TAGLN2-mediated ORAI1 stabilization promotes Ca2+-NF‑κB-dependent inflammatory responses in rifampicin allergy

Rifampicin-induced delayed-type hypersensitivity presents a significant challenge during standard anti-tuberculosis therapy, yet the underlying molecular mechanisms remain poorly elucidated. This study investigates the role of the actin-binding protein Transgelin-2 (TAGLN2) in the pathogenesis of T cell-mediated rifampicin hypersensitivity. A clinical cohort comprising 12 rifampicin-hypersensitive patients and 12 rifampicin-tolerant controls was enrolled. High-resolution proteomic profiling of peripheral blood mononuclear cells revealed a distinct upregulation of TAGLN2, PRTN3, ANXA3, POU2F1, S100A8/A9, and PCNA in three rifampicin-hypersensitive patients compared to three tolerant controls. These findings were validated by Western blotting and RT-qPCR, which confirmed the overexpression of these candidates in allergic cohorts, alongside elevated serum levels of TNF-α and IL-1β. Functional enrichment highlighted calcium-dependent protein binding, cytoplasmic translation, and secretory granule lumen pathways. PPI network analysis revealed two synergistic modules: Inflammatory/Effector Hub and Biosynthetic Hub. In vitro experiments confirm that overexpression of TAGLN2 in patient-derived T cells potentiated NF-κB activity, and TAGLN2 levels exhibited a significant positive correlation with pro-inflammatory cytokine expression. Cell surface biotinylation and calcium flux assays further revealed that TAGLN2 facilitates the retention of the calcium channel ORAI1 at the plasma membrane, thereby amplifying intracellular Ca 2+ influx; Conversely, TAGLN2 knockdown abrogated these effects. Furthermore, knockdown or pharmacological inhibition of ORAI1 not only suppressed NF-κB activation and cytokine secretion but also downregulated TAGLN2 expression, suggesting the existence of a positive feedback loop. Collectively, our findings indicate that TAGLN2 drives rifampicin-associated delayed-type hypersensitivity by stabilizing membrane-bound ORAI1, enhancing Ca 2+ influx, and triggering NF-κB-dependent pro-inflammatory cytokine production. This study identifies TAGLN2 as a critical mechanistic node, highlighting its potential as both a diagnostic biomarker and a therapeutic target for drug-induced hypersensitivity.