p66Shc silencing promotes aerobic glycolysis via signalling between the transcription factors NRF2 and HIF1-α.

Alzheimer's disease (AD) is characterized by the progressive accumulation of toxic amyloid-β (Aβ) plaques in the brain, leading to oxidative stress, synaptic loss, and neuronal death. Despite intensive efforts, therapies targeting Aβ production or clearance have shown limited efficacy, highlighting the need for alternative strategies. A notable feature of AD is reduced cerebral glucose metabolism, which contributes to neurodegeneration. Interestingly, elevated aerobic glycolysis has been shown to protect central nervous system (CNS) cells from Aβ toxicity, yet the regulatory mechanisms underlying the metabolic shift from oxidative phosphorylation (OXPHOS) to glycolysis remain unclear. We previously found that silencing p66Shc, an adaptor protein involved in apoptosis and reactive oxygen species (ROS) production, enhances glycolysis, reduces mitochondrial ROS, and protects against Aβ-induced toxicity. Here, we investigated whether p66Shc modulates glycolysis through the Kelch-like ECH associated protein 1 (KEAP1) - nuclear erythroid 2-related factor 2 (NRF2) pathway. In the B12 glial-like cell line, p66Shc knockdown reduced KEAP1 levels, leading to stabilization of NRF2. Elevated NRF2 increased hypoxia-inducible factor 1α (HIF1α) expression, driving up glycolytic enzyme levels and glycolytic activity. Importantly, p66Shc depletion conferred protection against Aβ toxicity in an NRF2-dependent manner. Consistent with these findings, Western blot analysis of AD transgenic mouse brain tissues revealed increased p66Shc and KEAP1, and decreased NRF2 levels compared to wild-type mice. These findings reveal a previously unrecognized role for p66Shc in regulating CNS metabolism through the KEAP1-NRF2-HIF1α axis and link its expression to susceptibility to Aβ toxicity. Collectively, these results uncover a novel metabolic regulatory pathway in CNS cells and position p66Shc as a key modulator of energy metabolism and Aβ vulnerability in AD. Targeting this pathway may offer a novel metabolic approach for therapeutic intervention in AD.