REST/NRSF Preserves muscle stem cell identity by repressing alternate cell fate.

Area of Science:

• Epigenetics
• Cell Biology
• Developmental Biology

Background:

• Cell fate determination requires precise gene activation and repression.
• Skeletal muscle stem cells rely on myogenic regulatory factors for activation, but repression mechanisms are less understood.
• The epigenetic regulator REST (Repressor Element-1 Silencing Transcription factor) is implicated in gene silencing.

Purpose of the Study:

• To investigate the role of REST in repressing non-muscle genes in skeletal muscle stem cells.
• To determine the impact of REST loss on muscle stem cell identity, differentiation, and regeneration.

Main Methods:

• CRISPR-Cas9 mediated knockout of REST in mouse skeletal muscle stem cells.
• Chromatin immunoprecipitation sequencing (ChIP-seq) to assess REST binding and chromatin accessibility.
• RNA sequencing (RNA-seq) to analyze gene expression profiles.
• In vivo studies of muscle regeneration and myofiber growth in REST-deficient mice.

Main Results:

• REST actively represses numerous non-lineage genes in skeletal muscle stem cells, even those with permissive chromatin.
• Loss of REST function disrupts muscle-specific epigenetic and transcriptional signatures.
• REST deficiency leads to impaired differentiation, increased apoptosis in progenitor cells, and depletion of the stem cell pool.
• REST-deficient mice exhibit compromised skeletal muscle regeneration and reduced postnatal myofiber growth.

Conclusions:

• REST is a critical epigenetic regulator essential for maintaining skeletal muscle stem cell identity.
• REST safeguards stem cell identity by actively repressing non-muscle and developmentally regulated genes.
• Dysregulation of REST impacts muscle stem cell function, leading to impaired regeneration and growth.