Related Experiment Video
Updated: Jul 1, 2025
A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation
Published on: March 15, 2018
Cyclin A1 (CCNA1) inhibits osteoporosis by suppressing transforming growth factor-beta (TGF-beta) pathway in
Xiao Du1, Chuanyi Zang1, Qinglei Wang2
1Department of Orthopedics, Beijing Geriatric Hospital, No.118 Hot Spring Road, Haidian District 100095, Beijing, China.
Background:
Osteoporosis is a genetic disease caused by the imbalance between osteoblast-led bone formation and osteoclast-induced bone resorption. However, further gene-related pathogenesis remains to be elucidated.
Methods:
The aberrant expressed genes in osteoporosis was identified by analyzing the microarray profile GSE100609. Serum samples of patients with osteoporosis and normal group were collected, and the mRNA expression of candidate genes was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The mouse cranial osteoblast MC3T3-E1 cells were treated with dexamethasone (DEX) to mimic osteoporosis in vitro. Alizarin Red staining and alkaline phosphatase (ALP) staining methods were combined to measure matrix mineralization deposition of MC3T3-E1 cells. Meanwhile, the expression of osteogenesis related genes including alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN), Osterix, and bone morphogenetic protein 2 (BMP2) were evaluated by qRT-PCR and western blotting methods. Then the effects of candidate genes on regulating impede bone loss caused by ovariectomy (OVX) in mice were studied.
Results:
Cyclin A1 (CCNA1) was found to be significantly upregulated in serum of osteoporosis patients and the osteoporosis model cells, which was in line with the bioinformatic analysis. The osteogenic differentiation ability of MC3T3-E1 cells was inhibited by DEX treatment, which was manifested by decreased Alizarin Red staining intensity, ALP staining intensity, and expression levels of ALP, OCN, OPN, Osterix, and BMP2. The effects of CCNA1 inhibition on regulating osteogenesis were opposite to that of DEX. Then, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that genes negatively associated with CCNA1 were enriched in the TGF-beta signaling pathway. Inhibitor of TGF-beta signaling pathway partly reversed osteogenesis induced by suppressed CCNA1. Furthermore, suppressed CCNA1 relieved bone mass of OVX mice in vivo.
Conclusion:
Downregulation of CCNA1 could activate TGF-beta signaling pathway and promote bone formation, thus playing a role in treatment of osteoporosis.
Insights
Downregulating Cyclin A1 (CCNA1) activates the TGF-beta signaling pathway, promoting bone formation. This finding offers a potential therapeutic strategy for treating osteoporosis by enhancing bone mass.
Area of Science:
- Genetics and Molecular Biology
- Bone Biology and Disease
- Biochemistry
Background:
- Osteoporosis is a genetic disorder characterized by an imbalance in bone formation and resorption.
- The precise gene-related pathogenesis of osteoporosis requires further elucidation.
Purpose of the Study:
- To identify key genes involved in osteoporosis pathogenesis.
- To investigate the role of Cyclin A1 (CCNA1) in bone metabolism.
- To explore the therapeutic potential of targeting CCNA1 in osteoporosis.
Main Methods:
- Microarray analysis (GSE100609) to identify differentially expressed genes in osteoporosis.
- Quantitative real-time polymerase chain reaction (qRT-PCR) for gene expression analysis in patient serum and cell models.
- In vitro studies using MC3T3-E1 cells treated with dexamethasone (DEX) to mimic osteoporosis.
- In vivo studies using ovariectomized (OVX) mice to assess bone mass changes.
Main Results:
- Cyclin A1 (CCNA1) was significantly upregulated in osteoporosis patients and models.
- Dexamethasone (DEX) treatment inhibited osteogenic differentiation in MC3T3-E1 cells, evidenced by reduced mineralization and key osteogenic gene expression.
- CCNA1 inhibition demonstrated opposite effects to DEX, promoting osteogenesis.
- KEGG analysis revealed enrichment of TGF-beta signaling pathway genes negatively associated with CCNA1.
- Inhibition of TGF-beta signaling partially reversed osteogenesis induced by CCNA1 suppression.
- Reduced CCNA1 expression ameliorated bone loss in OVX mice.
Conclusions:
- Downregulation of CCNA1 activates the TGF-beta signaling pathway.
- CCNA1 suppression promotes bone formation and could be a therapeutic target for osteoporosis.
- Targeting CCNA1 offers a promising strategy for enhancing bone mass in osteoporosis treatment.
Related Concept Videos
01:31Osteoclasts in Bone Remodeling
02:34Inhibition of Cdk Activity
00:50Anaphase Promoting Complex
01:17Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:16TGF - β Signaling Pathway
01:40Bone Remodeling