Search

Autoimmune diseases, among the most common disorders of young adults, are mediated by genetic and environmental factors. Although CD4 + FOXP3 + regulatory T cells (T regs ) play a central role in preventing autoimmunity, the molecular mechanism underlying their dysfunction is unknown. Here, we performed comprehensive transcriptomic and epigenomic profiling of T regs in the autoimmune disease multiple sclerosis (MS) to identify critical transcriptional programs regulating human autoimmunity. We found that up-regulation of a primate-specific short isoform of PR domain zinc finger protein 1 (PRDM1-S) induces expression of serum and glucocorticoid-regulated kinase 1 (SGK1) independent from the evolutionarily conserved long PRDM1 , which led to destabilization of forkhead box P3 (FOXP3) and T reg dysfunction. This aberrant PRDM1-S/SGK1 axis is shared among other autoimmune diseases. Furthermore, the chromatin landscape profiling in T regs from individuals with MS revealed enriched activating protein-1 (AP-1)/interferon regulatory factor (IRF) transcription factor binding as candidate upstream regulators of PRDM1-S expression and T reg dysfunction. Our study uncovers a mechanistic model where the evolutionary emergence of PRDM1-S and epigenetic priming of AP-1/IRF may be key drivers of dysfunctional T regs in autoimmune diseases.

Although inhibition of T cell coinhibitory receptors has revolutionized cancer therapy, the mechanisms governing their expression on human T cells have not been elucidated. In the present study, we show that type 1 interferon (IFN-I) regulates coinhibitory receptor expression on human T cells, inducing PD-1/TIM-3/LAG-3 while inhibiting TIGIT expression. High-temporal-resolution mRNA profiling of IFN-I responses established the dynamic regulatory networks uncovering three temporal transcriptional waves. Perturbation of key transcription factors (TFs) and TF footprint analysis revealed two regulator modules with different temporal kinetics that control expression of coinhibitory receptors and IFN-I response genes, with SP140 highlighted as one of the key regulators that differentiates LAG-3 and TIGIT expression. Finally, we found that the dynamic IFN-I response in vitro closely mirrored T cell features in acute SARS-CoV-2 infection. The identification of unique TFs controlling coinhibitory receptor expression under IFN-I response may provide targets for enhancement of immunotherapy in cancer, infectious diseases and autoimmunity., (© 2022. Springer Nature America, Inc.)