Seeking new molecular targets to control mitochondrial biogenesis

Abstract

Mitochondrial number and shape are constantly changing in response to increased energy demands. The ability to synchronize mitochondrial signaling pathways with environmental stimuli is a central aspect against obesity in mammals. The binding and regulation of transcriptional complexes at the promoter of mitochondrial genes are critical components of the mitochondrial biogenesis process. Specifically, these promoters contain cis‐regulatory elements that lead to the recruitment of selected nuclear receptors (NR) and transcriptional factors (TF). Although different molecular regulators of this system have been described, only a small number of nuclear receptors and transcription factors have been associated with the mitochondrial biogenesis process. In this study, therefore, we proposed to seek new targets for the regulation of the mitochondrial biogenesis process in C2C12 cells during differentiation through the integration of proteomic and transcriptomic analysis. As expected. mitochondrial function and biogenesis were strongly induced during C2C12 cell differentiation (Figure 1). By evaluating the signaling pathways and molecular networks during myogenesis using RNAseq data extracted from GEO datasets (GSE20846), we revealed the enrichment of several signaling pathways associated with mitochondrial biogenesis and oxidative metabolism such as OXPHOS and TCA cycle (Figure 2). These results showed a strong enrichment in the PPAR signaling which was validated through PPRE transactivation experiments and qPCR (Figure 2). Accordingly, Venn diagram analysis showed an overlap of 170 genes associated with mitochondrial function from upregulated genes during myogenesis and PPAR targets suggesting the involvement of PPAR activity in mitochondrial biogenesis (Figure 3). In addition, proteome analysis during C2C12 differentiation exhibited 609 proteins positively regulated, from which 246 overlapped with PPAR targets and also presented enrichment of mitochondrial signaling pathways. To investigate the involvement of other uncharacterized transcription factors and nuclear receptors in mitochondrial biogenesis accompanying skeletal muscle cell differentiation, we performed a over‐represented conserved transcription binding sites analysis (oPOSSUM 3.0) in the set of upregulated mitochondrial associated genes and proteins previously analyzed using GO‐term of cellular components (DAVID). These analyses revealed the role of several unrelated NRs and TFs in mitochondrial biogenesis accompanying skeletal muscle cell differentiation (Table 1).Support or Funding InformationThis work was supported by grants from Fundação de Amparo à Pesquisa do estado de São Paulo – FAPESP (2013/22733‐0; 2016/23008‐5) and CNPq (444323/2014).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.