Cystatin C regulates the cytotoxicity of infection-induced endothelial-derived β-amyloid

Area of Science:

• Cell Biology
• Infectious Disease
• Neuroscience

Background:

• Pseudomonas aeruginosa infection triggers release of cytotoxic oligomeric tau and beta-amyloid (Aβ) from rat pulmonary microvascular endothelial cells.
• These amyloid species contribute to cellular damage following infection.

Purpose of the Study:

• Characterize the cytotoxic amyloids produced during Pseudomonas aeruginosa infection.
• Identify and characterize cytoprotective factors released by endothelial cells in response to infection.

Main Methods:

• Proteinase K digestion, denaturation (phenol, DEPC, HFIP), and ultracentrifugation were used to characterize cytotoxic activity.
• Mass spectrometry identified potential secreted modulators of Aβ.
• Immunodepletion, co-immunoprecipitation, and ultracentrifugation identified cystatin C as the primary cytoprotective factor.

Main Results:

• Cytotoxic oligomeric tau and Aβ were partially resistant to proteinase K but sensitive to denaturants.
• Ultracentrifugation was required to remove cytotoxic activity.
• Cystatin C was identified as a cytoprotective protein released during infection, forming a complex with Aβ.

Conclusions:

• Pseudomonas aeruginosa infection induces release of both cytotoxic amyloids and protective factors from endothelial cells.
• Cystatin C acts as a cytoprotective agent by complexing with Aβ.
• Cystatin C represents a potential therapeutic target for mitigating long-term consequences of Pseudomonas aeruginosa infection.