IgLON cell adhesion molecules regulate synaptogenesis in hippocampal neurons

IgLON cell adhesion molecules (CAMs) belonging to the immunoglobulin superfamily comprise of LAMP, neurotrimin (Ntm), OBCAM, and Kilon. In the present study, we performed the single and double transfection of IgLON gene constructs into hippocampal neurons in vitro and evaluated synaptic number. The quantitative analysis showed that the single over-expression of LAMP or OBCAM increased synaptic number, while the over-expression of Kilon reduced synaptic number and Ntm had no effects. The double over-expression of Kilon-Ntm, Kilon-OBCAM, LAMP-Ntm, and Ntm-OBCAM decreased synaptic number and that of Kilon-LAMP and LAMP-OBCAM had no effect. These results suggest that IgLON CAMs participate in regulating synapse formation in hippocampal neurons.