Kcnq2, Kcnh1, Kcnn1, Kcnm, Kcnj10, Kcnn4, Kcnq1, Hcn3, Scn5a, and Scn8a) and scaffolding proteins (Table 2). Thus, to more directly explore the relationship between THC-induced DNA methylation changes and genes involved in the glutamatergic system and synaptic transmission, we used PPI databases (Lachmann and Ma'ayan, 2010) to assess the potential sharing of annotated mammalian PPIhubs by DMR genes and genes involved in the ‘regulation of synaptic plasticity' (n=146; GO:0048167) and ‘glutamatergic synaptic transmission' (n=79; GO:0035249). We found that physical protein–protein interaction networks from DMR genes were enriched for many of the same PPIhubs connected to synaptic plasticity/transmission gene sets (Figure 5b; Supplementary Table S5). For example, of the top 10 most significantly enriched PPIhubs, 7 were also significantly enriched for GO:0048167 and GO:0035249 gene sets (P<0.05). The most enriched hub for DMR-associated proteins, Dlg4, was also either the most significant or second most significant PPIhub in the other two gene set networks. Dlg4 encodes postsynaptic density protein 95 (Psd-95). The physical interaction network of Dlg4-associated genes from the three gene sets analyzed (n=35 genes) is shown in Figure 5b; in total there were 14 genes associated with THC-DMRs (9 hypermethylated; 5 hypomethylated) in the Dlg4 network.
