New in vivo microRNA biotechnology reveals specific roles for the miR‐200 family in craniofacial development

• Published in: The FASEB journal Vol. 32; no. S1; p. 776.13
• Main Authors: Sweat, Mason E., Yu, Wenjie, Eliason, Steven, Sweat, Yan Yan, Cao, Huojun, Hong, Liu, Amendt, Brad A.
• Format: Journal Article
• Language: English
• Published: The Federation of American Societies for Experimental Biology 01-04-2018
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.2018.32.1_supplement.776.13

The molecular regulators of stem cell differentiation are a hot topic and the proteins involved in this process have been well studied, but the function of microRNA (miR) remains elusive.
Objectives
To investigate the role of the miR‐200 family in the regulation of craniofacial development and dental epithelial stem cells (DESCs). Previously, we found that the miR‐200 family was highly expressed in the differentiated cell types of the lower incisor but was absent from the stem cell niche, suggesting it may contribute towards differentiation.
Methods
We constructed a plasmid‐based miR inhibitor system (PMIS) and used it to inhibit the miR‐200 family in mice. One inhibitor line specifically targets the seed sequence specific for miR‐200a, and ‐141, while the other is specific for the seed sequence found in miR‐200b,‐200c and ‐429, and crossing the lines allows the functional inhibition of the entire miR‐200 family.
Results
Double inhibitor mice are neonatal lethal and have poorly differentiated lower incisors. The teeth are smaller and they lack cells expressing cell differentiation markers (DSP and amelogenin) of mature odontoblasts and ameloblasts. Several transcription factor regulators of stemness which are direct targets of the miR‐200 family, including Sox2, are ectopically expressed in normally differentiated cells. A proliferation cell labeling BrdU assay demonstrated that the majority of dental epithelial cells are proliferating in double inhibitor mouse incisors.
Conclusions
This study is among the first to use targeted inhibition to study specific miRs and we found that the miR‐200 family is required for the appropriate differentiation of DESCs and the family functions by reducing the expression of transcription factors promoting stemness outside of the stem cell niche compartment of the lower incisor. Overall, craniofacial development is affected due to a lack of cell differentiation.
Support or Funding Information
University of Iowa College of Dentistry
This is from the Experimental Biology 2018 Meeting. There is no full text article associated with this published in The FASEB Journal.