Modulation of Deiodinase Types 2 and 3 during Skeletal Muscle Regeneration

Area of Science:

• Muscle regeneration
• Endocrinology
• Cell biology

Background:

• Muscle stem cell niches coordinate regeneration after injury.
• Thyroid hormones regulate skeletal muscle genes.
• Deiodinase types 2 and 3 (Dio2, Dio3) fine-tune local triiodothyronine (T3) levels.

Purpose of the Study:

• To identify the specific cell types and temporal expression patterns of Dio2 and Dio3 during muscle regeneration.
• To understand the therapeutic potential of deiodinases in muscle repair.

Main Methods:

• Confirmation of Dio2 and Dio3 expression in the tibialis anterior muscle.
• Single-cell analysis to determine cell-type specific expression of Dio2 and Dio3 post-injury.
• Temporal analysis of gene expression from day 0 onwards.

Main Results:

• Dio2 is expressed in paired box 7 (PAX7)-positive cells from day 5 and in platelet-derived growth factor subunit A (PDGFA)-expressing progenitor cells between days 7-14 post-injury.
• Dio3 is detected in myogenic differentiation (MYOD)-positive stem cells and macrophages immediately post-injury and thereafter.
• Dio2 and Dio3 RNA are not found in the same cell types throughout the regeneration process.

Conclusions:

• Deiodinases exhibit distinct cell-type specific and temporal expression patterns during muscle regeneration.
• These findings elucidate the crosstalk and synchronized regulation of T3 by deiodinases in injured muscle.
• The results offer insights into potential treatments for sarcopenia and other muscular diseases.