GSE183665
Binge Alcohol Disrupts Skeletal Muscle Core Molecular Clock Independent of Glucocorticoids
Circadian rhythms are central to optimal physiological functioning and their interruption contributes to the development of several chronic diseases. Alcohol (EtOH) intoxication disrupts circadian rhythms within liver, brain, and intestines, but it is unknown whether alcohol also disrupts components of the core clock in skeletal muscle. Female C57BL/6Hsd mice were randomized to receive either saline (control) or alcohol (EtOH) (5g/kg) via intraperitoneal injection at the start of the dark cycle (ZT12), and gastrocnemius was collected every 4hr from Control and EtOH treated mice for the next 48hr following isoflurane anesthetization. In addition, metyrapone was administered prior to alcohol intoxication in separate mice to determine whether the alcohol-induced increase in serum corticosterone contributed to circadian gene regulation. Finally, synchronized C2C12 myotubes were treated with alcohol (100mM) to assess the influence of centrally or peripherally mediated effects of alcohol on the muscle clock. Alcohol significantly disrupted the mRNA expression of Bmal1, Per1/2, and Cry1/2 in addition to perturbing the clock-controlled genes, Myod1, Dbp, Tef, and Bhlhe40 (p<0.05). Alcohol increased serum corticosterone levels and glucocorticoid target genes, Redd1 and Klf15, in muscle.  Metyrapone decreased serum corticosterone in EtOH mice but did not normalize the mRNA expression of Per1, Cry1 and Cry2 and Myod1 which were altered by EtOH. Alcohol did not alter core clock gene expression (Bmal, Per1/2, Cry1/2) at 4, 8, and 12hrs post treatment in synchronized C2C12 myotubes. Therefore, binge alcohol disrupted genes of the core molecular clock independently of elevated serum corticosterone. Overall design: Gastrocnemius and plantaris muscle mRNA from adult male ethanol treated or control C57BL/6 mice was analyzed by RNA sequencing of 5 biological replicates per group on and Illumina NovaSeq 6000.