Ramos-Alvarez Irene, Lee Lingaku, Jensen Robert T
Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States.
National Kyushu Cancer Center, Department of Hepato-Biliary-Pancreatology, Fukuoka, Japan.
Front Physiol. 2023 Apr 17;14:1147572. doi: 10.3389/fphys.2023.1147572. eCollection 2023.
The actin regulatory protein, cofilin plays a key signaling role in many cells for numerous cellular responses including in proliferation, development, motility, migration, secretion and growth. In the pancreas it is important in islet insulin secretion, growth of pancreatic cancer cells and in pancreatitis. However, there are no studies on its role or activation in pancreatic acinar cells. To address this question, we studied the ability of CCK to activate cofilin in pancreatic acinar cells, AR42J cells and CCK-R transfected Panc-1 cells, the signaling cascades involved and its effect on enzyme secretion and MAPK activation, a key mediator of pancreatic growth. CCK (0.3 and 100 nM), TPA, carbachol, Bombesin, secretin and VIP decreased phospho-cofilin (i.e., activate cofilin) and both phospho-kinetic and inhibitor studies of cofilin, LIM kinase (LIMK) and Slingshot Protein Phosphatase (SSH1) demonstrated these conventional activators of cofilin were not involved. Serine phosphatases inhibitors (calyculin A and okadaic acid), however inhibited CCK/TPA-cofilin activation. Studies of various CCK-activated signaling cascades showed activation of PKC/PKD, Src, PAK4, JNK, ROCK mediated cofilin activation, but not PI3K, p38, or MEK. Furthermore, using both siRNA and cofilin inhibitors, cofilin activation was shown to be essential for CCK-mediated enzyme secretion and MAPK activation. These results support the conclusion that cofilin activation plays a pivotal convergent role for various cell signaling cascades in CCK mediated growth/enzyme secretion in pancreatic acini.
肌动蛋白调节蛋白cofilin在许多细胞的众多细胞反应中发挥关键信号作用，这些反应包括增殖、发育、运动、迁移、分泌和生长。在胰腺中，它在胰岛胰岛素分泌、胰腺癌细胞生长和胰腺炎中起重要作用。然而，目前尚无关于其在胰腺腺泡细胞中的作用或激活的研究。为解决这一问题，我们研究了胆囊收缩素（CCK）激活胰腺腺泡细胞、AR42J细胞和CCK-R转染的Panc-1细胞中cofilin的能力、所涉及的信号级联及其对酶分泌和MAPK激活（胰腺生长的关键介质）的影响。CCK（0.3和100 nM）、佛波酯（TPA）、卡巴胆碱、蛙皮素、促胰液素和血管活性肠肽降低了磷酸化cofilin（即激活cofilin），对cofilin、LIM激酶（LIMK）和弹弓蛋白磷酸酶（SSH1）的磷酸化动力学和抑制剂研究表明，这些cofilin的传统激活剂并未参与其中。然而，丝氨酸磷酸酶抑制剂（花萼海绵诱癌素A和冈田酸）抑制了CCK/TPA-cofilin的激活。对各种CCK激活的信号级联的研究表明，蛋白激酶C/蛋白激酶D（PKC/PKD）、Src、PAK4、c-Jun氨基末端激酶（JNK）、Rho相关卷曲螺旋形成蛋白激酶（ROCK）的激活介导了cofilin的激活，但磷脂酰肌醇-3激酶（PI3K）、p38或丝裂原活化蛋白激酶激酶（MEK）未介导。此外，使用小干扰RNA（siRNA）和cofilin抑制剂均表明，cofilin激活对于CCK介导的酶分泌和MAPK激活至关重要。这些结果支持以下结论：在CCK介导的胰腺腺泡生长/酶分泌中，cofilin激活在各种细胞信号级联中起关键的汇聚作用。
