The calcium binding protein S100A9 is essential for pancreatic leukocyte infiltration and induces disruption of cell-cell contacts
The calcium binding protein S100A9 is essential for pancreatic leukocyte infiltration and induces disruption of cell-cell contacts
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DOI：
10.1002/jcp.21433
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发表时间：
2008-08-01
影响因子：
5.6
通讯作者：
Lerch, Markus M.
中科院分区：
文献类型：
--
作者：
Schnekenburger, Juergen;Schick, Verena;Lerch, Markus M.
白细胞浸润是急性胰腺炎发展的早期和关键事件。然而，白细胞移入胰腺的机制和白细胞在急性胰腺炎发生中的作用仍然知之甚少。在这里，我们研究了S100 A9（MRP 14），一种由多形核白细胞（PMN）特异性释放的钙结合蛋白，在急性实验性胰腺炎过程中的作用。通过在S100 A9缺陷型或S100 A9野生型小鼠中重复超最大剂量注射雨蛙肽诱导急性胰腺炎。然后，我们确定S100 A9的表达，胰蛋白酶原激活肽（TAP）水平，血清淀粉酶和脂肪酶的活动，和组织髓过氧化物酶（MPO）的活动。在体外分析细胞-细胞接触解离，用纯化的S100 A8/A9异二聚体孵育后分离的腺泡的生物体积测量，并在体内作为静脉内应用S100 A8/A9后伊文思蓝外渗的测量。胰腺炎诱导胰腺中S100 A9水平升高。然而，在S100 A9缺陷小鼠中，急性胰腺炎期间肺和胰腺中白细胞浸润和MPO活性降低，并与血清淀粉酶和脂肪酶活性显著降低以及胰腺内TAP水平降低相关。用纯化的S100 A8/A9-异二聚体孵育分离的胰腺腺泡导致腺泡细胞-细胞接触的快速解离，这是高度钙依赖的。与这些发现一致，在小鼠体内应用S100 A8/A9本身足以诱导胰腺细胞-细胞收缩解离，如伊文思蓝外渗所示。这些数据表明，胰腺内胰蛋白酶原激活的程度是由白细胞浸润到胰腺的程度，这反过来又取决于S100 A9的存在，是从PMN分泌的影响。S100 A9直接影响白细胞组织侵袭，并通过其钙结合特性介导细胞接触解离。
Leukocyte infiltration is an early and critical event in the development of acute pancreatitis. However, the mechanism of leukocyte transmigration into the pancreas and the function of leukocytes in initiating acute pancreatitis are still poorly understood. Here, we studied the role of S100A9 (MRP14), a calcium binding protein specifically released by polymorph nuclear leukocytes (PMN), in the course of acute experimental pancreatitis. Acute pancreatitis was induced by repeated supramaximal caerulein injections in S100A9 deficient or S100A9 wild-type mice. We then determined S100A9 expression, trypsinogen activation peptide (TAP) levels, serum amylase and lipase activities, and tissue myeloperoxidase (MPO) activity. Cell-cell contact dissociation was analyzed in vitro with biovolume measurements of isolated acini after incubation with purified S100A8/A9 heterodimers, and in vivo as measurement of Evans Blue extravasation after intravenous application of S100A8/A9. Pancreatitis induced increased levels of S100A9 in the pancreas. However, infiltration of leukocytes and MPO activity in the lungs and pancreas during acute pancreatitis was decreased in S100A9-deficient mice and associated with significantly lower serum amylase and lipase activities as well as reduced intrapancreatic TAP-levels. Incubation of isolated pancreatic acini with purified S100A8/A9-heterodimers resulted in a rapid dissociation of acinar cell-cell contacts which was highly calcium-dependent. Consistent with these findings, in vivo application of S100A8/A9 in mice was in itself sufficient to induce pancreatic cell-cell contract dissociation as indicated by Evans Blue extravasation. These data show that the degree of intrapancreatic trypsinogen activation is influenced by the extent of leukocyte infiltration into the pancreas which, in turn, depends on the presence of S100A9 that is secreted from PMN. S100A9 directly affects leukocyte tissue invasion and mediates cell contact dissociation via its calcium binding properties.