Iron overload triggers pathological remodeling of corneal stroma through ferroptosis and senescence-associated secretory phenotype in keratoconus.

Keratoconus (KC) remains a leading cause of blindness among adolescents with no available pharmacotherapies to halt its progression clinically. While stromal thinning and cell loss are established pathological hallmarks, the underlying molecular mechanisms driving disease pathogenesis have been poorly understood. Motivated by the clinical presence of the iron-associated Fleischer's ring, we investigated the role of iron overload in KC pathogenesis. Our subsequent analysis of single-cell RNA sequencing (scRNA-seq) data from human KC corneas ultimately revealed ferroptosis-an iron-dependent form of cell death-as the predominant mechanism underlying the loss of corneal stromal cells. Next, we confirmed significant iron accumulation and ferroptosis activation in both tissues and primary corneal stromal cells derived from KC patients. Further mechanistic exploration using transcriptomic profiling, pathway analysis and functional experiments revealed that iron overload induces not only ferroptosis but also cellular senescence, accompanied by a pronounced senescence-associated secretory phenotype (SASP). The SASP profile featured elevated collagen degradation, inflammatory activation, and dysregulated fibrosis, these processes directly contributing to stromal thinning and biomechanical weakening in KC. Importantly, these pathological cascades were reversible upon treatment with the iron chelator deferoxamine (DFO). Overall, our study establishes a novel mechanism in which iron overload drives KC progression via ferroptosis and senescence with SASP, and highlights iron chelation therapy as a promising disease-modifying strategy for patients with KC.