Characterization of the transcriptional profile in primary astrocytes after oxidative stress induced by Paraquat Birgitte Thuesen Olesen 1 , Jørgen Clausen, Ole Vang * Department of Science, Systems and Models, Roskilde University, DK-4000 Roskilde, Denmark Received 16 April 2007; accepted 21 August 2007 Available online 1 September 2007 In memory of Professor Jørgen Clausen. Abstract In the central nervous system oxidative stress has been implicated in the pathology of several neurological disorders. The ability to withstand reactive oxygen species and oxidative stress are essential for survival and therefore all aerobic cells are endowed with chemical and enzymatic antioxidative defense systems. The purpose of the present study was to investigate the antioxidative response at the transcriptional level following exposure of primary astrocytes to a pro-oxidant, Paraquat (PQ). This was done by investigating the time-dependent expression of selected genes encoding the antioxidative enzymes Mn- and CuZn superoxide dismutase (SOD) and catalase as well as the transcription factor component AP-1. Paraquat induced the expression of Mn- and CuZn SOD, catalase and decreases the expression of c-jun (a part of AP-1). Furthermore, the gene expression profiles were investigated after exposure to PQ using a commercial cDNA membrane array containing 207 genes from key oxidative stress pathways. The gene expression pattern clearly indicated that 60 mM PQ for 48 h induces genes related to oxidative stress, detoxification, mitotic arrest, DNA repair, and apoptosis. The PQ (48 h)-induced expressions of genes identified in cDNA array were confirmed by Northern blot analysis, which revealed a statistical significant up-regulation of genes involved in oxidative stress, detoxification, and DNA repair/synthesis and includes heme oxygenase-1 (11-fold), NAD(P)H dehydrogenase (8-fold), glutathione S-transferase P (7-fold), glucose-regulated 78-kDa protein (7-fold), glucose-regulated 75-kDa protein (6-fold), and growth-arrest and DNA-damage-inducible protein 45 (4.5-fold) and minor changes for heat shock 10-kDa protein, NADPH-cytochrome P450 reductase, heme oxygenase-2, proliferating cell nuclear antigen, and Bcl-2-associated death promoter. Thus, we could demonstrate a PQ-inducible effect of the mRNA of antioxidative enzymes, as well as the mRNAs of possible enzymes involved in the protection against oxidative stress. # 2007 Elsevier Inc. All rights reserved. Keywords: Astroglia cells; Northern blots; cDNA array; Antioxidative enzymes; Expression profile 1. Introduction In the central nervous system (CNS), oxidative stress has been implicated in the pathogenesis of neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases (Gibson et al., 1999; Hald and Lotharius, 2005; Jenner, 1996; Markesbery, 1997). Oxidative stress occurs when production of reactive oxygen species (ROS) exceeds the cell’s endogenous antioxidative defense thus the balance between pro- and antioxidative entities/activities is in favor of pro-oxidant species. The resulting imbalance may be damaging, leading to destruction of cellular components. In the CNS, astrocytes are known to interact with surrounding neurons by protecting, nourishing and modulating of growth and excitability (Nedergaard et al., 2003) and NeuroToxicology 29 (2008) 13–21 Abbreviations: AOE, antioxidative enzymes; AP-1, activator protein 1; BAD, Bcl-2-associated death promoter; CuZnSOD, Copper-Zinc superoxide dismutase; CypRM, NADPH-cytochrome P450 reductase; GADD45, growth- arrest and DNA-damage-inducible protein 45; GFAP, Glial fibrillary acids protein; GPx, glutathione peroxidase; GRP78, glucose-regulated 78-kDa pro- tein; GRP75, glucose-regulated 75-kDa protein; GST P, glutathione S-transfer- ase P subunit; HO-1, heme oxygenase-1; HO-2, heme oxygenase-2; HSP 10, heat shock 10-kDa protein; MnSOD, Mangan superoxide dismutase; NMOR1, NAD(P)H dehydrogenase, also called NAD(P)H menadione oxidoreductase; PCNA, proliferating cell nuclear antigen. * Corresponding author at: Department of Science, Systems and Models, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark. Tel.: +45 46742552; fax: +45 46743011. E-mail address: ov@ruc.dk (O. Vang). 1 Present address: Capio Diagnostik a.s., Nygaardsvej 32, DK-2100 Copen- hagen O, Denmark. 0161-813X/$ – see front matter # 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.neuro.2007.08.010