Role of STING/TMEM173 mutation in systemic lupus erythematosus: from animal model to intrinsic human genetics

ObjectiveWe aim to confirm the function of Sting/Tmem173 in pristane-induced lupus and identify the role of STING/TMEM173 variants in SLE susceptibility. MethodsPristane-induced lupus model was introduced in the Sting-deficient mice (ENU-induced Goldenticket mutant mice). Autoantibody, histopathology, and immunophenotypes were analyzed after pristane injection for six months. Isolated DNA from 302 SLE patients and 173 healthy donors were tested for STING genotyping. We calculated the Odd Ratios of each STING variant and the inheritance patterns that significantly increased SLE susceptibility. Then, we analyzed the associations between STING genotypes and lupus phenotypes. ResultsThe absence of STING signaling in the Goldenticket mutant mice reduced the autoantibody production and severity of glomerulonephritis in pristane-induced lupus. The human STING mutation at p.R284S (gain-of-function) significantly increased the SLE risk in autosomal dominant pattern [OR = 64.0860 (95%CI = 22.8605-179.6555), p < 0.0001], while the mutation at p.R232H (loss of function) reduced the SLE risk in autosomal recessive pattern [OR = 0.2515 (95%CI = 0.1648-0.3836), p < 0.0001]. The combination of STING variants in a specific inheritance pattern increased the higher OR than a single variant. The patient who had p.R284S with p.R232H showed milder disease activity than those who had p.R284S alone at the time of diagnosis. ConclusionThe inhibition of STING rescued autoimmune phenotypes in pristane-induced lupus. Gain-of-function STING mutation increased SLE susceptibility and severity of the disease. These data suggested the critical function via STING-mediated signaling in SLE. Targeted at STING may provide a favorable outcome in SLE patients.