β-amyloid clustering around ASC fibrils boosts its toxicity in microglia

LL Friker, H Scheiblich, IV Hochheiser, R Brinkschulte… - Cell reports, 2020 - cell.com
LL Friker, H Scheiblich, IV Hochheiser, R Brinkschulte, D Riedel, E Latz, M Geyer
Cell reports, 2020cell.com
Alzheimer's disease is the world's most common neurodegenerative disorder. It is
associated with neuroinflammation involving activation of microglia by β-amyloid (Aβ)
deposits. Based on previous studies showing apoptosis-associated speck-like protein
containing a CARD (ASC) binding and cross-seeding extracellular Aβ, we investigate the
propagation of ASC between primary microglia and the effects of ASC-Aβ composites on
microglial inflammasomes and function. Indeed, ASC released by a pyroptotic cell can be …
Summary
Alzheimer's disease is the world's most common neurodegenerative disorder. It is associated with neuroinflammation involving activation of microglia by β-amyloid (Aβ) deposits. Based on previous studies showing apoptosis-associated speck-like protein containing a CARD (ASC) binding and cross-seeding extracellular Aβ, we investigate the propagation of ASC between primary microglia and the effects of ASC-Aβ composites on microglial inflammasomes and function. Indeed, ASC released by a pyroptotic cell can be functionally built into the neighboring microglia NOD-like receptor protein (NLRP3) inflammasome. Compared with protein-only application, exposure to ASC-Aβ composites amplifies the proinflammatory response, resulting in pyroptotic cell death, setting free functional ASC and inducing a feedforward stimulating vicious cycle. Clustering around ASC fibrils also compromises clearance of Aβ by microglia. Together, these data enable a closer look at the turning point from acute to chronic Aβ-related neuroinflammation through formation of ASC-Aβ composites.
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