The International Journal of Biochemistry & Cell Biology 43 (2011) 1178–1186 Contents lists available at ScienceDirect The International Journal of Biochemistry & Cell Biology jo ur nal homep ag e: www.elsevier.com/locate/biocel NARP mutation and mtDNA depletion trigger mitochondrial biogenesis which can be modulated by selenite supplementation Marta Wojewoda, Jerzy Duszy ´ nski, Joanna Szczepanowska ∗ Laboratory of Bioenergetics and Biomembranes, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur St, 02-993 Warsaw, Poland a r t i c l e i n f o Article history: Received 14 December 2010 Received in revised form 11 April 2011 Accepted 18 April 2011 Available online 28 April 2011 Keywords: Mitochondrial biogenesis Mitochondrial disease Mitochondrial stress NARP Selenium a b s t r a c t The importance of mitochondrial biogenesis in the pathogenesis of mitochondrial diseases has been widely recognised but little is known about it with regard to NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) syndrome. Since such knowledge would contribute to the understanding of the pathogenesis of this disease, we designed a study to provide comprehensive overview of mitochondrial biogenesis in cybrid cells harboring NARP mutation (8993T > G). We also used Rho0 cells with the same nuclear background to show that distinct mtDNA defects lead to distinct cellular responses irrespective of nuclear genome. Mitochondrial biogenesis is regulated by mitochondria-to-nucleus (retrograde) communication which depends on intracellular signaling pathways sensitive to ROS. Since we previously found that selenite low- ered ROS in NARP cybrids, we hypothesised that selenite could also modulate mitochondrial biogenesis in these cells. Although the mitochondrial mass was not changed in NARP cybrids, we showed the compensatory upregulation of respiratory chain subunits which prompted us to investigate the transcription factors that regulate their expression such as PGC-1, NRFs, and TFAM. Selenite supplementation increased the level of NRF1 and nuclear accumulation of NRF2, but we did not detect any major changes in the levels of investigated respiratory chain proteins. These subtle changes in mitochondrial biogenesis in response to selenite treatment support the hypothesis that selenite could be considered as a potential therapeutic agent of NARP syndrome due to its antioxidant properties. Moreover, it could also be tested with regard to other mitochondrial disorders associated with ROS overproduction. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Mitochondrial biogenesis is tightly regulated to meet cellu- lar energy requirements. The main regulatory role is played by nuclear respiratory factors 1 (NRF1), 2 (NRF2) and mitochondrial transcription factors A (TFAM) and B. However, these transcrip- tion factors alone cannot account for the coordinated expression of about 1500 mitochondrial proteins. A growing body of evi- dence points to the integrative role of coactivators from the PGC-1 (PPAR-gamma coactivator 1) family that precisely orchestrate these transcription factors and their target genes into a program of mitochondrial biogenesis (Scarpulla, 2006, 2008). The importance of mitochondrial biogenesis with respect to pathogenesis of mitochondrial diseases has been widely recognised ∗ Corresponding author at: 3 Pasteur St, 02-093 Warsaw, Poland. Tel.: +48 225892345; fax: +48 228225342. E-mail addresses: m.wojewoda@nencki.gov.pl (M. Wojewoda), j.duszynski@nencki.gov.pl (J. Duszy ´ nski), j.szczepanowska@nencki.gov.pl (J. Szczepanowska). (Collombet et al., 1997; Heddi et al., 1993; Marusich et al., 1997; Reinecke et al., 2009). Although there is some data pointing to increased expression of genes related to oxidative phosphorylation and glycolysis in NARP (Neuropathy, Ataxia and Retinitis Pigmen- tosa) patient cells (Heddi et al., 1999), the comprehensive overview of mitochondrial biogenesis and its regulatory factors with regard to this mitochondrial disease is missing. To address this issue, we investigated the total mitochondrial mass and the level of repre- sentative subunits of respiratory chain complexes II (CII-30), III (CIII-core 2), IV (CIV-II) and ATP synthase (CV-) in NARP cybrid cells. We also extended our investigation to non-respiratory mito- chondrial proteins such as mitochondrial chaperone mtHsp70 that facilitates protein import into the mitochondrial matrix (Deocaris et al., 2008), uncoupling protein UCP3 that can attenuate mito- chondrial ROS production (Brand and Esteves, 2005) and electron carrier cytochrome c (Cyt C). Last but not least, we also investigated the levels of transcription factors NRF1, NRF2, TFAM and PGC-1 that regulate expression of genes encoding mitochondrial proteins. Since (García et al., 2000) used MRC5 Rho0 fibroblasts with the same nuclear background as NARP cybrids to compare the struc- ture, functioning and assembly of ATP synthase, we also compared 1357-2725/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocel.2011.04.011