CRTH2受体在AERD患者嗜酸性粒细胞中表达的调控机制及其介导的趋化作用研究

Aspirin-exacerbated respiratory disease (AERD) is characterized by asthma, chronic rhinosinusitis with nasal polyposis, and pathognomonic respiratory reactions to aspirin, which is still incurable. Pathologically, AERD is characterized by marked eosinophilic infiltration and increased prostglandin D2(PGD2), which caused the recurrence of nasal polyps. PGD2 was reported to play an important role in the chemotaxis of eosinophil, but the mechanism is still not fully understood. Our research demonstrated that, in eosinophil of AERD, the expression of CRTH2 which is a receptor of PGD2 was increased, suggesting the important role it plays in mediating PGD2 effects. The current studies are therefore performed to detect the expression and distribution of CRTH2 in eosinophils of AERD. In particular, we will also assess the role it plays in eosinophil chemotaxis. Further more, in order to investigate the regulatory mechanism of the differential expression of CRTH2 in eosinophils of AERD, we will perform the cytokine intervention experiments on mature eosinophils and CD34+ hemotopoietic stem cells, which will further underlie the pathophysiology of eosinophilic infiltration in AERD nasal polyps and identify new targets for therapeutic intervention of AERD.

阿司匹林耐受不良呼吸道疾病(AERD)以鼻息肉、哮喘及阿司匹林不耐受为特点，目前尚无有效治疗方法。嗜酸性粒细胞广泛浸润及前列腺素D2（PGD2）升高是该病的重要特征，与鼻息肉复发密切相关。研究发现PGD2可介导嗜酸性粒细胞趋化，但具体作用机制尚不明确。我们前期实验显示PGD2的受体CRTH2在AERD患者嗜酸性粒细胞高表达，并聚集于细胞膜，提示机体可能通过上调CRTH2受体表达而增强AERD患者嗜酸性粒细胞的趋化浸润。本课题拟在此基础上对AERD患者嗜酸性粒细胞中CRTH2总蛋白及膜表面蛋白的表达进行分别检测，分析其对嗜酸性粒细胞趋化迁移的影响；并进一步通过对外周血纯化嗜酸性粒细胞及CD34+造血干细胞的干预刺激实验，探索导致CRTH2在嗜酸性粒细胞内高表达及差异分布的细胞因子微环境、调控时机及调控机制，部分阐明AERD患者嗜酸性粒细胞趋化浸润机理，为AERD靶向干预治疗提供新的潜在靶点。

阿司匹林耐受不良呼吸道疾病(AERD)以复发性鼻息肉、重症哮喘及阿司匹林不耐受为特点，目前尚无有效治疗方法。嗜酸性粒细胞（EOS）广泛浸润及前列腺素D2（PGD2）升高是该病的重要特征，与鼻息肉复发密切相关。相关研究发现PGD2可介导EOS趋化，但具体作用机制尚不明确。本研究通过对PGD2受体CRTH2、DP1在AERD患者鼻息肉中表达及分布的检测，证实了CRTH2在AERD息肉组织的高表达，并且主要定位于EOS；进一步分离纯化外周血EOS进行检测也证实了CRTH2在AERD患者嗜酸性粒细胞mRNA及蛋白水平的高表达。同时，本研究通过对外周血EOS进行刺激实验，发现阿司匹林可活化EOS并促使CRTH2受体在细胞膜的表达，一定程度阐明了AERD相关微环境及刺激因素对EOS膜表面CRTH2表达的影响及相关调控作用。进一步研究发现CRTH2高表达与组织EOS浸润程度及息肉复发相关，提示AERD及复发性鼻息肉高表达的CRTH2通过介导EOS向息肉组织的趋化浸润而导致息肉复发的机制。在此基础上，我们进一步发现AERD、嗜酸性粒细胞性鼻息肉及变应性真菌性鼻窦炎等易于复发的鼻息肉患者细胞外基质的胶原蛋白I，III及纤维连接蛋白成分显著降低，组织结构疏松，有利于炎性细胞浸润，并且证实EOS浸润与总胶原蛋白及胶原蛋白III含量负相关，这种与EOS相关的不同亚型鼻息肉组织重塑形式的差别可能为息肉复发提供了一定的结构基础。这些研究初步揭示了AERD患者EOS高表达的CRTH2通过介导EOS趋化浸润而促使息肉复发的部分机制，为鼻息肉的精准分型及相关靶向药物用于复发性鼻息肉治疗提供了一定的理论基础。