Dysregulation of ectonucleotidase-mediated extracellular adenosine during postmenopausal bone loss

Adenosine and its receptors play a key role in bone homeostasis and regeneration. Extracellular adenosine is generated from CD39 and CD73 activity in the cell membrane, through conversion of adenosine triphosphate to adenosine monophosphate (AMP) and AMP to adenosine, respectively. Despite the relevance of CD39/CD73 to bone health, the roles of these enzymes in bona fide skeletal disorders remain unknown. We demonstrate that CD39/CD73 expression and extracellular adenosine levels in the bone marrow are substantially decreased in animals with osteoporotic bone loss. Knockdown of estrogen receptors ESR1 and ESR2 in primary osteoprogenitors and osteoclasts undergoing differentiation showed decreased coexpression of membrane-bound CD39 and CD73 and lower extracellular adenosine. Targeting the adenosine A2B receptor using an agonist attenuated bone loss in ovariectomized mice. Together, these findings suggest a pathological association of purine metabolism with estrogen deficiency and highlight the potential of A2B receptor as a target to treat osteoporosis.

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Scopolin Attenuates Osteoporotic Bone Loss in Ovariectomized Mice

Nutrients ◽

10.3390/nu12113565 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3565

Author(s):

Eunkuk Park ◽

Jeonghyun Kim ◽

Hyun-Seok Jin ◽

Chun Whan Choi ◽

Tae Hyun Choi ◽

...

Keyword(s):

Bone Loss ◽

Osteoclast Differentiation ◽

Bone Destruction ◽

Osteoporotic Bone ◽

Nodule Formation ◽

Mineral Density ◽

Bone Mineral Density Loss ◽

Treatment And Prevention ◽

Ovariectomized Mice ◽

Bioactive Constituent

Bone remodeling is a renewal process regulated by bone synthesis (osteoblasts) and bone destruction (osteoclasts). A previous study demonstrated that Lycii radicis cortex (LRC) extract inhibited ovariectomized (OVX)-induced bone loss in mice. This study investigated the anti-osteoporotic effects of bioactive constituent(s) from the LRC extract. The effective compound(s) were screened, and a single compound, scopolin, which acts as a phytoalexin, was chosen as a candidate component. Scopolin treatment enhanced alkaline phosphatase activity and increased mineralized nodule formation in MC3T3-E1 pre-osteoblastic cells. However, osteoclast differentiation in primary-cultured monocytes was reduced by treatment with scopolin. Consistently, scopolin treatment increased osteoblast differentiation in the co-culture of monocytes (osteoclasts) and MC3T3-E1 (osteoblast) cells. Scopolin treatment prevented bone mineral density loss in OVX-induced osteoporotic mice. These results suggest that scopolin could be a therapeutic bioactive constituent for the treatment and prevention of osteoporosis.

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CD73 Is Critical for the Resolution of Murine Colonic Inflammation

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/260983 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 29

Author(s):

Margaret S. Bynoe ◽

Adam T. Waickman ◽

Deeqa A. Mahamed ◽

Cynthia Mueller ◽

Jeffrey H. Mills ◽

...

Keyword(s):

Immune Responses ◽

Dextran Sulfate ◽

Adenosine Monophosphate ◽

Negative Regulator ◽

Cellular Damage ◽

Wild Type ◽

Extracellular Adenosine ◽

Glycosyl Phosphatidylinositol ◽

Cd73 Expression

CD73 is a glycosyl-phosphatidylinositol-(GPI-) linked membrane protein that catalyzes the extracellular dephosphorylation of adenosine monophosphate (AMP) to adenosine. Adenosine is a negative regulator of inflammation and prevents excessive cellular damage. We investigated the role of extracellular adenosine in the intestinal mucosa during the development of Dextran-Sulfate-Sodium-(DSS-)salt-induced colitis in mice that lack CD73 (CD73−/−) and are unable to synthesize extracellular adenosine. We have found that, compared to wild-type (WT) mice, CD73−/−mice are highly susceptible to DSS-induced colitis. CD73−/−mice exhibit pronounced weight loss, slower weight recovery, an increase in gut permeability, a decrease in expression of tight junctional adhesion molecules, as well as unresolved inflammation following the removal of DSS. Moreover, colonic epithelia in CD73−/−mice exhibited increased TLR9 expression, high levels of IL-1βand TNF-α, and constitutive activation of NF-κB. We conclude that CD73 expression in the colon is critical for regulating the magnitude and the resolution of colonic immune responses.

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Low-intensity ultrasound stimulation prevents osteoporotic bone loss in young adult ovariectomized mice

Journal of Orthopaedic Research® ◽

10.1002/jor.21191 ◽

2010 ◽

Vol 29 (1) ◽

pp. 116-125 ◽

Cited By ~ 16

Author(s):

Dohyung Lim ◽

Chang-Yong Ko ◽

Dong Hyun Seo ◽

Dae Gon Woo ◽

Jin Man Kim ◽

...

Keyword(s):

Young Adult ◽

Bone Loss ◽

Osteoporotic Bone ◽

Low Intensity ◽

Ultrasound Stimulation ◽

Ovariectomized Mice ◽

Low Intensity Ultrasound

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

Cellular Physiology and Biochemistry ◽

10.1159/000496039 ◽

2018 ◽

Vol 51 (6) ◽

pp. 2858-2871 ◽

Cited By ~ 8

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.

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Anti-Osteoporotic Effects of Combined Extract of Lycii Radicis Cortex and Achyranthes japonica in Osteoblast and Osteoclast Cells and Ovariectomized Mice

Nutrients ◽

10.3390/nu11112716 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2716 ◽

Cited By ~ 3

Author(s):

Eunkuk Park ◽

Jeonghyun Kim ◽

Subin Yeo ◽

Eunguk Lim ◽

Chun Whan Choi ◽

...

Keyword(s):

Bone Loss ◽

Osteoclast Differentiation ◽

Osteoporotic Bone ◽

Osteoblastic Cell ◽

Mouse Bone Marrow ◽

Osteoblastic Cell Line ◽

Ovariectomized Mice ◽

Achyranthes Japonica

Osteoporosis is characterized by low bone density and quality with high risk of bone fracture. Here, we investigated anti-osteoporotic effects of natural plants (Lycii Radicis Cortex (LRC) and Achyranthes japonica (AJ)) in osteoblast and osteoclast cells in vitro and ovariectomized mice in vivo. Combined LRC and AJ enhanced osteoblast differentiation and mineralized bone-forming osteoblasts by the up-regulation of bone metabolic markers (Alpl, Runx2 and Bglap) in the osteoblastic cell line MC3T3-E1. However, LRC and AJ inhibited osteoclast differentiation of monocytes isolated from mouse bone marrow. In vivo experiments showed that treatment of LRC+AJ extract prevented OVX-induced trabecular bone loss and osteoclastogenesis in an osteoporotic animal model. These results suggest that LRC+AJ extract may be a good therapeutic agent for the treatment and prevention of osteoporotic bone loss.

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Poria Cocos Ameliorates Bone Loss in Ovariectomized Mice and Inhibits Osteoclastogenesis In Vitro

Nutrients ◽

10.3390/nu12051383 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1383 ◽

Cited By ~ 1

Author(s):

Youn-Hwan Hwang ◽

Seon-A Jang ◽

Ami Lee ◽

Taesoo Kim ◽

Hyunil Ha

Keyword(s):

Bone Loss ◽

Postmenopausal Osteoporosis ◽

Osteoclast Differentiation ◽

Nuclear Factor ◽

Bone Homeostasis ◽

Estrogen Deprivation ◽

Activated T Cells ◽

Poria Cocos ◽

Ovariectomized Mice

Estrogen deprivation in postmenopausal women causes disruption of bone homeostasis, resulting in bone loss and osteoporosis. Conventional therapies can exert adverse effects. The sclerotum of Poria cocos has been used in traditional medicine and as a nutritional supplement and to treat various diseases. However, the effects of P. cocos on the bone remain largely undetermined. In this study, we examined the effects of P. cocos hydroethanolic extract (PC) on osteoclast differentiation and estrogen-deprivation-induced bone loss in an ovariectomized mouse model of postmenopausal osteoporosis. PC-mediated inhibition of receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation and resorption activity suppressed RANKL-induced expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1), which is a crucial transcription factor for osteoclast differentiation. In ovariectomized mice, PC markedly alleviated trabecular bone loss and reduced the accumulation of lipid droplets in the bone marrow. We additionally identified ten triterpenoid constituents of PC using UPLC-MS/MS analysis. Our results indicate that PC negatively regulated osteoclast differentiation and function, and can potentially be used to manage postmenopausal osteoporosis.

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BMP9 Prevents Bone Loss in Ovariectomized Mice by Dual Regulation of Bone Remodeling

SSRN Electronic Journal ◽

10.2139/ssrn.3422965 ◽

2019 ◽

Cited By ~ 1

Author(s):

Yan-man Zhou ◽

Yu-ying Yang ◽

Yi-xuan Jing ◽

Tian-jiao Yuan ◽

Li-hao Sun ◽

...

Keyword(s):

Bone Loss ◽

Bone Remodeling ◽

Ovariectomized Mice

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Cyclic Adenosine Monophosphate-dependent Phosphorylation of Specific Fat Cell Membrane Proteins by an Endogenous Membrane-bound Protein Kinase

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)42137-6 ◽

1974 ◽

Vol 249 (21) ◽

pp. 6854-6865 ◽

Cited By ~ 7

Author(s):

Kwen-Jen Chang ◽

Norman A. Marcus ◽

Pedro Cuatrecasas

Keyword(s):

Protein Kinase ◽

Membrane Proteins ◽

Cell Membrane ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Fat Cell ◽

Cell Membrane Proteins ◽

Membrane Bound

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

Biomedicines ◽

10.3390/biomedicines9020199 ◽

2021 ◽

Vol 9 (2) ◽

pp. 199

Author(s):

Urara Tanaka ◽

Shunichi Kajioka ◽

Livia S. Finoti ◽

Daniela B. Palioto ◽

Denis F. Kinane ◽

...

Keyword(s):

Dna Methylation ◽

Bone Resorption ◽

Bone Loss ◽

Inflammatory Cytokines ◽

Osteoclast Differentiation ◽

Tartrate Resistant Acid Phosphatase ◽

Dependent Manner ◽

Bone Homeostasis ◽

Osteoblastic Cell Line ◽

Anti Inflammatory

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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