Rescue from tau-induced neuronal dysfunction produces insoluble tau oligomers

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Alzheimer's disease and tauopathies are characterized by aggregated tau.
• Existing models suggest soluble tau or small oligomers cause toxicity, not necessarily large aggregates.

Purpose of the Study:

• To investigate the nature and toxicity of insoluble tau oligomers in vivo.
• To challenge the view that all tau oligomers are inherently toxic.

Main Methods:

• Utilized multiple techniques to analyze tau oligomer formation and toxicity in vivo.
• Investigated the impact of inhibiting glycogen-synthase-kinase-3beta (GSK-3β) on tau levels and oligomerization.

Main Results:

• Demonstrated that insoluble tau oligomers can form without causing tau-mediated dysfunction.
• Observed that tau oligomer formation correlates with increased tau levels upon GSK-3β inhibition.
• Found that these specific insoluble tau oligomers were not highly phosphorylated and lacked beta-pleated sheet structure, correlating with their lack of toxicity.

Conclusions:

• Tau can form non-toxic insoluble oligomers in vivo, distinct from previously reported toxic species.
• Therapeutic strategies targeting tau oligomer dissolution may need refinement to specifically address toxic species.
• The role of these non-toxic oligomers (inert or protective) requires further investigation.