Department of Anatomy and Cell Science, Kansai Medical University, Hirakata, Osaka 573‑1010, Japan.
SLEEP Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156‑8506, Japan.
Int J Mol Med. 2019 May;43(5):2164-2176. doi: 10.3892/ijmm.2019.4143. Epub 2019 Mar 20.
The hypocretin/orexin neuropeptide system coordinates the regulation of various physiological processes. Our previous study reported that a reduction in the expression of pleomorphic adenoma gene‑like 1 (Plagl1), which encodes a C2H2 zinc‑finger transcription factor, occurs in hypocretin neuron‑ablated transgenic mice, suggesting that PLAGL1 is co‑expressed in hypocretin neurons and regulates hypocretin transcription. The present study examined whether canonical prepro‑hypocretin transcription is functionally modulated by PLAGL1. Double immunostaining indicated that the majority of hypocretin neurons were positive for PLAGL1 immunoreactivity in the nucleus. Notably, PLAGL1 immunoreactivity in hypocretin neurons was altered in response to several conditions affecting hypocretin function. An uneven localization of PLAGL1 was detected in the nuclei of hypocretin neurons following sleep deprivation. Chromatin immunoprecipitation revealed that endogenous PLAGL1 may bind to a putative PLAGL1‑binding site in the proximal region of the hypocretin gene, in the murine hypothalamus. In addition, electroporation of the PLAGL1 expression vector into the fetal hypothalamus promoted hypothalamic hypocretin transcription. These results suggested that PLAGL1 may regulate hypothalamic hypocretin transcription.
下丘脑泌素/食欲素神经肽系统协调各种生理过程的调节。我们之前的研究报告称，在下丘脑泌素神经元敲除转基因小鼠中，多形性腺瘤基因样 1（Plagl1）的表达减少，Plagl1 编码一个 C2H2 锌指转录因子，提示 PLAGL1 与下丘脑泌素神经元共表达，并调节下丘脑泌素转录。本研究探讨了 PLAGL1 是否对经典前脑啡肽原转录具有功能调节作用。双重免疫染色表明，大多数下丘脑泌素神经元在核内呈 PLAGL1 免疫反应阳性。值得注意的是，PLAGL1 免疫反应在响应影响下丘脑泌素功能的几种条件下发生改变。在睡眠剥夺后，下丘脑泌素神经元中的 PLAGL1 免疫反应出现不均匀定位。染色质免疫沉淀显示，内源性 PLAGL1 可能结合到小鼠下丘脑前脑啡肽基因近端区域的一个假定 PLAGL1 结合位点。此外，将 PLAGL1 表达载体电穿孔到胎鼠下丘脑可促进下丘脑下丘脑泌素转录。这些结果表明，PLAGL1 可能调节下丘脑下丘脑泌素转录。
