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p38α MAPK is required for tooth morphogenesis and enamel secretion.
Matthew B Greenblatt1, Jung-Min Kim2, Hwanhee Oh2
1From the Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, mag3003@med.cornell.edu.
The Journal of Biological Chemistry
|November 20, 2014
Summary
The p38α MAPK pathway, activated by BMPs, is crucial for tooth development. Its absence in mice leads to defective enamel formation and impaired tooth cusp patterning, highlighting its role in ectodermal appendages.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Understanding molecular pathways is essential for tooth regeneration and diagnosing dental disorders.
- Ectodermal dysplasias involve defects in tissues derived from the ectoderm, including teeth.
Purpose of the Study:
- To investigate the role of p38α MAPK in tooth morphogenesis and enamel secretion.
- To identify the upstream regulators and downstream targets of p38α MAPK in dental development.
Main Methods:
- Conditional deletion of p38α MAPK in ectodermal appendages using K14-cre mice.
- Analysis of dental phenotypes, including cusp patterning and enamel quality.
- Assessment of gene expression (amelogenin, β4-integrin, p21) and protein activity.
- Investigating the role of MAP2K MKK6 and MKK3.
- Stimulation with BMP2/7 in explant cultures and cell lines.
Main Results:
- Conditional deletion of p38α MAPK in K14-cre mice resulted in ectodermal dysplasia with impaired dental cusp patterning.
- Mice lacking p38α MAPK exhibited defects in ameloblast differentiation and activity, leading to poor enamel production and reduced biomechanical strength.
- Reduced expression of amelogenin, β4-integrin, and p21 was observed in the absence of p38α.
- Mice lacking MKK6, but not MKK3, showed similar enamel defects, indicating MKK6 is an upstream kinase for p38α.
- BMP2/7 stimulation confirmed p38α acts downstream of BMPs in ameloblast development.
Conclusions:
- BMP-induced activation of the p38α MAPK pathway is critical for tooth cusp morphogenesis.
- The p38α MAPK pathway plays a vital role in dental enamel secretion through regulating ameloblast differentiation and activity.
- This study identifies a novel ectodermal dysplasia phenotype linked to p38α MAPK dysfunction.
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