Related Experiment Video
Updated: Jul 9, 2026
A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation
Published on: March 15, 2018
Myricitrin as a potent inhibitor of osteoclast differentiation via RAW264.7 Cells, BMMs and ovariectomized mouse
Jianliang Li1, Yanhuai Ma2,3,4, Jiale Mai5,6
1Department of Traditional Chinese Medicine, School of Medicine, the Second Affiliated Hospital of South China University of Technology, Guangzhou First People's Hospital, 1 Panfu Road, Yuexiu District, Guangzhou, 510180, China.
Background:
Osteoporosis is a prevalent skeletal disorder marked by progressive bone loss and elevated fracture risk, primarily driven by excessive osteoclast-mediated bone resorption. Current therapeutic agents are limited by adverse effects, necessitating the exploration of safer, naturally derived compounds. Myricitrin, a bioactive flavonoid from Myrica rubra, has demonstrated anti-inflammatory and antioxidant properties, but its role in bone metabolism remains underexplored.
Objective:
This study aimed to investigate Myricitrin's anti-osteoclastic effects and underlying molecular mechanisms using in vitro osteoclast differentiation models and an in vivo ovariectomized (OVX) mouse model of postmenopausal osteoporosis.
Methods:
We evaluated the effects of Myricitrin on osteoclastogenesis in RAW264.7 murine macrophage cells and primary bone marrow-derived macrophages (BMMs). Osteoclast formation was assessed using TRAP staining, and gene and protein expression analyses were performed via qRT-PCR and Western blotting. Immunofluorescence staining was used to visualize the F-actin ring and Vinculin formation. MAPK signaling pathway components (p-ERK, p-JNK, p-p38MAPK) were analyzed, and RNA-sequencing followed by KEGG and GO enrichment assessed transcriptomic changes, particularly in cytokine and chemokine pathways. Using histological and molecular analyses, an OVX-induced osteoporosis model in C57BL/6J mice was employed to evaluate Myricitrin's protective effects on bone loss.
Results:
Myricitrin significantly inhibited osteoclast differentiation in RAW264.7 and BMMs, as evidenced by reduced TRAP-positive multinucleated cells and downregulation of osteoclast-specific markers, including Acp5, NFAT2, CTSK, and c-fos. It impaired cytoskeletal reorganization by decreasing the F-actin ring and Vinculin expression. Mechanistically, Myricitrin suppressed phosphorylation of key MAPK pathway proteins (ERK1/2, JNK, p38MAPK) in a dose-dependent manner. Transcriptomic analysis revealed altered expression of cytokine and chemokine signaling pathway genes. In vivo, Myricitrin administration dose-dependently mitigated OVX-induced bone loss, reduced osteoclast numbers, and downregulated osteoclast-related protein expression in femoral bone tissue.
Conclusions:
Our findings demonstrate that Myricitrin effectively suppresses osteoclast differentiation through correlative and pharmacological evidences and inhibit the MAPK pathway and modulation of cytokine signaling. The compound also exhibits significant bone-protective effects in OVX mice. These results suggest Myricitrin's promise as a natural, potential, and multi-targeted therapeutic candidate for osteoporosis treatment.
Insights
Myricitrin, a natural compound, effectively inhibits osteoclast differentiation and protects against bone loss in osteoporosis models. It targets the MAPK pathway and cytokine signaling, showing promise for osteoporosis treatment.
Area of Science:
- Bone Biology and Metabolism
- Natural Product Chemistry
- Pharmacology
Background:
- Osteoporosis is characterized by bone loss and increased fracture risk due to excessive osteoclast activity.
- Existing osteoporosis therapies have limitations, driving the search for safer natural alternatives.
- Myricitrin, a flavonoid from Myrica rubra, possesses anti-inflammatory and antioxidant properties but its bone metabolism effects are unknown.
Purpose of the Study:
- To investigate the anti-osteoclastic effects of Myricitrin.
- To elucidate the molecular mechanisms underlying Myricitrin's action on osteoclasts.
- To evaluate Myricitrin's efficacy in an in vivo model of postmenopausal osteoporosis.
Main Methods:
- In vitro studies using RAW264.7 cells and primary bone marrow-derived macrophages (BMMs) to assess osteoclast differentiation.
- Analysis of osteoclast markers (TRAP, Acp5, NFAT2, CTSK, c-fos), cytoskeletal organization (F-actin, Vinculin), and MAPK signaling pathway activation (ERK, JNK, p38).
- In vivo evaluation in an ovariectomized (OVX) mouse model to assess bone protection, osteoclast numbers, and related protein expression.
Main Results:
- Myricitrin significantly inhibited osteoclast formation and downregulated key osteoclast markers.
- It disrupted cytoskeletal organization and suppressed MAPK pathway phosphorylation.
- In OVX mice, Myricitrin reduced bone loss, decreased osteoclast numbers, and lowered osteoclast-related protein expression.
Conclusions:
- Myricitrin effectively suppresses osteoclast differentiation by inhibiting the MAPK pathway and modulating cytokine signaling.
- Myricitrin demonstrates significant bone-protective effects in an osteoporosis model.
- Myricitrin is a promising multi-targeted natural therapeutic candidate for osteoporosis.
