# Cellular and molecular regulation of airway multiciliated cell specification and differentiation

> **NIH NIH F32** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2020 · $64,926

## Abstract

Project Summary/Abstract
 Lungs provide the means by which we transfer oxygen from air to the circulatory system, and the airway
epithelium provides the lungs’ first line of defense against inhaled pathogens. The lung epithelium is comprised
of three major cell types: basal stem cells (BCs), secretory cells (SCs) and multiciliated cells (MCCs). The
proportion of each of these cell types is tightly controlled and critical for airway function. In diseases such as
asthma and chronic obstructive pulmonary disease (COPD), hyperplasia of a subtype of SCs, goblet cells, at the
expense of MCCs results in an overproduction of mucus and a failure to clear pathogens. While MCCs are critical
for airway function, the cellular and molecular steps that generate MCCs from BCs are still not understood. My
preliminary single-cell RNA-sequencing data has identified an intermediate cell type between BCs and MCCs
marked by the transcription factor, Mycl. In this proposal, I will answer four questions to address major gaps in
airway biology 1) Is Mycl upstream or downstream of known early MCC regulators? I will utilize quantitative
cellular resolution fluorescent in situ hybridization and immunostaining to determine the expression patterns of
Mycl and early MCC regulators. Additionally, I will test the expansion or reduction of Mycl+ intermediate cells
upon perturbation of Notch signaling, a major regulator of SC and MCC fates. 2) Are Mycl+ intermediate cells a
transit-amplifying population? I will combine in situ hybridization with BrdU assays to determine the proliferation
status of Mycl+ intermediate cells. 3) What is the function of Mycl during MCC differentiation and ciliogenesis? I
will utilize CRISPR/Cas9 knockout technology in an in vitro airway culture system to identify the functional role
of the gene Mycl in MCC differentiation and ciliogenesis. 4) When do BCs commit to producing MCCs or SCs?
I will combine cellular barcoding and single-cell RNA-sequencing to simultaneously measure the clonal lineages
and transcriptional profiles of thousands of BCs. I will identify the clonal relationships of BC subtypes to determine
the precise timing of MCC specification. I hypothesize that Mycl is one of the earliest transcriptional
regulators of MCC specification, and marks a proliferative population regulated by Notch signaling.
Furthermore, I hypothesize that Mycl+ intermediate cells are a subtype of BCs, fated towards the MCC
lineage. These results will build a roadmap of MCC differentiation from BCs, and in the longer term, may help
identify the mechanisms leading to improper cell fate decisions during airway disease. During this proposal, I will
receive training in ciliary and airway biology, single-cell RNA-sequencing methodology, and computational
analysis of single-cell RNA-sequencing datasets. With expert advice and guidance from my mentor, Jeremy
Reiter, the vast resources of multiple cores and departments within UCSF, and a collaboration with the Chan
Zucker...

## Key facts

- **NIH application ID:** 10067258
- **Project number:** 1F32HL154611-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Lauren Byrnes
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $64,926
- **Award type:** 1
- **Project period:** 2020-08-01 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10067258

## Citation

> US National Institutes of Health, RePORTER application 10067258, Cellular and molecular regulation of airway multiciliated cell specification and differentiation (1F32HL154611-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10067258. Licensed CC0.

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