BACKGROUND: Mitochondrial-derived peptides (MDPs) such as MOTS-c and humanin have been studied for their cytoprotective functions. In mice, humanin-encodingis a mitochondrial pseudogene, and the humanin-like peptide is encoded by the nucleargene. However, endogenous tissue-specific expression profiles ofhave not yet been identified.
METHODS: andexpression was profiled via reverse transcription using only oligo(dT) primers from tissues of C57BL6/J mice. To analyze altered expression upon mitochondrial biogenesis, C2C12 myocytes and brown adipocytes were differentiated. Mitochondrial DNA copy numbers were quantified for normalization.
RESULTS: Bothandwere highly expressed in brown adipose tissue. When normalized against mitochondrial content,was identified as being highly expressed in the duodenum, followed by the jejunum. In models of mitochondrial biogenesis, bothandwere upregulated during myocyte and brown adipocyte differentiation. Increasedexpression during brown adipocyte differentiation remained significant after normalization against mitochondrial DNA copy number, whereas myocyte differentiation exhibited biphasic upregulation and downregulation in early and late phases, respectively.
CONCLUSION: Nuclear-encodedshowed similar expression patterns of mitochondrial-encoded. Brown adipose tissue presented the highest basal expression levels ofand. When normalized against mitochondrial DNA copy number, gut tissues exhibited the highest expression of. Upregulation ofduring mitochondrial biogenesis is independent of mitochondrial content.