Skeletal muscle mitochondria contain nuclear-encoded small and long RNA species prior to and following adaptation to exercise training in rats
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ABSTRACT: Mitochondria import over 1000 proteins encoded by the nuclear genome, but the RNA contained within the organelle is generally thought to be only that which is transcribed from the mitochondrial genome. Recent evidence however suggests the presence of specific nuclear-encoded small- and long-non-coding RNAs (ncRNAs) in the mitochondrial matrix, hinting at a previously underappreciated level of subcellular, ncRNA-mediated regulation on mitochondrial function. The aim of this study was to characterise the population of RNAs contained within mitochondria isolated from rat skeletal muscle, and to investigate whether it was altered in response to endurance training, a potent metabolic stimulus that induces mitochondrial adaptations. Rats underwent four weeks of moderate intensity treadmill exercise training that induced typical adaptive responses at the transcriptome and functional levels in heart and skeletal muscle. Mitochondria from gastrocnemius skeletal muscle were isolated by immunoprecipitation, further purified, then sequenced to assess the mitochondrial transcriptome. Approximately 24 nuclear-encoded, coding or non-coding ‘long’ RNAs were detected in purified mitochondria, in addition to ~50 miRNAs with >100 normalised read counts. None were differentially expressed in the exercise vs control group at FDR < 0.05, but exploratory analyses (p<0.05) pointed towards 3 differentially regulated miRNAs in the mitochondria isolated from trained compared with sedentary muscle. In conclusion, we report the presence of a small population of nuclear-encoded long- and small RNAs in the mitochondria isolated from rat muscle tissue. Further research is required to investigate how these are imported into the mitochondria, and their role(s) in regulating exercise adaptations and mitochondrial biology
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE267763 | GEO | 2025/06/27
REPOSITORIES: GEO
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