Yoon Ji Soo, Gamu Daniel, Gibson William T, Lynn Francis C
BC Children's Hospital Research Institute, Vancouver, BC, Canada V5Z 4H4.
Department of Surgery, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Endocrinology. 2025 May 19;166(7). doi: 10.1210/endocr/bqaf083.
Immediate early genes (IEGs), such as neuronal PAS domain protein 4 (Npas4), are induced as part of the response to environmental stimuli. In the arcuate nucleus (ARC), proopiomelanocortin (POMC) neurons are critical in detecting peripheral signals to regulate food intake. To date, Npas4 has not been studied in the context of regulating food intake, and its sites of action in the ARC are unknown. We found that Npas4 was induced in POMC neurons by refeeding, oral glucose, and a high-fat diet (HFD). In order to explore the role of NPAS4 in POMC neurons, a conditional knockout approach was used. Male mice with Npas4 knockout in POMC neurons showed significantly reduced body weight starting at 10 weeks of HFD, which was due to decreased food intake. Single-cell RNA sequencing on ARC cells demonstrated that POMC neurons of knockout mice showed an enhanced refeeding-induced transcriptional response, dysregulated IEG expression in response to refeeding, and reduced expression of genes encoding gamma-aminobutyric acid (GABA)-A receptor subunits. Cell-to-cell communication analysis revealed that POMC neurons of knockout mice lost inhibitory GABAergic signaling inputs and gained excitatory glutamatergic signaling inputs. Taken together, these results suggest that Npas4 tempers the activity of POMC neurons and loss of Npas4 causes impairments in nutrient intake sensing. Mechanistically, this results from reduced expression of inhibitory GABA-A receptors and an overall increase in the feeding-induced POMC neuron transcriptional response. In conclusion, we report a role for the transcription factor Npas4 in POMC neurons of the ARC and demonstrate its importance in controlling feeding behavior in states of overnutrition.
即刻早期基因（IEGs），如神经元PAS结构域蛋白4（Npas4），作为对环境刺激反应的一部分被诱导表达。在弓状核（ARC）中，阿黑皮素原（POMC）神经元在检测外周信号以调节食物摄入方面起着关键作用。迄今为止，尚未在调节食物摄入的背景下对Npas4进行研究，其在ARC中的作用位点也未知。我们发现，再喂食、口服葡萄糖和高脂饮食（HFD）可诱导POMC神经元中Npas4的表达。为了探究NPAS4在POMC神经元中的作用，采用了条件性敲除方法。POMC神经元中Npas4基因敲除的雄性小鼠从10周龄开始喂食HFD后体重显著减轻，这是由于食物摄入量减少所致。对ARC细胞进行单细胞RNA测序表明，敲除小鼠的POMC神经元显示出再喂食诱导的转录反应增强、对再喂食的即刻早期基因表达失调以及编码γ-氨基丁酸（GABA）-A受体亚基的基因表达降低。细胞间通讯分析显示，敲除小鼠的POMC神经元失去了抑制性GABA能信号输入，并获得了兴奋性谷氨酸能信号输入。综上所述，这些结果表明Npas4调节POMC神经元的活性，Npas4的缺失导致营养摄入感知受损。从机制上讲，这是由于抑制性GABA-A受体表达减少以及喂食诱导的POMC神经元转录反应总体增加所致。总之，我们报道了转录因子Npas4在ARC的POMC神经元中的作用，并证明了其在控制营养过剩状态下的进食行为中的重要性。
