Changes in the Blood Transcriptome Highlights Disturbed Peripheral Biochemical Homeostasis in Bipolar Disorder.

Objectives: Studies have reported changes in the transcriptome in the brain and blood from people with bipolar disorders (BD). We completed this study to test the hypothesis that there would be changes in the blood transcriptome that would mirror cortical changes in RNA levels in BD.

Methods: Levels of RNA were measured in blood from 19 people with BD and 19 controls using Affymetrix Human Exon 1.0 ST Arrays. Significant differences in levels of RNA with diagnosis were identified using JMP Genomics 9.0, and the potential biological impact of changes in RNA was investigated using the Panther Classification System.

Results: Levels of RNA for 19,473 coding and non-coding RNAs were detected. Compared to controls, there were changes in levels of 98 (65 with higher levels than controls) coding and non-coding RNAs at the criteria of fold ≥ ±20% and p < 0.05 in BD. The changes in levels of RNA were predicted to impact toll-like receptor function and Wnt signalling, response to virus, cell-cell signalling, and protein metabolic processing as well as post-synaptic organisation, dendritic spine morphogenesis, and pattern recognition receptor signalling pathways. Four of the RNAs found to be altered in blood in this study were also found to be altered in our previous study of the cortical transcriptome using tissue of people with BD.

Conclusions: This, and other studies, suggest changes in the blood transcriptome are affecting peripheral biochemical homeostasis in BD and some of the changes are present in the cortex of those with the disorder. Therefore, it could be possible that changes in the blood transcriptome in people with BD could contain diagnostic or theranostic markers for the disorder.