Contactin-5 (CNTN5), which is a member of the immunoglobulin superfamily of cell adhesion molecules, plays a role in synapse formation and maturation. In this study, I investigated the involvement of CNTN5 in the pathophysiology of schizophrenia, thro...
Contactin-5 (CNTN5), which is a member of the immunoglobulin superfamily of cell adhesion molecules, plays a role in synapse formation and maturation. In this study, I investigated the involvement of CNTN5 in the pathophysiology of schizophrenia, through an analysis of the association of promotor single nucleotide polymorphisms (SNPs) with schizophrenia, and the expression in the brains of schizophrenic-like mice. For the analysis of the association of promoter SNPs (rs1222589, rs11218061, rs4754573, and rs4754574), a total of 263 schizophrenia patients and 455 control subjects were recruited. In the allele frequency analysis, I observed that the G allele of rs4754573 was associated with an increased risk of schizophrenia (P = 0.012). In the haplotype analysis, a significant association between the AAGA haplotype consisting of rs1222589, rs11218061, rs4754573, and rs4754574, and schizophrenia was also shown (P = 0.028). The luciferase activity assay according to the alleles of 4 SNPs showed that the G allele of rs4754573 reduced the promotor activity, compared to the A allele. The promotor activity of the AAGA haplotype was also decreased, compared to the AAAA haplotype (reference haplotype). Furthermore, in the prefrontal cortex, striatum, and hippocampus of the schizophrenic-like MK-801-treated and maternal immune-activated (MIA) mice, I examined the protein and mRNA expression of CNTN5. In MK-801-treated mice, no significant change in the expression of CNTN5 was detected. In contrast, in MIA mice, a decrease in mRNA and protein expression of CNTN5 was observed in the prefrontal cortex on postnatal day (PND) 50 and 60. These results indicate that the G allele of rs4754573 and the AAGA haplotype in CNTN5 may be contributed to the susceptibility of schizophrenia, through the decreased transcription of CNTN5. The decreased expression of CNTN5 may be involved in the pathophysiology of schizophrenia.