Brain network and blood transcriptomic correlations underpin psychopathological phenotypes: A Preliminary Study

Depressive disorders and comorbid psychopathologies affect over 12% of humans and present debilitating symptoms. Prior studies identified systemic brain and peripheral biological dysregulations in depressive disorders, but the interrelated brain-body molecular pathobiology underlying these conditions is not well-defined. Here, we studied the molecular signatures of depressive and comorbid psychopathology in the same 14 postmortem brain anterior insula (Ant/Ins) and subgenual cingulate (sgACC) tissue and whole blood donors. We showed that the brain Ant/Ins and sgACC regions exhibited positive (concordant) brain-brain correlations in [~]50% and less than 10% negative (discordant) brain-brain correlations in our observed gene expression markers. In contrast, our observed gene expression/transcriptomic correlations between the brain regions and blood (brain-blood correlations) were more normally distributed, such that [~]20% were concordantly, and [~]20% were discordantly correlated. Using a mixed effects analysis, we showed that increased measures of comorbid psychopathology were associated with selective upregulation of inflammatory cytokine receptor gene TEC and neurodevelopmental olfactory receptor genes OR52E4 and OR56B2P transcriptomes across the two brain regions and blood. In contrast, an upregulation of the proinflammatory cytokine receptor gene IL18R1 and cellular developmental gene WIF1 and a downregulation of the brain protein signaling gene TECTB were more associated with comorbid psychopathology in blood than in the brain. Our findings of concordant and discordant transcriptomes in a well-phenotyped sample of 14 multi-tissue donors revealed tightly correlated brain-blood transcriptomic underpinnings of comorbid psychopathology. Our results provide a framework for identifying targetable brain-derived peripheral markers to advance novel diagnostic and therapeutic development for psychopathologic conditions.