# Cellular plasticity and testis regeneration

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $225,975

## Abstract

Abstract
Many adult tissues replace cells lost due to normal wear and tear via the activity of stem cells,
but can use entirely different strategies when injury occurs. The ability to understand and control
regeneration, or the regrowth of lost tissues or organs in response to injury, is a long-standing
goal in biology. Cells with the capacity to adopt the biological properties of other cell types under
specific conditions, or cellular plasticity, are key contributors to regeneration. Stem cells and
even differentiated cells can have surprising degrees of plasticity, allowing them to adopt new
fates and rebuild damaged tissues. This happens in response to altered microenvironments that
arise upon injury, but the mechanisms that regulate plasticity are poorly understood. In the prior
funding period, we showed that a damaged organ converts non-stem cells to stem cells to repair
the tissue. Since cellular plasticity is emerging as a general feature of tissue regeneration, we
identify mechanisms regulating the regeneration of adult somatic cells in vivo using two
functionally similar systems: mammalian and Drosophila testes. In Aim 1 we build on our
finding that quiescent somatic cells in the Drosophila testis transdifferentiate into stem cells
upon damage, using live imaging, lineage tracing and genetic manipulation to identify the
regulatory genes. We also study the aberrant consequence of regeneration, ectopic stem cell
niche formation in Drosophila testes, and obtain gene expression data from rare cells in this
tissue to piece together the mechanisms that control this process. In Aim 2 we extend our new
preliminary data showing that damage to the adult mouse testis, in the form of ablation of Leydig
cells, triggers regeneration of these important quiescent steroidogenic cells. We characterize
cells giving rise to new Leydig cells upon damage and aging at the cellular and molecular level.
Together these Aims will reveal the molecular cues regulating loss of quiescence and the
induction of regeneration within two different systems in vivo, providing a potent means to
determine the mechanisms sustaining damage-induced tissue repair.

## Key facts

- **NIH application ID:** 9977698
- **Project number:** 5R01HD052937-13
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Erika L Matunis
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $225,975
- **Award type:** 5
- **Project period:** 2007-03-01 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9977698

## Citation

> US National Institutes of Health, RePORTER application 9977698, Cellular plasticity and testis regeneration (5R01HD052937-13). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9977698. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*