Hedgehog regulation of epithelial cell state and morphogenesis in the larynx
The larynx enables speech while regulating swallowing and respiration. Larynx function hinges on the laryngeal epithelium which originates as part of the anterior foregut and undergoes extensive remodeling to separate from the esophagus and form vocal folds that interface with the adjacent trachea. Here we find that Sonic hedgehog (SHH) is essential for epithelial integrity in the mouse larynx as well as the anterior foregut. During larynx-esophageal separation, low Shh expression marks specific domains of actively remodeling epithelium that undergo an epithelial to mesenchymal transition (EMT) characterized by the induction of N-Cadherin and movement of cells out of the epithelial layer. Consistent with a role for SHH signaling in regulating this process, Shh mutants undergo an abnormal EMT throughout the anterior foregut and larynx, marked by a cadherin switch, movement out of the epithelial layer and cell death. Unexpectedly, Shh mutant epithelial cells are replaced by a new population of FOXA2-negative cells that likely derive from adjacent pouch tissues and form a rudimentary epithelium. These findings have important implications for interpreting the etiology of HH-dependent birth defects within the foregut. We propose that SHH signaling has a default role in maintaining epithelial identity throughout the anterior foregut and that regionalized reductions in SHH trigger epithelial remodeling.
Sequencing data have been deposited in GEO under accession code GSE190281.
Hedgehog signaling is essential to maintain epithelial identity during larynx and foregut morphogenesis.NCBI Gene Expression Omnibus, GSE190281.
Article and author information
National Institutes of Health (RO1 HD090163)
- Hongkai Ji
- Steven A Vokes
National Institutes of Health (RO1 HD093363)
- Aaron M Zorn
National Institutes of Health (F30 HL142201)
- Talia Nasr
University of Texas at Austin (Continuing Graduate Fellowship)
- Janani Ramachandran
University of Texas at Austin (Provost's Graduate Excellence Fellowship)
- Janani Ramachandran
University of Texas at Austin (TIDES Summer Fellowship)
- Anna E Bardenhagen
University of Texas at Austin (Experiential Learning Summer Scholarship)
- Ellen R Yates
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All experiments involving mice were approved by the Institutional Animal Care and Use Committee at the University of Texas at Austin (protocol AUP-2019-00233).
- Marianne E Bronner, California Institute of Technology, United States
- Received: January 14, 2022
- Preprint posted: January 20, 2022 (view preprint)
- Accepted: November 18, 2022
- Accepted Manuscript published: November 18, 2022 (version 1)
- Version of Record published: December 2, 2022 (version 2)
© 2022, Ramachandran et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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