CD151在鼻病毒诱导型哮喘气道重塑中的作用及分子机制研究

Viral respiratory infections are associated with the virus-induced asthma in adults as well as children. Human rhinovirus (RV) is a major pathogen of the virus-induced asthma exacerbation. However, the holistic understanding of how RV infection contributes to the asthma exacerbation is incomplete. We have reported that, CD151, a member of the tetraspanin superfamily, is upregulated in the airway structural cells in asthmatic patients’ lung samples and involved in the airway wall remodeling (AWR), a core histological feature of asthma. Based on these observations, we wonder whether the upregulation of CD151 in airway cells can be induced by RV infection. Our preliminary data showed that, CD151 was upregulated in the lungs of RV-ovalbumin (OVA) asthmatic mice. Furthermore, its expression was positively correlated with the degree of AWR, which warrants the further exploration of the underlying mechanism of CD151 modulating AWR process in RV-induced asthma exacerbation. To this end, our preliminary data showed that, upon RV infection, the overexpression of fibroblast growth factor 2 (FGF2) produced by airway epithelial cells was detected, and led to the elevated expression of CD151, and then amplified the FGF2 signaling through complexing with integrin αvβ3 in fibroblasts, the predominant profibrotic airway structural cell, and lead to its hyperplasia, extra cellular matrix (ECM) secretion and differentiation into myofibroblasts, and thus contribute to the AWR. On top of that, we hypothesize that RV-induced AWR effects upon is mediated by the key molecule CD151, through activation and positive feedback of FGF2-CD151-integrin αvβ3 signaling pathway in fibroblast. In this proposed study, we aim to 1) clarify the correlation between RV infection and CD151 expression during AWR; 2) investigate how the RV infection induce the overexpression of CD151 and its pathophysiological role during AWR; 3) explore the CD151 downstream signaling pathway(s); and 4) test the potential of CD151 as a pharmaceutical target in asthma prevention and control. This study holds the promise for elucidating the mechanism of CD151-mediated RV-induced asthma exacerbation, and exploration of CD151 as a novel pharmaceutical target.

鼻病毒（RV）是引起哮喘加重的首要病原体，但致病机制未明。我们研究发现，CD151在哮喘病人中表达上调，可能参与气道重塑。RV感染能否引起气道中CD151表达改变？预实验结果显示，RV感染哮喘模型小鼠中，CD151在气道结构细胞中表达显著上调，且与气道重塑的程度呈正相关。那么CD151介导RV诱导哮喘加重的机制是什么？进一步预实验显示，RV感染气道上皮细胞后释放的FGF2可上调CD151，激活和加强integrin αvβ3通路从而活化成纤维细胞，导致气道重塑。由此拟解决的核心科学问题：CD151是否是RV感染所致气道重塑的关键因子。我们拟进一步：明确CD151与RV诱导气道重塑的关联；分析RV感染如何诱导CD151的表达和功能；探讨可能的下游信号转导机制；验证以CD151为哮喘治疗靶点的可行性。项目的开展有望揭示CD151介导RV诱发型哮喘加重的分子机制，为寻找新的治疗靶点提供理论依据。

哮喘是全球最常见的慢性气道炎症性疾病之一。课题组前期研究发现哮喘加重因素鼻病毒可持续感染气道上皮细胞并诱导释放多种细胞因子和趋化因子，这其中我们重点关注了成纤维细胞生长因子2（FGF2）可能通过调节气道结构细胞上黏附分子以及分泌的促炎因子发挥炎症调节作用（Front Cell Dev Biol 2020最后通讯），而FGF2在哮喘中如何参与气道炎症调节未见报道，以此为切入点我们发现：①表达模式方面，哮喘患者和屋尘螨（HDM）诱导小鼠哮喘模型肺组织中FGF2相较于健康对照蛋白表达显著升高，且该升高水平不能被哮喘治疗用药-布地奈德所抑制，FGF2定位于气道上皮、上皮下基底膜、嗜中性粒细胞以及肺泡区域中；②调节炎症方面，在HDM小鼠模型中进行重组鼠源FGF2蛋白（rmFGF2）滴鼻处理，发现rmFGF2单独给药并不能诱导气道炎症，而 HDM+rmFGF2 组的肺组织炎症细胞浸润水平较 HDM 组显著增加，且两组之间血清总IgE 、HDM-IgE 水平及肺IL-4、IL-10 和 IL-13转录水平并无统计学差异，说明rmFGF2 可能通过非Th2炎症通路促进HDM诱导的气道炎症浸润；③在HDM+rmFGF2组中发现更多的嗜中性粒细胞募集到上皮下区域；④机制方面，体外细胞实验证实重组人源FGF2蛋白（rhFGF2）能加重促炎因子IL-1β介导的气道上皮细胞释放IL-6和IL-8，且该效应能被 FGFR抑制剂PD173074所抑制。信号通路分析rhFGF2可能通过FGFR-MAPK-NFκB通路促进了IL-β诱导的炎症因子释放（Military Medical Research 2022最后通讯）。以上发现将为哮喘新型治疗靶点开发奠定理论和实验依据。在项目资助下搭建起完备的气道炎症性疾病研究平台，共发表SCI论文6篇、中文核心2篇，培养研究生4名（已毕业2名），完成预期目标。

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