NEDD4介导的AQP5泛素化在过敏性鼻炎中的作用：对鼻黏膜屏障功能的影响

文献信息

中文摘要

背景： 过敏性鼻炎（AR）的病理主要源于鼻上皮屏障的破坏，但水通道蛋白5（AQP5）的作用尚未完全阐明。我们提出E3泛素连接酶NEDD4负责AQP5的降解，从而影响AR中的屏障稳态。
方法： 分别使用人鼻上皮细胞和卵清蛋白诱导的Sprague-Dawley大鼠作为体外和体内模型。通过共免疫沉淀、共聚焦显微镜和泛素化实验，比较对照组、AR组与siNEDD4组和ovAQP5组，以评估分子相互作用。采用跨上皮电阻（TER）、MUC5AC分泌和细胞因子释放来测量屏障功能。
结果： 我们证明NEDD4直接与AQP5相互作用并在赖氨酸257位点使其泛素化，导致其蛋白酶体降解。NEDD4被IL-13上调，且这种上调不改变AQP5 mRNA水平。降低NEDD4或增加AQP5表达可恢复屏障完整性，抑制MUC5AC和IL-6/IL-8的合成，并同时抑制p38 MAPK活化；这种抑制与AQP5介导的信号传导一致。用SB203580抑制p38可恢复屏障功能并抵消黏液高分泌。在大鼠中经鼻给予siNEDD4或ovAQP5可缓解过敏反应，减少炎症细胞浸润，并使NEDD4/p-p38/AQP5表达正常化。
结论： 我们确定了NEDD4-AQP5轴是AR的关键驱动因素和潜在治疗靶点。

英文摘要

BACKGROUND: Allergic rhinitis (AR) pathology is mainly due to disruption of the nasal epithelial barrier, but the role of aquaporin 5 (AQP5) is not fully understood. We propose that the E3 ubiquitin ligase NEDD4 is responsible for the degradation of AQP5 and thus affects barrier homeostasis in AR.
METHODS: Human nasal epithelial cells and ovalbumin-induced Sprague-Dawley rats were used as in vitro and in vivo models, respectively. Control and AR groups were compared with siNEDD4 and ovAQP5 groups using co-immunoprecipitation, confocal microscopy, and ubiquitination assays to assess molecular interactions. Transepithelial electrical resistance (TER), MUC5AC secretion, and cytokine release were used to measure barrier function.
RESULTS: We demonstrated that NEDD4 directly interacts with and ubiquitinates AQP5 at lysine 257, leading to its proteasomal degradation. NEDD4 was upregulated by IL-13, and this upregulation did not alter AQP5 mRNA levels. Decreasing NEDD4 or increasing AQP5 expression restored barrier integrity and inhibited MUC5AC and IL-6/IL-8 synthesis and concomitantly suppressed p38 MAPK activation; this suppression is consistent with AQP5-mediated signaling. Inhibiting p38 with SB203580 restored barrier function and counteracted mucus hypersecretion. Nasal administration of siNEDD4 or ovAQP5 in rats relieved allergic reactions, reduced inflammatory cell infiltration, and normalized NEDD4/p-p38/AQP5 expression.
CONCLUSIONS: We have identified the NEDD4-AQP5 axis as a crucial driver of AR and a potential therapeutic target.