A Novel Approach to Link Genetics and Human MRI Identifies AKAP7-Dependent Subicular/Prefrontal Functional Connectivity as Altered in Suicidality

Abstract

Background Brain imaging and genetics are fields acquiring data at increasing speed, but more information does not always result in a better understanding of the underlying biology. We developed the ProcessGeneLists (PGL) approach to use genetics and mRNA gene expression data to generate regions of interest for imaging studies. Methods We applied PGL to past suicide attempt (ATT): We averaged the mRNA expression levels of genes (n = 130) possibly associated with ATT (p ≤ 10 −3 in a published genome-wide association study, GWAS) in each brain region studied in the Human Allen Brain Atlas (6 ex-vivo brains, 158 to 946 regions/brain have mRNA expression data) and compared that to the averaged mRNA expression levels of all other genes in each region in each brain in the atlas. Results PGL revealed 8 regions where “attempt-related genes” were differentially expressed (Wilcoxon test with Bonferroni correction 8.88 −11 = <p < = 0.046). Using resting state functional connectivity (RSFC), we studied those regions in psychiatric inpatients (male/female, n = 132 with [ATT], n = 291 without [NAT] past attempt, unrelated to those in the GWAS). Among the 8 PGL-identified regions, the subiculum showed higher RSFC with habenula (p < 10 −6 ) and dorsolateral prefrontal cortex (dlPFC p FWE < 0.05) in ATT. We genotyped one single nucleotide polymorphism (SNP) in each of the five genes (within 130 from GWAS) with most important subicular expression. AKAP7 (A-Kinase Anchoring Protein 7, important in hippocampal memory processes) showed an interaction between genotype, ATT, and subiculum/dlPFC RSFC. Conclusion PGL uncovered a brain function/genotype interaction in ATT by using published GWAS data to inform imaging studies. This could inform individualized therapies in the future.