HLA-G - LILRB - SHP2 Axis in Airway Smooth Muscle

摘要 哮喘的人类气道平滑肌（HASM）与正常HASM至少在三个方面不同： 收缩迟缓、肌细胞肥大和异常趋化因子的产生--但这些机制并不清楚， 因此这些哮喘HASM表型仍然知之甚少。我们发现HLA-G - LILRB-SHP信号通路，这是已知的调节免疫系统的反应，也运作， HASM。重要的是，通过该途径的信号传导促进了所列出的哮喘HASM特征中的每一个 以上该提案的主要目标是分析这一途径的炎症和遗传调节- 方法，以确定预防或逆转这些哮喘HASM表型的新策略。 在初步研究中，我们发现LILRB 1、LILRB 2和它们的家族成员LILRB 4以及SHP 2（但不是 SHP 1）都在人ASM中表达; LILRB受体激活人气道肌细胞内的SHP 2; SHP 2增加收缩力和弹性，刺激Akt信号传导和肥大， 激活NF B和趋化因子。因此，HLA-G - LILRB -SHP 2信号传导通路是完整的。 HASM，其活化将哮喘样表型赋予气道肌肉。此外，HLA-G - LILRB - SHP 2轴可能在哮喘中异常放大，因为：可溶性HLA-G的丰度是正常的三倍。 在哮喘受试者的BAL液中发现的几种免疫调节分子， 哮喘气道可以增加LILRB表达;以及该途径每个组分的遗传变异 （HLA-G、LILRB 1、LILRB 2、LILRB 4和PTPN 11，其编码SHP 2）与哮喘相关和/或 支气管高反应性总之，这些数据表明，新的和生物学上合理的假设 过度活跃的HLA-G - LILRB -SHP 2信号传递赋予哮喘HASM表型， 干预这一信号通路可能改善哮喘患者的ASM异常。测试这些 假设，我们建议：1）确定选择的免疫调节分子如何影响HLA-G - 正常和哮喘HASM中的LILRB-SHP 2信号传导; 2）评估LILRB 1， 与BHR或哮喘相关的LILRB 2或LILRB 4影响HLA-G - LILRB -SHP 2信号传导， 正常或哮喘HASM;和3）描绘改变SHP 2信号传导的分子机制 导致正常HASM获得哮喘HASM表型。这些研究将揭示HLA-G - LILRB-SHP 2信号调节ASM功能;遗传和炎症机制调节 调节作用;以及抑制该途径是否可以预防或逆转哮喘的获得。 HASM表型。

ABSTRACT Asthmatic human airway smooth muscle (HASM) differs from normal HASM in at least three ways - dysregu- lated contraction, myocyte hypertrophy, and abnormal chemokine elaboration - but the mechanisms that un- derlie these asthmatic HASM phenotypes remain poorly understood. We have discovered that the HLA-G - LILRB - SHP signaling pathway, which is known to regulate immune system responses, also operates in HASM. Importantly, signaling through this pathway promotes each of the asthmatic HASM characteristics listed above. The major objective of this proposal is to analyze the inflammatory and genetic regulation of this path- way in HASM in order to identify novel strategies that prevent or reverse these asthmatic HASM phenotypes. In preliminary studies, we found that LILRB1, LILRB2, and their family member LILRB4, and SHP2 (but not SHP1) are all expressed in human ASM; that LILRB receptors activate SHP2 within human airway myocytes; and that SHP2 increases the force of contraction and elasticity, stimulates Akt signaling and hypertrophy, and activates NF¿B and chemokine elaboration. Thus, the HLA-G - LILRB - SHP2 signaling pathway is intact in HASM, and its activation imparts asthma-like phenotypes to airway muscle. Furthermore, the HLA-G - LILRB - SHP2 axis may be abnormally exaggerated in asthma because: soluble HLA-G is three times more abundant in BAL fluid of asthmatic subjects than normal volunteers; several immunomodulatory molecules found in asthmatic airways can increase LILRB expression; and genetic variations in each component of this pathway (HLA-G, LILRB1, LILRB2, LILRB4, and PTPN11, which encodes SHP2) are associated with asthma and/or bronchial hyperresponsiveness. Together, these data suggest the novel and biologically plausible hypotheses that overactive HLA-G - LILRB - SHP2 signaling imparts an asthmatic HASM phenotype, and that therapeutic intervention to interfere with this signaling pathway might ameliorate ASM abnormality in asthma. To test these hypotheses, we propose to: 1) determine how selected immunomodulatory molecules influence HLA-G - LILRB - SHP2 signaling in normal and asthmatic HASM; 2) evaluate how genetic variations in LILRB1, LILRB2, or LILRB4 that are associated with BHR or asthma influence HLA-G - LILRB - SHP2 signaling in normal or asthmatic HASM; and 3) delineate the molecular mechanisms by which altered SHP2 signaling causes normal HASM to acquire an asthmatic HASM phenotype. These studies will reveal how HLA-G - LILRB - SHP2 signaling regulates ASM function; which genetic and inflammatory mechanisms modulate that regulatory role; and whether inhibition of this pathway can prevent or reverse acquisition of the asthmatic HASM phenotype.