Sinclair Duncan, Cesare Joseph, McMullen Mary, Carlson Greg C, Hahn Chang-Gyu, Borgmann-Winter Karin E
Department of Psychiatry, Neuropsychiatric Signaling Program, University of Pennsylvania, Philadelphia, PA USA ; Present address: Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, New South Wales Australia.
Department of Psychiatry, Neuropsychiatric Signaling Program, University of Pennsylvania, Philadelphia, PA USA.
J Neurodev Disord. 2016 May 1;8:14. doi: 10.1186/s11689-016-9148-7. eCollection 2016.
Neurodevelopmental disorders such as autism spectrum disorders and schizophrenia differentially impact males and females and are highly heritable. The ways in which sex and genetic vulnerability influence the pathogenesis of these disorders are not clearly understood. The n-methyl-d-aspartate (NMDA) receptor pathway has been implicated in schizophrenia and autism spectrum disorders and changes dramatically across postnatal development at the level of the GluN2B-GluN2A subunit "switch" (a shift from reliance on GluN2B-containing receptors to reliance on GluN2A-containing receptors). We investigated whether sex and genetic vulnerability (specifically, null mutation of DTNBP1 [dysbindin; a possible susceptibility gene for schizophrenia]) influence the developmental GluN2B-GluN2A switch.
Subcellular fractionation to enrich for postsynaptic density (PSD), together with Western blotting and kinase assay, were used to investigate the GluN2B-GluN2A switch in the cortex and hippocampus of male and female DTNBP1 null mutant mice and their wild-type littermates. Main effects of sex and DTNBP1 genotype, and interactions with age, were assessed using factorial ANOVA.
Sex differences in the GluN2B-GluN2A switch emerged across development at the frontal cortical synapse, in parameters related to GluN2B. Males across genotypes displayed higher GluN2B:GluN2A and GluN2B:GluN1 ratios (p < 0.05 and p < 0.01, respectively), higher GluN2B phosphorylation at Y1472 (p < 0.01), and greater abundance of PLCγ (p < 0.01) and Fyn (p = 0.055) relative to females. In contrast, effects of DTNBP1 were evident exclusively in the hippocampus. The developmental trajectory of GluN2B was disrupted in DTNBP1 null mice (genotype × age interaction p < 0.05), which also displayed an increased synaptic GluN2A:GluN1 ratio (p < 0.05) and decreased PLCγ (p < 0.05) and Fyn (only in females; p < 0.0005) compared to wild-types.
Sex and DTNBP1 mutation influence the GluN2B-GluN2A switch at the synapse in a brain-region-specific fashion involving pY1472-GluN2B, Fyn, and PLCγ. This highlights the possible mechanisms through which risk factors may mediate their effects on vulnerability to disorders of NMDA receptor dysfunction.
自闭症谱系障碍和精神分裂症等神经发育障碍对男性和女性的影响存在差异，且具有高度遗传性。性别和遗传易感性影响这些疾病发病机制的方式尚不清楚。N-甲基-D-天冬氨酸（NMDA）受体通路与精神分裂症和自闭症谱系障碍有关，并且在出生后发育过程中，在GluN2B-GluN2A亚基“转换”（从依赖含GluN2B的受体转变为依赖含GluN2A的受体）水平上发生显著变化。我们研究了性别和遗传易感性（具体而言，DTNBP1基因[失调素；精神分裂症的一个可能的易感基因]的无效突变）是否影响发育过程中的GluN2B-GluN2A转换。
采用亚细胞分级分离法富集突触后致密物（PSD），结合蛋白质免疫印迹法和激酶测定法，研究雄性和雌性DTNBP1基因敲除突变小鼠及其野生型同窝小鼠大脑皮质和海马中的GluN2B-GluN2A转换。使用析因方差分析评估性别和DTNBP1基因型的主效应以及与年龄的相互作用。
在额叶皮质突触的发育过程中，GluN2B-GluN2A转换出现了性别差异，这些差异与GluN2B相关参数有关。不同基因型的雄性小鼠相对于雌性小鼠，显示出更高的GluN2B:GluN2A和GluN2B:GluN1比率（分别为p < 0.05和p < 0.01）、Y1472位点更高的GluN2B磷酸化水平（p < 0.01）以及更高的PLCγ丰度（p < 0.01）和Fyn丰度（p = 0.055）。相比之下，DTNBP1的影响仅在海马中明显。DTNBP1基因敲除小鼠中GluN2B的发育轨迹受到破坏（基因型×年龄相互作用p < 0.05），与野生型相比，其突触处GluN2A:GluN1比率增加（p < 0.05），PLCγ丰度降低（p < 0.05），Fyn丰度降低（仅在雌性小鼠中；p < 0.0005）。
性别和DTNBP1突变以脑区特异性方式影响突触处的GluN2B-GluN2A转换，涉及pY1472-GluN2B、Fyn和PLCγ。这突出了风险因素可能通过其对NMDA受体功能障碍性疾病易感性产生影响的潜在机制。
