Hou Kuan-Chu, Tsai Meng-Han, Akbarian Schahram, Huang Hsien-Sung
Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei 10051, Taiwan.
Department of Psychiatry, Icahn School of Medicine at Mount Sinai, NY 10029, USA.
Neuroscience. 2023 Oct 1;529:99-106. doi: 10.1016/j.neuroscience.2023.08.014. Epub 2023 Aug 19.
Genomic imprinting is a predominantly brain and placenta-specific epigenetic process that contributes to parent-of-origin-specific gene expression. While microRNAs are highly expressed in the brain, their imprinting status in this tissue remains poorly studied. Previous research demonstrated that Mir125b-2 is imprinted in the human brain and regulates hippocampal circuits and functions in mice. However, the imprinting status of another isoform of miR125b, Mir125b-1, in the human brain, as well as its spatiotemporal expression patterns in mice, have not been elucidated. Here, we show MIR125B1 is not imprinted in the human brain. Moreover, miR-125b-1 was highly expressed in the brains of mice. Furthermore, miR-125b-1 was down-regulated during brain development in mice. Specifically, miR-125b-1 displayed preferential expression in the olfactory bulb, thalamus, and hypothalamus of the mouse brain. Notably, miR-125b-1 was enriched in GABAergic neurons, particularly somatostatin-expressing GABAergic neurons, compared with glutamatergic neurons. Taken together, our findings provide the imprinting status and comprehensive spatiotemporal expression profiling of Mir125b-1 in the brain.
基因组印记是一种主要在大脑和胎盘中发生的特异性表观遗传过程，它有助于实现基因表达的亲本来源特异性。虽然微小RNA在大脑中高度表达，但其在该组织中的印记状态仍鲜有研究。先前的研究表明，Mir125b - 2在人类大脑中存在印记，并调节小鼠的海马回路和功能。然而，miR125b的另一种异构体Mir125b - 1在人类大脑中的印记状态，以及其在小鼠中的时空表达模式尚未阐明。在此，我们发现MIR125B1在人类大脑中不存在印记。此外，miR - 125b - 1在小鼠大脑中高表达。此外，miR - 125b - 1在小鼠大脑发育过程中表达下调。具体而言，miR - 125b - 1在小鼠大脑的嗅球、丘脑和下丘脑中呈现优先表达。值得注意的是，与谷氨酸能神经元相比，miR - 125b - 1在γ-氨基丁酸能神经元中富集，尤其是在表达生长抑素的γ-氨基丁酸能神经元中。综上所述，我们的研究结果揭示了Mir125b - 1在大脑中的印记状态以及全面的时空表达谱。
