The role of intracellular calcium signaling in premature protease activation and the onset of pancreatitis
The role of intracellular calcium signaling in premature protease activation and the onset of pancreatitis
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DOI：
10.1016/s0002-9440(10)64515-4
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发表时间：
2000-07-01
影响因子：
6
通讯作者：
Lerch, MM
中科院分区：
文献类型：
--
作者：
Krüger, B;Albrecht, E;Lerch, MM
外分泌胰腺合成并分泌大量消化蛋白酶作为无活性前体酶原。在生理条件下，多种细胞防御机制保护胰腺腺泡细胞免受这些酶原的过早和细胞内激活。当这些防御失败时，胰腺自身消化启动，急性胰腺炎卡尔发展。大量实验观察表明，细胞外钙浓度在胰腺蛋白酶激活的启动中起重要作用，但调节这一过程的细胞内信号事件尚不清楚。使用模型系统，其中我们使用胰腺腺泡（新鲜制备的活腺泡细胞的功能单位），我们能够模拟啮齿动物实验性胰腺炎期间发现的条件。通过细胞渗透荧光胰蛋白酶底物，我们可以证明，在这些腺泡，过早的蛋白酶激活启动在顶端腺泡细胞苍白，只发生在促分泌素浓度的存在下，超过了最大的分泌反应所需的。通过将该技术与Ca 2+敏感染料Fura-2的荧光比率成像相结合，我们可以进一步表明，这种蛋白酶激活高度依赖于空间以及时间分布的相应Ca 2+释放从存储在同一亚细胞隔室，它是不传播到相邻的腺泡细胞。
The exocrine pancreas synthesizes and secretes large amounts of digestive proteases as Inactive precursor zymogens. Under physiological conditions a variety of cellular defense mechanisms protect the pancreatic acinar cell against a premature and intracellular activation of these zymogens. When these defenses fail, pancreatic autodigestion is initiated and acute pancreatitis carl develop, A number of experimental observations suggest that extra- as wed as intracellular calcium concentrations play an important part in the initiation of pancreatic protease activation, but the intracellular signaling events that regulate this process are unknown. Using a model system in which we used pancreatic acini (freshly prepared functional units of living acinar cells), we were able to simulate the conditions found during experimental pancreatitis in rodents. By means of a cell permeant fluorescent trypsin substrate we could demonstrate in these acini that premature protease activation is initiated at the apical acinar cell pale and occurs only in the presence of secretagogue concentrations that exceed those required for a maximum secretory response. By combining this technique with fluorescence ratio imaging for the Ca2+-sensitive dye fura-2, we could further show that this protease activation is highly dependent on the spatial as well as the temporal distribution of the corrersponding Ca2+ release from stores within the same subcellular compartment and that it is not propagated to neighboring acinar cells.