Biotech Research and Innovation Center (BRIC), Copenhagen Biocenter, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Biol Psychiatry. 2022 Apr 15;91(8):727-739. doi: 10.1016/j.biopsych.2021.09.012. Epub 2021 Sep 24.
A number of rare copy number variants (CNVs) have been linked to neurodevelopmental disorders. However, because CNVs encompass many genes, it is often difficult to identify the mechanisms that lead to developmental perturbations.
We used 15q13.3 microdeletion to propose and validate a novel strategy to predict the impact of CNV genes on brain development that could further guide functional studies. We analyzed single-cell transcriptomics datasets containing cortical interneurons to identify their developmental vulnerability to 15q13.3 microdeletion, which was validated in mouse models.
We found that Klf13-but not other 15q13.3 genes-is expressed by precursors and neuroblasts in the medial and caudal ganglionic eminences during development, with a peak of expression at embryonic day (E)13.5 and E18.5, respectively. In contrast, in the adult mouse brain, Klf13 expression is negligible. Using Df(h15q13.3)/+ and Klf13 embryos, we observed a precursor subtype-specific impairment in proliferation in the medial ganglionic eminence and caudal ganglionic eminence at E13.5 and E17.5, respectively, corresponding to vulnerability predicted by Klf13 expression patterns. Finally, Klf13 mice showed a layer-specific decrease in parvalbumin and somatostatin cortical interneurons accompanied by changes in locomotor and anxiety-related behavior.
We show that the impact of 15q13.3 microdeletion on precursor proliferation is grounded in a reduction in Klf13 expression. The lack of Klf13 in Df(h15q13.3)/+ cortex might be the major reason for perturbed density of cortical interneurons. Thus, the behavioral defects seen in 15q13.3 microdeletion could stem from a developmental perturbation owing to selective vulnerability of cortical interneurons during sensitive stages of their development.
许多罕见的拷贝数变异（CNVs）与神经发育障碍有关。然而，由于 CNVs 包含许多基因，因此通常很难确定导致发育紊乱的机制。
我们使用 15q13.3 微缺失提出并验证了一种预测 CNV 基因对大脑发育影响的新策略，该策略可以进一步指导功能研究。我们分析了包含皮质中间神经元的单细胞转录组数据集，以确定其对 15q13.3 微缺失的发育易感性，这在小鼠模型中得到了验证。
我们发现，Klf13（而非其他 15q13.3 基因）在发育过程中，在中侧和尾侧神经节隆起的前体细胞和神经母细胞中表达，分别在胚胎日（E）13.5 和 E18.5 达到表达高峰。相比之下，在成年小鼠大脑中，Klf13 的表达可以忽略不计。使用 Df(h15q13.3)/+ 和 Klf13 胚胎，我们分别在 E13.5 和 E17.5 观察到中侧神经节隆起和尾侧神经节隆起的前体细胞亚型特异性增殖障碍，这与 Klf13 表达模式预测的易感性相对应。最后，Klf13 小鼠表现出特定于皮层的颗粒蛋白和生长抑素皮质中间神经元减少，并伴有运动和焦虑相关行为的改变。
我们表明，15q13.3 微缺失对前体细胞增殖的影响源于 Klf13 表达的减少。Df(h15q13.3)/+ 皮层中 Klf13 的缺乏可能是皮质中间神经元密度紊乱的主要原因。因此，15q13.3 微缺失中观察到的行为缺陷可能源于皮质中间神经元在其发育的敏感阶段选择性易损性导致的发育紊乱。
