Next Generation Sequencing Compares Effects of microRNA-9 perturbation in control and SZ hiPSC NPCs

To follow-up findings that miR-9 was abundantly expressed in control NPCs, significantly down-regulated in a subset of SZ NPCs, and that miR-9 levels/activity, neural migration and diagnosis were strongly correlated, we tested the effect of manipulating miR-9 at cellular, proteomic and transcriptomic levels. Unexpectedly, proteomic- and RNAseq-based analysis revealed that these effects were mediated primarily by small changes in expression of indirect miR-9 targets, rather than large changes in direct miR-9 targets; these indirect targets are enriched for migration-associated genes. Together these data indicate that aberrant levels and activity of miR-9 may be one of the many factors that contribute to SZ risk, at least in a subset of patients. Methods: We compared global transcription of forebrain NPCs from two control and two SZ patients with manipulated miR-9 levels by RNAseq. Results: Although RNAseq analysis revealed large inter-individual heterogeneity, we were able to resolve several functional consistencies in the effects of our miR-9 perturbations: i) the change in miR-9 activity was consistent with the inhibitory role of miR-9, ii) the gene expression fold-change of miR-9 target genes (between each perturbation and its corresponding control, summarized by the first principal component) was correlated (r=0.95, p=3.92e-04) with miR-9 fold change and iii) the differentially expressed (DE; p <0.01) gene list resulting from miR-9 perturbation (paired t-test) was enriched for miR-9 targets (1.53-fold, p=1.2e-5). Conclusions: We integrated the miR-9 perturbation RNAseq data with our existing RNAseq datasets contrasting control and SZ hiPSC NPC expression from our cohort 1 (six controls, four patients), to ask whether there was any relationship between the “SZ NPC signature” and “miR-9 perturbation” datasets; we observed that the DE (p-value <0.01) in “SZ NPC signature” is enriched for DE (fdr<0.01) in “miR-9 perturbation” (the overall enrichment is 2.31-fold (p=9.39e-09)); there is significant correlation between DE fold-change in these two datasets (overall genes r=0.188; p<10e-50). Effects were mediated primarily by small changes in expression of indirect miR-9 targets, rather than large changes in direct miR-9 targets; these indirect targets are enriched for migration-associated genes Overall design: Biological duplicates of passage-matched NPCs from 1 control (female) and 1 SZ patient (female) were transduced with either RV-GFP or RV-miR-9-GFP; GFP-positive NPCs were purified by fluorescent activated cell sorting (FACS) and expanded for two passages. In parallel, passage-matched NPCs from 2 controls (1 male, 1 female) and 2 SZ patients (1 male, 1 female) were transiently transfected with either scrambled or miR-9 LNA probes. In both instances, miR-9 perturbation was confirmed by qPCR.

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Topol A, Zhu S, Hartley BJ, English J, Hauberg ME, Tran N, Rittenhouse CA, Simone A, Ruderfer DM, Johnson J, Readhead B, Hadas Y, Gochman PA, Wang YC, Shah H, Cagney G, Rapoport J, Gage FH, Dudley JT, Sklar P, Mattheisen M, Cotter D, Fang G, Brennand KJ