Trilobatin ameliorates bone loss via suppression of osteoclast cell differentiation and bone resorptive function in vitro and in vivo

• Published in: Life sciences (1973) Vol. 270; p. 119074
• Main Authors: Kim, Seong Cheol, Kim, Hyeon Jeong, Park, Gi Eun, Pandey, Ramesh Prasad, Lee, Jisun, Sohng, Jae Kyung, Park, Yong Il
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.04.2021; Elsevier BV
• Subjects: Actin; Animal models; Animals; Anti-osteoporosis; Biomarkers; Biomedical materials; Bone Density - drug effects; Bone loss; Bone mineral density; Bone resorption; Bone Resorption - drug therapy; Bone Resorption - metabolism; Cathepsin K; Cell differentiation; Cell Differentiation - drug effects; Chemical compounds; Densitometers; Differentiation (biology); Disease Models, Animal; Enzyme-linked immunosorbent assay; Female; Flavone glycosides; Flavonoids; Flavonoids - metabolism; Flavonoids - pharmacology; Gelatinase B; Gene expression; Genes; Macrophages; Mice; Mice, Inbred C57BL; Oral administration; Osteoclast differentiation; Osteoclastogenesis; Osteoclasts; Osteogenesis - drug effects; Osteoporosis; Osteoporosis - drug therapy; Osteoprotegerin; Ovariectomy; Pharmacology; Phloretin; Polymerase chain reaction; Polyphenols - metabolism; Polyphenols - pharmacology; Post-menopause; Proteins; RAW 264.7 Cells; Signaling; Src protein; TRAF6 protein; TRANCE protein; Trilobatin; Osteoclast differentiation; RANKL; Phz; OPG; Trilobatin; Tri; TRAP; Alen; Bone resorption; Phl; TRAF6; Phloretin; Anti-osteoporosis
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2021.119074

Due to on-going safety concerns or lack of efficacy of currently used medications for the treatment of osteoporosis (OP), identifying new therapeutic agents is an important part of research. In the present study, potential anti-osteoporotic activity of a natural flavonoid glycoside, trilobatin (phloretin 4-O-glucoside, Tri) was evaluated. Osteoclastic cells were established by treating the RAW264.7 macrophage cells with RANKL and ovariectomized (OVX) C57BL/6 female mice were used as an animal model of postmenopausal OP. Actin ring formation, expression levels of osteoclastogenic marker genes and bone resorptive proteins were measured by RT-PCR, western blot, or fluorometric assays. Bone mineral density (BMD) was determined by pDEXA densitometric measurement and serum osteoprotegerin (OPG) and RANKL were measured by ELISA. Tri (5–20 μM) significantly inhibited osteoclast formation and actin ring formation in RANKL-induced osteoclasts. Tri attenuated expression of osteoclastogenic genes (MMP-9 and cathepsin K), bone resorptive proteins (CA II and integrin β3), and osteoclastogenic signalling proteins (TRAF6, p-Pyk2, c-Cbl, and c-Src). Oral administration of Tri to OVX mice augmented BMD and serum OPG/RANKL ratio. Interestingly, while Tri and phloretin aglycone (Phl) showed similar levels of in vitro anti-osteoclastogenic activity, Tri more potently ameliorated bone loss than Phl in OVX mice. This study demonstrated that Tri inhibits osteoclastic cell differentiation and bone resorption by down-regulating the expression of osteoclastogenic marker genes and signalling proteins, bone resorptive proteins, and by augmenting serum OPG/RANKL ratio, suggesting that Tri can be a novel anti-osteoporotic compound for treating senile and postmenopausal OP. [Display omitted] •Phloretin 4-O-glucoside (Trilobatin, Tri) inhibits osteoclastic cell differentiation.•Tri suppresses RANKL-TRAF6-c-Src signalling pathway and cytoskeletal reorganization.•Tri attenuates expression of bone resorptive proteins, CA II and integrin β3.•Tri augments bone mineral density and serum OPG-to-RANKL ratio in OVX mice.•Tri can be a novel anti-osteoporotic compound for treating senile osteoporosis.