The study focuses on the development of a high-affinity inhibitor for cyclic GMP-AMP synthase (cGAS), an enzyme crucial for innate immune response to cytosolic DNA. The inappropriate activation of cGAS is implicated in autoimmune diseases such as systemic lupus erythematosus (SLE). Therefore, inhibiting cGAS could offer therapeutic benefits.
Researchers identified PF-06928215 through a novel fluorescence polarisation (FP) assay that uses a Cy5-labelled cGAMP and a monoclonal antibody specific to cGAMP. This assay enabled high-throughput screening and optimisation of cGAS inhibitors. Initially, a low-affinity fragment hit was identified and subsequently optimised through structure-based drug design to develop PF-06928215, which binds to the cGAS active site with a dissociation constant (KD) of 200 nM.
The FP assay was crucial for this discovery, providing a sensitive and specific method to detect cGAS activity and screen potential inhibitors rapidly. This method proved advantageous over traditional assays, which are slower and more resource-intensive.
Key Takeaways:
- High-Affinity Inhibitor Identified: PF-06928215 was discovered as a high-affinity inhibitor of cGAS, binding to the active site with a KD of 200 nM, which demonstrates its potential as a therapeutic candidate for treating autoimmune diseases like SLE.
- Novel Fluorescence Polarisation Assay: The study developed a new high-throughput fluorescence polarisation assay that uses a Cy5-labelled cGAMP and a specific monoclonal antibody. This assay significantly improved the screening process for cGAS inhibitors by allowing rapid and specific detection of cGAS activity.
- Therapeutic Potential for Autoimmune Diseases: Given cGAS’s role in the innate immune response and its implication in autoimmune diseases, the inhibition of cGAS by PF-06928215 opens new avenues for therapeutic intervention in conditions characterised by inappropriate activation of the cGAS pathway.
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Originally posted on: Discovery Of PF-06928215 As A High Affinity Inhibitor of cGAS Enabled by a Novel Fluorescence Polarization Assay | ProSci Incorporated (prosci-inc.com)
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