Control of Vertebrate Multiciliogenesis by miR-449 Through Direct Repression of the Delta/Notch Pathway

Nat Cell Biol. 2011 Jun;13(6):693-9. doi: 10.1038/ncb2241. Epub 2011 May 22.

Abstract

Multiciliated cells lining the surface of some vertebrate epithelia are essential for various physiological processes, such as airway cleansing. However, the mechanisms governing motile cilia biosynthesis remain poorly elucidated. We identify miR-449 microRNAs as evolutionarily conserved key regulators of vertebrate multiciliogenesis. In human airway epithelium and Xenopus laevis embryonic epidermis, miR-449 microRNAs strongly accumulated in multiciliated cells. In both models, we show that miR-449 microRNAs promote centriole multiplication and multiciliogenesis by directly repressing the Delta/Notch pathway. We established Notch1 and its ligand Delta-like 1(DLL1) as miR-449 bona fide targets. Human DLL1 and NOTCH1 protein levels were lower in multiciliated cells than in surrounding cells, decreased after miR-449 overexpression and increased after miR-449 inhibition. In frog, miR-449 silencing led to increased Dll1 expression. Consistently, overexpression of Dll1 mRNA lacking miR-449 target sites repressed multiciliogenesis, whereas both Dll1 and Notch1 knockdown rescued multiciliogenesis in miR-449-deficient cells. Antisense-mediated protection of miR-449-binding sites of endogenous human Notch1 or frog Dll1 strongly repressed multiciliogenesis. Our results unravel a conserved mechanism whereby Notch signalling must undergo miR-449-mediated inhibition to permit differentiation of ciliated cell progenitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium-Binding Proteins
  • Cell Survival
  • Cells, Cultured
  • Cilia / metabolism*
  • Conserved Sequence
  • Epidermis / metabolism
  • Female
  • Flow Cytometry
  • Gene Expression Regulation, Developmental*
  • Gene Knockdown Techniques
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Membrane Proteins / metabolism*
  • MicroRNAs / metabolism*
  • Nasal Polyps / physiopathology
  • Receptor, Notch1 / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction*
  • Xenopus / embryology
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism*

Substances

  • Calcium-Binding Proteins
  • DLK1 protein, human
  • DLL1 protein, Xenopus
  • Intercellular Signaling Peptides and Proteins
  • MIRN449 microRNA, human
  • Membrane Proteins
  • MicroRNAs
  • Receptor, Notch1
  • Xenopus Proteins