# Examination of Lgr5+ Cochlear Progenitor Cell Fate Determinants and Plasticity

> **NIH NIH F30** · TUFTS UNIVERSITY BOSTON · 2020 · $50,520

## Abstract

PROJECT SUMMARY / ABSTRACT
Hearing loss affects more than 40 million people in the United States alone. Sensorineural hearing loss (SNHL)
commonly involves damage to cochlear hair cells (HCs), and since mammalian HCs are incapable of
regeneration, most forms of SNHL are permanent. Recent work has demonstrated the ability to isolate, clonally
expand, and differentiate neonatal murine Lgr5+ HC progenitors (LCPs) in high yield. These LCPs are found in
both the cochlear medial compartment (MC) with inner hair cells (IHCs) and the lateral compartment (LC) with
outer hair cells (OHCs). Following in vitro expansion and differentiation in 3D Matrigel, organoids derived from
the clonal expansion of single LCPs contain cells expressing either IHC markers or OHC markers, but both HC
markers are never found within the same organoid. Currently, it is not known what drives LCPs within clonally
derived organoids toward IHC or OHC fate. However, since uniform differentiation conditions give rise to both
IHC and OHC positive organoids, LCP fate may be pre-determined based on the compartmental origin of the
original cell. However, LCPs still may retain sufficient plasticity to differentiate into either IHCs or OHCs
regardless of whether they possess existing fate preferences. I hypothesize that LCP IHC and OHC fate is
pre-determined based on the medial or lateral compartmental origin of individual cells. I further
hypothesize that LCPs retain sufficient plasticity to enable them to adopt either IHC or OHC fate through
manipulation of Wnt3a and Bmp4 signaling. By utilizing two transgenic reporter mouse lines (Glast-
CreER;tdTomato and FgfR3-CreER;tdTomato) which respectively highlight the MC and LC of the postnatal
murine cochlea, we aim to perform in vitro lineage tracing experiments to examine the role of LCP compartmental
origin in determining HC fate following differentiation. Additionally, we aim to examine the plasticity of LCPs by
studying the effects of Wnt3a and Bmp4 on LCP fate determination in 3D culture. Finally, we aim to investigate
the importance of morphogen gradient signaling in the patterning of LCPs in 2D culture using a simple but
physiologically relevant silk fibroin film delivery system.
This work aims to provide insight into the determinants of LCP IHC and OHC fate specification with
respect to both the pre-programmed preferences of these cells and their competence to be driven
towards either IHC or OHC fate regardless of these preferences upon exposure to morphogens which
pattern the pro-sensory domain during development. Together, this project will provide me with
comprehensive cochlear developmental biology, regenerative medicine, and biomaterials engineering
training, equipping me with the necessary skills to achieve my long-term career goals of becoming an
otolaryngologist working to translate basic hearing loss research to the clinic.

## Key facts

- **NIH application ID:** 9857589
- **Project number:** 5F30DC017057-03
- **Recipient organization:** TUFTS UNIVERSITY BOSTON
- **Principal Investigator:** Craig Hanna
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $50,520
- **Award type:** 5
- **Project period:** 2018-02-01 → 2021-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9857589

## Citation

> US National Institutes of Health, RePORTER application 9857589, Examination of Lgr5+ Cochlear Progenitor Cell Fate Determinants and Plasticity (5F30DC017057-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9857589. Licensed CC0.

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