Establishment and Application of Mice Models for Tracing Gene Expression and Protein Product of TNF

Tumor necrosis factor α (TNF-α) is a pleiotropic cytokine crucial for immune function, cellular homeostasis, and disease progression, yet its complex roles in vivo remain unclear. Challenges in studying TNF-α include its widespread gene expression, variability in expression levels, diverse protein forms, and low baseline expression, which complicate traditional detection and tracking methods. To address these challenges, we constructed three distinct transgenic luciferase reporter mouse models (TNF-IRES-Luc, TNF-Nanoluc, and TNF-HiBiT) driven by the endogenous TNF-α gene, using CRISPR/Cas9 technology through homology-directed repair. The firefly luciferase gene, secreted NanoLuc gene, and HiBiT gene were individually integrated into the mouse genome under the control of the endogenous TNF-α promoter. Our results demonstrate that endogenous TNF-α expression can be effectively monitored by measuring luciferase levels in vivo and in vitro, using an in vivo imaging system and a luminometer. This was validated during inflammatory processes such as lipopolysaccharide (LPS)-induced sepsis and phorbol ester (TPA)-induced mouse ear edema. Furthermore, the anti-inflammatory drug dexamethasone (DXM) significantly inhibited TNF-α and luciferase expression in both inflammatory models. Our study demonstrates these mouse models are valuable tools for studying TNF-α expression in inflammatory responses and related diseases, as well as evaluating anti-inflammatory drug efficacy.