科研之友
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摘要
Alzheimer's disease (AD) is associated with peripheral metabolic disorders. Clinical/epidemiological data indicate increased risk of diabetes in AD patients. Here, we show that intracerebroventricular infusion of AD-associated A beta oligomers (A beta Os) in mice triggered peripheral glucose intolerance, a phenomenon further verified in two transgenic mouse models of AD. Systemically injected A beta Os failed to induce glucose intolerance, suggesting A beta Os target brain regions involved in peripheral metabolic control. Accordingly, we show that A beta Os affected hypothalamic neurons in culture, inducing eukaryotic translation initiation factor 2 alpha phosphorylation (eIF2 alpha-P). A beta Os further induced eIF2 alpha-P and activated proinflammatory IKK beta/NF-kappa B signaling in the hypothalamus of mice and macaques. A beta Os failed to trigger peripheral glucose intolerance in tumor necrosis factor-alpha (TNF-alpha) receptor 1 knockout mice. Pharmacological inhibition of brain inflammation and endoplasmic reticulum stress prevented glucose intolerance in mice, indicating that A beta Os act via a central route to affect peripheral glucose homeostasis. While the hypothalamus has been largely ignored in the AD field, our findings indicate that A beta Os affect this brain region and reveal novel shared molecular mechanisms between hypothalamic dysfunction in metabolic disorders and AD.
