BioProject

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.