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Novel antiosteoclastogenic activity of phloretin antagonizing RANKL ‐induced osteoclast differentiation of murine macrophages
Author(s) -
Kim JungLye,
Kang MinKyung,
Gong JuHyun,
Park SinHye,
Han SeonYoung,
Kang YoungHee
Publication year - 2012
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201100831
Subject(s) - phloretin , chemistry , rankl , osteoclast , bone resorption , cathepsin k , microphthalmia associated transcription factor , resorption , endocrinology , multinucleate , medicine , cathepsin , microbiology and biotechnology , biochemistry , activator (genetics) , receptor , transcription factor , biology , enzyme , gene
Scope Bone‐remodeling imbalance resulting in more bone resorption than bone formation is known to cause skeletal diseases such as osteoporosis. Phloretin, a natural dihydrochalcone compound largely present in apple peels, possesses antiphotoaging, and antiinflammatory activity. Methods and results Phloretin inhibited receptor activator of NF‐κB ligand (RANKL)‐induced formation of multinucleated osteoclasts and diminished bone resorption area produced during the osteoclast differentiation process. It was also found that ≥10 μM phloretin reduced RANKL‐enhanced tartrate‐resistance acid phosphatase activity and matrix metalloproteinase‐9 secretion in a dose‐dependent manner. The phloretin treatment retarded RANKL‐induced expression of carbonic anhydrase II, vacuolar‐type H + ‐ATPase D2 and β3 integrin, all involved in the bone resorption. Furthermore, submicromolar phloretin diminished the expression and secretion of cathepsin K elevated by RANKL, being concurrent with inhibition of TRAF6 induction and NF‐κB activation. RANKL‐induced activation of nuclear factor of activated T cells c1 (NFATc1) and microphthalmia‐associated transcription factor was also suppressed by phloretin. Conclusion These results demonstrate that the inhibition of osteoclast differentiation and bone resorption by phloretin entail a disturbance of TRAF6‐NFATc1‐NF‐κB pathway triggered by RANKL. Therefore, phloretin may be a potential therapeutic agent targeting osteoclast differentiation and bone resorption in skeletal diseases such as osteoporosis.