Faculty of Pharmacy, Université Laval, Quebec City, Quebec, Canada.
Quebec Heart and Lung Institute, Quebec City, Quebec, Canada.
Am J Physiol Endocrinol Metab. 2024 Nov 1;327(5):E626-E635. doi: 10.1152/ajpendo.00153.2024. Epub 2024 Sep 11.
The liver plays a major role in glucose and lipid homeostasis and acts as a key organ in the pathophysiology of metabolic diseases. Intriguingly, increased sympathetic nervous system (SNS) activity to the liver has been associated with the development and progression of type 2 diabetes and obesity. However, the precise mechanisms by which the SNS regulates hepatic metabolism remain to be defined. Although liver α1-adrenoceptors were suggested to play a role in glucose homeostasis, the specific subtypes involved are unknown mainly because of the limitations of pharmacological tools. Here, we generated and validated a novel mouse model allowing tissue-specific deletion of α-1b adrenoceptor () in hepatocytes to investigate the role of liver ADRA1B in energy and glucose metabolism. We found that selective deletion of in mouse liver has limited metabolic impact in lean mice. However, loss of in hepatocytes exacerbated diet-induced obesity, insulin resistance, and glucose intolerance in female, but not in male mice. In obese females, this was accompanied by reduced hepatic gluconeogenic capacity and reprogramming of gonadal adipose tissue with hyperleptinemia. Our data highlight sex-dependent mechanisms by which the SNS regulates energy and glucose homeostasis through liver ADRA1B. The sympathetic nervous system plays an important role in regulating hepatic physiology and metabolism. However, the identity of the adrenoceptors involved in these effects is still elusive. Using CRISPR-Cas9, we developed a novel transgenic tool to study the role of liver α-1b adrenoceptor (ADRA1B). We show that ADRA1B plays a key role in mediating the effects of the sympathetic nervous system on hepatic metabolism, particularly in female mice.
肝脏在葡萄糖和脂质稳态中发挥主要作用,并作为代谢疾病病理生理学的关键器官。有趣的是,增加到肝脏的交感神经系统 (SNS) 活性与 2 型糖尿病和肥胖的发展和进展有关。然而,SNS 调节肝代谢的确切机制仍有待确定。尽管肝 α1-肾上腺素受体被认为在葡萄糖稳态中起作用,但涉及的特定亚型尚不清楚,主要是因为药理学工具的限制。在这里,我们生成并验证了一种新型小鼠模型,允许在肝细胞中特异性缺失 α-1b 肾上腺素受体 (),以研究肝脏 ADRA1B 在能量和葡萄糖代谢中的作用。我们发现,在 lean 小鼠中,肝脏中选择性缺失 对代谢的影响有限。然而,肝细胞中 的缺失加剧了饮食诱导的肥胖、胰岛素抵抗和葡萄糖耐量受损,仅在雌性小鼠中,而不是在雄性小鼠中。在肥胖的雌性小鼠中,这伴随着肝糖异生能力的降低和性腺脂肪组织的重新编程,导致高瘦素血症。我们的数据强调了 SNS 通过肝脏 ADRA1B 调节能量和葡萄糖稳态的性别依赖性机制。交感神经系统在调节肝脏生理学和代谢中起着重要作用。然而,涉及这些影响的肾上腺素受体的身份仍然难以捉摸。使用 CRISPR-Cas9,我们开发了一种新型转基因工具来研究肝脏 α-1b 肾上腺素受体 (ADRA1B) 的作用。我们表明 ADRA1B 在介导交感神经系统对肝脏代谢的影响方面起着关键作用,特别是在雌性小鼠中。