Abstract

Hypoxia-induced gene expression profiling in neuron and oligodendrocyte.

H. TOMITA; C. TANAKA; Z. YU; K. KIMURA; W. E. BUNNEY
Society for Neuroscience. 2008.

Abstract

Molecular characterization of the effect of hypoxia on the brain is important in various aspects of research. It is beneficial for elucidating the molecular mechanisms of hypoxia-related medical conditions, including ischemia. Also, it is essential for evaluating the effect of hypoxia in agonal condition as a confounding factor in postmortem brain research for elucidating the pathological mechanisms of neuropsychiatric disorders, since previous findings consistently show that effects of cause of death/agonal condition, especially hypoxia, on molecular genetic condition are remarkable, considering the effect of pathogeneses of neuropsychiatric disorders are relatively subtle. The brain tissue is heterogeneous constitution of various types of cells, and it is reported that responses to hypoxia differs between cell types. So far, cell-type specific effect of hypoxia on gene expression profiles of neuron and glia remain unclear. In this study, in order to evaluate comprehensive gene expression profiles of neuron and oligodendrocyte, we evaluated the effect of hypoxia on molecular genetic conditions of human neuron-derived cell line (SK-N-SH) and human oligodendricyte- derived cell lines (OL). Each cell line was cultured in either normal condition culture chamber (20% O2, 5% CO2, humidified) or hypoxic condition culture chamber (2% O2, 5% CO2, humidified) for 48hr. Cell growth and mitochondria function were evaluated with cytometry and MTS (tetrazolium dye) reduction assay, and gene expression profiles were evaluated with microarray. In SK-N-SH cells, MTS reduction activity was increased, and the increase was independent from cell count in SK-N-SH, while an increment of both MTS reduction activity and cell count were observed in OL cells. Microarrays demonstrate that the number of regulated genes in OL cells was twice higher than SK-N-SH cells, and observed hypoxia-responsive genes were unique to each cell type. The result may be useful to understand the pathogeneses of hypoxia-related diseases, such as brain ischemia, and to evaluate the effect of hypoxia on gene expression profiles of postmortem brain tissue.