scholarly journals Fexaramine Inhibits Receptor Activator of Nuclear Factor-κB Ligand-induced Osteoclast Formation via Nuclear Factor of Activated T Cells Signaling Pathways

2017 ◽  
Vol 24 (4) ◽  
pp. 207 ◽  
Author(s):  
Ting Zheng ◽  
Na-Young Kim ◽  
Mijung Yim
2021 ◽  
Vol 30 ◽  
pp. 096368972199032
Author(s):  
Wei Wang ◽  
Bo Wang

Osteoporosis is a common bone disease that is characterized by decreased bone mass and fragility fractures. Isofraxidin is a hydroxy coumarin with several biological and pharmacological activities including an anti-osteoarthritis effect. However, the role of isofraxidin in osteoporosis has not yet been investigated. In the present study, we used receptor activator of nuclear factor-κB ligand (RANKL) to induce osteoclast formation in primary bone marrow macrophages (BMMs). Our results showed that RANKL treatment significantly increased tartrate-resistant acid phosphatase (TRAP) activity, as well as the expression of osteoclastogenesis-related markers including MMP-9, c-Src, and cathepsin K at both mRNA and protein levels; however, these effects were inhibited by isofraxidin in BMMs. In addition, luciferase reporter assay demonstrated that isofraxidin treatment suppressed the RANKL-induced an increase in nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) transcriptional activity. Besides, the decreased expression level of IκBα and increased levels of p-p65, p-IκBα, and p-Akt in RANKL-induced BMMs were attenuated by isofraxidin. Moreover, NFATc1 overexpression rescued the anti-osteoclastogenic effect of isofraxidin with increased expression levels of MMP-9, c-Src, and cathepsin K. Taken together, these findings indicated that isofraxidin inhibited RANKL-induced osteoclast formation in BMMs via inhibiting the activation of NF-κB/NFATc1 and Akt/NFATc1 signaling pathways. Thus, isofraxidin might be a therapeutic agent for the treatment of osteoporosis.


2019 ◽  
Vol 15 (64) ◽  
pp. 298 ◽  
Author(s):  
Shila Samuel ◽  
Ramasubramanian Venkatachalam ◽  
Shanmuganathan Pandiarajan ◽  
Tholcopiyan Loganathan ◽  
ShyamSundar Jaganathan ◽  
...  

2000 ◽  
Vol 20 (2) ◽  
pp. 702-712 ◽  
Author(s):  
Chi-Wing Chow ◽  
Roger J. Davis

ABSTRACT Calcium-stimulated nuclear factor of activated T cells (NFAT) transcription activity at the interleukin-2 promoter is negatively regulated by cyclic AMP (cAMP). This effect of cAMP is mediated, in part, by protein kinase A phosphorylation of NFAT. The mechanism of regulation involves the creation of a phosphorylation-dependent binding site for 14-3-3. Decreased NFAT phosphorylation caused by the calcium-stimulated phosphatase calcineurin, or mutation of the PKA phosphorylation sites, disrupted 14-3-3 binding and increased NFAT transcription activity. In contrast, NFAT phosphorylation caused by cAMP increased 14-3-3 binding and reduced NFAT transcription activity. The regulated interaction between NFAT and 14-3-3 provides a mechanism for the integration of calcium and cAMP signaling pathways.


Blood ◽  
2002 ◽  
Vol 100 (13) ◽  
pp. 4615-4621 ◽  
Author(s):  
Nicola Giuliani ◽  
Simona Colla ◽  
Roberto Sala ◽  
Matteo Moroni ◽  
Mirca Lazzaretti ◽  
...  

The biologic mechanisms involved in the pathogenesis of multiple myeloma (MM) bone disease are not completely understood. Recent evidence suggests that T cells may regulate bone resorption through the cross-talk between the critical osteoclastogenetic factor, receptor activator of nuclear factor-κB ligand (RANKL), and interferon γ (IFN-γ) that strongly suppresses osteoclastogenesis. Using a coculture transwell system we found that human myeloma cell lines (HMCLs) increased the expression and secretion of RANKL in activated T lymphocytes and similarly purified MM cells stimulated RANKL production in autologous T lymphocytes. In addition, either anti–interleukin 6 (anti–IL-6) or anti–IL-7 antibody inhibited HMCL-induced RANKL overexpression. Consistently, we demonstrated that HMCLs and fresh MM cells express IL-7 mRNA and secrete IL-7 in the presence of IL-6 and that bone marrow (BM) IL-7 levels were significantly higher in patients with MM. Moreover, we found that the release of IFN-γ by T lymphocytes was reduced in presence of both HMCLs and purified MM cells. Furthermore, in a stromal cell–free system, osteoclastogenesis was stimulated by conditioned medium of T cells cocultured with HMCLs and inhibited by recombinant human osteoprotegerin (OPG; 100 ng/mL to 1 μg/mL). Finally, RANKL mRNA was up-regulated in BM T lymphocytes of MM patients with severe osteolytic lesions, suggesting that T cells could be involved at least in part in MM-induced osteolysis through the RANKL overexpression.


2004 ◽  
Vol 32 (1) ◽  
pp. 113-115 ◽  
Author(s):  
P. Antony ◽  
J.B. Petro ◽  
G. Carlesso ◽  
N.P. Shinners ◽  
J. Lowe ◽  
...  

Engagement of the B-cell antigen receptor (BCR) induces the activation of various transcription factors, including NFAT (nuclear factor of activated T-cells) and NF-κB (nuclear factor κB), which participate in long-term biological responses such as proliferation, survival and differentiation of B-lymphocytes. We addressed the biochemical basis of this process using the DT40 chicken B-cell lymphoma. We discovered that Bruton's tyrosine kinase (BTK) and phospholipase C-γ2 (PLC-γ2) are required to activate NFAT and NF-κB, and to produce the lipid second messenger diacylglycerol in response to BCR cross-linking. Therefore the functional integrity of the BTK/PLC-γ2/diacylglycerol signalling axis is crucial for BCR-directed activation of both transcription factors NFAT and NF-κB.


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