title: Repression of Igf1 expression by Ezh2 prevents basal cell differentiation in the developing lung.
abstract: Epigenetic mechanisms involved in the establishment of lung epithelial cell lineage identities during development are largely unknown. Here, we explored the role of the histone methyltransferase Ezh2 during lung lineage determination. Loss of Ezh2 in the lung epithelium leads to defective lung formation and perinatal mortality. We show that Ezh2 is crucial for airway lineage specification and alveolarization. Using optical projection tomography imaging, we found that branching morphogenesis is affected in Ezh2 conditional knockout mice and the remaining bronchioles are abnormal, lacking terminally differentiated secretory club cells. Remarkably, RNA-seq analysis revealed the upregulation of basal genes in Ezh2-deficient epithelium. Three-dimensional imaging for keratin 5 further showed the unexpected presence of a layer of basal cells from the proximal airways to the distal bronchioles in E16.5 embryos. ChIP-seq analysis indicated the presence of Ezh2-mediated repressive marks on the genomic loci of some but not all basal genes, suggesting an indirect mechanism of action of Ezh2. We found that loss of Ezh2 de-represses insulin-like growth factor 1 (Igf1) expression and that modulation of IGF1 signaling ex vivo in wild-type lungs could induce basal cell differentiation. Altogether, our work reveals an unexpected role for Ezh2 in controlling basal cell fate determination in the embryonic lung endoderm, mediated in part by repression of Igf1 expression.
authors: ACRF Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
authors: Laura A
authors: LA
authors: Galvis
authors: ACRF Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia.
authors: Aliaksei Z
authors: AZ
authors: Holik
authors: Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia.
authors: Kieran M
authors: KM
authors: Short
authors: ACRF Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
authors: Julie
authors: J
authors: Pasquet
authors: Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
authors: Aaron T L
authors: AT
authors: Lun
authors: Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia Molecular Medicine Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
authors: Marnie E
authors: ME
authors: Blewitt
authors: Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia.
authors: Ian M
authors: IM
authors: Smyth
authors: Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia Molecular Medicine Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia Department of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria 3052, Australia.
authors: Matthew E
authors: ME
authors: Ritchie
authors: ACRF Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia labat@wehi.edu.au.
authors: Marie-Liesse
authors: ML
authors: Asselin-Labat
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D000071221:Enhancer of Zeste Homolog 2 Protein; D005434:Flow Cytometry; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D053555:Keratin-5 / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D051379:Mice; D063151:Polycomb Repressive Complex 2 / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction
chemical_list: D053555:Keratin-5; C519530:insulin-like growth factor-1, mouse; D007334:Insulin-Like Growth Factor I; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D063151:Polycomb Repressive Complex 2
keywords: Basal cells; Ezh2; IGF1; Lung development; Mouse; Polycomb repressive complex 2