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Timp-1, -2 and -3 show coexpression with gelatinases A and B during mouse tooth morphogenesis
C Sahlberg1, P Reponen, K Tryggvason
1Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Finland. carin.sahlberg@helsinki.fi
Abstract:
Matrix metalloproteinases (MMPs) have been implicated in tissue remodelling and in regulation of cell-matrix interactions during organ development. The activity of MMPs is regulated by members of the TIMP (tissue inhibitors of metalloproteinase) family. We analyzed by in situ hybridization the expression of gelatinase A (MMP-2) and gelatinase B (MMP-9) as well as Timp-1, -2 and -3 during different stages of mouse tooth development. Gene expression was generally found in mesenchymal tissues except for Timp-3, which also was found in dental epithelial cells. During early tooth development, gelatinase A and Timp-2 were widely expressed in the branchial arch, while gelatinase B and Timp-1 and Timp-3 expression showed clear association with epithelial morphogenesis and was restricted to the mesenchyme at the tip of the growing tooth bud. Gelatinase A and Timp-1 showed transient expression in secretory odontoblasts at the time of basement membrane degradation, while Timp-2 expression continued throughout the dental papilla. At the time of tooth eruption, Timp-3 was expressed in most dental epithelial cells except secretory ameloblasts, and gelatinase B was intensely expressed in osteoclasts in the jaw bone. The exact co-localization of gelatinase A and Timp-1 in secretory odontoblasts, and the correlation between gelatinase B and Timp-3 during bone resorption may indicate interaction of the proteins during degradation of the basement membrane and in the control of ECM turnover in connection with tooth eruption.
Insights
Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are crucial for tooth development. Their expression patterns reveal roles in tissue remodeling during mouse tooth formation and eruption.
Area of Science:
- Biochemistry
- Developmental Biology
- Oral Biology
Background:
- Matrix metalloproteinases (MMPs) regulate tissue remodeling and cell-matrix interactions during organogenesis.
- The activity of MMPs is controlled by tissue inhibitors of metalloproteinases (TIMPs).
Purpose of the Study:
- To investigate the expression patterns of gelatinase A (MMP-2), gelatinase B (MMP-9), and TIMP-1, -2, and -3 during mouse tooth development.
- To elucidate the roles of these proteins in tissue remodeling and extracellular matrix turnover during tooth formation and eruption.
Main Methods:
- In situ hybridization was used to analyze gene expression of MMP-2, MMP-9, TIMP-1, TIMP-2, and TIMP-3.
- Expression patterns were examined across different developmental stages of mouse teeth.
Main Results:
- MMP-2 and TIMP-2 were widely expressed in mesenchymal tissues, while MMP-9, TIMP-1, and TIMP-3 were associated with epithelial morphogenesis.
- Specific co-localization of MMP-2 and TIMP-1 in secretory odontoblasts suggests a role in basement membrane degradation.
- MMP-9 and TIMP-3 showed correlation during bone resorption by osteoclasts at tooth eruption.
Conclusions:
- The study highlights the dynamic expression of MMPs and TIMPs throughout tooth development, indicating their involvement in key processes.
- Specific protein interactions are suggested during basement membrane degradation and extracellular matrix turnover in tooth eruption.