Chlamydia trachomatis infection induces ferroptosis and enhances chlamydial replication.

Chlamydia trachomatis (C. trachomatis) has been shown to activate multiple programmed cell death pathways, which contribute significantly to host immune responses. Nevertheless, the precise molecular mechanisms by which C. trachomatis induces cell death remain poorly characterized. Ferroptosis, a recently identified form of iron-dependent, lipid peroxidation-driven regulated cell death, may represent a previously unrecognized pathway in chlamydial pathogenesis. To investigate the mechanisms underlying C. trachomatis-induced cell death, we first performed transcriptomic analysis to identify differentially expressed genes and enriched pathways in infected HeLa cells. Concurrently, we quantified intracellular iron levels, reactive oxygen species (ROS) accumulation, and lipid peroxidation, all of which are hallmarks of ferroptosis. Transmission electron microscopy (TEM) further revealed distinct mitochondrial alterations in C. trachomatis-infected cells, suggesting potential dysfunction in cellular redox homeostasis. To directly assess the role of ferroptosis in chlamydial infection, we treated cells with the ferroptosis-specific inhibitor Ferrostatin-1 (Fer-1) and evaluated its effects on chlamydial replication and host inflammatory responses. Bioinformatic analysis demonstrated significant enrichment of iron homeostasis and ferroptosis-related pathways in C. trachomatis-infected cells, with the ferroptosis signaling pathway exhibiting particularly strong activation. Experimentally, infection disrupted the expression of key iron transporters (e.g., TFR and FPN1), causing dysregulated iron uptake and storage. Concurrently, C. trachomatis downregulated the critical ferroptosis inhibitors SLC7A11 and GPX4, leading to elevated lipid peroxidation. Ultrastructural analysis via TEM revealed pronounced mitochondrial abnormalities in infected HeLa cells, including marked swelling and cristae disintegration-a hallmark of ferroptotic damage. Notably, pharmacological inhibition of ferroptosis using Fer-1 not only attenuated infection-induced cell death but also significantly suppressed bacterial replication, suggesting ferroptosis as a host-pathogen interaction nexus. This study provides evidence that C. trachomatis infection induces ferroptosis in host cells, and that targeting the ferroptosis pathway may represent a novel therapeutic strategy for controlling C. trachomatis infections.

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