Chronic Type I interferons signaling promotes lipid peroxidation-driven terminal CD8+T cell exhaustion and curtails anti-PD-1 treatment efficacy

Identifying signals that govern the differentiation of tumor-infiltrating CD8 + T cells (CD8 + TILs) towards exhaustion can improve current therapeutic approaches for cancer. Here, we show that type I interferons (IFN-Is) act as environmental cues enhancing terminal CD8 + T cell exhaustion in tumors. We found enrichment of IFNIs-stimulated genes (ISGs) within exhausted CD8 + T cells (Tex cells) in patients across various cancer types, with heightened ISG levels correlating with poor response to immune checkpoint blockade (ICB) therapy. In preclinical models, CD8 + TILs devoid of IFN-Is signaling developed less exhaustion features, provided better tumor control and showed greater response to ICB-mediated rejuvenation. Mechanistically, chronic IFN-Is stimulation perturbed lipid metabolism and redox balance in Tex cells, leading to aberrant lipid accumulation and elevated oxidative stress. Collectively, these defects promoted lipid peroxidation, which potentiated metabolic and functional exhaustion of Tex cells. Thus, cell intrinsic IFN-Is signaling regulates the extent of CD8+ TIL exhaustion, and has important implications for immunotherapy. For RNA-seq, the peripheral blood CD8+ T cells purified from heathy donors were stimulated with a-CD3/a-CD28 conjugated microbeads in the presence of IFN-Is, and then the alive CD8+ T cells were harvested on the day 2. Their high-quality RNA were extracted to submit pair-end RNA sequencing. For ATAC-seq, the peripheral blood CD8+ T cells purified from heathy donors were stimulated with a-CD3/a-CD28 conjugated microbeads, and 50,000 live CD8+ T cells were sorted by flow cytometry immediately before library generation at day2. ATAC-seq libraries were prepared for the paired-end sequencing using Omni-ATAC protocol (Corces et al. Nature Methods 2017)