Tau accumulation triggers STAT1-dependent memory deficits by suppressing NMDA receptor expression

Area of Science:

• Neuroscience
• Molecular Biology
• Pathology

Background:

• Intracellular tau accumulation forming neurofibrillary tangles is a hallmark of Alzheimer's disease (AD).
• The precise mechanisms by which tau pathology induces synaptic impairment remain largely unknown.
• Understanding these mechanisms is crucial for developing effective AD therapies.

Purpose of the Study:

• To elucidate the molecular pathway linking intracellular tau accumulation to synaptic dysfunction in Alzheimer's disease.
• To investigate the role of JAK2/STAT1 signaling in tau-induced suppression of N-methyl-D-aspartate receptors (NMDARs).
• To explore potential therapeutic strategies targeting this pathway for memory deficits in AD.

Main Methods:

• Overexpression of human full-length wild-type tau (hTau) in a cellular or animal model to mimic AD tau pathology.
• Assessing the activation of Janus Kinase 2 (JAK2) and Signal Transducer and Activator of Transcription 1 (STAT1) phosphorylation.
• Analyzing STAT1 dimerization, nuclear translocation, and binding to NMDAR gene promoters.
• Utilizing STAT1 knockdown or dominant-negative STAT1 expression to rescue hTau-induced effects.
• Evaluating synaptic function and memory performance in treated models.

Main Results:

• hTau accumulation activates JAK2, leading to STAT1 phosphorylation, dimerization, and nuclear translocation.
• Activated STAT1 directly suppresses the expression of NMDAR subunits (GluN1, GluN2A, GluN2B) by binding to their promoter regions.
• STAT1 knockdown or inhibition of STAT1 activation rescues hTau-induced NMDAR suppression.
• Restoration of NMDAR expression ameliorates synaptic dysfunction and improves memory performance in hTau-expressing models.

Conclusions:

• hTau accumulation impairs synaptic plasticity via the JAK2/STAT1 signaling pathway, leading to NMDAR suppression.
• This study reveals a novel molecular mechanism underlying tau-associated synapse and memory deficits in Alzheimer's disease.
• Targeting the JAK2/STAT1/NMDAR axis presents a promising therapeutic avenue for Alzheimer's disease.