Multi-transcriptome analysis following an acute skeletal muscle growth stimulus yields tools for discerning global and MYC regulatory networks

Authors

Kevin A. Murach, University of Arkansas
Zhengye Liu, Karolinska Institute
Baptiste Jude, Karolinska Institute
Vandre C. Figueiredo, University of Kentucky
Yuan Wen, University of Kentucky
Sabin Khadgi, University of Arkansas
Seongkyun Lim, University of Arkansas
Francielly Morena da Silva, University of Arkansas
Nicholas P. Greene, University of Arkansas
Johanna T. Lanner, Karolinska Institute
John J. McCarthy, University of Kentucky
Ivan Jose Vechetti Jr, University of Nebraska-LincolnFollow
Ferdinand von Walden, Karolinska Institute

Document Type

Article

Date of this Version

9-15-2022

Citation

J. Biol. Chem. (2022) 298(11) 102515. https://doi.org/10.1016/j.jbc.2022.102515

Comments

Open Access.

Abstract

Myc is a powerful transcription factor implicated in epigenetic reprogramming, cellular plasticity, and rapid growth as well as tumorigenesis. Cancer in skeletal muscle is extremely rare despite marked and sustained Myc induction during loading-induced hypertrophy. Here, we investigated global, actively transcribed, stable, and myonucleus-specific transcriptomes following an acute hypertrophic stimulus in mouse plantaris. With these datasets, we define global and Myc-specific dynamics at the onset of mechanical overload-induced muscle fiber growth. Data collation across analyses reveals an under-appreciated role for the muscle fiber in extracellular matrix remodeling during adaptation, along with the contribution of mRNA stability to epigenetic-related transcript levels in muscle. We also identify Runx1 and Ankrd1 (Marp1) as abundant myonucleus-enriched loading-induced genes. We observed that a strong induction of cell cycle regulators including Myc occurs with mechanical overload in myonuclei. Additionally, in vivo Myc-controlled gene expression in the plantaris was defined using a genetic muscle fiber-specific doxycycline-inducible Myc-overexpression model. We determined Myc is implicated in numerous aspects of gene expression during early-phase muscle fiber growth. Specifically, brief induction of Myc protein in muscle represses Reverbα, Reverbβ, and Myh2 while increasing Rpl3, recapitulating gene expression in myonuclei during acute overload. Experimental, comparative, and in silico analyses place Myc at the center of a stable and actively transcribed, loading-responsive, muscle fiber–localized regulatory hub. Collectively, our experiments are a roadmap for understanding global and Myc-mediated transcriptional networks that regulate rapid remodeling in postmitotic cells. We provide open webtools for exploring the five RNA-seq datasets as a resource to the field.