Fig 2: Expression of circARL15, miR-431-5p, and DISC1 in IDD. (A–C) The expressions of circARL15 (A), miR-431-5p (B), and DISC1 (C) in IDD and the normal samples. (D–F) circARL15 was positively correlated with DISC1 (D) and negatively correlated with miR-431-5p (E), while miR-431-5p was negatively correlated with DISC1 (F) *p < 0.05.

Fig 3: circARL15 modulates the expression of DISC1 through miR-431-5p. NP cells were treated with negative control, circARL15 overexpression (OE) plasmid, miR-431-5p mimics and circARL15-OE + miR-431-5p mimics. (A,B) Immunofluorescence staining of DISC1. (C) DISC1 protein expression levels were analyzed by western blot analysis. *p < 0.05 compared with control; #p < 0.05 compared with miR-431-5p mimics. &p < 0.05 compared with circARL15-OE.

Fig 4: Immunofluorescence of BDNF is reduced in NRG1-KO and DISC1-LI primary PFC neuronal cultures, but rescued by Ppy-DBSA with electrical stimulation.(a,b) Ppy-DBSA with electrical stimulation reversed the reduced BDNF immunofluorescence induced by NRG1-KO or DISC1-LI, in primary PFC neuronal cultures. Scale bar = 5 µm. *p < 0.05 vs wild-type, control; ^^p < 0.01 vs NRG1-KO, control; #p < 0.05 vs DISC1-LI, control. Error bars indicate SEM.

Fig 5: NRG1-KO or DISC1-LI inhibits neurite outgrowth in mice primary PFC neuronal cultures.(a–c) Neurite length and the number of neurite branches are reduced in PFC primary neuronal cultures from NRG1-KO and DISC1-LI mice, compared to wild-type. Scale bar = 50 µm. *p < 0.05 vs wild-type; **p < 0.01 vs wild-type. Error bars indicate SEM.