Caerulein-induced intracellular pancreatic zymogen activation is dependent on calcineurin
Caerulein-induced intracellular pancreatic zymogen activation is dependent on calcineurin
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DOI：
10.1152/ajpgi.00500.2006
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发表时间：
2007-06-01
影响因子：
4.5
通讯作者：
Shah, Ahsan U.
中科院分区：
文献类型：
--
作者：
Husain, Sohail Z.;Grant, Wayne M.;Shah, Ahsan U.
胰腺腺泡细胞中异常的胞浆Ca 2+通量对于急性胰腺炎中观察到的病理性胰腺酶原激活至关重要，但下游效应物尚不清楚。在这项研究中，我们研究了钙激活蛋白磷酸酶2B（或钙调神经磷酸酶）在酶原激活中的作用。分离的胰腺腺泡细胞用超生理雨蛙肽（100 nM）刺激，有或没有钙调磷酸酶抑制剂FK 506或细胞渗透性钙调磷酸酶抑制肽（CiP）。胰凝乳蛋白酶活性作为酶原活化的标志物进行测量，淀粉酶分泌百分比用作酶分泌的量度。使用扫描共聚焦显微镜在加载有中间Ca 2+亲和染料fluo-5 F的腺泡细胞中记录胞浆Ca 2+变化。用1 μ M FK 506或10 μ M CiP预处理后，观察到胰凝乳蛋白酶活性降低50%。这些预处理并不影响淀粉酶分泌或雨蛙素刺激后胞浆Ca 2+的上升。这些结果表明，钙调神经磷酸酶介导雨蛙素诱导的腺泡内酶原激活，但不酶分泌或初始雨蛙素诱导的胞质Ca 2+信号。
Aberrant cytosolic Ca2+ flux in pancreatic acinar cells is critical to the pathological pancreatic zymogen activation observed in acute pancreatitis, but the downstream effectors are not known. In this study, we examined the role of Ca2+-activated protein phosphatase 2B ( or calcineurin) in zymogen activation. Isolated pancreatic acinar cells were stimulated with supraphysiological caerulein ( 100 nM) with or without the calcineurin inhibitors FK506 or cell-permeable calcineurin inhibitory peptide ( CiP). Chymotrypsin activity was measured as a marker of zymogen activation, and the percent amylase secretion was used as a measure of enzyme secretion. Cytosolic Ca2+ changes were recorded in acinar cells loaded with the intermediate Ca2+- affinity dye fluo-5F using a scanning confocal microscope. A 50% reduction in chymotrypsin activity was observed after pretreatment with 1 mu M FK506 or 10 mu M CiP. These pretreatments did not affect amylase secretion or the rise in cytosolic Ca2+ after caerulein stimulation. These findings suggest that calcineurin mediates caerulein- induced intra- acinar zymogen activation but not enzyme secretion or the initial caerulein-induced cytosolic Ca2+ signal.