Transmembrane protein 108 involves in adult neurogenesis in the hippocampal dentate gyrus.

Background: Transmembrane protein 108 (Tmem108) is a risk gene of psychiatric diseases including schizophrenia, bipolar disorder and major depression disorder. However, the pathophysiological mechanisms of Tmem108 are largely unknown.

Results: Here we investigated the pathophysiological function of Tmem108 in the hippocampal dentate gyrus by using mutant mice. Tmem108 highly expressed in the dentate gyrus and CA3 of the hippocampus. Dentate gyrus is a brain region where adult neurogenesis occurs, and aberrant adult neurogenesis in dentate gyrus has been implicated in major depression disorder. Indeed, mutant mice had lower immobility than wild type mice in tail suspension test and forced swimming test. BrdU and anti-Ki67 antibody staining indicated that adult neurogenesis of the hippocampal dentate gyrus region decreased in Tmem108 mutant mice. qPCR results showed that expression of Axin2, DISC1 and β-Catenin, three dentate gyrus adult neurogenesis related genes in Wnt/β-Catenin signaling pathway, decreased in mutant mice. Furthermore, Tmem108 enhanced free β-Catenin level in dual luciferase assay.

Conclusions: Thus, our data suggest that Tmem108 increases adult neurogenesis and plays a complexity role in psychiatric disorders.