XB-ART-54695J Cell Biol January 1, 2018; 217 (6): 1941-1955.
TRRAP is a central regulator of human multiciliated cell formation.
The multiciliated cell (MCC) is an evolutionarily conserved cell type, which in vertebrates functions to promote directional fluid flow across epithelial tissues. In the conducting airway, MCCs are generated by basal stem/progenitor cells and act in concert with secretory cells to perform mucociliary clearance to expel pathogens from the lung. Studies in multiple systems, including Xenopus laevis epidermis, murine trachea, and zebrafish kidney, have uncovered a transcriptional network that regulates multiple steps of multiciliogenesis, ultimately leading to an MCC with hundreds of motile cilia extended from their apical surface, which beat in a coordinated fashion. Here, we used a pool-based short hairpin RNA screening approach and identified TRRAP, an essential component of multiple histone acetyltransferase complexes, as a central regulator of MCC formation. Using a combination of immunofluorescence, signaling pathway modulation, and genomic approaches, we show that (a) TRRAP acts downstream of the Notch2-mediated basal progenitor cell fate decision and upstream of Multicilin to control MCC differentiation; and (b) TRRAP binds to the promoters and regulates the expression of a network of genes involved in MCC differentiation and function, including several genes associated with human ciliopathies.
PubMed ID: 29588376
Article link: J Cell Biol
Genes referenced: ccno foxj1.2 itga6 mcc mcidas muc5b myb notch2 pcbd1 pcnt rfx3 tp63 trrap
Article Images: [+] show captions
|Fig 3 TRRAP is enriched in ciliated cells and accumulates before FOXJ1. (A–D) During the course of differentiation at ALI, cultures were stained with antibodies to TRRAP, FOXJ1 (ciliated cells), MUC5B (goblet cells), SCGB1A1 (club cells), and p63 (basal cells). Colocalization was quantified at days 0, 3, 7, and 14 at ALI (A′′′–D′′′). At ALI day 14, TRRAP colocalizes with FOXJ1 in ciliated cells (arrows in A–A′′) but rarely accumulates in other cell types (A′–D′′). (E–G) At day 0, before culture at ALI, TRRAP has begun to accumulate in nuclei with a small subset of those being coenriched for FOXJ1 (arrows; A′′′; arrow in E–E′′). At days 3 and 7 of culture at ALI, the number of cells enriched for both TRRAP and FOXJ1 increases (A′′′; arrows in F–G′′), and the number of TRRAP-only cells decreases. Notably, cells with high TRRAP accumulation have low FOXJ1 (F–G′′, arrowheads), whereas cells with high FOXJ1 accumulation have low TRRAP (F–G′′, arrows), suggesting that their expression is temporally distributed in the same cell type. Bars, 20 µm.|
References [+] :
Boon, MCIDAS mutations result in a mucociliary clearance disorder with reduced generation of multiple motile cilia. 2016, Pubmed, Xenbase