MiR-200b is involved in Tgf-β signaling to regulate mammalian palate development

Histochem Cell Biol. 2012 Jan;137(1):67-78. doi: 10.1007/s00418-011-0876-1. Epub 2011 Nov 10.

Abstract

Various cellular and molecular events are involved in palatogenesis, including apoptosis, epithelial-mesenchymal transition (EMT), cell proliferation, and cell migration. Smad2 and Snail, which are well-known key mediators of the transforming growth factor beta (Tgf-β) pathway, play a crucial role in the regulation of palate development. Regulatory effects of microRNA 200b (miR-200b) on Smad2 and Snail in palatogenesis have not yet been elucidated. The aim of this study is to determine the relationship between palate development regulators miR-200b and Tgf-β-mediated genes. Expression of miR-200b, E-cadherin, Smad2, and Snail was detected in the mesenchyme of the mouse palate, while miR-200b was expressed in the medial edge epithelium (MEE) and palatal mesenchyme. After the contact of palatal shelves, miR-200b was no longer expressed in the mesenchyme around the fusion region. The binding activity of miR-200b to both Smad2 and Snail was examined using a luciferase assay. MiR-200b directly targeted Smad2 and Snail at both cellular and molecular levels. The function of miR-200b was determined by overexpression via a lentiviral vector in the palatal shelves. Ectopic expression of miR-200b resulted in suppression of these Tgf-β-mediated regulators and changes of apoptosis and cell proliferation in the palatal fusion region. These results suggest that miR-200b plays a crucial role in regulating the Smad2, Snail, and in apoptosis during palatogenesis by acting as a direct non-coding, influencing factor. Furthermore, the molecular interactions between miR-200b and Tgf-β signaling are important for proper palatogenesis and especially for palate fusion. Elucidating the mechanism of palatogenesis may aid the design of effective gene-based therapies for the treatment of congenital cleft palate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Cadherins / genetics
  • Cadherins / metabolism
  • Cell Proliferation
  • HEK293 Cells
  • Humans
  • Immunohistochemistry
  • Mice
  • Mice, Inbred ICR
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Palate / cytology
  • Palate / growth & development*
  • Palate / metabolism*
  • Real-Time Polymerase Chain Reaction
  • Signal Transduction* / genetics
  • Smad2 Protein / genetics
  • Smad2 Protein / metabolism
  • Snail Family Transcription Factors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*

Substances

  • Cadherins
  • MicroRNAs
  • Mirn200 microRNA, mouse
  • Smad2 Protein
  • Smad2 protein, mouse
  • Snail Family Transcription Factors
  • Transcription Factors
  • Transforming Growth Factor beta