Figure 1

(A) Strategy of episode-dependent gene shift detection using microchip analysis. A three-step strategy was used to identify candidate genes that are expressed in an episode-specific fashion: Eight blood samples were collected (always at 8:00 a.m.) in two consecutive depressed and manic episodes on two consecutive days each. After screening by microarrays, the data set was submitted to two bioinformatic processing steps. Genes were subtracted that differed between the two consecutive days within a particular episode (arbitrary daily variation). Further genes were excluded that were differentially expressed within the two depressed or within the two manic episodes (arbitrary monthly variation). The expression pattern of the remaining depressed and manic episode genes was subsequently compared. (B–E) Episode-specific PBMC gene expression involves different groups of genes. Genes found to be differentially expressed by microchip screening were confirmed by qRT-PCR in all samples. Moreover, blood sampling was extended beyond the initial screening period, and regulated genes were again validated more than one year later. Genes were grouped (B–E) according to biological categories. Each bar represents mean ± SEM of 6 to 12 determinations from cDNAs obtained from PBMC on different days in independent manic (n = 6; open bars) and depressed (n = 5; filled bars) episodes. The chart for hemoglobins contains an insert with hemoglobin (protein) concentrations in whole blood (n = 7 samples of independent manic and depressed episodes, respectively). Mean values were compared using independent Student t test (two-tailed).