Transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells: 4h

The deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. The effects of UCB treatment to SH-SY5Y neuroblastoma cell line were examined by high-density oligonucleotide microarrays. 230 genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that a large group of UCB-induced genes were components of the ER stress response. Independent experimental validation of molecular events crucial for the ER stress response is presented. The results show that UCB exposure induces the ER stress response as a major intracellular homeostatic response in neuroblastoma cells in vitro. Our finding may provide valuable information for new therapeutic strategies in the treatment of BE. We used high-density oligonucleotide microarrays to analyze the gene expression profile of human neuroblastoma SH-SY5Y cells upon UCB treatment. Three replicates of UCB-treated cells were analyzed. As controls, we used three replicates of the same cells treated with DMSO only (the solvent used for UCB treatment).