CSNK1A1/CK1α suppresses autoimmunity by restraining the CGAS-STING1 signaling

ABSTRACTSTING1 (stimulator of interferon response cGAMP interactor 1) is the quintessential protein in the CGAS-STING1 signaling pathway, crucial for the induction of type I IFN (interferon) production and eliciting innate immunity. Nevertheless, the overactivation or sustained activation of STING1 has been closely associated with the onset of autoimmune disorders. Notably, the majority of these disorders manifest as an upregulated expression of type I interferons and IFN-stimulated genes (ISGs). Hence, strict regulation of STING1 activity is paramount to preserve immune homeostasis. Here, we reported that CSNK1A1/CK1α, a serine/threonine protein kinase, was essential to prevent the overactivation of STING1-mediated type I IFN signaling through autophagic degradation of STING1. Mechanistically, CSNK1A1 interacted with STING1 upon the CGAS-STING1 pathway activation and promoted STING1 autophagic degradation by enhancing the phosphorylation of SQSTM1/p62 at serine 351 (serine 349 in human), which was critical for SQSTM1-mediated STING1 autophagic degradation. Consistently, SSTC3, a selective CSNK1A1 agonist, significantly attenuated the response of the CGAS-STING1 signaling by promoting STING1 autophagic degradation. Importantly, pharmacological activation of CSNK1A1 using SSTC3 markedly repressed the systemic autoinflammatory responses in the trex1-/- mouse autoimmune disease model and effectively suppressed the production of IFNs and ISGs in the PBMCs of SLE patients. Taken together, our study reveals a novel regulatory role of CSNK1A1 in the autophagic degradation of STING1 to maintain immune homeostasis. Manipulating CSNK1A1 through SSTC3 might be a potential therapeutic strategy for alleviating STING1-mediated aberrant type I IFNs in autoimmune diseases.Abbreviations: BMDMs: bone marrow-derived macrophages; cGAMP: cyclic GMP-AMP; CGAS: cyclic GMP-AMP synthase; HTDNA: herring testes DNA; IFIT1: interferon induced protein with tetratricopeptide repeats 1; IFNA4: interferon alpha 4; IFNB: interferon beta; IRF3: interferon regulatory factor 3; ISD: interferon stimulatory DNA; ISGs: IFN-stimulated genes; MEFs: mouse embryonic fibroblasts; PBMCs: peripheral blood mononuclear cells; RSAD2: radical S-adenosyl methionine domain containing 2; SLE: systemic lupus erythematosus; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1.KEYWORDS: AutoimmunityautophagyCSNK1A1STING1type I IFN AcknowledgementsWe thank Dr. Ronggui Hu (State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences) and Dr. Hong Peng (Laboratory of Medical Virology, School of Medicine, Sun Yat-sen University) for sharing the p62 KO MEF cell line. Dr. Yong Yang (The School of Basic Medical Sciences and Clinical Pharmacy, China Pharmaceutical University) and Dr. Xianjing Li (The Institute of Pharmaceutical Sciences, China Pharmaceutical University) for technical support of electroporation. Dr. Wenfeng Tan (Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University) for collecting SLE patient blood samples. Dr. Chen Wang was supported by the National Key R&D Program of China (2021YFF0702003, 2022YFC2303200), the National Natural Science Foundation of China (31730018, 81672029, 82171751), the Open Project of State Key Laboratory of Natural Medicines (SKLNMZZCX201802), the “Double First-Class” Project of China Pharmaceutical University (CPU2022QZ01). Dr. Haiyang Hu was supported by the National Key R&D Program of China (2022YFC2303200, 2021YFF0702003), the Natural Science Foundation of Chongqing (CSTB2022NSCQ-MSX1114), Key R&D Project of Jiangsu Province (BE2020725), the “Double First-Class” Project of China Pharmaceutical University (CPU2022QZ01), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). Dr. Mingyu Pan was supported by the National Natural Science Foundation of China (82202008), the Natural Science Foundation of Jiangsu Province (BK20221029), the Jiangsu Funding Program for Excellent Postdoctoral Talen (2022ZB307). Dr. Lingxiao Xu was supported by the National Natural Science Foundation of China (82271844), Suqian Sci&Tech Program (KY202201).Disclosure statementNo potential conflict of interest was reported by the authors.Data availability statementAll original RNA-seq data are deposited in the Gene Expression Omnibus database, https://www.ncbi.nlm.nih.gov/geo (accession no. GSE226593).Supplementary materialSupplemental data for this article can be accessed online at https://doi.org/10.1080/15548627.2023.2256135Additional informationFundingThe work was supported by the National Key R&D Program of China [2021YFF0702003]; the National Key R&D Program of China [2022YFC2303200]; the National Natural Science Foundation of China [82171751]; the Open Project of State Key Laboratory of Natural Medicines [SKLNMZZCX201802]; the Natural Science Foundation of Chongqing [CSTB2022NSCQ-MSX1114]; Key R&D Project of Jiangsu Province [BE2020725]; the “Double First-Class” Project of China Pharmaceutical University [CPU2022QZ01]; and the Priority Academic Program Development of Jiangsu Higher Education Institutions [PAPD]; the National Natural Science Foundation of China [82202008]; the Natural Science Foundation of Jiangsu Province [BK20221029]; the Jiangsu Funding Program for Excellent Postdoctoral Talen [2022ZB307]; the National Natural Science Foundation of China [82271844]; Suqian Sci&Tech Program [KY202201].