Small-molecule inhibitors directly target CARD9 and mimic its protective variant in inflammatory bowel disease

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 114; no. 43; pp. 11392 - 11397
• Main Authors: Leshchiner, Elizaveta S., Rush, Jason S., Durney, Michael A., Cao, Zhifang, Dančík, Vlado, Chittick, Benjamin, Wu, Huixian, Petrone, Adam, Bittker, Joshua A., Phillips, Andrew, Perez, Jose R., Shamji, Alykhan F., Kaushik, Virendar K., Daly, Mark J., Graham, Daniel B., Schreiber, Stuart L., Xavier, Ramnik J.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.10.2017
• Subjects: Biochemistry; Biological Sciences; CARD Signaling Adaptor Proteins - antagonists & inhibitors; CARD Signaling Adaptor Proteins - genetics; Cytokines; Drug Evaluation, Preclinical; Enzyme-Linked Immunosorbent Assay - methods; Genetic Markers; Genetic Variation; Genetics; Genome-wide association studies; Genomes; High-Throughput Screening Assays; Humans; Inflammatory bowel disease; Inflammatory bowel diseases; Inflammatory Bowel Diseases - drug therapy; Inflammatory Bowel Diseases - genetics; Intestine; Multiplexing; NF-κB protein; Protein Binding; Proteins; Recruitment; Sensitivity and Specificity; Tripartite Motif Proteins - antagonists & inhibitors; Tripartite Motif Proteins - genetics; Ubiquitin; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - antagonists & inhibitors; Ubiquitin-Protein Ligases - genetics; therapeutics; inflammatory bowel disease; small molecules; CARD9
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1705748114

Advances in human genetics have dramatically expanded our understanding of complex heritable diseases. Genome-wide association studies have identified an allelic series of CARD9 variants associated with increased risk of or protection from inflammatory bowel disease (IBD). The predisposing variant of CARD9 is associated with increased NF-κB–mediated cytokine production. Conversely, the protective variant lacks a functional C-terminal domain and is unable to recruit the E3 ubiquitin ligase TRIM62. Here, we used biochemical insights into CARD9 variant proteins to create a blueprint for IBD therapeutics and recapitulated the mechanism of the CARD9 protective variant using small molecules. We developed a multiplexed bead-based technology to screen compounds for disruption of the CARD9–TRIM62 interaction. We identified compounds that directly and selectively bind CARD9, disrupt TRIM62 recruitment, inhibit TRIM62-mediated ubiquitinylation of CARD9, and demonstrate cellular activity and selectivity in CARD9-dependent pathways. Taken together, small molecules targeting CARD9 illustrate a path toward improved IBD therapeutics.