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Abstract: Stimulation of adenosine A2A receptors results in anti-inflammatory effects in a variety of cell types. Lipopolysaccharide (LPS) and pro-inflammatory cytokines, such as TNF-α and IL-1, have been reported to up-regulate the expression of adenosine A2A receptors and thereby enhance the functional activity of adenosine A2A receptors in human and murine monocyte/macrophage cell lines and in monocytes/macrophages isolated from those species. In this study, we investigated the effects of LPS and TNF-α on the expression and functional activity of adenosine A2A receptors in isolated equine peripheral blood monocytes. The results of this study indicate that LPS and TNF-α up-regulate the transcription of adenosine A2A receptors for up to 24h; the response to LPS was of greater magnitude than the response to TNF-α. In this study, incubation with LPS, but not with TNF-α, resulted in down-regulation of adenosine A3 receptor mRNA expression. Furthermore, incubation of these cells with LPS significantly increases the surface density of adenosine A2A receptors, and incubation with low concentrations of either LPS or TNF-α significantly increases the potency of the adenosine A2A receptor agonist, ATL313, to inhibit LPS-induced production of TNF-α. These findings suggest that the increased expression of adenosine A2A receptors and the enhanced functional potency of adenosine A2A receptor agonists after exposure to pro-inflammatory substances such as LPS or TNF-α may render adenosine A2A receptor agonists particularly important in the treatment of the systemic inflammatory response syndrome that occurs secondary to endotoxemia and bacterial infections in adult horses and neonatal foals. [Copyright &y& Elsevier]

Abstract: Adenosine is an endogenous nucleoside that has potent receptor-mediated immunomodulatory effects on macrophage/monocyte function. In this study, we determined the effects of an adenosine A2A receptor agonist, ATL313, on the expression of mRNAs for four pro-inflammatory mediators, IL-1β, IL-8, COX-2, and TNF-α, and the mRNA and protein for the anti-inflammatory cytokine, IL-10 in equine monocytes incubated with lipopolysaccharide (LPS). The results indicate that ATL313 significantly reduces LPS-induced expression of COX-2 and TNF-α, enhances the expression of IL-10 and IL-8, but does not alter the expression of IL-1β. These effects of ATL313 were reversed by co-incubation with the selective adenosine A2A antagonist ZM241385, and were mimicked by the cAMP analogue dibutyryl cAMP. These differential effects of adenosine A2A receptor activation were in contrast to those obtained using the P38 MAPK inhibitor, SB203580, which nearly abolished all LPS-induced changes in mRNA expression as well as the production of TNF-α protein. These findings, which indicate that adenosine A2A receptor activation modulates the transcription of several, but not all, pro-inflammatory mediators and exerts a synergistic effect on the induction of at least one anti-inflammatory cytokine, suggest that selective adenosine A2A agonists may reduce the early pro-inflammatory effects of endotoxemia in horses. [Copyright &y& Elsevier]

Abstract: Adenosine is an endogenous nucleoside that regulates many physiological processes by activating one or more adenosine receptor subtypes, namely A1, A2A, A2B and A3. The results of previous studies indicate that adenosine analogues inhibit lipopolysaccharide (LPS)-induced production of reactive oxygen species (ROS) by equine neutrophils primarily through activation of A2A receptors. Because peripheral blood monocytes produce cytokines that are responsible for many of the deleterious effects of LPS, the current study was performed to evaluate the effects of an array of novel adenosine receptor agonists on LPS-induced production of tumor necrosis factor-α (TNF-α), and to assess the selectively of these agonists for equine adenosine A2A over the A1 receptor. Radioligand binding studies performed with equine tissues expressing adenosine A1 and A2A receptor subtypes yielded a rank order of affinity for the equine A2A receptor of ATL307>ATL309≈ATL310≈ATL313>ATL202≈ATL361≈ATL376>ATL372>CGS21680>NECA. Co-incubation of equine peripheral blood monocytes with LPS and these agonists resulted in inhibition of TNF-α production with a rank order of potency that strongly correlated with their binding affinities for equine adenosine A2A receptors. Results of experiments performed with one of the adenosine receptor agonists (ATL313) and selective adenosine receptor antagonists confirmed that inhibition of LPS-induced production of TNF-α occurred via stimulation of A2A receptors. Although incubation of monocytes with IB-MECA, a compound purported to act as an adenosine A3 receptor agonist, reduced LPS-induced TNF-α production, this effect of IB-MECA was inhibited by the A2A selective antagonist ZM241385 but not by the A3 receptor antagonist MRS1220. These results indicate that the adenosine receptor subtype responsible for regulation of LPS-induced cytokine production by equine monocytes is the A2A receptor. To address the signal transduction mechanism responsible for the anti-inflammatory effects of ATL313 in equine monocytes, production of cAMP was compared in the presence and absence of either the adenosine A2A receptor antagonist ZM241385 or the adenosine A2B receptor antagonist MRS1706. In the absence of the antagonists, ATL313 increased production of cAMP; ZM241385 inhibited this effect of ATL313, whereas MRS1706 did not. Furthermore, incubation of monocytes with either the stable analogue of cAMP, dibutyryl cAMP, or forskolin, an activator of adenylyl cyclase, also inhibited LPS-induced production of TNF-α production by equine monocytes. Collectively, the results of the current study indicate that adenosine analogues inhibit LPS-induced production of TNF-α by equine monocytes primarily via activation of adenosine A2A receptors and do so in a cAMP-dependent manner. The results of this study indicate that stable adenosine analogues that are selective for adenosine A2A receptors may be suitable for development as anti-inflammatory drugs in horses. [Copyright &y& Elsevier]

Abstract: The antagonistic interactions between adenosine A1 receptors and dopamine D1 receptors were studied in a human embryonic kidney 293 cell line stably cotransfected with human adenosine A1 receptor and dopamine D1 receptor cDNAs. In the cotransfected cells, but not in control cells only transfected with dopamine D1 receptors, adenosine A1 receptor agonist N 6-cyclopentyladenosine (CPA, 10 μM) increased the K d of dopamine D1 receptor antagonist [N-methyl-3H]R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine ([3H]SCH23390) without affecting the B max. Moreover, CPA induced a concentration-dependent decrease in the affinity of dopamine D1 receptors for the agonist (±)-1-Phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF38393) and inhibited dopamine D1 receptor-mediated cyclic AMP response element recruitment. Furthermore, pertussis toxin treatment completely counteracted the effects of low concentrations of CPA but only partially counteracted the effects of high concentrations of CPA. These results suggest that adenosine A1 receptors antagonistically modulate dopamine D1 receptors at the level of receptor binding and the second messenger generation. Furthermore, the antagonistic interactions between these two receptors induced by low concentrations of CPA might have a different manner with those induced by high concentrations of CPA. [Copyright &y& Elsevier]

Abstract: Pyruvate acid can protect cells against oxidative damage. However, its instability limits its usefulness as a therapeutic agent. In this study, we examined the effect of ethyl pyruvate, an aliphatic ester derived from pyruvate acid, on dopamine-induced cytotoxicity in rat pheochromocytoma PC12 cells. The results demonstrated that dopamine induced apoptosis in PC12 cells accompanied with increases of intercellular reactive oxygen species, nuclear translocation of nuclear transcription factor kappa B (NF-κB) and expression of p53 and decrease of mitochondrial transmembrane potential. Ethyl pyruvate markedly reduced the dopamine-induced production of reactive oxygen species, nuclear translocation of NF-κB, upregulation of p53, loss of mitochondrial transmembrane potential and apoptosis in PC12 cells. The results suggested that ethyl pyruvate might protect PC12 cells against dopamine by suppressing intercellular oxidative stress and modulating key signal pathways of apoptosis, and that ethyl pyruvate might be used as a potential therapeutic agent for Parkinson''s disease. [Copyright &y& Elsevier]

We have previously reported that the lignin‐like compounds, Tatarinan O (TO) and Tatarinan N (TN), extracted from the roots of Acorus tatarinowii Schott, inhibit receptor activator of nuclear factor‐κB ligand (RANKL)‐induced osteoclastogenesis. In the present study, the potential function of the α‐asarone‐derived lignins, Tatarinan T (TT) and Tatarinan A (TA), to regulate RANKL‐induced osteoclastogenesis was investigated, and it was found that only early treatment with TT may inhibit RANKL‐triggered formation of osteoclasts and resorption. The results revealed repressed expression levels of several osteoclast marker genes, including ATPase H+‐transporting V0 subunit d2 (Atp6v0d2), αvβ3 integrin, and osteoclast‐associated receptor (OSCAR), following TT treatment during osteoclastogenesis. Moreover, TT reduced the expression levels of the core transcription elements, nuclear factor of activated T‐cells cytoplasmic 1 (NFATc1) and c‐Fos. However, western blotting analysis showed that TT treatment did not alter nuclear factor‐κΒ (NF‐κB) activation or mitogen‐activated protein kinase (MAPK) or Syk/Btk/phospholipase Cγ2 (PLCγ2) phosphorylation. Taken together, these results suggest the potential of TT in the treatment of diseases of increased bone resorption. [ABSTRACT FROM AUTHOR]

Abstract Osteoclasts are multinucleated cells that originate from hemopoietic stem cells. Targeting over activated osteoclasts is thought to be an effective therapeutic approach to osteoporosis. In a previous study, we reported that Tatarinan O , a lignin-like compound, suppressed RANKL-induced osteoclastogenesis. In this study, we further examined the effects on osteoclast formation of three lignin-like compounds including Tatarinan N (TN), Tatarinan U (TU) and Tatarinan V (TV), all containing a common structure of asarone. We found that only TN suppressed RANKL-induced osteoclast differentiation, bone resorption pit formation and F-acting ring formation. TU and TV did not influence RANKL-induced osteoclastogenesis. We also found that TN dose-dependently inhibited the expression of osteoclastogenesis-associated genes, including TRAP, cathepsin K and MMP-9. Furthermore, we found that TN down-regulated the key transcription factor NFATc1 and c-Fos by preventing the activation of NF-κB and phosphorylation of MAPKs including ERK1/2 and p38 but not JNK. TN attenuated calcineurin expression via suppression of the Btk-PLCγ2 cascade and reduction of intracellular Ca2+, modulating NFATc1 activation. Taking together, our results indicated that TN might have therapeutic potential for osteoporosis. Highlights • Tatarinan N inhibited RANKL-induced osteoclast formation, F-actin ring formation and bone resorption. • Tatarinan N suppressed RANKL-induced expression of TRAP, CTSK, MMP-9, c-Fos and NFATc1. • Tatarinan N inhibited RANKL-induced activation of NF-κB and phosphorylation of ERK1/2 and p38. • Tatarinan N attenuated Btk/PLCγ2/Ca2+ oscillation/calcineurin signaling. [ABSTRACT FROM AUTHOR]

Previous studies reported that sciadopitysin (Sc), a type of biflavonoids, protects reactive oxygen species (ROS)-mediated osteoblast dysfunction, but its role in osteoclastogenesis remains unclear. In this study, we observed that Sc dose-dependently suppressed RANKL-induced osteoclastogenesis and bone resorption. Our results indicated that Sc treatment strongly reduced RANKL-induced osteoclast-specific genes expression, including cathepsin K (CTSK), tartrate-resistant acid phosphatase (TRAP) and MMP-9. Furthermore, Sc apparently attenuated RANKL-increased expressions of c-Fos and NFATc1. Meanwhile, Sc also strikingly inhibited the activation of NF-κB without altering the phosphorylation of MAPKs (p38, JNK and ERK1/2). Finally, our study demonstrated that Sc administration could reverse the bone loss in LPS-induced mice model. This study suggests that Sc inhibits RANKL-induced osteoclastogenesis and bone loss by inhibiting NF-κB activation and reducing the expression of c-Fos and NFATc1. Therefore, Sc might be benefit for RANKL-mediated osteolytic bone diseases. [ABSTRACT FROM AUTHOR]

This paper reported the fabrication of high-performance ZnInS photocatalysts using ionic liquid microemulsion-mediated hydrothermal method under facile conditions. The influences of reaction temperature and aging time on the catalytic properties of the specimens were investigated. The crystal phase, optical property, and morphological structure of the obtained catalysts were characterized using X-ray diffraction, UV-visible spectrometer, electronic microscope, and N adsorption-desorption techniques. The results indicated that all of the ZnInS samples prepared by this method consisted of the hexagonal phase and exhibited excellent photoresponse capability and photocatalytic performance. The sample prepared at 60 °C with an aging time of 6 h showed the best photocatalytic performance, and the corresponding degradation rate of methyl orange was measured as 98.5% after 10 min. The current study highlights an efficient and environmental method for the formulation of high-performance ZnInS. [ABSTRACT FROM AUTHOR]

Osteoclasts (OC) are large multinucleated cells derived from monocyte/macrophage precursors. Suppressing osteoclastogenesis is considered as an effective therapeutic approach to erosive bone disease. The root of Acorus tatarinowii Schott , a well-known traditional Chinese medicine was used to treat rheumatosis and other inflammatory disease. However, the effects of tatarinan O (TO), one of the lignin-like compounds isolated from the roots of Acorus tatarinowii Schott during bone development are still unclear. In the present study, we explored the effect of TO on RANKL-induced osteoclastogenesis in vitro. TO was found to suppress osteoclast differentiation from RANKL-stimulated mouse bone marrow macrophages (BMMs) without significant cytotoxicity. TO also dose-dependently suppressed bone resorption activity of mature osteoclasts. Additionally, TO apparently inhibited the expression of osteoclastic marker genes, such as MMP-9, Cts K and TRAP. Furthermore, our results showed that TO decreased RANKL-induced expression of c-Fos and NFATc1 without influencing NF-κB activation and MAPK phosphorylation. Hence, for the first time we revealed that TO dose-dependently inhibited osteoclastogenesis from RANKL-stimulated mouse BMMs via decreasing the expression of NFATc1 and c-Fos. [ABSTRACT FROM AUTHOR]

Osteoclasts (OC) are bone-specific multinucleated giant cells (MNCs) derived from the monocyte/macrophage hematopoietic lineage cells. Inhibiting osteoclast formation is considered as an effective therapeutic approach for the treatment of the pathological bone loss. In this study, we investigated effects of 17-hydroxy-jolkinolide A (HJA), an ent-abietane diterpenoid isolated from the dried root of Euphorbia fischeriana , on osteoclastogenesis induced by RANKL. The results showed that HJA significantly inhibited RANKL-induced osteoclast formation from primary bone marrow macrophages (BMMs). HJA also prevented bone resorption by mature osteoclasts in a dose-dependent manner. In addition, the expression of osteoclastic marker genes, such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (Cts K) and MMP-9, was significantly inhibited by HJA. Furthermore, HJA also significantly inhibited RANKL-induced activation of NF-κB and phosphorylation of MAPK. Our results indicate that HJA has an inhibitory role in the bone loss by preventing osteoclast formation as well as its bone resorptive activity. Therefore, HJA may be useful as a therapeutic reagent for bone loss-associated diseases. [ABSTRACT FROM AUTHOR]

• AGR inhibited RANKL-induced osteoclast formation. • AGR inhibited F-actin ring formation and osteoclast-mediated bone resorption. • AGR did not affect NF-κB, MAPKs and calcineurin activation and GSK3β inactivation. • AGR inhibited transcription of NFATc1 and its target genes via Blimp1-Bcl6 axis. • AGR mitigated LPS-induced bone loss in mice. Excessive activity of osteoclasts causes many bone-related diseases, such as rheumatoid arthritis and osteoporosis. Agrimophol (AGR), a phenolic compound, originated from Agrimonia pilosa Ledeb. In prior studies, AGR is reported to possess schistosomicidal and mycobactericidal activities. However, no reports covered its anti-osteoclastogenesis characteristic. In this study, we found that AGR inhibited RANKL-induced osteoclastogenesis, bone-resorption, F-actin ring formation, and the mRNA expression of osteoclast-associated genes such as CTSK, TRAP, MMP-9, and ATP6v0d2 in vitro. In addition, AGR suppressed RANKL-induced expression of c-Fos and NFATc1. However, AGR treatment did not affect NF-κB activation and MAPKs phosphorylation in RANKL-stimulated BMMs, which implicated that AGR might not influence the initial expression of NFATc1 mediated by NF-κB and MAPKs signaling. Our results further indicated that AGR did not alter phosphorylation levels of GSK3β and the expression of calcineurin, which implicated that AGR treatment might not interfere with phosphorylation and de-phosphorylation of NFATc1 mediated by GSK3β and calcineurin, respectively. B-lymphocyte-induced maturation protein-1 (Blimp1), which was regarded as a transcriptional repressor of negative regulators of osteoclastogenesis, was markedly attenuated in the presence of AGR, leading to the enhanced expression of B-cell lymphoma 6 (Bcl-6). Meanwhile, Blimp1 knockdown in BMMs by siRNA strongly enhanced the expression of Bcl6 and reduced NFATc1 induction by RANKL. These findings suggested that AGR inhibited RANKL-induced osteoclast differentiation through Blimp1-Bcl-6 signaling mediated modulation of NFATc1 and its target genes. Consistent with these in vitro results, AGR exhibited a protective influence in an in vivo mouse model of LPS-induced bone loss by suppressing excessive osteoclast activity and attenuating LPS-induced bone destruction. Hence, these results identified that AGR could be considered as a potential therapeutic agent against bone lysis disease. [ABSTRACT FROM AUTHOR]