The augmenter of liver regeneration induces mitochondrial gene expression in rat liver and enhances oxidative phosphorylation capacity of liver mitochondria

Background. The mammalian augmenter of liver regeneration gene encodes a pr otein involved in the unique process of liver regeneration. The augmenter o f liver regeneration respective protein stimulates hepatocyte proliferation in hepatectomized rats and inhibits cytotoxic activity of liver-derived Na tural Killer cells from intact rats. Augmenter of liver regeneration protei n shares homology with a Saccaromyces Cerevisiae protein essential for the viability, oxidative phosphorylation and cell-division cycle. Aims. To demonstrate if augmenter of liver regeneration protein, like the h omologous in the yeast, plays a role in the regulation of biogenesis of mit ochondria. Methods. Augmenter of liver regeneration protein was injected in intact rat s and, in the hepatic tissue, the expression of two genes located in two di fferent regions of the mitochondrial genome, mitochondrial ATPase 6/8, and ND1 subunit, and of a nuclear gene, mitochondrial Transcription Factor A, w ere considered in addition, cytochrome content and oxidative phosphorylatio n capacity of liver-derived mitochondria were evaluated. Results. The augmenter of liver regeneration protein administration induces an increase in the mitochondrial gene expression and enhances cytochrome c ontent and oxidative phosphorylation capacity of liver-derived mitochondria . Conclusions. The present data demonstrate a comparable role in the regulati on of mitochondria biogenesis in the eukaryotic cell like the yeast protein . This phenomenon could be part of the complex mechanism through which augm enter of liver regeneration regulates hepatocyte proliferation.