A phenotypic high‑content, high‑throughput screen identifies inhibitors of NLRP3 inflammasome activation
Summary by N Hartopp
Background:
Inflammatory responses in the brain are an important protective mechanism, but we now know that these responses can also contribute to cell death in Parkinson’s and other neurodegenerative diseases when they are over-stimulated. The “NLRP3 inflammasome” is a group of proteins which come together in the cell to stimulate inflammatory responses. Evidence suggests there may be more of some of these proteins in the brains of people with Parkinson’s Disease, and that reducing activation of the NLRP3 inflammasome may be beneficial for the treatment of the disease.
Why is the study important?
One strategy for identifying new therapeutics is to test large numbers of different potential drug molecules for their effect on a particular biological mechanism, such as activation of the NLRP3 inflammasome leading to inflammatory responses. In order to do this it is necessary to be able to accurately detect and measure the impact of these potential drug molecules. This study developed a way to test the effect of thousands of compounds on NLRP3 inflammasome activation.
What did the authors do and how did they do it?
The authors developed a way to measure the activation of the NLRP3 inflammasome in human cells. The test involves the addition a fluorescently labelled protein which is part of the group of proteins that come together to form the inflammasome. When these proteins come together, the fluorescently labelled protein forms small specks of fluorescence which can be counted to quantify inflammasome activation. Cells were treated with an inflammatory stimulator and the different molecules to be tested. The number of specks per cell were counted to determine which compounds could reduce the inflammatory response. Compounds that were found to reduce inflammasome activation were further tested to validate their activity by measuring the production of inflammatory signalling molecules. Finally, to screen out any compounds that reduced inflammasome activation because they were toxic, the levels of a substance that indicates cell death were measured.
What are the results?
81 000 compounds were screened for their ability to reduce the activation of the NLRP3 inflammasome. 244 compounds prevented inflammasome activation by 30% when compared to that of cells without the compounds. A sub-set of these compounds were used in the further tests to measure the production of inflammatory signalling molecules and confirmed the accuracy of the initial screen. Most importantly, compounds already known to inhibit inflammasome formation were successfully identified and validated by this screen, further supporting the use of this approach as a tool to identify new compounds to reduce inflammasome activation.
What do the finding mean going forward for people with the disease?
Although this study did not investigate Parkinson’s Disease specifically, it details a robust set of tests to identify high numbers of compounds to reduce inflammasome activation in live human cells. This provides a useful tool for researchers and pharmaceutical companies working on Parkinson’s Disease, and indeed companies including Ventus and NodThera are already investigating the potential of drug molecules to reduce NLRP3 inflammasome activation.
This study can be found at
https://www.nature.com/articles/s41598-021-94850-w
Paper title
A phenotypic high‑content, high‑throughput screen identifies inhibitors of NLRP3 inflammasome activation
Author list
Sohaib Nizami, Val Millar, Kanisa Arunasalam, Tryfon Zarganes‑Tzitzikas, David Brough, Gary Tresadern, Paul E. Brennan, John B. Davis, Daniel Ebner, Elena Di Daniel
Publication details including date of publication
28/07/2021