IRE1 signaling exacerbates Alzheimer's disease pathogenesis

Area of Science:

• Neuroscience
• Molecular Biology
• Pathology

Background:

• Altered proteostasis, endoplasmic reticulum (ER) stress, and protein aggregation are hallmarks of Alzheimer's disease (AD).
• The unfolded protein response (UPR) is activated by ER stress, involving key transducers like IRE1, which regulates adaptive and proapoptotic pathways.
• A polymorphism in the XBP1 promoter, downstream of IRE1, has been linked to AD risk.

Purpose of the Study:

• To investigate the role of IRE1 signaling in Alzheimer's disease pathogenesis.
• To determine the therapeutic potential of targeting IRE1 in AD models.

Main Methods:

• Correlation analysis of IRE1 activation with AD histopathology in human brain tissue.
• Genetic ablation of IRE1's RNase domain in a transgenic mouse model of AD.
• Assessment of amyloid deposition, oligomer levels, astrocyte activation, cognitive function, synaptic plasticity (LTP), and amyloid precursor protein (APP) expression.
• In vitro studies on IRE1 inhibition and APP degradation pathways.

Main Results:

• A positive correlation was observed between AD progression and IRE1 activation in human brains.
• Genetic deletion of IRE1's RNase domain in AD mice significantly reduced amyloid-beta deposition and oligomers.
• IRE1 deficiency restored learning and memory, improved synaptic function, and enhanced long-term potentiation in AD mice.
• IRE1 deletion decreased APP expression and promoted its proteasomal degradation in vitro and in vivo.

Conclusions:

• IRE1 plays a significant, previously unrecognized role in AD pathogenesis.
• Targeting IRE1 signaling presents a novel therapeutic strategy for Alzheimer's disease intervention.