Large-scale mutational analysis identifies UNC93B1 variants that drive TLR-mediated autoimmunity in mice and humans
Victoria E. Rael, Julian A. Yano, John Huizar, Leianna C. Slayden, Madeleine A. Weiss, Elizabeth A Turcotte, J M Terry, Wenqi Zuo, Isabelle Thiffault, Tomi Pastinen, Emily Farrow, Janda Jenkins, Mara L. Becker, Stephen C. Wong, Anne M. Stevens, Catherine Otten, Eric J. Allenspach, Devon Bonner, Jonathan A. Bernstein, Matthew T. Wheeler, Robert A. Saxton, Undiagnosed Diseases Network, Maria T. Acosta, David R. Adams, Raquel L. Alvarez, Justin Alvey, Aimee Allworth, Ashley Andrews, Euan A. Ashley, Ben Afzali, Carlos A. Bacino, Güney Bademci, Ashok Balasubramanyam, Dustin Baldridge, Jim Bale, Michael J. Bamshad, Deborah Barbouth, Pınar Bayrak‐Toydemir, Anita E. Beck, Alan H. Beggs, Edward M. Behrens, Gill Bejerano, Hugo J. Bellen, Jimmy Bennett, Jonathan A. Bernstein, Gerard T. Berry, Anna Bican, Stephanie Bivona, Elizabeth Blue, John Bohnsack, Devon Bonner, Lorenzo D. Botto, Lauren C. Briere, Gabrielle Brown, Elizabeth A. Burke, Lindsay C. Burrage, Manish J. Butte, Peter H. Byers, William E. Byrd, John M. Carey, Thomas Cassini, Sirisak Chanprasert, Hsiao‐Tuan Chao, Iván K. Chinn, Gary Clark, Terra R. Coakley, Laurel A. Cobban, Joy D. Cogan, Matthew Coggins, F. Sessions Cole, Heather A. Colley, Rosario I. Corona, William J. Craigen, Andrew B. Crouse, Michael L. Cunningham, Precilla D’Souza, Hongzheng Dai, Surendra Dasari, Joie Davis, Jyoti G. Dayal, Margaret Delgado, Esteban C. Dell’Angelica, Katrina M. Dipple, Daniel Doherty, Naghmeh Dorrani, Argenia L. Doss, Emilie D. Douine, Dawn Earl, David J. Eckstein, Lisa Emrick, Christine M. Eng, Marni J. Falk, Elizabeth L. Fieg, Paul G. Fisher, Brent L. Fogel, Jiayu Fu, William A. Gahl, I. S. Glass, Pagé C. Goddard, Rena A. Godfrey
Abstract
Nucleic acid-sensing Toll-like receptors (TLR) 3, 7/8, and 9 are key innate immune sensors whose activities must be tightly regulated to prevent systemic autoimmune or autoinflammatory disease or virus-associated immunopathology. Here, we report a systematic scanning-alanine mutagenesis screen of all cytosolic and luminal residues of the TLR chaperone protein UNC93B1, which identified both negative and positive regulatory regions affecting TLR3, TLR7, and TLR9 responses. We subsequently identified two families harboring heterozygous coding mutations in UNC93B1, UNC93B1+/T93I and UNC93B1+/R336C, both in key negative regulatory regions identified in our screen. These patients presented with cutaneous tumid lupus and juvenile idiopathic arthritis plus neuroinflammatory disease, respectively. Disruption of UNC93B1-mediated regulation by these mutations led to enhanced TLR7/8 responses, and both variants resulted in systemic autoimmune or inflammatory disease when introduced into mice via genome editing. Altogether, our results implicate the UNC93B1-TLR7/8 axis in human monogenic autoimmune diseases and provide a functional resource to assess the impact of yet-to-be-reported UNC93B1 mutations.