Carbonic anhydrase II regulates differentiation of ameloblasts via intracellular pH-dependent JNK signaling pathway.
Differentiation of ameloblasts from undifferentiated epithelial cells is controlled by diverse growth factors, as well as interactions between epithelium and mesenchyme. However, there is a considerable lack of knowledge regarding the precise mechanisms that control ameloblast differentiation and enamel biomineralization. We found that the expression level of carbonic anhydrase II (CAII) is strongly up-regulated in parallel with differentiation of enamel epithelium tissues, while the enzyme activity of CA was also increased along with differentiation in ameloblast primary cultures. The expression level of amelogenin, a marker of secretory-stage ameloblasts, was enhanced by ethoxzolamide (EZA), a CA inhibitor, as well as CAII antisense (CAIIAS), whereas the expression of enamel matrix serine proteinase-1 (EMSP-1), a marker for maturation-stage ameloblasts, was suppressed by both. These agents also promoted ameloblast proliferation. In addition, inhibition of ameloblast differentiation by EZA and CAIIAS was confirmed using tooth germ organ cultures. Furthermore, EZA and CAIIAS elevated intracellular pH in ameloblasts, while experimental decreases in intracellular pH abolished the effect of CAIIAS on ameloblasts and triggered the activation of c-Jun N-terminal kinase (JNK). SP600125, a JNK inhibitor, abrogated the response of ameloblasts to an experimental decrease in intracellular pH, while the inhibition of JNK also impaired ameloblast differentiation. These results suggest a novel role for CAII during amelogenesis, that is, controlling the differentiation of ameloblasts. Regulation of intracellular pH, followed by activation of the JNK signaling pathway, may be responsible for the effects of CAII on ameloblasts.
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
Xiaogu
X
Wang
Tetsuo
T
Suzawa
Hirotada
H
Ohtsuka
Baohong
B
Zhao
Yoichi
Y
Miyamoto
Tomohiko
T
Miyauchi
Riko
R
Nishimura
Tomio
T
Inoue
Masanori
M
Nakamura
Kazuyoshi
K
Baba
Ryutaro
R
Kamijo
D000565:Ameloblasts / Q000187:drug effects / Q000201:enzymology*; D053523:Amelogenin / Q000378:metabolism; D000818:Animals; D024402:Carbonic Anhydrase II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007610:Kallikreins / Q000378:metabolism; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D009924:Organ Culture Techniques; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014083:Tooth Germ / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*
D053523:Amelogenin; D002257:Carbonic Anhydrase Inhibitors; D016376:Oligonucleotides, Antisense; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D048031:JNK Mitogen-Activated Protein Kinases; D007610:Kallikreins; C120801:kallikrein 4; D024402:Carbonic Anhydrase II