Discovery of Clonixeril as a Sub-Femtomolar Modulator of the Human STING Receptor
Stimulator of interferon genes (STING) is a transmembrane endoplasmic reticulum (ER) resident protein involved in innate immunity. STING activation occurs by binding of cyclic guanosine-(2'→5')-monophosphate-adenosine-(3'→5')-monophosphate (2',3'-cGAMP) to STING, which leads to downstream production of type 1 interferons (IFN-1). We generated molecular dynamics (MD) equilibrated agonist and antagonist models of human STING (hSTING) for computer-based screening and now report the discovery of clonixeril (CXL) as the most potent non-nucleotide hSTING modulator discovered to date. We demonstrate <i>in vitro</i> and <i>in cellulo</i> that CXL has two modes of interaction with hSTING, one with an EC<sub>50</sub> above 1 nM and the other with an EC<sub>50</sub> in the 1 fM-100 aM range (10<sup>-15</sup>-10<sup>-16</sup> M). In cell-based experiments, when CXL is titrated below 1 nM, it displays inverse dose-dependent antagonistic behavior toward hSTING. We have substantiated that CXL displays this exceptionally strong inhibitory effect on hSTING mediated IFN-1 production using a THP-1 cell luciferase reporter for interferon regulatory factor 3 (IRF3). Further characterization of CXL was performed in HEK293 cells by using biophysical and biochemical techniques.
Authors
- Mildred Acevedo‐Duncan
- Niketa Patel (ORCID: https://orcid.org/0000-0003-4811-8596)
- Joseph Nunziata
- Rainer Metcalf
- Guy Bradley
- Robert P. Sparks (ORCID: https://orcid.org/0000-0002-0485-8317)
- Timothy H. Tran (ORCID: https://orcid.org/0000-0003-1342-7620)
- Alan C. Mullen (ORCID: https://orcid.org/0000-0002-4096-3106)
- William F. Lawless (ORCID: https://orcid.org/0000-0002-3142-6923)
- Linette Harding
- Robert M. Green
- Wesley H. Brooks (ORCID: https://orcid.org/0000-0002-5604-3769)
- Michelle I. Wilde
- Paul R. Thompson (ORCID: https://orcid.org/0000-0002-1621-3372)
- James W. Leahy (ORCID: https://orcid.org/0000-0003-3647-4489)
- Wayne C. Guida (ORCID: https://orcid.org/0000-0003-3353-4853)
- Jaret Crews
- Douglas K. Trask (ORCID: https://orcid.org/0000-0003-0550-442X)
- Sauradip Chaudhuri (ORCID: https://orcid.org/0000-0003-3578-5293)
- Christine Gambino
- Mark Eschenfelder
- Grace Binder (ORCID: https://orcid.org/0000-0002-0717-8456)
- Yan Yang (ORCID: https://orcid.org/0000-0001-9727-0987)
- Kenyon G. Daniel
- Rekha Patel (ORCID: https://orcid.org/0009-0002-7329-4516)
- Anna Kharitonova
- Sarah Lawless
- Mansi Gopu
- Elizabeth Nompleggi
- Emilia Dalamangas
Institutions
- College of the Holy Cross (US)
- University of Massachusetts Chan Medical School (US)
- University of South Florida (US)
- Moffitt Cancer Center (US)
- James A. Haley Veterans' Hospital (US)
- Institute of Molecular Biology and Biotechnology (BG)
- Center for Discovery (US)
- Tampa Bay Research Institute (US)
Publication Details
- Journal
- ACS Central Science
- Published
- 2025-06-06
- DOI
- https://doi.org/10.1021/acscentsci.4c01982
- Primary Topic
- interferon and immune responses
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Institute of Allergy and Infectious Diseases