# Role of Twist2+ myogenic progenitor cells in adult skeletal muscle

> **NIH NIH R01** · UT SOUTHWESTERN MEDICAL CENTER · 2021 · $345,708

## Abstract

Role of Twist2 myogenic progenitor cells in adult skeletal muscle
Project Summary/Abstract
Adult skeletal muscle can adapt muscle mass and myofiber size under physiological and pathological
conditions. Mechanical overload and hormone stimulation result in muscle growth in the form of hypertrophy
and enhanced muscle strength and function. In contrast, loss of muscle mass and strength during aging and
disease has profound negative consequences, leading to frailty, disability and mortality. With the world’s
elderly population growing dramatically, there is an urgent need to understand the requirements for maintaining
muscle homeostasis and to development therapeutic treatments for sarcopenia and cachexia. Recently, we
identified a novel myogenic progenitor marked by the expression of a bHLH transcription factor Twis2 (Tw2). In
adult muscle, Tw2 is expressed in interstitial cells but not mature myofibers or satellite cells. Genetic lineage
tracing revealed that the Tw2+ progenitor cell population contributes specifically to type IIb/x myofibers in adult
muscle during homeostasis and regeneration. Ablation of these Tw2+ cells causes type IIb fiber specific
myofiber atrophy during aging. These findings highlight the unique role of Tw2+ cells in maintaining type IIb
myofibers during aging. The overall goals of this project are designed to decipher the mechanisms whereby
Tw2+ cells contribute to type IIb/x myofibers, to elucidate the mechanisms whereby Tw2 controls stemness
and quiescence of Tw2+ cells, and to define the roles of Tw2+ cells in skeletal muscle hypertrophy and atrophy.
Ultimately, we hope to use these insights to develop new strategies to therapeutically modulate muscle mass,
strength and function during aging and disease.

## Key facts

- **NIH application ID:** 10171558
- **Project number:** 5R01AR071980-04
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** Ning Liu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $345,708
- **Award type:** 5
- **Project period:** 2018-05-15 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10171558

## Citation

> US National Institutes of Health, RePORTER application 10171558, Role of Twist2+ myogenic progenitor cells in adult skeletal muscle (5R01AR071980-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10171558. Licensed CC0.

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