Related Experiment Video
Updated: Sep 20, 2025
Estrogen-Like Effect of Bazi Bushen Capsule in Ovariectomized Rats
Published on: April 7, 2023
ED-71 inhibited osteoclastogenesis by enhancing EphrinB2-EphB4 signaling between osteoclasts and osteoblasts in
Yuan Zhang1, Yuying Kou1, Panpan Yang1
1Department of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, China; Center of Osteoporosis and Bone Mineral Research, Shandong University, Jinan, China.
Background:
Osteoporosis is a degenerative skeletal disease essentially caused by bone remodeling disorder. EphrinB2-EphB4 signaling play critical regulatory roles in bone remodeling via communication between osteoclasts and osteoblasts. Eldecalcitol (ED-71), a new vitamin D analog, is a high-potential drug for treating osteoporosis; however, its mechanism has yet to be determined. This study aims to investigate whether EphrinB2-EphB4 signal mediates the process of osteoporosis improved by ED-71.
Materials And Methods:
An ovariectomized (OVX) rat model was constructed in vivo. ED-71 at 30 ng/kg was orally administered once daily for 8 weeks. Osteoclast activity and EphrinB2-EphB4 expression were evaluated by hematoxylin and eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemical staining. The mRNA levels of oxidation stress factors in the bone tissue were tested by reverse transcription polymerase chain reaction (RT-PCR). An H2O2-stimulated model in vitro was established to simulate the status of osteoporosis. Osteoclastogenesis and associated protein were detected by TRAP staining, F-actin ring formation assay, PCR, and Western blot analysis. EprhrinB2 and EphB4 levels were determined by immunofluorescence, PCR, and Western blot analysis. EprhrinB2 small-interfering RNA knocked down the EprhrinB2 in osteoclasts, and an EphB4 antibody blocked EphB4 in osteoblasts.
Results:
ED-71 prevented bone loss and decreased the number of osteoclasts in vivo relative to the OVX group. In addition, the bone tissue of OVX rat displayed as an increased level of oxidation stress, which could be inhibited by ED-71. In vitro, in the simulation of osteoporosis with H2O2, ED-71 reversed the increase H2O2-induced oxidative stress. ED-71 then inhibited osteoclastogenesis and osteoclast function, accompanied by increased EphrinB2 expression in osteoclasts. Notably, EphrinB2 knockdown reversed the inhibitory effect of ED-71 on osteoclasts. ED-71 also enhanced EphB4 expression in osteoblasts in vivo and in vitro. Further research showed that ED-71 inhibited osteoclastogenesis in co-culture systems, which was weakened by blocking EphB4 in osteoblasts.
Conclusions:
ED-71 inhibited osteoclastogenesis by enhancing EphrinB2-EphB4 signaling between osteoclasts and osteoblasts, preventing osteoporosis. This theory explains the role of ED-71 in the treatment of osteoporosis.
Insights
Eldecalcitol (ED-71) prevents osteoporosis by enhancing EphrinB2-EphB4 signaling, which regulates communication between bone cells. This vitamin D analog treatment reduces osteoclast activity and bone loss in osteoporosis models.
Area of Science:
- Bone Biology and Skeletal Diseases
- Pharmacology and Drug Mechanisms
- Cell Signaling Pathways
Background:
- Osteoporosis is a skeletal disease characterized by bone remodeling imbalance.
- EphrinB2-EphB4 signaling is crucial for osteoclast and osteoblast communication in bone remodeling.
- Eldecalcitol (ED-71), a vitamin D analog, shows potential for osteoporosis treatment, but its mechanism is unclear.
Purpose of the Study:
- To investigate if EphrinB2-EphB4 signaling mediates the therapeutic effects of Eldecalcitol (ED-71) in osteoporosis.
- To elucidate the mechanism by which ED-71 improves osteoporosis.
Main Methods:
- Established an ovariectomized (OVX) rat model and an in vitro H2O2-induced osteoporosis model.
- Administered ED-71 and evaluated bone loss, osteoclast activity, and EphrinB2-EphB4 expression using various assays (staining, PCR, Western blot).
- Utilized EphrinB2 knockdown and EphB4 blocking to assess the role of the signaling pathway.
Main Results:
- ED-71 treatment prevented bone loss and reduced osteoclast numbers in OVX rats, also mitigating oxidative stress.
- In vitro, ED-71 inhibited H2O2-induced oxidative stress, osteoclastogenesis, and osteoclast function, increasing EphrinB2 in osteoclasts.
- EphrinB2 knockdown reversed ED-71's inhibitory effects, while ED-71 enhanced EphB4 in osteoblasts, and blocking EphB4 weakened ED-71's anti-osteoclastogenic effect.
Conclusions:
- ED-71 inhibits osteoclastogenesis by enhancing EphrinB2-EphB4 signaling between osteoclasts and osteoblasts.
- This EphrinB2-EphB4 signaling pathway is a key mechanism through which ED-71 exerts its osteoporosis-preventing effects.
Related Concept Videos
01:31Osteoclasts in Bone Remodeling
01:22Role of Ephrin-Eph Signalling in Intestinal Stem Cell Renewal
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...
01:40Bone Remodeling
01:15Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
01:29Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...