Disruption of Nfic Causes Dissociation of Odontoblasts by Interfering With the Formation of Intercellular Junctions and Aberrant Odontoblast Differentiation
Tae-Yeon Lee 1, Dong-Seol Lee 1, Hyun-Man Kim 1, Jea Seung Ko 1, Richard M. Gronostajski 1, Moon-Il Cho 1, Ho-Hyun Son 1 and Joo-Cheol Park 1*
1 Department of Conservative Dentistry and Dental Research Institute, College of Dentistry (T-YL,H-HS) and Department of Oral Histology-Developmental Biology, Dental Research Institute, and BK21 Program, School of Dentistry (D-SL,H-MK,J-CP), Seoul National University, Seoul, Korea, and Department of Biochemistry, Program in Neuroscience, Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences (RMG) and Department of Oral Biology, School of Dental Medicine (M-IC), State University of New York at Buffalo, Buffalo, New York
* To whom correspondence should be addressed. E-mail: jcapark{at}snu.ac.kr.
Submitted on August 28, 2008
Accepted on 5 January 2009
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Abstract |
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We reported previously that Nfic-deficient mice exhibit short and abnormal molar roots, and severely deformed incisors. The objective of this study is to address the mechanisms responsible for these changes using morphological, immunohistochemical and RT-PCR analysis. Nfic-deficient mice exhibited aberrant odontoblasts and abnormal dentin formation in molar roots and the labial crown analog of incisors. The most striking changes observed in these aberrant odontoblasts were the loss of intercellular junctions and the decreased expression of ZO-1 and occludin. As a result, they became dissociated, had a round shape, and lost their cellular polarity and arrangement as a sheet of cells. Further, the dissociated odontoblasts became trapped in dentin-like mineralized tissue, resembling osteodentin in the overall morphology. These findings suggest that loss of the Nfic gene interferes with the formation of intercellular junctions that causes aberrant odontoblast differentiation and abnormal dentin formation. Collectively, these changes in odontoblasts contributed to development of molars with short and abnormal roots in Nfic-deficient mice.
Key Words:
Nfic, odontoblast, abnormal dentin, root formation, osteodentin