A proteomic approach to the bilirubin‐induced toxicity in neuronal cells reveals a protective function of DJ‐1 protein

Abstract

Unconjugated bilirubin (UCB) is a powerful antioxidant and a modulator of cell growth through the interaction with several signal transduction pathways. Although newborns develop a physiological jaundice, in case of severe hyperbilirubinemia UCB may become neurotoxic causing severe long-term neuronal damages, also known as bilirubin encephalopathy. To investigate the mechanisms of UCB-induced neuronal toxicity, we used the human neuroblastoma cell line SH-SY5Y as an in vitro model system. We verified that UCB caused cell death, in part due to oxidative stress, which leads to DNA damage and cell growth reduction. The mechanisms of cytotoxicity and cell adaptation to UCB were studied through a proteomic approach that identified differentially expressed proteins involved in cell proliferation, intracellular trafficking, protein degradation and oxidative stress response. In particular, the results indicated that cells exposed to UCB undertake an adaptive response that involves DJ-1, a multifunctional neuroprotective protein, crucial for cellular oxidative stress homeostasis. This study sheds light on the mechanisms of bilirubin-induced neurotoxicity and might help to design a strategy to prevent or ameliorate the neuronal damages leading to bilirubin encephalopathy.

Cytochrome P450 2A5 and bilirubin: Mechanisms of gene regulation and cytoprotection

“…BR also induces ER stress by disrupting intracellular calcium (iCa 2+ ) homeostasis and increasing ROS production resulting in activation of caspase-3 (Gao et al, 2011). Furthermore, DNA oxidation by BR-induced oxidative stress can also trigger apoptosis (Deganuto et al, 2010). Our results support previous findings by demonstrating that BR induces caspase-3 activation in both Hepa 1-6 and primary mouse hepatocytes.…”

“…BR-induced oxidative stress causes DNA damage and cell growth reduction in a human neuroblastoma cell line thereby impairing S-phase cell cycle progression and triggering apoptosis (Deganuto et al, 2010). It has also been reported that BR treatment induces cell cycle arrest by activation of extracellular signal-regulated kinase 1 and 2…”

“…Furthermore, many reports show that the cytotoxic effects of BR extend down to nucleus. Previous studies have demonstrated that BR induces DNA damage and disrupt cell growth via DNA oxidation and activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) (Ollinger et al, 2007;Nguyen et al, 2008;Deganuto et al, 2010).…”

In-depth Identification of Pathways Related to Cisplatin-induced Hepatotoxicity through an Integrative Method Based on an Informatics-assisted Label-free Protein Quantitation and Microarray Gene Expression Approach

“…In addition, it will lead to better predictive models of toxicity for use in drug development (19). Among proteomic technologies, two-dimensional gel electrophoresis has recognized changes in expression to identify several proteins with antioxidant and pro-surviving activities in the toxicology field (20). With the recent availability of techniques such as LC-MS/ MS-based shotgun proteomics, which significantly increase the number of proteins identified, the more proteins related to drug toxicity mechanisms have been discovered (13).…”

The protective effect of docosahexaenoic acid on the bilirubin neurotoxicity

“…Although UCB was suggested a powerful antioxidant and a modulator of cell growth, recent studies have provided strong evidence in the last decade that, UCB neurotoxicity in part due to oxidative stress, which leads to DNA damage and cell growth reduction 46 . The organism's defence system against oxidative stress and reactive oxygen species includes non-enzymatic mechanisms (vitamin A, E and C) and enzymes such as SOD, CAT and GPx 47 .…”