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Cell Host Microbe. 2009 Jul 23;6(1):45-53. doi: 10.1016/j.chom.2009.05.020.

Responses to amyloids of microbial and host origin are mediated through toll-like receptor 2.

Author information

1
Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA 95616-8645, USA.

Abstract

Curli fibrils are proteinaceous bacterial structures formed by amyloid fibrils composed of the major curli subunit CsgA. Like beta-amyloid 1-42, which is associated with brain inflammation and Alzheimer's disease, curli fibrils have been implicated in the induction of host inflammatory responses. However, the underlying mechanisms of amyloid-induced inflammation are not fully understood. In a mouse sepsis model, we show that curli fibrils contributed to Nos2 expression, a hallmark of inflammation, by stimulating Toll-like receptor (TLR) 2. The TLR2 agonist activity was reduced by an amyloidogenicity-lowering amino acid substitution (N122A) in CsgA. Amyloid-forming synthetic peptides corresponding to beta-amyloid 1-42 or CsgA 111-151 stimulated Nos2 production in macrophages and microglia cells through a TLR2-dependent mechanism. This activity was abrogated when an N122A substitution was introduced into the synthetic CsgA peptide. The induction of TLR2-mediated responses by bacterial and eukaryotic amyloids may explain the inflammation associated with amyloids and the resulting pathologies.

PMID:
19616765
PMCID:
PMC2745191
DOI:
10.1016/j.chom.2009.05.020
[Indexed for MEDLINE]
Free PMC Article

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