Mouse Femur Fracture Model through Talin-1

Background/Aims: Bone resorption mediated by osteoclasts plays an important role in bone healing. Endothelial progenitor cells (EPCs) promote bone repair by stimulating neovascularization and osteogenesis. However, the role of EPCs in osteoclast formation and function is not well defined. The aim of this study was to elucidate mechanisms of EPCs in osteoclast formation and function. Methods: In this study, we examined the effects of EPCs on the proliferation, migration and osteoclastic differentiation of primary mouse bone marrow-derived macrophages (BMMs) in a co-culture system in vitro. We also evaluated the effects of EPC co-transplantation on the homing and osteoclastic differentiation of transplanted BMMs in a mouse bone fracture model in vivo. The technology of immunofluorescence, immunohistochemical, western blot, Rt-PCR, cell co-culture and Transwell were used in this study. Results: EPCs secreted TGF-β1 in the EPC-BMM co-culture medium and increased Talin-1 expression in the co-cultured BMMs. Treatment with a TGF-β1 neutralizing antibody or Talin-1 silencing in BMMs completely inhibited BMM osteoclastic differentiation in the co-culture system. These results indicated that the osteoclastogenic effects of EPCs were mediated by TGF-β1-mediated Talin-1 expression in BMMs. In the femur fracture model, BMMs co-transplanted with EPCs exhibited enhanced engraftment into the fracture site and osteoclastic differentiation compared with those transplanted alone. Mice treated with EPC-BMM co-transplantation exhibited increased neovascularization at the fracture site and accelerated fracture healing compared with those treated with BMMs alone. Conclusion: Taken together, the results suggest that EPCs can promote bone repair by enhancing recruitment and differentiation of osteoclast precursors.

Abstract 20953: M1 and M2 Specific Purinergic Receptor Repertoire Alters Response to Damage Associated Molecular Patterns

Introduction: Dying cells release damage associated molecular patterns (DAMPs) like nucleotides into the extracellular fluid, orchestrating a profound immune response. Purinergic receptors decrypt the composition of extracellular nucleotides and translate it to distinct cellular reactions. M1 and M2 macrophages are immune cells involved in many diseases which react in a completely different way. Nevertheless, how the microenvironment exactly triggers their behavior is not fully understood. Hypothesis: We hypothesize a distinct expression pattern of purinergic receptors on M1 and M2 macrophages which leads to an unique microenvironment recognition and behavior. Methods: Macrophages were generated by bone marrow isolation and cultivation with macrophage colony stimulating factor (M-CSF). Bone marrow derived macrophages (BMDMs) were differentiated to M1 via addition of IFNγ and LPS. M2 differentiation was initiated by the addition of IL-4. Gene transcription quantification was assessed by real-time PCR. Intracellular Ca 2+ signaling was quantified by Fluo-4 AM. Results: Differentiation of BMDMs with either IFNγ/LPS or IL-4 leads to the upregulation of M1 or M2 specific gene transcription. Subsequent real-time PCR analysis of purinergic receptors revealed a strong relationship between the expression pattern and the differentiation to M1 or M2 macrophages. Whereas M1 macrophages upregulate predominantly G αi coupled metabotropic P2Y receptors, M2 macrophages preferentially upregulate G αq coupled P2Y receptors. Comparison of the two ADP-dependent P2Y receptors (P2Y 1 and P2Y 13 ) showed a M1 and M2 specific expression pattern with M1 macrophages solely expressing the G αi coupled P2Y 13 and M2 macrophages exclusively expressing the G αq coupled P2Y 1 receptor. In agreement with the specific expression pattern, ADP stimulation evokes a significant Ca 2+ flux in M2 macrophages but failed to induce it in M1 macrophages. Conclusion: Our experiments revealed for the first time that M1 and M2 macrophages express a unique purinergic receptor repertoire and sense the nucleotide based microenvironment differently. With this knowledge we could interfere with one macorphage subtype without disturbing the others.

Effects of paeonol on the function of bone marrow-derived macrophage from Porphyromonas gingivalis-induced mice

This work aims to examine the effects of paeonol treatment on the ability of bone marrow-derived macrophage (BMM) to excrete inflammatory factors and to differentiate into osteoclasts upon induction with Porphyromonas gingivalis (P. gingivalis). This work also aims to investigate the underlying mechanisms of these abilities. BMM culture was treated with different paeonol concentrations at for 1 h and then stimulated with P. gingivalis for 24 h before programmed death-ligand 1 (PD-L1) was quantified with flow cytometry. Tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were detected by enzyme-linked immunosorbent assay (ELISA). The BMM culture was treated with the receptor activator for nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF), and then with paeonol for 1 h prior to induction with P. gingivalis. Then, osteoclast formation was assessed using tartrate resistant acid phosphatase (TRAP) staining. The osteoclast-related proteins TRAP and receptor activator of nuclear factor-κB (RANK) were quantified by Western blotting. Paeonol was nontoxic to BMM within a range of 10-50 μmol·L⁻¹. Flow cytometry showed that paeonol inhibited PD-L1 expression in P. gingivalis-induced BMM in a dose-dependent manner. ELISA indicated that paeonol dose-dependently inhibited the excretion of TNF-α, IL-1β, and IL-6 by P. gingivalis-induced BMM (P<0.01). TRAP staining revealed that paenol treatment inhibited the differentiation of P. gingivalis-induced BMM into osteoclasts. Western blot results suggested that paeonol decreased the expression of TRAP and RANK in BMM. Paeonol dose-dependently inhibited the excretion of the inflammatory factors TNF-α, IL-1β, and IL-6 by P. gingivalis-induced BMM in a dose-dependent manner. Moreover, paenol treatment prevented the differentiation of P. gingivalis-induced BMM differentiation into osteoclasts. .

Osteoclast differentiation gene expression profiling reveals chemokine CCL4 mediates RANKL-induced osteoclast migration and invasion via PI3K pathway.

The migration of osteoclasts (OCs) from circulation and bone marrow into bone surface plays a critical role in the pathogenesis of some bone resorptive diseases, such as rheumatoid arthritis and osteoporosis. To date, how the migration of OCs remains unclear. We investigated gene expression profiling in osteoclastic differentiation of bone marrow-derived macrophages (BMMs) into OCs by microarray analysis. We identified 387 genes overexpressed in osteoclastic differentiation of BMMs. Among them, chemokine CCL4 showed a robust up-regulation signal. High expression of CCL4 was validated in primary BMMs and OC precursor cell line RAW264.7 during differentiation into OCs. The CCL4 neutralization decreased RANKL-induced OC precursor cell migration and invasion in Matrigel-coated transwell membranes assay and in vitro wound healing assay. However, CCL4 inhibition did not affect OCs differentiation and differentiation associated gene expression. The CCL4 inhibition promoted the PI3K phosphorylation at 45 to 60minutes after RANKL stimulation in RAW264.7. This study indicated that chemokine CCL4 is an important regulator for OCs migration via PI3K pathway, providing a novel therapy target for bone resorptive diseases.

Secreted Ectodomain of SIGLEC-9 and MCP-1 Synergistically Improve Acute Liver Failure in Rats by Altering Macrophage Polarity

Effective treatments for acute liver failure (ALF) are still lacking. We recently reported that a single intravenous administration of serum-free conditioned medium from stem cells derived from human exfoliated deciduous teeth (SHED-CM) into the D-galactosamine (D-Gal)-induced rat ALF model improves the liver injury. However, the specific factors in SHED-CM that are responsible for resolving ALF remain unclear. Here we found that depleting SHED-CM of two anti-inflammatory M2 macrophage inducers—monocyte chemoattractant protein-1 (MCP-1) and the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (sSiglec-9)—abolished its ability to resolve rat ALF. Furthermore, treatment with MCP-1/sSiglec-9 alone dramatically improved the survival of ALF rats. This treatment induced anti-inflammatory M2, suppressed hepatocyte apoptosis, and promoted hepatocyte proliferation. Treatment with an M2-depletion reagent (mannosylated clodronate liposomes) suppressed the recovery. In addition, MCP-1 and sSiglec-9 synergistically promoted the M2 differentiation of bone marrow-derived macrophages via CCR2, accompanied by the production of multiple liver-regenerating factors. The conditioned medium from MCP-1/sSiglec-9-activated M2 macrophages, but not from interleukin-4-induced ones, suppressed the D-Gal- and LPS-induced apoptosis of primary hepatocytes and promoted their proliferation in vitro. The unique combination of MCP-1/sSiglec-9 ameliorates rat ALF by inhibiting hepatocellular apoptosis and promoting liver regeneration through the induction of anti-inflammatory/tissue-repairing M2 macrophages.

The dental resin monomers HEMA and TEGDMA have inhibitory effects on osteoclast differentiation with low cytotoxicity.

The dental resin monomers 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) are released from the resin matrix due to unpolymerized monomers; once released, they influence various biological functions and the viability of cells in the oral environment. Although HEMA and TEGDMA have various effects on cells, including inflammation, inhibition of cell proliferation or differentiation, and apoptosis, the effects of these monomers on osteoclasts remain unknown. In this study, we investigated the effects of HEMA and TEGDMA on osteoclast differentiation of bone marrow-derived macrophages or murine monocytic cell line RAW-D. Both HEMA and TEGDMA inhibited osteoclast formation and their bone-resorbing activity at non-cytotoxic concentrations. Moreover, HEMA and TEGDMA decreased the expression of nuclear factor of activated T cells cytoplasmic-1 (NFATc1), a master regulator of osteoclast differentiation, and of osteoclast markers that are transcriptionally regulated by NFATc1, including Src and cathepsin K. Regarding their effects on signaling pathways involved in osteoclast differentiation, HEMA impaired the phosphorylation of extracellular signal-regulated kinase and Jun N-terminal kinase, whereas TEGDMA attenuated the phosphorylation of Akt and Jun N-terminal kinase. Thus, HEMA and TEGDMA inhibit osteoclast differentiation through different signaling pathways. This is the first report on the effects of the monomers HEMA and TEGDMA on osteoclasts. Copyright © 2017 John Wiley & Sons, Ltd.

Nitro-oleic acid regulates growth factor-induced differentiation of bone marrow-derived macrophages

Many diseases accompanied by chronic inflammation are connected with dysregulated activation of macrophage subpopulations. Recently, we reported that nitro-fatty acids (NO2-FAs), products of metabolic and inflammatory reactions of nitric oxide and nitrite, modulate macrophage and other immune cell functions. Bone marrow cell suspensions were isolated from mice and supplemented with macrophage colony-stimulating factor (M-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) in combination with NO2-OA for different times. RAW 264.7 macrophages were used for short-term (1–5min) experiments. We discovered that NO2-OA reduces cell numbers, cell colony formation, and proliferation of macrophages differentiated with colony-stimulating factors (CSFs), all in the absence of toxicity. In a case of GM-CSF-induced bone marrow-derived macrophages (BMMs), NO2-OA acts via downregulation of signal transducer and activator of transcription 5 and extracellular signal-regulated kinase (ERK) activation. In the case of M-CSF-induced BMMs, NO2-OA decreases activation of M-CSFR and activation of related PI3K and ERK. Additionally, NO2-OA also attenuates activation of BMMs. In aggregate, we demonstrate that NO2-OA regulates the process of macrophage differentiation and that NO2-FAs represent a promising therapeutic tool in the treatment of inflammatory pathologies linked with increased accumulation of macrophages in inflamed tissues.

Docosahexaenoic acid signaling attenuates the proliferation and differentiation of bone marrow-derived osteoclast precursors and promotes apoptosis in mature osteoclasts

Docosahexaenoic acid (DHA), a component of omega-3 fatty acids, has been reported to protect against inflammatory bone diseases such as osteoporosis and rheumatoid arthritis. However, its exact mechanism in bone resorbing cells has not been elucidated. In this study, we investigated the effects and the molecular mechanism of DHA on the proliferation, differentiation, and survival of osteoclast lineage cells using mouse bone marrow-derived macrophages (BMMs). DHA suppressed the macrophage colony-stimulating factor (M-CSF)-induced proliferation of osteoclast precursors, BMMs, in a dose-dependent manner. The attenuated proliferation of DHA-treated BMMs was related to M-CSF inhibition that selectively decreased Akt activation and downregulated cyclin D1 and cyclin D2 expression. DHA also blocked receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation from BMMs. At the molecular level, DHA inhibited JNK, ERK, and p38 MAPKs. In addition, it inhibited NF-κB signaling cascades, as demonstrated by the suppression of RANKL-mediated IκBα phosphorylation, NF-κB subunit p65 nuclear translocation, and NF-κB transcriptional activation. Accordingly, DHA attenuated the induction of c-Fos and nuclear factor of activated T cells c1 (NFATc1). Furthermore, DHA accelerated the apoptosis of mature osteoclasts by inducing Bim expression, a critical modulator of osteoclast apoptosis. Collectively, our data demonstrate that DHA exerts an anti-osteoclastogenic effect by suppressing the proliferation and differentiation of BMMs and enhancing the apoptosis of mature osteoclasts, thereby resulting in a diminished number of bone-resorptive cells.

Lysosomal Ca2+ Signaling is Essential for Osteoclastogenesis and Bone Remodeling.

Lysosomal Ca2+ emerges as a critical component of receptor-evoked Ca2+ signaling and plays a crucial role in many lysosomal and physiological functions. Lysosomal Ca2+ release is mediated by the transient receptor potential (TRP) family member TRPML1, mutations that cause the lysosomal storage disease mucolipidosis type 4. Lysosomes play a key role in osteoclast function. However, nothing is known about the role of lysosomal Ca2+ signaling in osteoclastogenesis and bone metabolism. In this study, we addressed this knowledge gap by studying the role of lysosomal Ca2+ signaling in osteoclastogenesis, osteoclast and osteoblast functions, and bone homeostasis in vivo. We manipulated lysosomal Ca2+ signaling by acute knockdown of TRPML1, deletion of TRPML1 in mice, pharmacological inhibition of lysosomal Ca2+ influx, and depletion of lysosomal Ca2+ storage using the TRPML agonist ML-SA1. We found that knockdown and deletion of TRPML1, although it did not have an apparent effect on osteoblast differentiation and bone formation, markedly attenuated osteoclast function, RANKL-induced cytosolic Ca2+ oscillations, inhibited activation of NFATc1 and osteoclastogenesis-controlling genes, suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs), and markedly reduced the differentiation of bone marrow-derived macrophages into osteoclasts. Moreover, deletion of TRPML1 resulted in enlarged lysosomes, inhibition of lysosomal secretion, and attenuated the resorptive activity of mature osteoclasts. Notably, depletion of lysosomal Ca2+ with ML-SA1 similarly abrogated RANKL-induced Ca2+ oscillations and MNC formation. Deletion of TRPML1 in mice reduced the TRAP-positive bone surfaces and impaired bone remodeling, resulting in prominent osteopetrosis. These findings demonstrate the essential role of lysosomal Ca2+ signaling in osteoclast differentiation and mature osteoclast function, which play key roles in bone homeostasis. © 2016 American Society for Bone and Mineral Research.

Follistatin-like 1 promotes osteoclast formation via RANKL-mediated NF-κB activation and M-CSF-induced precursor proliferation

Follistatin-like 1 (FSTL1) functions as a pivotal modulator of inflammation and is implicated in many inflammatory diseases such as rheumatoid arthritis. Here, we report that FSTL1 is strongly upregulated and secreted during osteoclast differentiation of bone marrow-derived macrophages (BMMs) and that FSTL1 positively regulates osteoclast formation induced by RANKL and M-CSF. The overexpression of FSTL1 or treatment with recombinant FSTL1 (rFSTL1) in BMMs enhances the formation of multinuclear osteoclasts and the induction of c-Fos and NFATc1, transcription factors important for osteoclastogenesis. Conversely, knockdown of FSTL1 using a small hairpin RNA suppresses osteoclast formation and the expression of these transcription factors. While FSTL1 does not affect RANKL-stimulated activation of p38 MAPK, phosphorylation of IκBα, JNK, and ERK were increased by overexpression or addition of rFSTL1. Furthermore, rFSTL1 increased RANKL-induced NF-κB transcriptional activity in a dose-dependent manner. In addition to its role in osteoclastogenesis, FSTL1 promotes proliferation of osteoclast precursors by increasing M-CSF-induced ERK activation, which in turn leads to accelerated osteoclast formation. Together, our findings demonstrate that FSTL1 is a secreted osteoclastogenic factor that plays a critical role in osteoclast formation via the NF-κB and MAPKs signaling pathways.

Arginase 1 is a negative regulator of osteoclast differentiation.

Arginase 1 (Arg1) limits the availability of l-arginine for producing nitric oxide (NO) and ornithine, a substrate for polyamine synthesis. Anti-osteoclastogenic activities of NO and polyamines, and the involvement of Arg1 on the dendritic cell differentiation of dendritic cells have been reported, but the relevance of Arg1 to osteoclast differentiation has not been investigated. Here, we observed Arg1 down-regulation during the RANKL-induced differentiation of bone marrow-derived macrophages into osteoclasts. Arg1 overexpression significantly inhibited osteoclast differentiation with low NO production, while Arg1 knockdown enhanced osteoclast differentiation with high NO production. These results suggest that Arg1 and NO have reciprocal roles as negative and positive regulators, respectively, of osteoclast differentiation. We conclude that Arg1 is down-regulated during osteoclast differentiation and may negatively regulate osteoclast differentiation by regulating NO production.

Bropirimine inhibits osteoclast differentiation through production of interferon-β

Bropirimine is a synthetic agonist for toll-like receptor 7 (TLR7). In this study, we investigated the effects of bropirimine on differentiation and bone-resorbing activity of osteoclasts in vitro. Bropirimine inhibited osteoclast differentiation of mouse bone marrow-derived macrophages (BMMs) induced by receptor activator of nuclear factor κB ligand (RANKL) in a concentration-dependent manner. Furthermore, it suppressed the mRNA expression of nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1), a master transcription factor for osteoclast differentiation, without affecting BMM viability. Bropirimine also inhibited osteoclast differentiation induced in co-cultures of mouse bone marrow cells (BMCs) and mouse osteoblastic UAMS-32 cells in the presence of activated vitamin D3. Bropirimine partially suppressed the expression of RANKL mRNA in UAMS-32 cells induced by activated vitamin D3. Finally, the anti-interferon-β (IFN-β) antibody restored RANKL-dependent differentiation of BMMs into osteoclasts suppressed by bropirimine. These results suggest that bropirimine inhibits differentiation of osteoclast precursor cells into osteoclasts via TLR7-mediated production of IFN-β.

Chondroitin Sulfate-E Binds to Both Osteoactivin and Integrin αVβ3 and Inhibits Osteoclast Differentiation.

Integrins and their ligands have been suggested to be associated with osteoclast-mediated bone resorption. The present study was designed to investigate whether chondroitin sulfate E (CS-E), which is one of the sulfated glycosaminoglycans (GAGs), is involved in osteoactivin (OA) activity, and osteoclast differentiation. The binding affinity of sulfated GAGs to integrin and its ligand was measured using biotin-labeled CS-E, and the osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase staining and a pit formation assay. CS-E as well as CS-B, synthetic chondroitin polysulfate, and heparin inhibited osteoclast differentiation of bone marrow-derived macrophages. Pre-coating of OA to synthetic calcium phosphate-coated plates enhanced the osteoclastic differentiation of RAW264 cells, and addition of a neutralizing antibody to OA inhibited its differentiation. CS-E bound not only to OA, fibronectin, and vitronectin, but also to its receptor integrin αVβ3, and inhibited the direct binding of OA to integrin αVβ3. Furthermore, CS-E blocked the binding of OA to cells and inhibited OA-induced osteoclastic differentiation. On the other hand, heparinase treatment of RAW264 cells inhibited osteoclastic differentiation. Since binding of OA to the cells was inhibited by the presence of heparan sulfate or heparinase treatment of cells, heparan sulfate proteoglycan (HSPG) was also considered to be an OA receptor. Taken together, the present results suggest that CS-E is capable of inhibiting OA-induced osteoclast differentiation by blocking the interaction of OA to integrin αVβ3 and HSPG.

WHI-131 Promotes Osteoblast Differentiation and Prevents Osteoclast Formation and Resorption in Mice.

The small molecule WHI-131 is a potent therapeutic agent with anti-inflammatory, antiallergic, and antileukemic potential. However, the regulatory effects of WHI-131 on osteoblast and osteoclast activity are unclear. We examined the effects of WHI-131 on osteoblast and osteoclast differentiation with respect to bone remodeling. The production of receptor activator of nuclear factor kappa-B ligand (RANKL) by osteoblasts in response to interleukin (IL)-1 or IL-6 stimulation decreased by 56.8% or 50.58%, respectively, in the presence of WHI-131. WHI-131 also abrogated the formation of mature osteoclasts induced by IL-1 or IL-6 stimulation. Moreover, WHI-131 treatment decreased RANKL-induced osteoclast differentiation of bone marrow-derived macrophages, and reduced the resorbing activity of mature osteoclasts. WHI-131 further decreased the mRNA and protein expression levels of c-Fos and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) by almost twofold, and significantly downregulated the mRNA expression of the following genes: tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), DC-STAMP, OC-STAMP, ATP6v0d2, and cathepsin K (CtsK) compared with the control group. WHI-131 further suppressed the phosphorylation of protein kinase B (Akt) and degradation of inhibitor of kappa B (IκB); Ca(2+) oscillation was also affected, and phosphorylation of the C-terminal Src kinase (c-Src)-Bruton agammaglobulinemia tyrosine kinase (Btk)-phospholipase C gamma 2 (PLCγ2) (c-Src-Btk-PLCg2 calcium signaling pathway) was inhibited following WHI-131 treatment. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway was activated by WHI-131, accompanied by phosphorylation of STAT3 Ser727 and dephosphorylation of STAT6. In osteoblasts, WHI-131 caused an approximately fourfold increase in alkaline phosphatase activity and Alizarin Red staining intensity. Treatment with WHI-131 increased the mRNA expression levels of genes related to osteoblast differentiation, and induced the phosphorylation of Akt, p38, and Smad1/5/8. Furthermore, 5-week-old ICR mice treated with WHI-131 exhibited antiresorbing effects in a lipopolysaccharide-induced calvaria bone loss model in vivo and increased bone-forming activity in a calvarial bone formation model. Therefore, the results of this study show that WHI-131 plays a dual role by inhibiting osteoclast differentiation and promoting osteoblast differentiation. Thus, WHI-131 could be a useful pharmacological agent to treat osteoporosis by promoting bone growth and inhibiting resorption.

Punicalagin attenuates osteoclast differentiation by impairing NFATc1 expression and blocking Akt- and JNK-dependent pathways.

Punicalagin is a bioactive polyphenol that is classified as an ellagitannin. Although punicalagin has been shown to have various pharmacological effects, such as anti-oxidative, anti-inflammatory, and anti-tumor effects, no studies have reported the effects of punicalagin on osteoclasts (OCLs). In this study, we investigated the effects of punicalagin on OCL differentiation by receptor activator of nuclear factor kappa-B ligand in the murine monocytic RAW-D cell line and bone marrow-derived macrophages (BMMs). Treatment with punicalagin significantly inhibited OCL formation from RAW-D cells and BMMs and prevented bone resorption of BMM-derived OCLs. Moreover, punicalagin impaired multinucleation and actin-ring formation in OCLs, and decreased the protein levels of nuclear factor of activated T cells cytoplasmic-1 (NFATc1), which is a master regulator of OCL differentiation, and concomitantly reduced the expression levels of Src and cathepsin K, which are transcriptionally regulated by NFATc1. The effects of punicalagin on intracellular signaling during the OCL differentiation of BMMs indicated that punicalagin-treated OCLs displayed markedly reduced phosphorylation of Jun N-terminal kinase and Akt, and partially impaired phosphorylation of extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and inhibitor of nuclear factor kappa-B alpha compared with untreated OCLs. Thus, punicalagin may affect bone metabolism by inhibiting OCL differentiation.

Secreted ectodomain of sialic acid-binding Ig-like lectin-9 and monocyte chemoattractant protein-1 promote recovery after rat spinal cord injury by altering macrophage polarity.

Engrafted mesenchymal stem cells from human deciduous dental pulp (SHEDs) support recovery from neural insults via paracrine mechanisms that are poorly understood. Here we show that the conditioned serum-free medium (CM) from SHEDs, administered intrathecally into rat injured spinal cord during the acute postinjury period, caused remarkable functional recovery. The ability of SHED-CM to induce recovery was associated with an immunoregulatory activity that induced anti-inflammatory M2-like macrophages. Secretome analysis of the SHED-CM revealed a previously unrecognized set of inducers for anti-inflammatory M2-like macrophages: monocyte chemoattractant protein-1 (MCP-1) and the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (ED-Siglec-9). Depleting MCP-1 and ED-Siglec-9 from the SHED-CM prominently reduced its ability to induce M2-like macrophages and to promote functional recovery after spinal cord injury (SCI). The combination of MCP-1 and ED-Siglec-9 synergistically promoted the M2-like differentiation of bone marrow-derived macrophages in vitro, and this effect was abolished by a selective antagonist for CC chemokine receptor 2 (CCR2) or by the genetic knock-out of CCR2. Furthermore, MCP-1 and ED-Siglec-9 administration into the injured spinal cord induced M2-like macrophages and led to a marked recovery of hindlimb locomotor function after SCI. The inhibition of this M2 induction through the inactivation of CCR2 function abolished the therapeutic effects of both SHED-CM and MCP-1/ED-Siglec-9. Macrophages activated by MCP-1 and ED-Siglec-9 extended neurite and suppressed apoptosis of primary cerebellar granule neurons against the neurotoxic effects of chondroitin sulfate proteoglycans. Our data suggest that the unique combination of MCP-1 and ED-Siglec-9 repairs the SCI through anti-inflammatory M2-like macrophage induction.

Water extract of Magnolia officinalis cortex inhibits osteoclastogenesis and bone resorption by downregulation of nuclear factor of activated T cells cytoplasmic 1

BackgroundMagnolia officinalis cortex has been traditionally used to treat stomach and intestine diseases in traditional Korean medicine. In this study, we investigated the effect of water extract of M. officinalis cortex (WEMC) on osteoclast differentiation and function. MethodsPhytochemical characterization of WEMC was performed by high-performance liquid chromatography analysis. Osteoclast differentiation of bone marrow-derived macrophages was determined by tartrate-resistant acid phosphatase activity assay. Receptor activator of nuclear factor-κB ligand (RANKL) signaling factors and transcription factors regulating osteoclast differentiation were analyzed by Western blot and real-time polymerase chain reaction. Bone resorption function of mature osteoclasts was examined by using culture plate coated with inorganic crystalline calcium phosphate. Furthermore, the in vivo effect of WEMC on osteoporosis was examined using RANKL-induced bone loss model, characterized by micro-computed tomography and bone metabolism marker analysis. ResultsWEMC inhibited RANKL-induced osteoclast differentiation and the bone resorbing activity of mature osteoclasts. WEMC contains gallic acid and honokiol as active constituents contributing to the inhibitory effect of WEMC on osteoclast differentiation. Further, WEMC suppressed RANKL-induced activation of p38 and nuclear factor-κB pathways and expression of osteoclastogenic transcription factors such as c-Fos for AP-1 and nuclear factor of activated T cells cytoplasmic 1. Ectopic overexpression of a constitutive active form of nuclear factor of activated T cells cytoplasmic 1 rescued the antiosteoclastogenic effect of WEMC. Consistent with the in vitro results, WEMC suppressed RANKL-induced trabecular bone loss in mice. ConclusionWEMC might have a therapeutic potential to treat pathological bone diseases due to increased osteoclast differentiation and function.

Inhibition of osteoclast differentiation by gold nanoparticles functionalized with cyclodextrin curcumin complexes.

Gold nanoparticles (GNPs) have been previously reported to inhibit osteoclast (OC) formation. However, previous research only confirmed the osteoclastogenesis inhibitory effect under in vitro conditions. The aim of this study was to develop a therapeutic agent for osteoporosis based on the utilization of GNPs and confirm their effect both in vitro and in vivo. We prepared β-cyclodextrin (CD) conjugated GNPs (CGNPs), which can form inclusion complexes with curcumin (CUR-CGNPs), and used these to investigate their inhibitory effects on receptor activator of nuclear factor-κb ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages (BMMs). The CUR-CGNPs significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells in BMMs without inducing cytotoxicity. The mRNA expressions of genetic markers of OC differentiation including c-Fos, nuclear factor of activated T cells 1 (NFATc1), TRAP, and osteoclast associated receptor (OSCAR) were significantly decreased in the presence of CUR-CGNPs. In addition, the CUR-CGNPs inhibited OC differentiation of BMMs through suppression of the RANKL-induced signaling pathway. Additionally, CUR-CGNPs caused a decrease in RANKL-induced actin ring formation, which is an essential morphological characteristic of OC formation allowing them to carry out bone resorption activity. Furthermore, the in vivo results of an ovariectomy (OVX)-induced osteoporosis model showed that CUR-CGNPs significantly improved bone density and prevented bone loss. Therefore, CUR-CGNPs may prove to be useful as therapeutic agents for preventing and treating osteoporosis.

Cancer stem-like cells from osteosarcoma with highly expressed beta 1,6 GlcNAc branched N-glycan induce a phenotypic switch in polarization of bone marrow-derived macrophages

Objective To investigate the effect of cancer stem-like cells (CSCs) from osteosarcoma cell line on the polarization of macrophages.Methods CSCs were pre-treated with different doses of swainsonine and co-cultured with macrophages,and the phenotypic specific markers on macrophages were detected respectively.Results Compared to the control group,the expression of Arg-1 [(12.0 ± 3.1) ％ vs.(40.0±2.6)％,P＜0.05] and interleukin (IL)-10 [(90.0±4.4) ng/Lvs.(150.0±6.8) ng/L,P ＜0.05] in macrophages co-cultured with CSCs pre-treated with swainsonine (1 mg/L) was decreased,whereas inducible nitric oxide synthase (iNOS) [(50.0 ±2.1)％ vs.(12.0 ± 1.3)％,P＜0.05] and tumor necrosis factor (TNF)-α [(240.0 ± 8.1) ng/L vs.(50.0 ± 3.3) ng/L,P ＜ 0.05] increased.Conclusion Increased expression of beta-1,6-oligosaccharide in CSCs derived from osteosarcoma cell line induced the differentiation of bone marrow-derived macrophages into anti-inflammatory M2 macrophages. Key words: Osteosarcoma; Cancer stem-like cells ; N-glycan ; Macrophages