Haploinsufficiency in bromodomain containing 2 (Brd2) gene remodels synaptic transmission in female mouse striatum in a sex-specific manner

Our previous work showed that Brd2+/- mouse models the sex specific characteristics of juvenile myoclonic epilepsy, a subsyndrome of idiopathic generalized epilepsy. Here, we investigated a role of Brd2 gene in modulating the genomic fabrics responsible for the glutamatergic, GABAergic, dopaminergic, cholinergic and serotonergic transmission in the striatum of female mice. Agilent two-color gene expression arrays and the genomic fabric paradigm were used to determine whether the expression and networking of genes involved in the synaptic transmission differ between Brd2+/- and wildtype mice and whether these differences are sex-specific. As in Brd+/- male mice we found relatively few regulated genes in Brd2+/-female mice with respect to their wildtype counterparts. However, most of the regulated genes were directly related to control of anxiety and seizures, justifying the role of Brd2 upstream control of these traits. Remarkably, the sets of regulated genes in the two sexes did not overlap, supporting the conclusion of sex-specific control of traits by Brd2. Agilent mouse two-color gene expression arrays to profile striata of the prefrontal cortices of wildtype (W) and Brd2+/- (H) mouse female (F) adult C57Bl/6j mice. Differently labeled biological replicates were cohybridized with each array. Results of similarly labeled different conditions were compared then averaged for the two fluorescent labels. For instance: FW1 & FW3 were compared with FH1 & FH3, FW2 & FW4 were compared with FH2 & + FH4, and the results of the comparisons averaged. This design uses 100% of the resources, has a better normlaiztion and allows all possible comparisons among the conditions.我们的前期研究证实，Brd2+/-小鼠（Brd2+/- mouse）可模拟特发性全面性癫痫（idiopathic generalized epilepsy）的亚型——青少年肌阵挛癫痫（juvenile myoclonic epilepsy）的性别特异性表型特征。 本研究聚焦雌性小鼠纹状体（striatum）内介导谷氨酸能、GABA能、多巴胺能、胆碱能及5-羟色胺能信号传递的基因组架构（genomic fabrics），探究Brd2基因在此过程中的调控作用。 本研究采用安捷伦双色基因表达芯片（Agilent two-color gene expression arrays）与基因组架构范式（genomic fabric paradigm），旨在明确突触传递相关基因的表达及调控网络在Brd2+/-小鼠与野生型（wildtype）小鼠间是否存在差异，且此类差异是否具有性别特异性。 与Brd2+/-雄性小鼠的研究结果一致，相较于同背景野生型对照，Brd2+/-雌性小鼠中差异表达的调控基因数量相对较少。但绝大多数调控基因均直接参与焦虑与癫痫发作的调控过程，这印证了Brd2作为上游调控因子对上述表型的调控作用。值得注意的是，雌雄两性的差异调控基因集合完全无交集，进一步支持了Brd2对表型的调控具有性别特异性的结论。 本研究使用安捷伦小鼠双色基因表达芯片，对成年C57Bl/6j雌性野生型（W）、Brd2+/-（H）小鼠的前额叶皮层纹状体样本开展转录组表征。将带有不同荧光标记的生物学重复样本与每张芯片进行共杂交；将带有相同荧光标记的不同实验组样本的杂交结果进行比较后，对两种荧光通道的结果取平均值。例如：将FW1与FW3分别与FH1与FH3进行比较，将FW2与FW4分别与FH2及FH4进行比较，随后对两组比较所得结果取平均。该实验设计可100%利用实验资源，具备更优的归一化效果，且可实现各组实验条件间所有可能的两两比较。