| Theme | Osteoimmunology | |
|---|---|---|
| Title | Regulation of osteoclast differentiation by Toll-like receptors | |
| Publish Date | 2008/01 | |
| Author | Masamichi Takami | Department of Biochemistry, School of Dentistry, Showa University |
| Author | Baohong Zhao | Department of Biochemistry, School of Dentistry, Showa University |
| [ Summary ] | Toll-like receptors (TLRs) are membrane-type proteins that recognize a range of microbial constituents such as lipopolysaccharide (LPS) and nucleotides released from invading bacteria and viruses, triggering inflammation. In the early stages of osteoclast differentiation, activation of TLRs inhibits osteoclast differentiation. However, activation of TLRs induces osteoclast differentiation in the late differentiation stage. Activation of TLRs also helps mature osteoclasts survive by blocking apoptosis. On the other hand, TLRs expressed in osteoblasts induce the expression of RANKL, which in turn induces osteoclast differentiation. It is highly probable that osteoclast differentiation is promoted by the production of inflammatory factors such as TNF-α and PGE2. | |