Salt-sensitive hypertension promotes neuronal mitochondrial stress and neurodegenerative alterations via neuro-vascular metabolic reprogramming and local RAS signaling.

Hypertension increases risks for cognitive impairment and Alzheimer’s disease (AD). In renal patients with both hypertension and cognitive decline, via rest-state fMRI, their cerebral cortical region showed maintained cerebral blood flow (CBF), but reduced signals of blood-oxygen-level-dependent (BOLD). In mice, although CBF was unchanged, deoxycorticosterone acetate (DOCA)-salt treatment markedly reduced cerebrovascular reactivity, with altered transcriptomic pattern in cortical endothelial cells (ECs) and astrocytes, showing downregulated expression of glucose transport 1 (GluT1) but upregulated metabolic reprogramming. Lipidomic analysis using prefrontal cortex (PFC) further revealed enhanced catabolism of glycerophospholipids and accumulation of free fatty acids. In the PFC of hypertensive mice, neurodegenerative alterations were observed, including reduced number of neuronal dendritic spines and more expression of phosphorylated Tau (p-Tau). Via both morphological and molecular tests, we identified that DOCA-salt hypertension was associated with significant mitochondrial injury and upregulated lysine succinylation in the PFC neurons. Upregulated lysine succinylation was largely mitochondria-located, and they were functionally enriched in gluconeogenesis-related energy metabolic pathways, the tricarboxylic acid (TCA) cycle, oxidative stress, and neurodegenerative diseases. In hypertensive mice, angiotensinogen (Agt) expression was markedly upregulated in most astrocytes, together with neuronal expression of Agtr1a. In cultured neuronal cells, angiotensin II (ang II) elevated mitochondrial membrane potential and ATP biosynthesis. In mice with neuronal AT1aR knockout (AT1N), DOCA-salt failed to induce cognitive impairment. Additionally, DOCA-salt-associated reduction of acetylcholine, accumulation of p-Tau, and upregulation of lysine succinylation were not observed in AT1N mice. Direct anti-hypertensive treatment did not abolish DOCA-salt-related pathological phenotypes, and enhanced lysine succinylation was not detected in hypertension models induced by norepinephrine or L-NAME. Our data provide evidence that hypertension induced metabolic rearrangement (enhanced energy metabolism from non-glucose source and upregulated mitochondrial oxidative phosphorylation) in the neuro-vascular unit, due to downregulated glucose uptake in ECs. Increased neuronal energy consumption, via local ang II/AT1R signaling, further exacerbated mitochondrial stress and neurodegenerative alterations. Together, by multi-omics analysis, this study provided novel insights regarding how hypertension increases the risk for age-related cognitive impairment.