Integration of postmortem amygdala expression profiling, GWAS, and functional cell culture assays: neuroticism-associated synaptic vesicle glycoprotein 2A (SV2A) gene is regulated by miR-133a and miR-218

Abstract

Recent genome-wide studies have begun to identify gene variants, expression profiles, and regulators associated with neuroticism, anxiety disorders, and depression. We conducted a set of experimental cell culture studies of gene regulation by micro RNAs (miRNAs), based on genome-wide transcriptome, proteome, and miRNA expression data from twenty postmortem samples of lateral amygdala from donors with known neuroticism scores. Using Ingenuity Pathway Analysis and TargetScan, we identified a list of mRNA-protein-miRNA sets whose expression patterns were consistent with miRNA-based translational repression, as a function of trait anxiety. Here, we focused on one gene from that list, which is of particular translational significance in Psychiatry: synaptic vesicle glycoprotein 2A (SV2A) is the binding site of the anticonvulsant drug levetiracetam ((S)-α-Ethyl-2-oxo-1-pyrrolidineacetamide), which has shown promise in anxiety disorder treatments. We confirmed that SV2A is associated with neuroticism or anxiety using an original GWAS of a community cohort (N = 1,706), and cross-referencing a published GWAS of multiple cohorts (Ns ranging from 340,569 to 390,278). Postmortem amygdala expression profiling implicated three putative regulatory miRNAs to target SV2A: miR-133a, miR-138, and miR-218. Moving from association to experimental causal testing in cell culture, we used a luciferase assay to demonstrate that miR-133a and miR-218, but not miR-138, significantly decreased relative luciferase activity from the SV2A dual-luciferase construct. In human neuroblastoma cells, transfection with miR-133a and miR-218 reduced both endogenous SV2A mRNA and protein levels, confirming miRNA targeting of the SV2A gene. This study illustrates the utility of combining postmortem gene expression data with GWAS to guide experimental cell culture assays examining gene regulatory mechanisms that may contribute to complex human traits. Identifying specific molecular mechanisms of gene regulation may be useful for future clinical applications in anxiety disorders or other forms of psychopathology.

MicroRNA regulation of prefrontal cortex development and psychiatric risk in adolescence

“…However, microRNAs in non-cortical regions are also likely to contribute to PFC development and to the etiology of MDD, schizophrenia and substance use disorders. Indeed, miR-218 levels have been shown to be also elevated in the postmortem lateral amygdala of individuals with neuroticism and anxiety [138]. In rodents, the disruption of PFC dopamine development by exposure to recreational-like doses of stimulant drugs of abuse in adolescence requires miR-218 upregulation in the ventral tegmental area [139].…”

miR - 218 - 2 regulates cognitive functions in the hippocampus through complement component 3–dependent modulation of synaptic vesicle release

“…Recently, miR-218 has been suggested to show abnormal expression in a variety of neurodegenerative and neuropsychiatric disorders, including Alzheimer's disease, Parkinson's disease, schizophrenia, depression, and anxiety (19)(20)(21)(22)(23)(24). miR-218 includes miR-218-1 and miR-218-2, which are located in the introns of the tumor suppressor genes SLIT2 and SLIT3, respectively (25).…”

A New Player in Depression: MiRNAs as Modulators of Altered Synaptic Plasticity

“…The results indicated that miR-133a and miR-128 in the amygdala generated the same expression pattern and translation inhibition function with regard to synaptic vesicle glycoprotein 2A (SV2A) regulation. Cell experiments also confirmed that miR-133a and miR-128 targeted Sv2A 3 UTR to inhibit its expression [60]. Another study on the LPS-induced model showed that miR-96 was targeted and negatively regulated SV2C expression in the hippocampal CA1 region, decreased 5-hydroxyindole acetic acid (5-HT) and dopamine (DA) release, and induced the development of depres-sion [61].…”