Involvement of Hsp70, a stress protein, in the resistance of long-term culture of PC12 cells against sodium nitroprusside (SNP)-induced cell death

Abstract

Sodium nitroprusside (SNP)-treated PC12 cell line is being used in our laboratory as a cell model of nitric oxide (NO)-mediated damage for in vitro evaluation of potential neuroprotective compounds, thus cell response to SNP must be standardized to gain reproducible data. The NO-donor SNP has been shown to induce cell death at high concentrations in undifferentiated PC12 cells. Differences were found in sensitivity to SNP between cells from short- and long-term cultured cells. After 24-h exposure to 100-500 microM SNP, a decrease of cell viability was observed in both short- (17, 21 and 23rd passages) and long-term cultures (46, 49 and 50th passages), with IC(50) values of 312.72 and 462.90 microM, respectively. In cells from early passages, SNP-induced cell death was accompanied by significant increases of LDH leakage, nitrite production, malondialdehyde (MDA) levels, catalase (CAT) activity, cleavage of poly(ADP-ribose)polymerase (PARP) and caspase-3 activation in comparison with those from late passages. Furthermore, untreated and SNP-treated cells from long-term cultures displayed an increase of the stress protein Hsp70 levels when compared with those from short-term cultures. Up-regulated levels of Hsp70 may be associated with cell survival. Therefore, cells may acquire a certain resistance to SNP-induced toxicity associated with an increase in cell passage-dependent Hsp70. The protein Hsp70 might modulate the cellular response to the toxic insult by increasing CAT and GSH-Px activities and decreasing caspase-3 activation. Finally, it is crucial for the standardization of this cell model of neurotoxicity, at least in part, the use of PC12 cells in an optimum and reliable range of passages.

Antioxidant properties ofTaraxacum officinalefruit extract are involved in the protective effect against cellular death induced by sodium nitroprusside in brain of rats

“…This result is consistent with previous observations in brain slices (Ávila et al, 2008) and cortical neurons, since SNP induces cell death and apoptosis-related mitochondrial dysfunction (Fukushima et al, 2006;Romero et al, 2010). The neurotoxic effect of SNP has been attributed to the production of ROS and release of NO…”

“…Several mechanisms have been proposed for NO • -induced cell death, including oxidative stress and mitochondrial alterations (Riobo et al, 2001;Fukushima et al, 2006;Romero et al, 2010). NO…”

“…• induces oxidative stress, neuronal toxicity, and apoptotic cell death, which is accompanied by mitochondrial dysfunction (Riobo et al, 2001;Fukushima et al, 2006;Romero et al, 2010). NO…”

“…• is a known mediator of inflammatory processes that play an important role in the pathogenesis of several neurodegenerative diseases (Brown, 2007;Calabrese et al, 2007); therefore, models of NO • -mediated cytotoxicity may serve as tools to evaluate active compounds for further treatment (Romero et al, 2010).…”

Role of heat shock proteins in stress response and carcinogenesis

“…These ''puffs'' were the consequence of increased expression of heat shock proteins. Today, it is well known that different types of stress conditions, including inflammation, infection, hypoxia, starvation, and-particularly relevant for our community-exposure of chemicals can also increase the expression of these proteins (Choi et al 2011;Chattopadhyay et al 2011;Romero et al 2010;Zainul, 2011;Stewart 2011).…”