Unfolding Immune Dysregulation in COPD: Identification of a Three-Gene Signature and Functional Validation of TCF7 in Human Lung Tissue and T Lymphocytes

Chronic obstructive pulmonary disease (COPD) is a leading global cause of mortality. Its molecular pathogenesis, especially systemic immune dysregulation, remains unclear. Public transcriptomic datasets underwent machine learning to identify biomarkers, which were validated in external cohorts and single-cell RNA-seq. In vitro and ex vivo validations included: qRT-PCR and ELISA in CSE/LPS-stimulated macrophages to assess drug efficacy (Celecoxib/Lovastatin); RORC overexpression; Western blotting in patient-derived primary T cells and TCF7-deficient Jurkat cells with genetic rescue; and immunofluorescence of human lungs. A three-gene signature (RORC, TCF7, and CLEC4D) consistently discriminated COPD. CLEC4D localized to myeloid cells, while RORC/TCF7 mapped to lymphoid lineages. Celecoxib and Lovastatin attenuated macrophage inflammation, partially via RORC preservation. Crucially, the TCF7 protein was depleted in COPD primary T cells. TCF7 knockdown downregulated pro-caspase-8, which was fully reversed by TCF7 re-expression. Immunofluorescence confirmed disrupted TCF7/caspase-8 spatial patterns in COPD lungs. This signature highlights innate hyperactivation and adaptive T-cell alterations in COPD, providing novel mechanistic insights into immune dysregulation and potential pharmacological targets.