A diet rich in salt is linked to an increased risk of cerebrovascular diseases and dementia, but it remains unclear how dietary salt harms the brain. We report that, in mice, excess dietary salt suppresses resting cerebral blood flow and endothelial function, leading to cognitive impairment. The effect depends on expansion of TH17 cells in the small intestine, resulting in a marked increase in plasma interleukin-17 (IL-17). Circulating IL-17, in turn, promotes endothelial dysfunction and cognitive impairment by the Rho kinase-dependent inhibitory phosphorylation of endothelial nitric oxide synthase and reduced nitric oxide production in cerebral endothelial cells. The findings reveal a new gut-brain axis linking dietary habits to cognitive impairment through a gut-initiated adaptive immune response compromising brain function via circulating IL-17. Thus, the TH17 cell-IL-17 pathway is a putative target to counter the deleterious brain effects induced by dietary salt and other diseases associated with TH17 polarization.

中文翻译：

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饮食盐通过肠道引发的TH17反应促进神经血管和认知功能障碍。

富含盐的饮食与增加脑血管疾病和痴呆的风险有关，但尚不清楚饮食盐如何损害大脑。我们报道，在小鼠中，过量的食盐会抑制静息的脑血流量和内皮功能，从而导致认知障碍。效果取决于小肠中TH17细胞的扩增，导致血浆白介素17（IL-17）显着增加。循环中的IL-17通过内皮一氧化氮合酶的Rho激酶依赖性抑制磷酸化，进而促进脑内皮细胞中一氧化氮的产生，促进了内皮功能障碍和认知障碍。这些发现揭示了一个新的肠脑轴，通过肠道启动的适应性免疫应答，通过循环的IL-17损害了脑功能，从而将饮食习惯与认知障碍联系在一起。