Extracellular Monomeric Tau Is Internalized by Astrocytes

Area of Science:

• Neuroscience
• Cell Biology
• Neurodegenerative Diseases

Background:

• Tau protein is crucial for neuron function but aggregates in tauopathies.
• In tauopathies, Tau accumulates in non-neuronal cells like astrocytes and microglia.
• Heparan sulfate proteoglycans (HSPGs) are implicated in fibrillary Tau uptake by some cells.

Purpose of the Study:

• To investigate if astrocytes internalize monomeric Tau from the extracellular environment.
• To determine the mechanism of monomeric Tau uptake by astrocytes.
• To compare Tau uptake mechanisms between astrocytes and other glial cells like microglia.

Main Methods:

• Primary astrocyte cultures were utilized.
• Monomeic Tau was added to the extracellular medium.
• Uptake was assessed, and the role of HSPGs was specifically investigated.

Main Results:

• Astrocytes successfully internalized monomeric Tau from the extracellular medium.
• The internalization mechanism of monomeric Tau by astrocytes was independent of HSPGs.
• This contrasts with proposed HSPG-mediated uptake of fibrillary Tau.

Conclusions:

• Astrocytes can internalize monomeric Tau via a non-HSPG dependent pathway.
• Understanding Tau internalization in astrocytes is vital for tauopathy research.
• This finding opens new avenues for exploring Tau propagation in the brain.