Tau is necessary for Pseudomonas aeruginosa-induced blood-brain barrier dysfunction

Area of Science:

• Neuroscience
• Immunology
• Infectious Disease

Background:

• Lung infections, particularly bacterial pneumonia, are associated with an increased risk of dementia.
• Cytotoxic tau protein released from the lungs during pneumonia can cause cognitive deficits and tau seeding in the brain.
• The precise mechanisms linking lung infection to neuroinflammation and dementia remain incompletely understood.

Purpose of the Study:

• To investigate the impact of pneumonia on blood-brain barrier (BBB) permeability, glial activation, and tau phosphorylation in the brain.
• To determine the role of tau protein in mediating pneumonia-induced brain pathologies.

Main Methods:

• Mice models were used, including C57BL/6J and tau knockout (KO) mice.
• Lung infection was induced using Pseudomonas aeruginosa (P. aeruginosa).
• BBB permeability, glial activation (astrocyte activation), and phosphorylated tau (ptau) levels were assessed 24 hours post-infection.

Main Results:

• Pneumonia significantly increased BBB permeability, astrocyte activation, and ptau levels in the brain of C57BL/6J mice.
• Tau knockout mice showed no significant BBB injury or glial activation following pneumonia.
• Both infected C57BL/6J and tau KO mice exhibited increased levels of specific kinases and pro-inflammatory cytokines.

Conclusions:

• Tau protein is a critical mediator of pneumonia-induced blood-brain barrier dysfunction and astrocyte reactivity.
• Tau may serve as an innate immune response component connecting lung infections to dementia development.
• Targeting tau could offer a therapeutic strategy for preventing cognitive decline after respiratory infections.