Rebuilding the Mucociliary Apparatus in ECRS: TSLP/IL-33 Signaling Synergy and the Residual Molecular Scar of DNASE1L3 Following IL-4/13 Blockade

Background: Eosinophilic chronic rhinosinusitis (ECRS) is characterized by refractory nasal polyps and severely impaired mucociliary clearance (MCC). The molecular mechanisms underlying the modulation of mucociliogenesis following IL-4/13 blockade with dupilumab remain poorly understood, notwithstanding its proven clinical efficacy. Methods: Bulk RNA Barcoding and sequencing (BRB-seq) was performed on nasal polyp tissues collected from healthy controls (n = 6), patients with non-ECRS (n = 8), and patients with ECRS both before and four weeks after dupilumab treatment (n = 9) to identify the early molecular drivers underlying ciliary regeneration. Comprehensive gene-set scoring systems were developed to evaluate multiciliogenesis master regulators, master regulators of core/ciliary planar cell polarity (PCP) and PCP components. Interaction scores for epithelial-derived cytokines—thymic stromal lymphopoietin (TSLP), IL-25, and IL-33—were calculated based on ligand and cognate receptor subunit expression. Results: The ciliary master regulatory hierarchy (e.g., FOXJ1, RFX2/3), PCP components (CELSR1 and the ciliogenesis and planar polarity effector (CPLANE) module: FUZ, INTU, WDPCP), and structural ciliogenesis pathways were robustly restored following IL-4/13 blockade. The TSLP interaction score correlated with global mucosal damage, serving as a trigger for compensatory multiciliogenesis. The pre-treatment IL-33 interaction score emerged as a significant predictor of transcriptomic ciliary recovery (p < 0.05). DNASE1L3—the primary endonuclease for degrading eosinophilic extracellular traps (EETs)—remained persistently downregulated post-treatment. Conclusions: IL-4/13 blockade successfully restores the structural and directional “hardware” of the respiratory epithelium but fails to rectify the enzymatic “software” required for mucus degradation. This “residual molecular scar” may explain the persistent mucus hyperviscosity observed in some ECRS patients even after clinical polyp resolution.