FXR Activation Accelerates Early Phase of Osteoblast Differentiation Through COX-2-PGE<sub>2</sub>-EP4 Axis in BMP-2-Induced Mouse Mesenchymal Stem Cells
Farnesoid X receptor (FXR), a nuclear receptor, is expressed in calvaria and bone marrow stromal cells and plays a role in bone homeostasis. However, the mechanism of FXR-activated osteoblast differentiation remains unclear. In this study, we investigated the regulatory mechanism underlying FXR-acti...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/1/58 |
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| Summary: | Farnesoid X receptor (FXR), a nuclear receptor, is expressed in calvaria and bone marrow stromal cells and plays a role in bone homeostasis. However, the mechanism of FXR-activated osteoblast differentiation remains unclear. In this study, we investigated the regulatory mechanism underlying FXR-activated osteoblast differentiation using bone morphogenetic protein-2 (BMP-2)-induced mouse ST-2 mesenchymal stem cells. We also synthesized a novel FXR agonist, <b>FLG390</b>, and compared its biological effects in osteoblast differentiation with a known FXR agonist, chenodeoxycholic acid (CDCA). As an FXR agonist, <b>FLG390</b> accelerated osteoblast differentiation to a comparable extent with CDCA, enhancing alkaline phosphatase (ALP) activity and the expression of osteoblast differentiated-related genes such as ALP, collagen type 1 α1 chain (COL1A1), and runt-related transcription factor 2 (RUNX2). FXR activation elevated the expression of cyclooxygenase (COX)-2 and the production of prostaglandin (PG) E<sub>2</sub> in the early phase of osteoblast differentiation. A selective COX-2 inhibitor and an antagonist of EP4 receptors, one of PGE<sub>2</sub> receptors, partially suppressed FXR-activated osteoblast differentiation. Moreover, treatment with either inhibitor during the first 6 h after initiating osteoblast differentiation repressed FXR-activated osteoblast differentiation to the same extent as did the treatment for 6 d. Therefore, a novel FXR agonist, <b>FLG390,</b> exhibited potency comparable to CDCA. FXR activation promoted the early phase of osteoblast differentiation via the COX-2-PGE<sub>2</sub>-EP4 axis, representing a potential target for control of bone metabolism. |
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| ISSN: | 1420-3049 |