Hedgehog signaling enhances core-binding factor a1 and receptor activator of nuclear factor-kappaB ligand (RANKL) gene expression in chondrocytes.
Hedgehog signaling is considered to play a crucial role in chondrogenesis by regulation through a network of cytokine actions, which is not fully understood. We examined the effect of hedgehog signaling on the expression of core-binding factor a1 (Cbfa1), a critical transcription factor for the development of bone and cartilage. Primary chondrocytes prepared from the costal cartilage of newborn mice were treated with N-terminal fragment of recombinant murine sonic hedgehog (rmShh-N). Northern blot analysis indicated that Cbfa1 mRNA expression levels in the chondrocyte cultures were elevated by the treatment with rmShh-N. rmShh-N treatment enhanced 1.8 kb Cbfa1 promoter activity in chondrocytes, suggesting the presence of transcriptional control. As Cbfa1-binding site(s) have been located in the promoter of the receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) gene, we also examined RANKL expression. rmShh-N treatment upregulated RANKL and RANK mRNA expression levels in chondrocytes. Interestingly, RANKL suppressed the hedgehog enhancement of alkaline phosphatase activity in chondrocytes, suggesting the presence of a link between these signaling molecules. We conclude that hedgehog signaling activates Cbfa1 gene expression through its promoter in chondrocytes, and also activates and interacts with RANKL to maintain cartilage development.
Takamoto
M
M
Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
Tsuji
K
K
Yamashita
T
T
Sasaki
H
H
Yano
T
T
Taketani
Y
Y
Komori
T
T
Nifuji
A
A
Noda
M
M
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern / Q000379:methods; D002352:Carrier Proteins / Q000235:genetics*; D019902:Chondrocytes / Q000378:metabolism*; D050657:Core Binding Factor alpha Subunits; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D053823:Hedgehog Proteins; D008156:Luciferases / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008813:Mice, Inbred ICR; D053245:RANK Ligand; D012333:RNA, Messenger / Q000032:analysis; D053246:Receptor Activator of Nuclear Factor-kappa B; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000494:pharmacology*; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection
D002352:Carrier Proteins; D050657:Core Binding Factor alpha Subunits; D004268:DNA-Binding Proteins; D053823:Hedgehog Proteins; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; C406688:core binding factor alpha; D008156:Luciferases