Semberova, T. | Search bioRxiv

bioRxiv2026

T cells restrain inflammation driven by TNF-induced cell death

TNF is a potent proinflammatory cytokine that can induce cell death by activating the kinase RIPK1. The adaptor proteins TANK and AZI2 protect against cell death by recruiting TBK1 to the TNF receptor signaling complex, thereby inhibiting RIPK1. While deficiency of either adaptor alone is well tolerated, combined loss of TANK and AZI2 results in partial embryonic lethality and severe TNF- and RIPK1-driven autoinflammation. Here, we show that TANK/AZI2-deficient mice exhibit a striking expansion of regulatory T cells (Tregs), most of which display an effector phenotype with high expression of immunosuppressive genes. Although thymic Treg generation is modestly increased, Tregs arise predominantly in the periphery through a largely cell-intrinsic mechanism. The marked accumulation of effector Tregs suggested that the T-cell compartment may limit TNF-driven pathology in this model. Supporting this, T cell ablation in TANK/AZI2-deficient mice markedly exacerbates disease progression and enhances TNF-driven, RIPK1-mediated inflammation. Similarly, T cells protect against acute TNF-induced systemic inflammatory response syndrome by limiting RIPK1-mediated cell death. Together, our findings identify TANK and AZI2 as negative regulators of Treg formation, demonstrate that T cells restrain TNF-driven inflammation by limiting RIPK1-dependent cell death, and suggest that this protective effect is mediated primarily by Tregs.

immunology↗

bioRxiv2025

CMTM6 suppresses cell-surface expression of death receptor FAS in mice but not in humans

The transmembrane protein CMTM6 was shown to promote plasma membrane expression of immune checkpoint PD-L1, an important suppressor of anti-tumor immunity. Targeting of CMTM6 was proposed as a strategy to decrease surface PD-L1 and trigger cytotoxicity against tumors. In accord, ablation of CMTM6 in mouse cancer models was shown to efficiently suppress tumor growth in a manner partially independent of PD-L1, which suggested that CMTM6 might regulate other proteins involved in anti-tumor immunity. Using mass spectrometry, we discovered that mouse CMTM6 strongly associates with the cell death receptor FAS and negatively regulates its expression in mice. Deletion of CMTM6 promotes FAS membrane localization and renders murine cells sensitive to FASL-mediated cytotoxicity. However, the interaction between CMTM6 and FAS is lost in human cells due to the difference in three amino acids at the boundary of the FAS extracellular and transmembrane domains. Altogether, our data urge caution when transferring promising data regarding the targeting of CMTM6 from mouse cancer models to potential human therapies.

immunology↗