scholarly journals Evaluation of Isoflavones as Bone Resorption Inhibitors upon Interactions with Receptor Activator of Nuclear Factor-κB Ligand (RANKL)

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 206 ◽  
Author(s):  
Małgorzata Zakłos-Szyda ◽  
Grażyna Budryn ◽  
Joanna Grzelczyk ◽  
Horacio Pérez-Sánchez ◽  
Dorota Żyżelewicz

Receptor activator of nuclear factor-κB ligand (RANKL) is a cytokine responsible for bone resorption. It binds its receptor RANK, which activates osteoporosis. High levels of osteoprotegerin (OPG) competitively binding RANKL limit formation of ligand-receptor complexes and enable bone mass maintenance. The new approach to prevent osteoporosis is searching for therapeutics that can bind RANKL and support OPG function. The aim of the study was to verify the hypothesis that isoflavones can form complexes with RANKL limiting binding of the cytokine to its receptor. Interactions of five isoflavones with RANKL were investigated by isothermal titration calorimetry (ITC), by in silico docking simulation and on Saos-2 cells. Daidzein and biochanin A showed the highest affinity for RANKL. Among studied isoflavones coumestrol, formononetin and biochanin A showed the highest potential for Saos-2 mineralization and were able to regulate the expression of RANKL and OPG at the mRNA levels, as well as osteogenic differentiation markers: alkaline phosphatase (ALP), collagen type 1, and Runt-related transcription factor 2 (Runx2). Comparison of the osteogenic activities of isoflavones showed that the use of physicochemical techniques such as ITC or in silico docking are good tools for the initial selection of substances showing a specific bioactivity.

Endocrinology ◽  
2007 ◽  
Vol 148 (6) ◽  
pp. 2708-2715 ◽  
Author(s):  
Kiyoshi Hiramatsu ◽  
Yutaro Asaba ◽  
Sunao Takeshita ◽  
Yuji Nimura ◽  
Sawako Tatsumi ◽  
...  

We previously identified γ-glutamyltransferase (GGT) by expression cloning as a factor inducing osteoclast formation in vitro. To examine its pathogenic role in vivo, we generated transgenic mice that overexpressed GGT in a tissue-specific manner utilizing the Cre-loxP recombination system. Systemic as well as local production of GGT accelerated osteoclast development and bone resorption in vivo by increasing the sensitivity of bone marrow macrophages to receptor activator of nuclear factor-κB ligand, an essential cytokine for osteoclastogenesis. Mutated GGT devoid of enzyme activity was as potent as the wild-type molecule in inducing osteoclast formation, suggesting that GGT acts not as an enzyme but as a cytokine. Recombinant GGT protein increased receptor activator of nuclear factor-κB ligand expression in marrow stromal cells and also stimulated osteoclastogenesis from bone marrow macrophages at lower concentrations. Thus, GGT is implicated as being involved in diseases characterized by accelerated osteoclast development and bone destruction and provides a new target for therapeutic intervention.


Endocrinology ◽  
2002 ◽  
Vol 143 (9) ◽  
pp. 3658-3670 ◽  
Author(s):  
Edith Bonnelye ◽  
Vanessa Kung ◽  
Catherine Laplace ◽  
Deborah L. Galson ◽  
Jane E. Aubin

Abstract The orphan nuclear estrogen receptor-related receptor α (ERRα) is expressed by osteoblastic cells and plays a functional role in osteoprogenitor proliferation and differentiation. To dissect further the role of ERRα in bone, we investigated the effects of estrogen (E2) on ERRα both in vitro and in vivo. Chronic treatment of fetal rat calvaria cells with E2-stimulated bone nodule formation and up-regulated ERRα mRNA expression at early (10 h and d 8) but not later times in culture, suggesting a link between ERRα and E2 during osteoprogenitor proliferation. ERRα mRNA levels were significantly lower in ovariectomized adult rat bones vs. those of sham-operated rats early (1 d and 1 wk) post surgery, but levels returned to control levels thereafter. ERRα is also expressed in osteoclasts (tartrate-resistant acid phosphatase + multinucleated cells) in vivo and in vitro (RAW 264.7 cells) and ovariectomization lowered the OPG/receptor activator of nuclear factor κB ligand expression ratio. Down-regulation of ERRα expression via antisense treatment of rat calvaria cells not only inhibited osteogenesis but also increased adipocyte colony formation and changed the OPG/receptor activator of nuclear factor κB ligand ratio. These data suggest that ERRα is regulated by estrogen in bone in which it may play a functional role at several levels (osteoblasts, adipocytes, and osteoclasts) in E2 deficiency diseases such as osteoporosis.


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