Satoh Akihiko, Gukovskaya Anna S, Edderkaoui Mouad, Daghighian Melissa S, Reeve Joseph R, Shimosegawa Tooru, Pandol Stephen J
Veterans Affairs Greater Los Angeles Health Care System and University of California, 90073, USA.
Gastroenterology. 2005 Aug;129(2):639-51. doi: 10.1016/j.gastro.2005.05.005.
BACKGROUND & AIMS: Although tumor necrosis factor alpha is implicated as an important mediator of the inflammatory response in acute pancreatitis, its role in other pathologic features of the disease remains unknown. We investigated the role for tumor necrosis factor alpha in cytoskeletal responses and the underlying signaling mechanisms in pancreatic acinar cells.
In isolated rat pancreatic acini and AR42J cells, we determined the effect of tumor necrosis factor alpha on the actin cytoskeleton by rhodamine-phalloidin. Using pharmacological and molecular approaches, we assessed the involvement of protein kinase C, Src kinases, and proline-rich tyrosine kinase 2 in the process. We also studied the involvement of these signaling pathways in tumor necrosis factor-alpha-induced nuclear factor-kappaB activation and apoptosis.
Tumor necrosis factor-alpha increased the tyrosine phosphorylation of proline-rich tyrosine kinase 2 in acinar cells. The broad-spectrum protein kinase C inhibitor and the Src kinase inhibitor both inhibited tumor necrosis factor-alpha-induced proline-rich tyrosine kinase 2 phosphorylation, but at different tyrosine residues. Using protein kinase C isoform-specific inhibitors and the antisense approach, we showed that protein kinase C delta and mediate proline-rich tyrosine kinase 2 tyrosine phosphorylation. Tumor necrosis factor-alpha caused disorganization of the actin cytoskeleton by a mechanism dependent on protein kinase C, Src kinases, and proline-rich tyrosine kinase 2. Inhibition of protein kinase C, but not Src kinases, decreased tumor necrosis factor-alpha-induced apoptosis. Furthermore, with antisense transfections, we showed that protein kinase C delta and , but not proline-rich tyrosine kinase 2, mediate tumor necrosis factor alpha-induced nuclear factor-kappaB activation.
Tumor necrosis factor-alpha activates proline-rich tyrosine kinase 2 to cause cytoskeletal disorganization and nuclear factor-kappaB to cause inflammatory response, and it triggers cell death signaling through divergent mechanisms mediated by protein kinase C. The results provide insights into the mechanisms in pancreatic acinar cells that link tumor necrosis factor alpha to critical processes in acute pancreatitis.
尽管肿瘤坏死因子α被认为是急性胰腺炎炎症反应的重要介质，但其在该疾病其他病理特征中的作用仍不清楚。我们研究了肿瘤坏死因子α在胰腺腺泡细胞细胞骨架反应中的作用及其潜在的信号传导机制。
在分离的大鼠胰腺腺泡和AR42J细胞中，我们通过罗丹明 - 鬼笔环肽确定肿瘤坏死因子α对肌动蛋白细胞骨架的影响。使用药理学和分子方法，我们评估了蛋白激酶C、Src激酶和富含脯氨酸的酪氨酸激酶2在此过程中的参与情况。我们还研究了这些信号通路在肿瘤坏死因子α诱导的核因子κB激活和细胞凋亡中的参与情况。
肿瘤坏死因子α增加了腺泡细胞中富含脯氨酸的酪氨酸激酶2的酪氨酸磷酸化。广谱蛋白激酶C抑制剂和Src激酶抑制剂均抑制肿瘤坏死因子α诱导的富含脯氨酸的酪氨酸激酶2磷酸化，但作用于不同的酪氨酸残基。使用蛋白激酶C同工型特异性抑制剂和反义方法，我们表明蛋白激酶Cδ和介导富含脯氨酸的酪氨酸激酶2的酪氨酸磷酸化。肿瘤坏死因子α通过依赖于蛋白激酶C、Src激酶和富含脯氨酸的酪氨酸激酶2的机制导致肌动蛋白细胞骨架紊乱。抑制蛋白激酶C而非Src激酶可减少肿瘤坏死因子α诱导的细胞凋亡。此外，通过反义转染我们表明，蛋白激酶Cδ和而非富含脯氨酸的酪氨酸激酶2介导肿瘤坏死因子α诱导的核因子κB激活。
肿瘤坏死因子α激活富含脯氨酸的酪氨酸激酶2导致细胞骨架紊乱，激活核因子κB导致炎症反应，并通过蛋白激酶C介导的不同机制触发细胞死亡信号。这些结果为胰腺腺泡细胞中连接肿瘤坏死因子α与急性胰腺炎关键过程的机制提供了见解。
