Transcriptomic profiling of wild-type and Bmal1-/- myoblasts under normoxia or actue hypoxia conditions

Purpose: The goal of this study is to investigate the role of interplay between circadian clock and oxygen-sensing pathways in determining myogenic progenitor cell fate. Methods: Total RNAs were extracted from wild-type and Bmal1-/- myoblasts following exposure to normoxia (21% O2) or hypoxia (1% O2) for 6 hours, and subjected to RNA-sequencing. Results: There were significantly up-regulated (443 in normoxia versus 477 in hypoxia) and down-regulated (745 in normoxia versus 796 in hypoxia) genes in Bmal1-/- cells compared to wild-type, with a large degree of overlap between hypoxia and normoxia, although the fold change of differential gene expression was generally greater under hypoxia versus normoxia. Conclusion: Loss of Bmal1 in myoblasts leads to a premature differentiation-prone transcriptome, which was exaggerated following exposure to hypoxia. Overall design: Primary myoblasts obtained from TA muscle tissues of wild-type and Bmal1-/- C57b6/J mice were exposed to normoxia (21% O2) or hypoxia (1% O2) for 6 hours, and then immediately total RNA extraction. Whole genome-wide transcriptom was characterized by RNA sequencing.