缺氧诱导因子-1α调控的中性粒细胞功能及表型在急性胰腺炎病情演变过程中的作用及机制研究

The main reason for mortality in patients with acute pancreatitis (AP) is the systemic inflammatory response leading to multiple organ failure. The role of neutrophils in AP had been widespread concern, but the exact molecular mechanism is not clear. We have reported reverse-migrated (rTEM) neutrophils were associated with the systemic inflammatory and the lung injury in AP. HIF-1α is an essential regulator of neutrophils during inflammation, which plays an important role in regulating neutrophil rTEM, apoptosis and pro-inflammatory function. Our preliminary study shows peripheral neutrophil HIF-1α increased significantly in AP patients, with deceased level in severe cases compared with mild ones. Thus, HIF-1α is supposed to be involved in the development of inflammation in AP by the regulation of neutrophils. In this study, we will investigate the expression of HIF-1α in both murine AP models and the clinical AP cases to establish its role in regulating neutrophil function and phenotype as well as in pancreatic injury in the progress of AP. Furthermore, antagonist and stabilizer of HIF-1α will be applied in vitro and in vivo to determine whether it could affect neutrophil function and phenotype and prevent or exacerbate AP. These results will help unravel the molecular pathogenesis of mechanism of AP and may provide insight into the development of novel therapeutic agent for the disease.

急性胰腺炎（AP）患者死亡的主因为全身炎症反应导致多脏器功能衰竭，中性粒细胞在AP中的作用已受关注，但确切机制不明。我们报道反向迁移（rTEM）的中性粒细胞与AP时全身炎症反应和脏器损伤程度呈正相关。缺氧诱导因子1-α（HIF-1α）与中性粒细胞关系密切，通过影响中性粒细胞rTEM、凋亡及促炎功能参与炎症反应。我们预实验发现AP患者外周血中性粒细胞HIF-1α表达明显升高，但SAP的HIF-1α水平较MAP下降。据此提出HIF-1α可能通过对中性粒细胞上述功能及表型的调控参与AP病情演变过程。本研究拟通过不同严重程度AP小鼠模型和临床病例明确AP演变过程中HIF-1α对中性粒细胞功能表型调控的特点，阐明其在AP中的作用，并通过特异性药物抑制和稳定HIF-1α的表达，观察其对中性粒细胞功能表型以及AP病情演变的影响。研究的完成将进一步阐明AP发病机制，为治疗及新药研发提供新的思路和依据。

背景：缺氧诱导因子1α (HIF-1α) 是调控中性粒细胞功能及表型的关键因子，在炎症反应过程发挥重要的促炎或抗炎作用，但其在急性胰腺炎（AP）发病及病情演变过程中的具体作用以及机制尚不明确。.方法：通过检测不同严重程度的AP患者及小鼠AP模型的外周血中性粒细胞表达HIF-1α的情况及其凋亡程度和产生炎症因子（TNF-α, IL-1β, IL-6）的水平，找出HIF-1α表达与中性粒细胞的凋亡及促炎能力之间的关系，并进一步通过HIF-1α的稳定剂（DMOG）及抑制剂（17-DMAG）在体内和体外干预HIF-1α的表达，观察HIF-1α表达变化对中性粒细胞凋亡、促炎能力以及AP模型的影响。.结果：中性粒细胞表达的HIF-1α在AP患者外周血中存在上调，且与疾病严重程度呈正相关，HIF-1α的上调伴随着外周血中性粒细胞凋亡减少及其产生炎症因子能力的增强，分离外周血中性粒细胞并在体外通过17-DMAG下调HIF-1α表达后中性粒细胞凋亡增多，产生炎症因子能力减弱；而通过DMOG上调HIF-1α表达后中性粒细胞凋亡减少，产生炎症因子能力增强；在小鼠AP模型中，外周血中性粒细胞表达的HIF-1α同样与模型的严重程度呈正相关，并与中性粒细胞凋亡程度呈负相关，这与AP患者外周血的情况类似，而通过17-DMAG下调HIF-1α表达后胰腺组织内中性粒细胞凋亡增多，胰腺组织炎症因子表达减少，胰腺组织炎症减轻；而通过DMOG上调HIF-1α表达后胰腺组织内中性粒细胞凋亡减少，胰腺组织炎症因子表达增加，并伴随胰腺组织炎症的加重。.结论：在AP中HIF-1α通过调控中性粒细胞凋亡及其促炎能力参与疾病的发展过程，是调控中性粒细胞凋亡及其促炎能力的关键分子。抑制HIF-1α的表达可以通过促进中性粒细胞凋亡进而降低中性粒细胞产生炎症因子的能力，从而进而减轻炎症反应，可能成为今后治疗AP的靶点。本研究从全新角度阐明了AP的发病机制，为AP的治疗提供了可能的新思路。.