Research Paper Volume 16, Issue 8 pp 7141—7152

Aberrant expression of thyroidal hormone receptor α exasperating mitochondrial dysfunction induced sarcopenia in aged mice

Yunlu Sheng1, *, , Xiaoxia Zhu1, *, , Lijun Wei1, , Yuxin Zou1, , Xinyu Qi1, , Runqing Shi1, , Wenli Xu1, , Xiaodong Wang1, , Guoxian Ding1, , Yu Duan1, ,

  • 1 Division of Geriatric Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, People’s Republic of China
* Equal contribution

Received: June 5, 2023       Accepted: March 18, 2024       Published: April 18, 2024
How to Cite

Copyright: © 2024 Sheng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Disrupted mitochondrial dynamics and mitophagy contribute to functional deterioration of skeletal muscle (SM) during aging, but the regulatory mechanisms are poorly understood. Our previous study demonstrated that the expression of thyroid hormone receptor α (TRα) decreased significantly in aged mice, suggesting that the alteration of thyroidal elements, especially the decreased TRα, might attenuate local THs action thus to cause the degeneration of SM with aging, while the underlying mechanism remains to be further explored. In this study, decreased expression of myogenic regulators Myf5, MyoD1, mitophagy markers Pink1, LC3II/I, p62, as well as mitochondrial dynamic factors Mfn1 and Opa1, accompanied by increased reactive oxygen species (ROS), showed concomitant changes with reduced TRα expression in aged mice. Further TRα loss- and gain-of-function studies in C2C12 revealed that silencing of TRα not only down-regulated the expression of above-mentioned myogenic regulators, mitophagy markers and mitochondrial dynamic factors, but also led to a significant decrease in mitochondrial activity and maximum respiratory capacity, as well as more mitochondrial ROS and damaged mitochondria. Notedly, overexpression of TRα could up-regulate the expression of those myogenic regulators, mitophagy markers and mitochondrial dynamic factors, meanwhile also led to an increase in mitochondrial activity and number. These results confirmed that TRα could concertedly regulate mitochondrial dynamics, autophagy, and activity, and myogenic regulators rhythmically altered with TRα expression. Summarily, these results suggested that the decline of TRα might cause the degeneration of SM with aging by regulating mitochondrial dynamics, mitophagy and myogenesis.


SM: skeletal muscle; TRα: thyroid hormone receptor α; THs: thyroid hormones; FT3: free triiodothyronine.