Protective Effects of Estradiol on Ethanol-Induced Bone Loss Involve Inhibition of Reactive Oxygen Species Generation in Osteoblasts and Downstream Activation of the Extracellular Signal-Regulated Kinase/Signal Transducer and Activator of Transcription 3/Receptor Activator of Nuclear Factor-κB Ligand Signaling Cascade

2007 ◽  
Vol 324 (1) ◽  
pp. 50-59 ◽  
Author(s):  
Jin-Ran Chen ◽  
Kartik Shankar ◽  
Shanmugam Nagarajan ◽  
Thomas M. Badger ◽  
Martin J. J. Ronis
Keyword(s):  
Reactive Oxygen Species Generation ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Oxygen Species ◽  
Protective Effects ◽  
Signal Transducer ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Receptor Activator ◽  
Transcription 3

scholarly journals Lack of NOD2 attenuates ovariectomy-induced bone loss via inhibition of osteoclasts

2017 ◽  
Vol 235 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Ke Ke ◽  
Ok-Joo Sul ◽  
Soo-Wol Chung ◽  
Jae-Hee Suh ◽  
Hye-Seon Choi
Keyword(s):  
Bone Loss ◽  
Nuclear Factor Kappa B ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nuclear Factor Κb ◽  
Innate Immune ◽  
Nuclear Factor ◽  
Oxygen Species ◽  
Receptor Activator ◽  
Recognition Receptor ◽  
Oligomerization Domain

Nucleotide-binding oligomerization domain-2 (NOD2) is a pattern recognition receptor of the innate immune system. It interacts with serine–threonine kinases to induce activation of nuclear factor κB (NF-κB), which is important for receptor activator of nuclear factor kappa-B ligand (RANKL) signaling. We tested the idea that NOD2 modulates bone metabolism via an action on osteoclasts (OCs). The absence of NOD2 reduced ovariectomy-induced bone loss in mice, and lowered the area and the activity of OCs, by impairing RANKL signaling. It also reduced the level of reactive oxygen species (ROS), as well as of NF-κB-DNA binding upon RANKL exposure. NOD2 was found to physically interact with nicotinamide adenine dinucleotide phosphate oxidase 1, and this led to increased production of ROS in OCs. Our data suggest that NOD2 contributes to bone loss in estrogen deficiency by elevating ROS levels in OCs.

scholarly journals Interleukin-6 Inhibits Receptor Activator of Nuclear Factor κB Ligand-Induced Osteoclastogenesis by Diverting Cells into the Macrophage Lineage: Key Role of Serine727 Phosphorylation of Signal Transducer and Activator of Transcription 3

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3688-3697 ◽  
Author(s):  
Laurence Duplomb ◽  
Marc Baud’huin ◽  
Céline Charrier ◽  
Martine Berreur ◽  
Valérie Trichet ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Mouse Bone Marrow ◽  
Nuclear Factor ◽  
Signal Transducer ◽  
Blood Monocytes ◽  
Receptor Activator ◽  
Few Data ◽  
Macrophage Lineage

Osteoclasts are bone-resorptive cells that differentiate from hematopoietic precursors upon receptor activator of nuclear factor κB ligand (RANKL) activation. Previous studies demonstrated that IL-6 indirectly stimulates osteoclastogenesis through the production of RANKL by osteoblasts. However, few data described the direct effect of IL-6 on osteoclasts. To investigate this effect, we used several models: murine RAW264.7 cells, mouse bone marrow, and human blood monocytes. In the three models used, the addition of IL-6 inhibited RANKL-induced osteoclastogenesis. Furthermore, IL-6 decreased the expression of osteoclast markers and up-modulated macrophage markers. To elucidate this inhibition, signal transducer and activator of transcription (STAT) 3, the main signaling molecule activated by IL-6, was analyzed. Addition of two STAT3 inhibitors completely abolished RANKL-induced osteoclastogenesis, revealing a key role of STAT3. We demonstrated that a basal level of phosphorylated-STAT3 on Serine727 associated with an absence of phosphorylation on Tyrosine705 is essential for osteoclastogenesis. Furthermore, a decrease of Serine727 phosphorylation led to an inhibition of osteoclast differentiation, whereas an increase of Tyrosine705 phosphorylation upon IL-6 stimulation led to the formation of macrophages instead of osteoclasts. In conclusion, we showed for the first time that IL-6 inhibits RANKL-induced osteoclastogenesis by diverting cells into the macrophage lineage, and demonstrated the functional role of activated-STAT3 and its form of phosphorylation in the control of osteoclastogenesis.

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