在 Tau 转基因小鼠模型中脑胰岛素反应和外周代谢变化。

Brain insulin response and peripheral metabolic changes in a Tau transgenic mouse model.

机构信息

Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, F-59000 Lille, France; LabEx DISTALZ, F-59000 Lille, France.

Brain & Cognition, Faculty of Psychology & Educational Sciences, KU Leuven, Belgium; Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar.

出版信息

Neurobiol Dis. 2019 May;125:14-22. doi: 10.1016/j.nbd.2019.01.008. Epub 2019 Jan 19.

Abstract

Accumulation of hyper-phosphorylated and aggregated Tau proteins is a neuropathological hallmark of Alzheimer's Disease (AD) and Tauopathies. AD patient brains also exhibit insulin resistance. Whereas, under normal physiological conditions insulin signaling in the brain mediates plasticity and memory formation, it can also regulate peripheral energy homeostasis. Thus, in AD, brain insulin resistance affects both cognitive and metabolic changes described in these patients. While a role of Aβ oligomers and APOE4 towards the development of brain insulin resistance emerged, contribution of Tau pathology has been largely overlooked. Our recent data demonstrated that one of the physiological function of Tau is to sustain brain insulin signaling. We postulated that under pathological conditions, hyper-phosphorylated/aggregated Tau is likely to lose this function and to favor the development of brain insulin resistance. This hypothesis was substantiated by observations from patient brains with pure Tauopathies. To address the potential link between Tau pathology and brain insulin resistance, we have evaluated the brain response to insulin in a transgenic mouse model of AD-like Tau pathology (THY-Tau22). Using electrophysiological and biochemical evaluations, we surprisingly observed that, at a time when Tau pathology and cognitive deficits are overt and obvious, the hippocampus of THY-Tau22 mice exhibits enhanced response to insulin. In addition, we demonstrated that the ability of i.c.v. insulin to promote body weight loss is enhanced in THY-Tau22 mice. In line with this, THY-Tau22 mice exhibited a lower body weight gain, hypoleptinemia and hypoinsulinemia and finally a metabolic resistance to high-fat diet. The present data highlight that the brain of transgenic Tau mice exhibit enhanced brain response to insulin. Whether these observations are ascribed to the development of Tau pathology, and therefore relevant to human Tauopathies, or unexpectedly results from the Tau transgene overexpression is debatable and discussed.

摘要

过度磷酸化和聚集的 Tau 蛋白的积累是阿尔茨海默病 (AD) 和 Tau 病的神经病理学标志。AD 患者的大脑也表现出胰岛素抵抗。然而,在正常的生理条件下,大脑中的胰岛素信号转导介导可塑性和记忆形成,它也可以调节外周能量稳态。因此,在 AD 中,大脑胰岛素抵抗会影响这些患者描述的认知和代谢变化。虽然 Aβ 寡聚体和 APOE4 在大脑胰岛素抵抗的发展中起作用,但 Tau 病理学的贡献在很大程度上被忽视了。我们最近的数据表明,Tau 的生理功能之一是维持大脑胰岛素信号转导。我们假设,在病理条件下,过度磷酸化/聚集的 Tau 可能会失去这种功能,并有利于大脑胰岛素抵抗的发展。这一假设得到了来自纯 Tau 病患者大脑的观察结果的证实。为了研究 Tau 病理学与大脑胰岛素抵抗之间的潜在联系,我们评估了 AD 样 Tau 病理学 (THY-Tau22) 转基因小鼠模型中大脑对胰岛素的反应。使用电生理和生化评估,我们惊讶地发现,在 Tau 病理学和认知缺陷明显和明显的时候,THY-Tau22 小鼠的海马体对胰岛素的反应增强。此外,我们证明,i.c.v. 胰岛素促进体重减轻的能力在 THY-Tau22 小鼠中增强。与此一致,THY-Tau22 小鼠表现出较低的体重增加、低瘦素血症和低胰岛素血症,最终对高脂肪饮食产生代谢抵抗。目前的数据强调了转基因 Tau 小鼠的大脑对胰岛素的反应增强。这些观察结果是归因于 Tau 病理学的发展,因此与人类 Tau 病有关,还是出人意料地归因于 Tau 转基因的过度表达,这是有争议的,并进行了讨论。

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