Mitochondrial calcium uniporter knockdown in hippocampal neurons effectively attenuates synaptic plasticity impairment and pathology in APP/PS1/tau model of Alzheimer's disease.

Abstract

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline, in which mitochondrial dysfunction plays a critical role. The mitochondrial calcium uniporter (MCU) is a key regulator of mitochondrial calcium (mCa) uptake, and its dysregulation contributes to calcium imbalance and mitochondrial impairment. In this study, we investigated the effects of MCU knockdown in hippocampal neurons on synaptic plasticity and neuropathology in APP/PS1/tau mice. It was found that MCU knockdown reduced mCaoverload, restored mitochondrial membrane potential (MMP), and attenuated excessive reactive oxygen species (ROS) production in the hippocampus. These mitochondrial improvements were associated with a rescue of impaired synaptic plasticity, including enhanced long-term potentiation (LTP) and reduced long-term depression (LTD) through activating the CaMKII/CREB/BDNF/TrkB signaling pathway. Furthermore, MCU knockdown alleviated hippocampal amyloid β (Aβ) pathology by decreasing APP/BACE1/RAGE levels while increasing NEP/LRP1 levels, and mitigated tau pathology through downregulation of GSK3β/CDK5 expression. In addition, hippocampal neuronal number and activity were improved, as reflected by increased N-acetylaspartic acid (NAA)/creatine (Cr) and glutamic acid (Glu)/Cr. Collectively, these findings indicated that MCU knockdown in hippocampal neurons ameliorated mitochondrial dysfunction, synaptic deficits, and AD-related pathology, highlighting MCU as a potential therapeutic target for AD.