TY - JOUR
T1 - Smad3 Deficiency Leads to Mandibular Condyle Degradation via the Sphingosine 1-Phosphate (S1P)/S1P3 Signaling Axis
AU - Mori, Hiroki
AU - Izawa, Takashi
AU - Tanaka, Eiji
N1 - Funding Information:
Supported by the Ministry of Education, Science, Sport, and Culture of Japan grants-in-aid for scientific research 25713063 (T.I.), 15K15757 (T.I.), and 26293436 (E.T.).
Publisher Copyright:
© 2015 American Society for Investigative Pathology.
PY - 2015/10
Y1 - 2015/10
N2 - Temporomandibular joint osteoarthritis is a degenerative disease that is characterized by permanent cartilage destruction. Transforming growth factor (TGF)-β is one of the most abundant cytokines in the bone matrix and is shown to regulate the migration of osteoprogenitor cells. It is hypothesized that TGF-β/Smad3 signaling affects cartilage homeostasis by influencing sphingosine 1-phosphate (S1P)/S1P receptor signaling and chondrocyte migration. We therefore investigated the molecular mechanisms by which crosstalk may occur between TGF-β/Smad3 and S1P/S1P receptor signaling to maintain condylar cartilage and to prevent temporomandibular joint osteoarthritis. Abnormalities in the condylar subchondral bone, including dynamic changes in bone mineral density and microstructure, were observed in Smad3-/- mice by microcomputed tomography. Cell-free regions and proteoglycan loss characterized the cartilage degradation present, and increased numbers of apoptotic chondrocytes and matrix metalloproteinase 13+ chondrocytes were also detected. Furthermore, expression of S1P receptor 3 (S1P3), but not S1P1 or S1P2, was significantly down-regulated in the condylar cartilage of Smad3-/- mice. By using RNA interference technology and pharmacologic tools, S1P was found to transactivate Smad3 in an S1P3/TGF-β type II receptor-dependent manner, and S1P3 was found to be required for TGF-β-induced migration of chondrocyte cells and downstream signal transduction via Rac1, RhoA, and Cdc42. Taken together, these results indicate that the Smad3/S1P3 signaling pathway plays an important role in the pathogenesis of temporomandibular joint osteoarthritis.
AB - Temporomandibular joint osteoarthritis is a degenerative disease that is characterized by permanent cartilage destruction. Transforming growth factor (TGF)-β is one of the most abundant cytokines in the bone matrix and is shown to regulate the migration of osteoprogenitor cells. It is hypothesized that TGF-β/Smad3 signaling affects cartilage homeostasis by influencing sphingosine 1-phosphate (S1P)/S1P receptor signaling and chondrocyte migration. We therefore investigated the molecular mechanisms by which crosstalk may occur between TGF-β/Smad3 and S1P/S1P receptor signaling to maintain condylar cartilage and to prevent temporomandibular joint osteoarthritis. Abnormalities in the condylar subchondral bone, including dynamic changes in bone mineral density and microstructure, were observed in Smad3-/- mice by microcomputed tomography. Cell-free regions and proteoglycan loss characterized the cartilage degradation present, and increased numbers of apoptotic chondrocytes and matrix metalloproteinase 13+ chondrocytes were also detected. Furthermore, expression of S1P receptor 3 (S1P3), but not S1P1 or S1P2, was significantly down-regulated in the condylar cartilage of Smad3-/- mice. By using RNA interference technology and pharmacologic tools, S1P was found to transactivate Smad3 in an S1P3/TGF-β type II receptor-dependent manner, and S1P3 was found to be required for TGF-β-induced migration of chondrocyte cells and downstream signal transduction via Rac1, RhoA, and Cdc42. Taken together, these results indicate that the Smad3/S1P3 signaling pathway plays an important role in the pathogenesis of temporomandibular joint osteoarthritis.
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U2 - 10.1016/j.ajpath.2015.06.015
DO - 10.1016/j.ajpath.2015.06.015
M3 - Article
C2 - 26272361
AN - SCOPUS:84943618774
VL - 185
SP - 2742
EP - 2756
JO - American Journal of Pathology
JF - American Journal of Pathology
SN - 0002-9440
IS - 10
M1 - 2116
ER -