Related Experiment Video
Updated: May 11, 2026
11:10
Expression, Purification, and Antimicrobial Activity of S100A12
Published on: May 13, 2017
Amyloid-β peptide-induced extracellular S100A9 depletion is associated with decrease of antimicrobial peptide
Eun Ok Lee1, Ji Hye Yang, Keun-A Chang
1Department of Microbiology, School of Medicine, Ewha Medical Research Institute, Ewha Womans University, 911-1, Mok-6-dong, Yangcheonku, Seoul 158-710, Republic of Korea.
Journal of Neuroinflammation
|June 1, 2013
Summary
Amyloid-beta 1-42 monomers reduce S100A9 protein release, a key antimicrobial peptide, in monocytes. This down-regulation impairs the innate immune system's antimicrobial activity, suggesting a novel Alzheimer's disease mechanism.
Area of Science:
- Neuroimmunology
- Infectious Disease
Background:
- S100A9 protein is a key inflammatory marker and antimicrobial peptide.
- S100A9 is implicated in Alzheimer's disease (AD) pathology, but mechanisms are unclear.
Purpose of the Study:
- Investigate S100A9 release mechanisms upon amyloid-beta (Aβ) stimulation.
- Determine the role of extracellular S100A9 in Aβ-induced cytotoxicity and innate immune response.
Main Methods:
- THP-1 monocytes were stimulated with Aβ1-42 monomers.
- Techniques included Ca(2+) imaging, MTT assays, siRNA knockdown, and antimicrobial activity assays.
Main Results:
- Aβ1-42 monomers decreased S100A9 release and increased intracellular Ca(2+).
- This decrease did not correlate with cytotoxicity; S100A9 depletion showed minimal toxicity.
- Extracellular S100A9 depletion reduced antimicrobial activity, while recombinant S100A9 enhanced it.
Conclusions:
- Monomeric Aβ1-42 negatively regulates the innate immune system by reducing S100A9 secretion.
- S100A9 is a primary mediator of antimicrobial activity in monocyte-conditioned media.
