Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Dorothy Hodgkin Building, Bristol, United Kingdom.
Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany.
Mol Metab. 2022 Sep;63:101542. doi: 10.1016/j.molmet.2022.101542. Epub 2022 Jul 6.
Dynamic changes to neuropeptide hormone synthesis and secretion by hypothalamic neuroendocrine cells is essential to ensure metabolic homeostasis. The specialised molecular mechanisms that allow neuroendocrine cells to synthesise and secrete vast quantities of neuropeptides remain ill defined. The objective of this study was to identify novel genes and pathways controlled by transcription factor and endoplasmic reticulum stress sensor Creb3l1 which is robustly activated in hypothalamic magnocellular neurones in response to increased demand for protein synthesis.
We adopted a multiomic strategy to investigate specific roles of Creb3l1 in rat magnocellular neurones. We first performed chromatin immunoprecipitation followed by genome sequencing (ChIP-seq) to identify Creb3l1 genomic targets and then integrated this data with RNA sequencing data from physiologically stimulated and Creb3l1 knockdown magnocellular neurones.
The data converged on Creb3l1 targets that code for ribosomal proteins and endoplasmic reticulum proteins crucial for the maintenance of cellular proteostasis. We validated genes that compose the PERK arm of the unfolded protein response pathway including Eif2ak3, Eif2s1, Atf4 and Ddit3 as direct Creb3l1 targets. Importantly, knockdown of Creb3l1 in the hypothalamus led to a dramatic depletion in neuropeptide synthesis and secretion. The physiological outcomes from studies of paraventricular and supraoptic nuclei Creb3l1 knockdown animals were changes to food and water consumption.
Collectively, our data identify Creb3l1 as a comprehensive controller of the PERK signalling pathway in magnocellular neurones in response to physiological stimulation. The broad regulation of neuropeptide synthesis and secretion by Creb3l1 presents a new therapeutic strategy for metabolic diseases.
确保代谢平衡，下丘脑神经内分泌细胞的神经肽激素合成和分泌的动态变化至关重要。允许神经内分泌细胞合成和分泌大量神经肽的特殊分子机制仍未得到明确界定。本研究的目的是确定新的基因和途径，这些基因和途径受转录因子和内质网应激传感器 Creb3l1 控制，Creb3l1 在响应蛋白质合成需求增加时在下丘脑大细胞神经元中被强烈激活。
我们采用多组学策略来研究 Creb3l1 在大鼠大细胞神经元中的特定作用。我们首先进行染色质免疫沉淀，然后进行基因组测序（ChIP-seq），以鉴定 Creb3l1 的基因组靶点，然后将这些数据与生理刺激和 Creb3l1 敲低大细胞神经元的 RNA 测序数据进行整合。
数据集中在编码核糖体蛋白和内质网蛋白的 Creb3l1 靶标上，这些蛋白对于维持细胞蛋白稳态至关重要。我们验证了组成未折叠蛋白反应途径 PERK 臂的基因，包括 Eif2ak3、Eif2s1、Atf4 和 Ddit3，它们是 Creb3l1 的直接靶标。重要的是，下丘脑中 Creb3l1 的敲低导致神经肽合成和分泌的急剧减少。对室旁核和视上核 Creb3l1 敲低动物的研究的生理结果是食物和水消耗的变化。
总之，我们的数据将 Creb3l1 确定为大细胞神经元中 PERK 信号通路对生理刺激的综合控制器。Creb3l1 对神经肽合成和分泌的广泛调节为代谢疾病提供了一种新的治疗策略。
