PGC-1α Regulates The Cell Cycle Through ATP And ROS In CH1 Cells

Mitochondrial oxidative phosphorylation (OXPHOS) is the major source of cellular energy. In mitochondria, defective oxidative phosphorylation occurs with low ATP production and high reactive oxygen species (ROS) followed by attenuated cell growth and metabolism. Bcl-2 localized in mitochondria, which could eliminate the accumulation of ROS in mitochondria. PGC-la (Peroxisome proliferator-activated receptor-y coactivator la) with localization of nucleus and mitochondria, plays a key role in energy metabolism. However, whether there are interactions between Bcl-2 and PGC-la, and the detailed regulation mechanisms of energy metabolism remain little understood. This study aims to reveal that PGC-1α regulated cell cycle from ATP and ROS homeostasis, and direct or indirect interaction with Bcl-2.First, we obtained PGC-la-overexpression CHI cell line with pBABE-neo as vector control. Following siRNA strategy to PGC-1α-overexpression CHI cells show that PGC-1α contributes to ATP production, ROS decrease and cell cycle by cytometry analysis. Western Blot displayed CyclinBl/D1 elevation in PGC-1α-overexpression CHI cells. Subsequently, to assess whether they work on cell cycle through affecting the cell cycle related protein by altering the level of ATP and ROS. The result suggested that inhibiting the ATP production in PGC-1α-overexpression CHI cells conducted by Oligomycin and increasing ROS level dealt with H2O2, both resulted in significant down-regulation of CyclinDland CyclinBl.Next, we obtained Bcl-2-overexpression NIH3T3 cell line with PB as vector control. Using two synchronization processing methods (contact inhibition and serum starvation),Bcl-2-overexpression NIH3T3 cells increase Bcl-2 expression compared with PB control cells. After transfection with Bcl-2 siRNA, U251 cells, in which both expressions of Bcl-2 and PGC-1α were increased, weakened PGC-la expression. On the contrary, PGC-1α RNA interference increased Bcl-2 expression. Although immunoprecipitation analysis show there is no direct interaction between PGC-1α and Bcl-2, we detected a positive band with 70 kDa molecular weight that may response to a variant of PGC-1. This result will be confirmed in future studies.In summary, expressions of CyclinDl and CyclinBl and levels of ATP and ROS are responsible for PGC-la-regulated cell cycle. Our study will bring benefits to clear PGC-la regulation of mitochondria and further target mitochondria related diseases. The possible interaction of Bcl-2 with PGC-1α can be potential for illustrating Bcl-2 anti-cancer properties and Bcl-2 signaling pathways in mitochondrial diseases, all of it will contribute to pathology study of neoplasm.