Figure 1.

Graphic illustration of the normalized expression levels of Mn²⁺-altered genes in primary human astrocytes. Primary human astrocytes were treated with or without 200 μM Mn²⁺ for 7 days. RNA samples were extracted from these cells, and cRNA probes were generated and were hybridized to the Human Genome U133 Plus 2.0 arrays and scanned. Data were analyzed by using various algorithms in GeneSpring, including nonparametric two-way ANOVA, and with the Benjamini & Hochberg false discovery rate multiple testing correction (p-value less than 0.05). The differentially expressed genes in Mn²⁺-treated vs. untreated cells were subjected to four consecutive filtering processes to identify genes whose overall expression level in three independent batches of astrocytes was altered at least twofold and whose expression level in each batch of astrocytes was altered at least 1.5-fold. The expression levels of up-regulated genes (Top) and down-regulated genes (Bottom) by Mn²⁺ in three batches of independent astrocytes were plotted.