Steatotic donor livers are becoming more and more common in liver transplantation. However, the current use of steatotic grafts is less acceptable than normal grafts due to their higher susceptibility to ischemia/reperfusion (I/R) injury. To investigate the mechanism underlying the susceptibility of steatotic liver to I/R injury, we detected cell death markers and inflammation in clinical donor livers and animal models. We found that caspase-8–mediated hepatic apoptosis is activated in steatotic liver I/R injury. However, ablation of caspase-8 only slightly mitigated steatotic liver I/R injury without affecting inflammation. We further demonstrated that RIPK1 kinase induces both caspase-8–mediated apoptosis and cell death–independent inflammation. Inhibition of RIPK1 kinase significantly protects against steatotic liver I/R injury by alleviating both hepatic apoptosis and inflammation. Additionally, we found that RIPK1 activation is induced by Z-DNA binding protein 1 (ZBP1) but not the canonical TNF-α pathway during steatotic liver I/R injury. Deletion of ZBP1 substantially decreases the steatotic liver I/R injury. Mechanistically, ZBP1 is amplified by palmitic acid–activated JNK pathway in steatotic livers. Upon I/R injury, excessive reactive oxygen species trigger ZBP1 activation by inducing its aggregation independent of the Z-nucleic acids sensing action in steatotic livers, leading to the kinase activation of RIPK1 and the subsequent aggravation of liver injury. Thus, ZBP1-mediated RIPK1-driven apoptosis and inflammation exacerbate steatotic liver I/R injury, which could be targeted to protect steatotic donor livers during transplantation.

The global burden of liver diseases continues to rise, encompassing diverse pathologies such as viral hepatitis, alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and hepatocellular carcinoma (HCC). In recent years, TNFR1-associated death domain protein (TRADD), a pivotal adaptor molecule in the TNF signaling pathway, has been found to play a dual regulatory role in the pathogenesis of liver diseases. Through its death domain, TRADD binds to TNFR1 and dynamically recruits downstream factors (e.g., TRAF2, RIPK1, FADD) to form Complex I or IIa, thereby activating pro-survival or pro-apoptotic signals that dictate hepatocyte fate and modulate the inflammatory microenvironment. This review systematically summarizes the molecular structure and functional networks of TRADD, along with its mechanistic roles in liver diseases: in HCC, TRADD expression correlates with tumor differentiation and is regulated by miRNA targeting; in ALD and MASLD, TRADD-mediated apoptosis is closely linked to fibrotic progression; and in acute liver injury, TRADD signaling is modulated by factors such as HO-1 to mitigate damage. Furthermore, TRADD inhibitors and antisense oligonucleotides demonstrate therapeutic potential. This review highlights the clinical translational value of TRADD as a diagnostic, therapeutic, and prognostic biomarker for liver diseases, providing a theoretical foundation for future precision medicine strategies.