PARP-1调控急性肺损伤中中性粒细胞浸润和活化的作用及其分子机制研究

The activation and infiltration of neutrophils play a critical role in the progress and exacerbation of acute lung injury (ALI). Increasing evidences indicate that poly(ADP-ribose) polymerase-1(PARP-1) was involved in the inflammation responses in several animal models. In the previous study, inhibition of PARP-1 decreased the infiltration of neutrophils in lung tissue and attenuated the inflammation responses in a LPS-induced ALI model, suggesting that PARP-1 may modulate neutrophil migration and activation. Preliminary results found that inhibition of PARP-1 blocked neutrophil ROS production and decreased IL-8-induced neutrophil chemotaxis. In this proposal, we would like to explore the molecular mechanisms of PARP-1-mediated neutrophil migration and activation, which is beneficial for understanding the roles of neutrophils in the pathogenesis of ALI. . This study is divided into 3 parts: (1) the role of activation and infiltration of neutrophil modulated by PARP-1 in ALI. (2) the mechanism of PARP-1-mediated neutrophil migration, including the detection of the expression and activation of receptors, adhesion molecules and key neutrophil migration regulators. (3) the function of PARP-1 in regulating neutrophil activation, such as degranulation, secretion of cytokines and chemokines, ROS generation. Our studies will provide new mechanisms and pharmacological target for treatment of ALI.

在急性肺损伤中，中性粒细胞的活化和组织浸润是重要参与因素之一。研究表明，PARP-1与组织炎症反应密切相关。前期实验发现，抑制PARP-1活性可减少脂多糖引起的肺组织中浸润的中性粒细胞，并有效缓解了肺组织损伤；阻断PARP-1直接影响中性粒细胞ROS的释放和IL-8诱导的细胞迁移，表明PARP-1与中性粒细胞的活化和浸润有重要关系。本项目拟对PARP-1调控中性粒细胞迁移和活化的分子机制进行研究，以加深对急性肺损伤中中性粒细胞作用机制的了解。. 研究包括：（1）PARP-1调控中性粒细胞浸润和活化参与急性肺损伤的研究；（2）PARP-1对中性粒细胞迁移的调控作用及分子机制，检测细胞表面受体、黏附分子和细胞迁移重要分子的表达和活化；（3）PARP-1对中性粒细胞活化的影响，检测脱粒作用、细胞因子、反应活性氧。本研究将为急性肺损伤的治疗提供理论依据，也将为相关药物研发提供参考。

中性粒细胞是天然免疫的重要组成部分，在机体防御中发挥重要作用，但中性粒细胞大量浸润和过度活化会导致急性肺损伤和肺癌疾病恶化，然而对于中性粒细胞影响疾病恶化的分子机制尚不清楚。本研究通过离体细胞实验、分子生物学实验以及小鼠体内实验逐层探寻和验证中性粒细胞导致疾病恶化的作用机制。研究一发现PARP-1在活化的中性粒细胞中高表达，敲低或抑制PARP-1减少中性粒细胞受体CXCR2和CXCR4表达，进而导致中性粒细胞迁移能力降低，肺组织浸润数量减少，肺损伤减轻，小鼠生存期延长。研究二发现活化的中性粒细胞通过释放基质金属蛋白酶MMP9和血管生长因子VEGF，促进肺癌细胞A549和H1299细胞侵袭、迁移，诱导肺癌血管生成，利用抑制剂阻断中性粒细胞活化产物中MMP9活性消除中性粒细胞对肺癌细胞侵袭、迁移的促进作用；PARP-1调控中性粒细胞MMP9表达，阻断或敲低PARP-1中性粒细胞MMP9表达及分泌减少，进一步通过免疫共沉淀技术发现PARP-1可以与MMP9关键调节蛋白Alox5相互作用，进而影响MMP9表达；小鼠Lewis肺癌皮下移植瘤模型发现，中性粒细胞促进肺癌生长，特异性靶向抑制中性粒细胞PARP-1完全消除中性粒细胞对肺癌生长的促进作用；因此，中性粒细胞可能通过PARP-1/Alox5/MMP9通路影响肺癌进展。宗之，靶向抑制PARP-1能降低中性粒细胞活化程度与组织浸润数量，减缓疾病进展，为靶向中性粒细胞治疗急性肺损伤或肺癌提供辅助手段，具有重要的临床指导价值和实际意义。