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Anat Rec (Hoboken). 2015 Aug;298(8):1502-8. doi: 10.1002/ar.23118. Epub 2015 Feb 27.

Dental and Cranial Pathologies in Mice Lacking the Cl(-) /H(+) -Exchanger ClC-7.

Author information

1
Herman Ostrow School of Dentistry of USC, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, USA.
2
Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York, USA.

Abstract

ClC-7 is a 2Cl(-) /1H(+) -exchanger expressed at late endosomes and lysosomes, as well as the ruffled border of osteoclasts. ClC-7 deficiencies in mice and humans lead to impaired osteoclast function and therefore osteopetrosis. Failure of tooth eruption is also apparent in ClC-7 mutant animals, and this has been attributed to the osteoclast dysfunction and the subsequent defect in alveolar bone resorptive activity surrounding tooth roots. Ameloblasts also express ClC-7, and this study aims to determine the significance of ClC-7 in enamel formation by examining the dentitions of ClC-7 mutant mice. Micro-CT analysis revealed that the molar teeth of 3-week old ClC-7 mutant mice had no roots, and the incisors were smaller than their age-matched controls. Despite these notable developmental differences, the enamel and dentin densities of the mutant mice were comparable to those of the wild-type littermates. Scanning electron microscopy showed normal enamel crystallite and prismatic organization in the ClC-7 mutant mice, although the enamel was thinner (hypoplastic) than in controls. These results suggested that ClC-7 was not critical to enamel and dentin formation, and the observed tooth defects may be related more to a resulting alveolar bone phenotype. Micro-CT analysis also revealed abnormal features in the calvarial bones of the mutant mice. The cranial sutures in ClC-7 mutant mice remained open compared to the closed sutures seen in the control mice at 3 weeks. These data demonstrate that ClC-7 deficiency impacts the development of the dentition and calvaria, but does not significantly disrupt amelogenesis.

KEYWORDS:

ameloblast; amelogenesis; biomineralization; chloride channels; craniofacial development; enamel; pH regulation

PMID:
25663454
PMCID:
PMC4503507
DOI:
10.1002/ar.23118
[Indexed for MEDLINE]
Free PMC Article

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