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Inhibitory Effects of Red Raspberry Polyphenols on Osteoclastogenesis in RANKL‐Stimulated RAW264.7 Murine Macrophages
Author(s) -
Thomas Amber,
South Sanique,
Imrhan Victorine,
Prasad Chandan,
Vijayagopal Parakat,
Juma Shanil
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.691.31
Subject(s) - rankl , osteoclast , chemistry , tumor necrosis factor alpha , microbiology and biotechnology , bone remodeling , cytokine , biochemistry , cancer research , activator (genetics) , endocrinology , immunology , receptor , biology
Osteoclasts and osteoblasts regulate skeletal mass, structure, and strength via their respective roles in resorbing and forming bone. Osteoclasts, the cells associated with breakdown of bone, are stimulated by a cytokine known as RANKL (receptor activator of nuclear factor κB ligand), a member of the tumor necrosis factor (TNF) superfamily. Polyphenols such as flavonoids found in plant‐derived foods have demonstrated anti‐inflammatory effects in various tissues. Red raspberries are a rich source of such polyphenolic compounds. Using mouse macrophage cells (RAW 264.7), we examined whether red raspberry polyphenols (RRP) could inhibit the proliferation and activity of RANKL‐induced osteoclastic cells in a dose‐dependent manner. Tartrate resistant acid phosphatase (TRAP) activity and staining of TRAP positive multinucleated osteoclasts, used as indicators of osteoclast differentiation and activity, decreased in a dose dependent manner with RRP treatment. Although, nitrite concentrations were not influenced by RRP treatment, there was a reduction in interleukin (IL)‐1β and IL‐6 with RPP demonstrating its anti‐inflammatory role in bone cells. Western blot analyses showed a dose‐dependent reduction in expression of inducible nitric oxide synthase (iNOS) protein and bone morphogenetic protein‐2 (BMP‐2) by RRP indicating that the polyphenols act to retrain the RANKL mediated osteoclastogenesis. Overall, these findings suggest that the polyphenols associated with red raspberry would inhibit the negative effects of osteoclasts on bone health. Further investigation is warranted to elucidate the molecular mechanisms by which RRP affect osteoclastogenesis. Support or Funding Information Supported by funds from the Undergraduate Research Microgrant Program at Texas Woman's University. Lyophilized red raspberry was generously provided by Van Drunen Farms.