15LO1介导的自噬在鼻息肉上皮细胞铁死亡中的保护作用及机制研究

鼻息肉是以Th2炎症为特征的疾病。上皮细胞屏障受损是引起鼻息肉的重要因素，但其机制仍不明确。既往单细胞基因测序发现15LO1在鼻息肉上皮表达升高，携带15LO1突变基因人群患鼻息肉风险降低65%以上。我们前期研究证实15LO1在息肉上皮细胞中表达显著升高，IL-13诱导鼻上皮细胞合成15LO1，15LO1代谢产物15-HpETE-PE是引起铁死亡的重要分子，同时15LO1促进LC3脂质化（LC3Ⅱ）激活细胞自噬，阻断自噬能促进细胞发生铁死亡。我们据此提出假说：在鼻息肉上皮细胞，高表达15LO1虽然可诱导细胞发生铁死亡，但同时激活细胞自噬修复以保护上皮细胞免于发生铁死亡，进而维持上皮细胞的稳态。本项目拟通过体外培养原代鼻上皮细胞对15LO1及LC3进行调控，建立15LO1基因敲除小鼠模型，探究15LO1介导的细胞自噬在鼻上皮细胞铁死亡中的保护作用及调控机制，为鼻息肉上皮损伤治疗提供实验依据。

Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by type 2 (T2) inflammation. It is well documented that defects in airway epithelial barrier function are associated with CRSwNP, however, the mechanisms are still unclear. Recently a single-cell RNA-sequencing study reported ALOX15 to be one of the most differentially expressed genes in NPs. Another genome-wide association study of patients with NPs across several cohorts consistently identified a single nucleotide polymorphism (SNP) in the ALOX15 gene associated with a greater than 65% reduction in the risk of NPs. Our recent data showed that 15LO1 expression is increased in nasal epithelial cells (NECs) from patients with CRSwNP, IL-13 induces 15LO1 expression in vitro. 15LO1 specifically generates higher levels of 15HpETE-PE, a key ferroptotic cell death signal. LC3II/autophagy is elevated in NECs ex vivo and induced by IL-13 in vitro through 15LO1 dependent mechanisms, LC3 inhibition promotes ferroptotic cell death in NECs. Based on these studies, we hypothesized that autophagy protects from 15LO1-mediated ferroptotic cell death in NECs, therefore maintains the function and immune homeostasis of NECs. Accordingly, primary NECs from both CRSwNP patients and healthy control subjects obtained from nasal brushings were cultured under an air-liquid interface (ALI) system with or without ALOX15 and LC3 inhibition. Alox15 knockout mice are sensitized with IL-13 by the intranasal route to build the Th2 nasal inflammation model to determine whether 15LO1 regulates autophagy and ferroptosis in NECs. Together, this study strongly supports 15LO1 as a potential therapeutic target with the potential to inhibit defects in nasal epithelial cells in patients with CRSwNP.