Figure 4. Lithium modulates transcription of ATP-synthesis, post-synapse, and cation-channel associated gene sets most prominently in Layer 2/3 excitatory neurons of the mPFC as assessed by RNAseq with single cell resolution.

(A) The anterior cingulate cortex (ACC) portion of the medial prefrontal cortex (mPFC) was selected as region of interest. (B) UMAP dimension plot of lithium treated animals identifies 15 major cell populations, shown in distinct colors. Seven subclasses of excitatory cortical neurons, four subtypes of inhibitory neurons and four major glial cell types were identified (black, blue and grey coloured in the legend, respectively). (C) No differences in cell type clusters were detected between WT and DKO samples. (D) Barplot of significantly deregulated gene-sets (corrected q < 0.05) identified with GSEA against the gene ontology cellular component (GO-CC) collection shows most responses in layer 2/3 excitatory cells (49 up- and 27 down-regulated gene-sets) compared to all other cell types. (E) Condensed heatmap of all up- and down-regulated gene-sets (corrected q < 0.05) ordered for q-values shows the highly layer 2/3 specific response architecture with only sparsely overlapping gene sets enriched in other cell types. (F,G) Dotplot of the ten most significantly up- (F) and down-regulated (G) gene-sets ranked by the −log10 transformed q-value showing 6/10 upregulated gene-sets associated with mitochondrial ATP-synthesis and 3/10 with ribosome associated protein translation (F) and 5/10 and 3/10 down-regulated gene-sets associated with the post-synapse and cation-channel activities.

L: cortical layer, EN: excitatory neurons, IT: intratelencephalic, PT: pyramidal tract, NP: near-projecting, CT: corticothalamic, IN: inhibitory neurons; Sst: Somatostatin, Pval: Parvalbumin, Vip: Vaso-Intestinal Peptide, OPC: oligodendrocyte precursor cell, NES: nominal enrichment score.