Common variants on 17q25 and gene-gene interactions conferring risk of schizophrenia in Han Chinese population and regulating gene expressions in human brain
MOLECULAR PSYCHIATRY
Authors: Guan, L.; Wang, Q.; Wang, L.; Wu, B.; Chen, Y.; Liu, F.; Ye, F.; Zhang, T.; Li, K.; Yan, B.; Lu, C.; Su, L.; Jin, G.; Wang, H.; Tian, H.; Wang, L.; Chen, Z.; Wang, Y.; Chen, J.; Yuan, Y.; Cong, W.; Zheng, J.; Wang, J.; Xu, X.; Liu, H.; Xiao, W.; Han, C.; Zhang, Y.; Jia, F.; Qiao, X.; Zhang, D.; Zhang, M.; Ma, H.
Abstract
Recently, two genome-wide association studies (GWASs) of schizophrenia (SCZ) in Han Chinese identified several susceptibility loci. Replication efforts aiming to validate the GWAS findings were made and focused on the top hits. We conducted a more extensive follow-up study in an independent sample of 1471 cases and 1528 matched controls to verify 26 genetic variants by including nine top single-nucleotide polymorphisms (SNPs) that reached genome-wide significance and 17 promising SNPs nominated in the initial discovery phase. rs8073471 in an intron of tubulin-folding cofactor D (TBCD) obtained nominal significance (P<0.01) in single SNP analysis. Logistic regression identified significant interaction between rs3744165 (5'-untranslated region variant of exon 2 of zinc finger protein 750 (ZNF750), and in an intron of TBCD) and rs8073471 (Deviance test P-value = 2.77 x 10(-34)). Both SNPs are located at 17q25, an interesting region that has been implicated in SCZ. By using the Genotype-Tissue Expression (GTEx) data set, we implemented an expression quantitative trait loci epistasis analysis to explore the association between the genotype combinations of the two SNPs and gene expression levels in 13 areas of human central nervous system. We observed that rs3744165 x rs8073471 interaction modulated the expression profile of TEAD3 (P = 1.87 x 10(-8)), SH3TC2 (P = 2.00 x 10(-8)), KCNK9 (P = 5.20 x 10(-7)) and PPDPF (P = 1.13 x 10(-6)) in postmortem cortex tissue; EFNA1 (P = 7.26 x 10(-9)), RNU4ATAC (P = 2.32 x 10(-8)) and NUPL2 (P = 6.79 x 10(-8)) in cerebellum tissue. To the best of our knowledge, our study is the first one that links TBCD and ZNF750 mutations to SCZ susceptibility and to the transcript levels in human brain tissues. Further efforts are needed to understand the role of those variants in the pathogenesis of SCZ.
Immunocytochemical Localization of TASK-3 Protein (K(2P)9.1) in the Rat Brain
CELLULAR AND MOLECULAR NEUROBIOLOGY
Authors: Marinc, Christiane; Derst, Christian; Pruess, Harald; Veh, Ruediger W.
Abstract
Among all K2P channels, TASK-3 shows the most widespread expression in rat brain, regulating neuronal excitability and transmitter release. Using a recently purified and characterized polyclonal monospecific antibody against TASK-3, the entire rat brain was immunocytochemically analyzed for expression of TASK-3 protein. Besides its well-known strong expression in motoneurons and monoaminergic and cholinergic neurons, TASK-3 expression was found in most neurons throughout the brain. However, it was not detected in certain neuronal populations, and neuropil staining was restricted to few areas. Also, it was absent in adult glial cells. In hypothalamic areas, TASK-3 was particularly strongly expressed in the supraoptic and suprachiasmatic nuclei, whereas other hypothalamic nuclei showed lower protein levels. Immunostaining of hippocampal CA1 and CA3 pyramidal neurons showed strongest expression, together with clear staining of CA3 mossy fibers and marked staining also in the dentate gyrus granule cells. In neocortical areas, most neurons expressed TASK-3 with a somatodendritic localization, most obvious in layer V pyramidal neurons. In the cerebellum, TASK-3 protein was found mainly in neurons and neuropil of the granular cell layer, whereas Purkinje cells were only faintly positive. Particularly weak expression was demonstrated in the forebrain. This report provides a comprehensive overview of TASK-3 protein expression in the rat brain.