PINK1-dependent NFKB signaling contributes to amyloid pathology in Alzheimer disease

Mitochondrial dysfunction plays a preponderant role in the development of Alzheimer disease (AD). We have demonstrated that activation of PINK1 (PTEN induced kinase 1)-dependent mitophagy ameliorates amyloid pathology, attenuates mitochondrial and synaptic dysfunction, and improves cognitive function. However, the underlying mechanisms remain largely unknown. Using a newly generated PINK1-AD transgenic mouse model and AD neuronal cell lines, we provide substantial evidence supporting the contribution of PINK1-mediated mitochondrial ROS (reactive oxygen species) and NFKB/NF-κB (nuclear factor kappa B) signaling to altering APP (amyloid beta precursor protein) processing and Aβ metabolism. Enhancing neuronal PINK1 is sufficient to suppress Aβ-induced activation of NFKB signal transduction in PINK1-overexpressed Aβ-AD mice and Aβ-producing neurons. Blocking PINK1-mediated NFKB activation inhibits activities of BACE1 (beta-secretase 1) and γ-secretase, which are key enzymes for cleavage of APP processing to produce Aβ. Conversely, loss or knockdown of PINK1 produces excessive ROS, along with increased phosphorylated NFKB1/p50 and RELA/p65 subunits, APP-related BACE1 and γ-secretase, and Aβ accumulation. Importantly, these detrimental effects were robustly blocked by the addition of scavenging PINK1 Aβ-induced mitochondrial ROS, leading to the suppression of NFKB activation, restoration of normal APP processing, and limitation of Aβ accumulation. Thus, our findings highlight a novel mechanism underlying PINK1-mediated modulation of Aβ metabolism via a ROS-NFKB-APP processing nexus. Activation of PINK1 signaling could be a potential therapeutic avenue for the early stages of AD by combining improving mitochondrial quality control with limiting amyloid pathology in AD.