热休克蛋白GRP78途径调节的急性胰腺炎炎症反应的机制研究

Pancreatitis remains a disease with significant morbidity and lethality,Its pathogenesis is incompletely understood.Endoplasmic reticulum stress and the increase of GRP78 may be responsible for the progress of pancreatitis.It.is speculated that the induction of GRP78 after pancreatitis may be a survival mechanism that confers protection from subsequent stress and potentially aids in the refolding of intracellular proteins that were damaged during acute pancreatitis.The aim of this study is to investigate the relationship among GRP78 protein, endoplasmic reticulum and acute pancreatitis.. In-vivo experiments will be conducted to detect the the fuction of GRP78 protein throngh the pathway of the induction of apoptosis in pancreatic acinar cells during the state of acute pancreatitis.. Furthermore, the expression of protein factors including PEK-Pi, eIF2α-Pi, GADD43 and CHOP will be studied by using the GRP78 agonist ,tyrosine kinase inhibitor, and the GRP78 inhibitor,the calcium antagonists.And the damage of pancreas and other organs will also be observed as well.. At the same time, body fluid specimens of patients with acute pancreatitis will be collected. The expression of GRP78 and apoptosis related proteins will also be investigated.We try to provide new thought for the pathogenesis and clinical treatment for acute pancreatitis.

急性胰腺炎的发病机制迄今未完全明确，在急性胰腺炎时，内质网应激和GRP78蛋白表达升高，而GRP78升高后可能通过诱导凋亡机制稳定内质网，从而减轻胰腺和全身其他脏器的毒性反应。.本课题运用体内实验，验证在急性胰腺炎的状态下，胰腺腺泡细胞发生内质网应激，GRP78蛋白参与诱导细胞凋亡；寻找内质网应激以及GRP78蛋白引起凋亡的通路，并分别运用酪氨酸激酶抑制剂诱导GRP78表达以及钙离子拮抗剂下调GRP78表达，观察急性胰腺炎后，内质网应激现象中的PERK-Pi、PEK-Pi、eIF2α-Pi、GADD43、CHOP等因子表达情况，以及胰腺和其他脏器损伤情况。同时，收集急性胰腺炎患者体液标本，观察GRP78和凋亡蛋白表达与患者胰腺损伤及其预后的相关性，尝试为急性胰腺炎的发病机制和临床治疗提供新的诊断思路和治疗依据。

雨蛙肽诱导的急性水肿型胰腺炎和胰管逆注射诱导的急性坏死性胰腺炎均有GRP78家族表达增高，其机理可能与诱导凋亡途径有关。其机制可能是一方面GRP78作为钙结合蛋白，参与内质网应激，在急性胰腺炎情况下，巨噬细胞吞噬氧化脂质增加，从而加强应激保护机制；另一方面急性胰腺炎时，胰腺组织钙超载，胞浆内的钙增多引发线粒体钙摄取增多，导致氧化应激和线粒体膜破裂，从而加重急性胰腺炎的氧化应激反应，可能导致GRP78升高。.内质网应激现象的标志分子是Bip/GRP78、PERK和eIF2α蛋白的磷酸化、XBP-1的剪接、caspase-12。急性胰腺炎能引起GRP78升高，而GRP78升高后可能通过诱导凋亡机制稳定内质网，从而减轻胰腺和全身其他脏器的毒性反应。在本实验中，MAP和SAP造模后，PERK、eIF2α-Pi、XBP1、caspase-12、CHOP、JNK1、GRP78表达较正常胰腺组织明显上调。在加用酪氨酸激酶抑制剂Genistein诱导内质网应激后，胰腺组织PERK、eIF2α-Pi、XBP1、caspase-12、CHOP、JNK1、GRP78 蛋白质表达均较未诱导表达组明显上调。而加用钙离子拮抗剂尼莫地平抑制内质网应激后，eIF2α-Pi、XBP1、caspase-12、CHOP、JNK1、GRP78 mRNA均分别较单纯MAP组和SAP组明显下调。这一结果显示，急性胰腺炎时，胰腺腺泡细胞凋亡增加，诱导内质网应激会进一步加重胰腺腺泡凋亡，而使用钙离子拮抗剂尼莫地平抑制内质网应激则缓解胰腺腺泡凋亡，为钙离子拮抗剂在急性胰腺炎的临床治疗提供新的依据。